HAFLER DH-120, DH-200 DH-220 POWER SUPPLY UPGRADE

Description: * Please contact me BEFORE BUYING so that I can determine your exact needs. * ** This listing is for Parts AND Installation. ** *** Unfortunately parts are becoming more difficult to find and in some cases have quadrupled in price. The specific Power Supply Capacitors I have been using have reached their 'end of life' from the manufacturer. Similar Capacitors & other parts have seen a 100-400% increase because of supply chain shortages and increased tariffs. Even with the increase, you will find that these upgrades are a great value when you consider the increased performance & reliability of these upgraded Hafler Amplifiers. *** **** Turn-around time for this set of upgrades, is typically 2 weeks once I begin your project. I do this work part-time and never rush my work as this is very detailed, custom work. I want to make sure that everything sounds just right before sending your amp back to you. As time allows, I contact my buyers as to their position on my list as I move through my projects. The wait may be long, but it is SOOO worth it- just read my testimonials below. **** Because the demand for my upgrades has been growing in popularity, I have 4 projects on my 'Waiting List'. Some of these projects are 'boards only' which only take me a couple nights to complete. It typically has been taking me 2 weeks to complete each project, so do the math on the wait. I apologize for the long wait. As I move through the list, I send out updates as to your position. When I begin the project in front of yours, I will let you know to ship me your amp so I can begin work on your project. I also will send you regular progress updates with pictures so you can see how things are coming along. I ALWAYS open, and inspect your amp when I first receive it BEFORE doing anything. I check the fuses, look for physical issues like bad solder work, wrong wire types, user mods, then power it up. I check the Power Supply voltages 'as-is' before I run some music through it to make sure there are no other issues. I will also advise you if anything unexpected reveals itself.-------------------------------------------------------------------------------------------------------------- Do you want to revitalize your 30+ year old Hafler Amp, but don't have the technical knowledge or skills to do your own installation, let me professionally rebuild your Power Supply for you. This is one of the FIRST things that should be done on these vintage amplifiers. This alone will improve the sound of your amp. Upgrading your Power Supply will add stability, reduce clipping due to a sagging Power Supply, improve filtering & capacity, improve dynamics and bass response. I have been an Engineer in the Broadcast industry for 30+ years and have worked as a Studio Recording Engineer as well. I take great pride in the quality of my work. Being an Audiophile has been a lifelong passion of mine. Here's what you will get: You will get your DH-120 Amplifier Power Supply rebuilt with (2) new 18,000uF 63V Nippon Filter Capacitors and a new, higher current, 25 Amp Rectifier Bridge and 16A, 1 Ohm Inrush Limiter, 16A Power Switch, Snubber Disc Capacitor, 16A Inrush Limiter and (3) new 1/4" Push-On Connectors. And for those with DH-200/220 Amplifiers, you will get your Power Supply rebuilt with (2) new 18,000 or 30,000uF 75V Nippon Filter Capacitors (based on availability) and a new, higher current, 35 Amp Rectifier Bridge and 16A, 1 Ohm Inrush Limiter, 16A Power Switch, Snubber Disc Capacitor, 16A Inrush Limiter and (3) new 1/4" Push-On Connectors. This listing is for PARTS AND INSTALLATION AND CALIBRATION. I will also re-calibrate the DC Offset and Bias currents to original factory specifications. I will also make sure your amp's grounding system is done properly & install a 12-gauge, Solid Copper Main Ground and rewire the 'Star Grounding System' as needed to reduce the possibility of noise induction. I HIGHLY recommend having this rebuild done if you still have the original 30+ year old caps installed. If your Power Supply is not solid, not balanced or sagging, your sound quality will suffer and may even cause premature failure of the output MOSFETS if one of those big capacitors blow! If you plan on doing any upgrades and plan on keeping your amp running reliably for the next 30 years and sounding its best, do the Power Supply rebuild. As part of my upgrade service, I will clean your Input and Output Connectors (I can upgrade those too for an additional cost). I will also make sure you have the correct Internal Power Supply & Speaker Fuses installed at no additional cost. 2A-3A Speaker Fuses are usually adequate for most speaker systems and provide a safe level of protection. I will also include a Speaker Fuse Selection Chart if you should elect to change the rating to better suit your listening habits or change your speakers. Only make 1/2 amp increases at a time to avoid damaging your speakers. These amplifiers are capable of up to a 20 Amp output which would destroy almost any speaker, so choose wisely. Once completed, I put each amplifier through a minimum 2 days of rigorous 'in-system' testing to make sure everything sounds just right. --------------------------------------------------------------------------------------------------------------------------------- Shipping: (Please Read Carefully) Buyer pays ALL Shipping Costs, to and from me and will specify shipping method if other than UPS Ground. Estimated shipping cost each way: $18.40 - $45.76 (cost varies by buyer's location). Please include a PREPAID UPS GROUND RETURN SHIPPING LABEL in the box along with your amp so that there is no delay in returning your amp to you once completed. You MUST make sure that your amplifier is packaged properly as they can weight upwards of 35 lbs.! I suggest having it double boxed. It would be a shame to have it damaged in shipping. I will be using YOUR packaging to return ship your amp once completed. Buyer assumes all responsibility.----------------------------------------------------------------------------------------------------------------------------------------- Other Upgrade Services Available: *** Because our supplier of the EXICON MOSFET's is currently unable to provide devices that meet our specification requirements. Once my current stock of reliable EXICONS are gone, I WILL NOT BE OFFERING THIS OPTION until we can source MOSFET's that are suitable. ******I do have a very 'limited' amount of some good, 'matched' stock Hitachi MOSFET pairs that have been recovered from other amplifier upgrades that I can possibly use to replace any bad ones in your amp if needed to get your amp running.*** Got a dead channel? If your Output MOSFET Transistors are blown, I can take care of that too. A new set of 8 (4 matched pairs on the DH200/220) will need to be installed at an additional cost (message me for a quote). *Because I have accumulated several working 'matched' pairs of original Hitachi MOSFET's, there's a chance that I may have some that match the series used in your amp to save you from replacing all the MOSFET's in both channels to keep with the same sonic signature. All MOSFET's are $20/ea. + labor. I also replace the MICA Insulators & Heat Paste when changing them. Message me with any questions about the other available upgrades. If you decide to have a complete set of upgrades, Power Supply, FANTASIA AUDIO PC-1 Boards (and New MOSFETS- if needed), you will have one of the finest sounding stereo amplifiers one can own! Take the time to read the new and improved specs provided by the FANTASIA AUDIO PC-1 Driver Board Upgrade Kit: PC-1 DESIGN GOAL REALIZATION:A. Precise PC board layout with no track crossover.B. First stage single ended JFET/bipolar cascode differential amplifier with CCS regulation. JFETS incorporated are genuine Toshiba 2SK170BL devices with IDSS closely matched. If you know anything about this JFET, I need not say anything else. High input impedance, high gain, tube like presence, and eerie low noise in listening tests makes it a no brainer. Cascode configuration reduces Miller effect, drastically increasing bandwidth and lowering distortion. This all important first stage configuration eliminates the need for massive gain and feedback used in many amps to cover up distortions and design flaws.C. Second stage also uses SE bipolar cascode amplifier with CCS regulation. Again, Miller effect is reduced and bandwidth is not compromised.D. Simple bias control and emitter follower circuit to drive output stage is added and all that is needed to complete the design goal. DH500: Clipping now occurs at 335 watts into 8 ohms instead of the 270 watts from original PC-10 or PC-19.DH220, DH200, P220 & P230: Clipping now occurs at 150-160 watts into 8 ohms instead of the 110-115 watts from original PC-6 or PC-19.E. Polypropylene capacitors throughout with all HE electrolytic caps bypassed with polypropylene's.F. Vital 'Star Grounding' realized with pictorial showing proper wiring arrangement"IMPROVED SPECIFICATIONS:Signal to Noise Ratio, unweighted:Exceeds 100 db referred to 100 watts into 8 ohms 103 dB TypicalTypical THD at 100 watts into 8 ohms:20 Hz: 0.0025%1 kHz: 0.0025%20 kHz: 0.008%Input Impedance:33,000 ohms.Frequency Response into 8 ohms:- 3 db, 4.8 Hz to 225 kHz at 1 watt. -------------------------------------------------------------------------------------------------------------------------------------------- And if all those specs are a little too technical for you, your ears will tell you the rest of the story! I was blown away the very first time I heard an upgraded DH-500 and you will be too. You will have a deeper, wider sound stage, better dynamics, better sound articulation and a cleaner, quieter, much more 'musical' sounding amp. FANTASIA AUDIO only uses the highest quality components and closely 'matches' all semiconductors to ensure that the best specifications are achieved. This will be the single most significant improvement to your sound system you can make. Better Architecture + Better Components = Better Sound. Add professional, hand-built assembly, custom installation and you've got a truly 'high-end' audiophile grade amplifier! I am very lucky to have been mentored & working directly with Ed, the designer at QUA-CO(now Fantasia Audio) for 4 yrs. now. No one knows these vintage Hafler amplifiers better than Ed. Thanks for looking.___________________________________________________________________________ Want more from your amp?Here's what you COULD get: If you have a DH-200/220 Hafler Amplifier that has become old and tired, but still works and needs some new life breathed into it or you are still searching for true 'high-end' Audiophile quality sound without the 'high-end' price tag, then let me install FANTASIA AUDIO's Ultimate PC-1 Driver Board Upgrade Kit to get you to that next level. I exclusively use FANTASIA AUDIO's upgrade parts and kits. I have had nothing but FANTASTIC results using their upgrade kits. These upgraded Hafler Amplifiers have NEVER sounded better! Just read my customer's testimonies below. See my other listings for Installation of the FANTASIA AUDIO PC-1 Driver Board Upgrade Kit if you really want a major amplifier upgrade. Ed spent many years working at Hafler as the Amplifier Project Manager, but his own PC-1 Driver Boards, that he designed to work specifically in these Hafler amps, are a culmination of his years of experience. Your fully modified amp will go head-to-head with amps costing several thousand dollars! After listening to my first fully modified Hafler I did for a guy who worked many years for several 'high-end' audio equipment companies, we were BOTH immediately convinced that Ed, the designer at FANTASIA AUDIO had truly designed something really special. Here's what he had to say about Ed's design and my installation work: Jim,The work you did on my Hafler DH500 EXCEEDED expectation! Between you and Ed at QUA-CO, I would put my amp up against ANY other in the $5,000+ price range.The modifications designed by Ed and your technical expertise and commitment to quality assembly is well noted. The fact that you even went to the extent of rebuilding and balancing the power supply (something others might not check) is a show of your professionalism and commitment to the art of high-end audio.I now have a brand new amp utilizing what was left of my old, limping DH500 and incorporating the newest technology and techniques that will stand the test of time for another 30 years!As an audiophile that has always demanded the best sound possible, an Adcom Rep from the 1980's and a Hafler enthusiast since the mid 1970's, I can easily say, that your ability to perform such high quality work on mine, as well as many other high-end amps of that era, that I would not hesitate referring you to my closest friends. Many Thanks.Sincerely,R. J. CaseAshland, Ohio Here's some of my customer's comments: Jim, January is on it's way out the door but my Hafler amp is staying put! It sounds great. I have it driving a pair of Vandersteen 2Ce speakers using a Rotel CD11 Tribute, Everything sounds so good, friends just can't believe the clean signal, the separations and the sheer quality of the entire system. I have played several types of music ranging from the Acid Rock of my youth to the quieter sounds of wooden guitar music and all sound superb. I have put this amp thru several days of intense listening and I have not heard a flaw in any of the tunes I have played. Separation between instruments has been spot on and each sound as I believe they should. Most importantly the program being played is smooth and not in your face (that's the Mosfet system at work I believe). This now brings me to a crossroad. Do I go back to collecting vinyl and buy a good turn table or buy a good used reel to reel for extended listening time when socializing? Either way my wife will think I'm nuts!!!Thank you again for doing a wonderful job in restoring this amp. It makes it impossible to NOT listen to the system, it's a real joy.I really hope you enjoy the great work you do.David L. What an amp!! Music is my first love – listening, playing, and performing. To me, the best quality home stereo equipment reproduces the original signal as accurately and invisibly as possible, i.e. without adding or subtracting anything. A straight piece of wire with gain, as the saying goes. My Hafler sounded excellent before shipping it to you, and sounds stellar after receiving your upgrades. I’m using an Emotiva pre, with the QC-280 driving a pair of 1978 vintage Klipsch Cornwall's and couldn’t be happier with the sound at all volume levels – warm, punchy, dynamic, detailed, revealing, deeply enjoyable without fatigue.Additionally, your customer service is second to none – the amount of communication and the detail therein along with all the documentation provided, is truly exceptional. It is very clear that you love what you do, which is immediately evident from your level of workmanship. Being the electromechanical systems technician and lifetime nerd that I am, I was obligated to open the case and have a look – inside I observed some of the most perfect wiring and soldering that I have ever seen performed by human hands. Meticulous, careful, patient. I am confident that this now heirloom quality audio component will function flawlessly for at least another 40 years.Lastly, I don’t think there is a power amp out there anywhere close to the price point of the QC-280 that can come within a country mile of its performance. Thank you Jim, I am very pleased with my investment!Jesse Stunning, phenomenal, accurate, precise, I could go on describing the sound!!!! Top notch impeccable build quality. Parts quality spot on . Jim stayed in touch with me every step of the way. Phone, email, text message every method was used. This was an awesome experience all the way around. If you are on the fence about doing this to your amp. I can't stress enough DO IT !!!! You will be glad you did. Sonic purity !!!! You will hear things that you didn't before.Capt. Mark L. Hey Jim,Well, I've been having a marvelous time with my QC-280, and so have a friend or two. We've thrown a variety of speakers at it, both bookshelf and floor-standing, as well as different amps and preamps. I've gotten to know its sound pretty well and am convinced of its long-term reliability. So here goes the testimonial I promised. I hope it isn't too corny as I tend to wax. When referencing you and your service, I just used the name "Jim". Here goes…I'm a repeat customer of Jim's Hafler Amp upgrade service on eBay. So, I think I can speak with some authority on Jim's overall professionalism, reliability, timeliness, and quality of the upgrades he offers. If you appreciate true high-end sound and can do without the boutique looks and exorbitant prices of today's new amps, then I urge you to get in touch with Jim on eBay. I'll explain why.Jim's first upgrade for me was a complete recap of a Hafler DH-120 that I built from a kit in the mid 1980's. Along with some new hardware for more solid connections, this upgrade also included a new switch, surge protection and higher value power supply filter capacitors. I was completely stunned at the improvement in smoothness, bass slam and overall musicality Jim brought to this little medium power amplifier.While no circuit mods were performed on my DH-120, the overall improvement in sound quality whetted my appetite for what Jim could do with his "audiophile upgrades" to Hafler's higher power amplifiers. So, I patiently waited and watched on eBay for a used DH-220, that was still in working condition, had the cosmetics I was willing to live with and at a price I was willing to pay. I didn't have to wait long and snagged my 220. I immediately contacted Jim. He went over the upgrade options and prices with me, and I didn't hesitate to opt for the full audiophile circuit upgrade, speaker protection circuit and the other hardware component upgrades to transform my amp.Jim supplies instructions on how to safely pack your amp for shipment to his location. So, I sent Jim the agreed upon down payment and shipped him my amp with no consternation at all. These upgrades are getting pretty popular, so Jim let me know my place in his working queue and the approximate time it would take to complete the upgrades on my amp. Once that started, Jim provided me with an overall assessment of my stock amp, made a few adjustments to bring it within spec and started the upgrades. He sent me photos each step of the way so I could see exactly what he was doing. He also sent me a link where I could download the new circuit schematic and a description of the new circuit's operation as well as other useful technical information. My amp was completed within a couple of weeks of Jim starting work on it, tested in Jim's own listening environment, and promptly shipped back to me.I've been listening for a few weeks to the upgraded 220, now called the QC-280, as these upgrades add an additional 20 watts of power to each channel and wanted to provide a few thoughts on its sound. I'm not a professional reviewer, but I'll use the power of 3 and summarize my thoughts into 3 categories. I'll call these Slam, Space and Soul.SLAM: Jim advised me beforehand that I might no longer need to use a subwoofer in my listening setup as the QC-280 could provide all the bass power, slam, and testicles that anyone could want. He was so right! I've already reassigned my subwoofer to home theater duties. The difference the upgraded 280 makes is actually startling. And that's not all - bass notes now have quality and texture - something I had not heard before out of my Nola Contender speakers.SPACE: With a good preamp, in my case a Benchmark LA4, the QC-280 will reveal all of the spacial queues that are captured on your recordings or streaming services. Individual instruments are precisely located in space and provide separation from other instruments in that recorded space. The stereo image is 3D with great front to back depth and lateral spread. I think this is a hallmark of the new circuit design and a quality usually only heard in very expensive amps. It really puts the high in high-end and creates a listening experience that you wouldn't think possible at this price-point.SOUL: Ok, so this is the hardest part to describe in words, but you will certainly know it when you hear it. I like to go to a lot of live performances of Jazz, choral, orchestral, and small ensembles around where I live. This helps keep my ears attuned to what live instruments and voices really sound like. Real, live music has texture, tones, overtones, and ambiances that help make a live musical performance such an emotional experience. We want that in our home music systems too, but it's hard to obtain. The QC-280 gets you a long way there. You can hear the husky growl and sexiness in Diana Krall's voice, the sweet and lush string tones of the Vienna Philharmonic, the hall ambiance of Severance Hall and the Cleveland orchestra, the bite of Coltrane's horn, and all the percussive effects of Fourplay and today's modern music.Needless to say, I'm completely happy with my upgraded QC-280. It has provided me with much musical value and happiness at a price I never imagined possible. I urge you to contact Jim soon. Jim,I’ve been letting your upgrade of the DH-200 soak into my musical brain for a few weeks now. Wow! I never imagined how profound an improvement it could make in my system! It’s hard to stop listening and yes, I’m rediscovering my music collection all over again!! I’m driving a pair of DefTech BP-10s and it’s handling the 6 ohm nominal very well. Everything sounds so tight, so much more detailed with a good soundstage even for the bipolar speakers. As an acoustic guitar and banjo playing nutter, I’m especially impressed with how “real” acoustic instruments appear…the attack, decay and resonance are amazing. Also, the transients and percussives are so tight! High quality recordings like my re-mastered Miles Davis will lock me in my chair and I can’t stop smiling!! Thanks again for your guidance, your outstanding workmanship and the value you built into this amp!! I’ve got several musical instruments and this amp may be the best one I’ve got! Highly recommend!Dave Hi Jim,First, all I can say for now is the results of your efforts are "Simply Unbelievable". I have never had my Hafler perform like it is now even when it was new. The clarity and crispness have blown me away. The amp is really fantastic!Thanks, Tom Hi Jim........My name is Mike and you did a Hafler DH-500/QC-600 upgrade last year for me....and it is flawless.... I have hundreds of hours on it now and you may use me as a reference anytime......any prospective clients can come to listen to my Lancaster, PA. system anytime. It will be a lifetime relationship with this amp! Hi Jim,It's Cam here from Nelson BC , Canada.I have to commend you and Ed's for your combined work contributing to the rebirth of my DH 200.I am delighted with the outcome and couldn't be happier!The words that sum up my listening to the rebuilt amp for the first time is simply WOW! I can't thank you enough for your support to my friend Jim S. who did the install of the boards.It was so worth the wait, the additional power from the upgrade has made my Kef 105.2's sing to new highs! Many many thanks! Kind regards ,Cam (another happy customer) Jim,The amp sounds terrific, and your electronic workmanship is top-notch!Thank you!Doug A. Jim,As I promised, I’ll share my impressions and thoughts about the QC600 upgrade that I’ve been listening to for the past couple of weeks. I plugged the amp in and listened as the amp seemed to start opening up after an hour or two of on time. It did sound pretty good, but it really got better after being on for 24 hours or so. Improvements after a day or so are subtle, but noticeable. What I’ve heard is an expansion of the perceived stage. The image is both deeper and wider (more 3-D) than any of the other amps I have that I’ve recently listened to. For me, I’ve discovered that the leading edges of a note, chord or a voice also seem much cleaner. To me, that leading edge reveals a lot about the amp in its ability to direct current in the proper direction in the proper amount of time to make the music sound as I think it should. The amp isn’t “mushy”, nor is it giving a crystalline quality. It just sounds right to me.On well recorded sources, the image can expand beyond the outside edges of the speakers. It’s funny, as in my old house, this phenomenon more often occurred in the right channel, and in the house I’m in now, it happens mostly in the left channel. It’s got to have something to do with speaker/room interactions and how the speaker is situated with room boundaries and listener position. The QC600 is good at presenting a stable image, wide, tall and deep, and you will hear room artifacts if the music was recorded in a larger space or was injected post-recording. I prefer the real stuff, but if it’s there, you’ll notice it.The amp is very good and quite honestly, has exceeded my expectations. It is quiet, clean and has plenty of power to keep the Magnepans singing. This amp really is a quality upgrade.Good job! Thanks for spending the time and energy to get this thing working so well!Regards,Steve Hi Jim,I hope all is well with you and your family. Now that I’ve listened to my upgraded Hafler 500, I just wanted to let you know that I’m super happy with it. It’s more than I imagined! The thing that really sets it apart for me is the way it drives my 1.7 Maggie’s. I was previously using a Hafler 220, and while the sound was good, I noticed that some recordings were lacking in bass. With the upgraded 500 driving them, that issue is long gone. The 500 drives them wonderfully, and there is plenty of bass!I will likely send you a Hafler 220 next. 😊 Thank you Jim, I’m very appreciative!!Rick Hi Jim,I unpacked and plugged in the amp today and it does sound fantastic! Incredibly crisp and clear, with easy power.After more listening:I've really been enjoying the QC-280. It sounds great with all kinds of music. It's nuanced and precise playing The Nutcracker (my 2-year-old daughter's current favorite), with easy separation of instruments and a wide sound stage. It handles the dynamic range very well, with barely any loss of detail in the quiet parts. The controlled power of the guitar riff on Dire Straits' "Money for Nothing" was enough for my Infinity CS-3008's to knock a picture off the wall--with the volume at 1:00. Ella Fitzgerald and Count Basie sound like they're playing "Honeysuckle Rose" right in the room with you. I wish I could say more, but I'm more of a music lover than an audiophile. Joe Hi, Jim: I've been listening to my new QC-600, and I have to say all the reviews I've read are right on and then some. My Klipsch Heresy speakers sound different than before the upgrade: bass is deeper, highs and mids more out front, instruments more separated, more air around everything. It's extraordinary. Great job on the amp, Jim. Ed, your design on the PC boards is fantastic. Very happy with the sound. Truly the finest my music has ever sounded. Jim, your communication while I was waiting for my turn in your queue, while you worked on my amp, and follow-up with photos and documentation chronicling the upgrade were above and beyond my expectations. I feel very lucky to have found you guys on eBay. Jim,It sounds fantastic! The day my reworked amp arrived, I spent the entire evening listening to a wide variety of music and loved every minute of it - straight out of the box. No fiddling with the controls on my preamp, no acclimating my ears to the sound - just sonic bliss. To describe this upgraded amp as "musical" falls short. It lends liveliness and presence to songs that I've heard a million times previously but had never ‘experienced’ them like this before. I love it! You can listen to music for hours with this amp, without the fatigue that was an a facet of the character of the original DH-220.Its also important that I mention the communication by the seller was top notch every step of the way. I got daily updates via email on the progress of the upgrade and prompt replies to my email queries before, during, and after the sale. If I owned another Hafler amp, I wouldn’t hesitate to upgrade it.-Jon G. If you own a vintage Hafler amplifier do not hesitate to get the full PC1 upgrade Jim is offering. I’ll break this down into two parts. First is the work and Jim himself. At every step of the upgrade Jim kept me informed including photos of my amplifier as he transformed it. Every picture showed me that this man is meticulous and conscientious in the work he does. Craftsmanship is rare these days and Jim is truly a craftsman. Now how does the amplifier sound. Is this hyperbole or the real deal? To remove any variables I kept my audio system the same as it was, the only difference is I connected my new QC280 amplifier Jim built to the pre-out on my NAD C368 BluOs and reconnected my KEF XQ10's to the new amp leaving my KEF 400b subwoofer on the sub out. My source material was CD’s ripped with Exact Audio Copy and 32/192 kHz streaming through the BluOs. This amplifier was a revelation! The soundstage was massive, both wide and deep and truly holographic in its’ imaging. Dynamics were crisp and instantaneous. I put on Steve Reich’s Music for 18 Musicians and every instrument was clearly defined and organic in timbre. Next up was Miles Davis In a Silent Way. Again, from Miles’s trumpet to Shorter’s sax to DeJohnette’s brush work on drums and cymbals and McLaughlin’s guitar runs all seemed to be in the room with me. I stayed up until dawn going through every genre, classical, jazz, rock and roll, Afro-Pop, and all of it was like I was truly hearing it for the first time. This amplifier upgrade is the best value I have found in a very long time and Jim himself is a gem. I am currently building myself a pair of CSS 1TD speakers and I can’t wait to hook them up to this amazing amp.Yours in the love of music and high fidelity, Jeff Young Jim,I have had a chance to put the amp through a wide range of my musical tastes and can only come to one noticeable difference - EVERYTHING!!!I have been able to listen for a long period of time at a high level without any listening ‘fatigue'. I am hearing things on recordings I have been listening to for may years that I never heard before. Especially subtle differences as a song I’ve known for many years now hearing there is some reverb and delay in the recording I never heard. I can clearly hear the differences in how recordings are produced, some very minimally (clean instruments and vocals) and others that sound ‘over produced‘. My wife who is not an audiophile says everything sounds so much more clear with defined presence. I hear complete silence through the speakers where before I would hear a hum at high levels. I thought my speakers were past their prime and ready to replace, but now its like I’m listening to new speakers. I installed a few more cooling fans in the cabinet that my stereo components are in because before your upgrade the amp fan would usually kick on to the high speed. Now the cabinet temperature is at around 10 -15 º cooler and I have yet to hear the fan go to high, and can’t hear it on low because it is so quiet.I have had this amp for over 40 years and about 10 years ago began looking for someone who could diagnose and replace/upgrade what it needed so I wouldn’t have to part with it. It basically has been idle for that time until I came across your ad on eBay. My only regret is not packing the amp as you suggested by double boxing. I believe I had enough cushioning but another box around it with more insulation would have protected it on the way home. The dent it suffered is hidden by the cabinet, so the fact that it works flawlessly is what I care about. The wait time to send the amp and get it back was well worth it. Your attention to detail and meticulous workmanship is hard to find today. It really shows how much you care and love what you do. You have definitely made a big impact on my love and appreciation for a good sound system. I can’t thank you enough. I would recommend you to anyone looking to upgrade a Hafler amp needing some TLC. P.S. The first album I played was Lyle Lovett ‘Step inside this House‘ double album all the way through. It was a good first test because the album although recorded in 1998 is one of my favorite quality recordings of great musicians and well produced. Turn it up loud for ‘Rolin By'. Another favorite is Dire Straits ‘Brothers in Arms’, I was blown away listening to the remastered recording.Thank you.Stephen Grzeszkiewicz Jim, It’s been almost a year since you upgraded my Hafler DH-200. When I last emailed you, I had only been listening to the amp for an hour or so, though it sounded quite good. It’s been some time now, and it just keeps sounding better. No problems with it at all since the upgrade. Thanks again,John V. Hi Jim, I hope all is well with you and your family. I just wanted to let you know that I finally finished the PC-1 upgrades to my DH-200. It took a while. I only was able to work on it a few hours here and there. On Tuesday I did the final adjustments. The bias pots only need @ 1.5 turns to get a very steady 225ma. The dc-offset pots only needed a nudge and I got -00.3mv and -00.5mv and called it a day. So now was the time for sound testing. I hooked up the QC-280 to my MC DH-101 (never heard since I got it back from upgrading), added my Gamma 20 Tuner and my 30-year-old Philips cd player. On Saturday my wife, using a 1990s Technics receiver and a 1990s Technics cd player was playing some of her cd’s one being Broadway songs. The speakers were about 5 feet apart, on the floor, and were sounding the best I have ever heard them (this being before I heard Ed’s PC-1 boards). I was very happy with the sound to the point that my wife asked if I wanted to hear one of my cd’s and I responded “no, I am very happy just sitting here and listening to the sound coming out of the speakers”. The sound seemed as if you were in the audience of the show. So, on Tuesday, thru the Philips cd player and the upgraded Hafler, I played the Beatles ‘Love’ discs and Eric Clapton ‘Unplugged’. On Wednesday, I played ‘The Essentials of Billy Joel’. The song “The River of Dreams” was unbelievable. I had to listen a second time the sound was so fantastic. On Thursday, I listened to Steely Dan ‘Aja’, a cd of big band songs, and Brian Seltzer ‘Dirty Boogie’. As you know, the sound is phenomenal. It is more than I ever imagined. It is everything the testimonials say. The guitar strings, piano notes, the drums, the horns, the stand-up bass, the chimes, cymbals, the strings, the back-up singers you never heard before, the singers stretching out the notes, etc. You hear everything. I thought the system I bought 40 years ago was a nice sound. But I think the PC-1 upgrade lets thru twice the sound the original Hafler produced. I could not be happier. - Danny Danny’s ‘Follow-up’ Comments: I just wanted to let you know what I have been experiencing. And I would assume it will be things you have heard many, many times. As you may remember, I have some big, old KLH’s for speakers. These QuaCo / Hafler amps are great. As I have said before, its more than I could have ever imagined. This week I have been listening to it for a couple of hours a night. After an hour and half or so, the amp starts sounding very good. The problem is, it is now getting late and I should be going to bed, but I can’t. Last night about 11:00, The Blues Brothers song, “Sweet Home Chicago” came on. OMG, the musical sound you heard! The soundstage / imaging was great. I just closed my eyes and listened in amazement. I could not go to bed yet, I just had to listen to a few more songs. It was great. A few months ago, I never would have thought that from a 30-year-old cd player I got for $100 and 20-year-old bargain basement speakers for less than $200, that they would produce this kind of sound. I cannot imagine what the sound will be like out of a good pair of speakers. My thought is - once the amp gets about 100 - 125 hours of play time, it will be very close to its ultimate sound. Hopefully, by then my ears will be accustom to the much bigger soundstage and I will be more prepared to audition better speakers so that I can hear what the amp is truly able to give. When the time comes, I will start with the speaker companies you have suggested. In hindsight, I am so happy that in one of your earlier emails you commented that you would gladly just refurbish my DH–200, but if and when I wanted, you could take the amp to a whole new level. And I know it took me awhile to realize that the additional cost was minimal (maybe $100 or so), but I am very glad you made the comment and planted the seed in my head. Thank you so much. - Danny Cisco's 'follow-up' comments: This IS an important detail: my super thirsty RTi A9 Polk's have ALWAYS needed to be bi-amped to really get them to open up and sound full and big—especially on the low end. To wit, I had them wired with an Adcom GFA-555SE for the Bass/low end, and either an Adcom 555SE (special boutique upgrade akin to your QC-600, custom driver board, silver solder matched components, etc., etc.) or a Yaquin 100B Tube amp with VERY expensive and exotic tubes rolled into it for the top end/mids/highs. I alternated with solid state and tubes so that I could use the SS amp for movies and theater and the tubes for music just to help conserve tube lifespan. I have bee driving the whole thing with a Krell Foundation 4k preamp, using their automatic room correction. Anyway, when used in this combination, the amps really light up the Polk's, and the sound is phenomenal, especially the solid state/tube combo. The speakers easily handle around 200-300 watts RMS, and really need that extra power they get from being bi-amped for the bass to appear at all. With this setup, there is no need for a separate subwoofer—these babies shake the house! Now, on to the most important part: with the QC-600, I get the same level of bass and sound, except clearer, cleaner, wider, more open, faster, more detailed, and if you can believe it—even more powerful—FROM A SINGLE AMP. That’s right—the QC600 effortlessly outperforms two other expensive amplifiers COMBINED—both a pure SS and a tube/SS setup. I was able to A/B every possible combination directly, and I can say with absolute certainty that by the end of my experimenting, I was convinced. I literally pulled all the old amps from my cabinet right then and there and replaced them—PERMANENTLY. The results are just that good. And they’re only getting better as the amp burns in and opens up more and more every day. Thanks once again—I wanted to add this extra bit so you can use it in your ads should you choose. I think it’s important for people like me who are naturally skeptical to understand that if they are even a little hesitant about doing this upgrade—DON’T BE. It is the single best investment I have ever made in my long audio career in terms of sheer value. It’s not an exaggeration or hyperbole of any kind to say that this upgraded amplifier can hold its own against amps priced far higher. So to anyone who may read this: "JUMP. Make the leap. You.. WILL.. Not.. Regret.. It. Audio Nirvana is closer than you think!” Thanks again Jim, and I WILL be back to use your amazing services again very soon! Sincerely,Cisco OH MY GOODNESS!!Is it working? Is? It? Working? IS IT WORKING?????Never in my life have I heard anything like this! Audio nirvana! My Polk RTi A9's have always been super thirsty, which is why I bi-amp them—till now it’s been the only way to get decent bass. Their sensitivity is garbage. Well, once I finally had time to hook up the amp, I fired up a test song from one of my favorite playlists. I had only intended to verify the amp was working, but an hour later, I realized that the speakers had disappeared and I had just sat there enjoying songs I’ve heard a hundred times like they were brand new. Expansive soundstage—it was just me and the music.Bass was deep and tight, not boomy or loose in any way, but still powerful and commanding. The mids, my god the mids! They stood out on their own with a clarity and smoothness that was astonishing. The highs were so clean and airy—I had not even a HINT of listening fatigue after the hour session—in fact, I had to tear myself away from the music to get some work done. Another awesome thing was that the music sounded fantastic at all levels—even quiet, it still had powerful presence and compelling clarity.Before I quit though, I did an A-B with my Adcom 555SE (a not inconsequential $1400 amp), and a heavily modded Yaquin tube amp I had nearby. The Adcom had great mids, but nowhere NEAR the commanding presence and incredible bass of the QC600. It sounded shrill, hollow and empty, flat and disappointing. (It actually sounded great, but after the QC…well now I am officially SPOILED!!) The tube amp was nice and warm, but just didn’t have the power that the Polk's needed. It too, while sounding really great, was greatly disappointing after hearing the QC600.This amp has been one of the most expensive investments I’ve ever made, because now my other amps are all worthless, hahaha! But seriously, NEVER in all my years of audio have I gotten so much value from my investment. This was worth the wait and the money 100x over. Thank you so, so much for sharing your gift with the world, and with me. I can tell you with absolute certainty that I will be back for more in the future! It was an absolute joy working with you. I will remember in the future also your advice about double-boxing, it was an eye-opener just how close I came to having something bad happen to this absolute treasure!With the quality I see inside this amp, I would expect it to play faithfully for maybe 20-30 years with no problems. I’d love to pass it on to my son someday :)Thank you, Jim. I wish you and yours a wonderful year, filled with happiness, health, laughter, family, smiles, friends, and MUSIC.Sincerely,Cisco Hi Jim: I bought my Hafler in the late 1970’s along with a Luxman tube pre-amp. At the time this was a big step up in affordable quality. Eventually I put my gear in storage, which ended up being for 25 years. I decided to resurrect this equipment last January. I happened upon your eBay offering and after giving you a call, decided to move forward with it. I was expecting maybe marginal improvement in performance but I was looking to at least to have an evaluation and replace any aged parts. During this time I also re-tubed my preamp and cleaned it up in anticipation of the audition of 21st century electronics. Your communication was excellent during this process. You provided very affordable recommendations. Just a note, anybody out there, if Jim makes a recommendation for parts - don’t go cheap. Follow his direction. When I received the amp, I hooked up the Luxman, and I was off to the races. The initial impression was the surfacing of music in the tracks that were never clearly audible before. Separation in stereo was markedly improved. The new N.O.S. stock tubes in the pre-amp brought a sound stage to this amplifier that was nothing short of profound. THIS AMPLIFIER IS MADE FOR TUBES. This prompted me to look in the marketplace for new technology in a tube pre-amp. I settled upon a PrimaLuna Dialogue pre-amp. Outstanding performance and build quality. After rolling some N.O.S. tubes, this turned out to be superior to the Luxman. Now I’m hearing vocal back tracks in Jan and Dean that I never heard before. The Doobie Brothers tracks I thought were out-takes because there is so much more music that I never heard before. Jim’s efforts are one of the great open secrets in audio. This quality in sound is the biggest bargain I’ve run across. Thanks again Jim Hi Jim,I can tell you that the original 500 you reconstructed sounds incredible! (more 3D than my other older one, but with the same perfect frequency balance). In fact, the 3D enhanced 500, due to the increased depth of the sound, provides more space between sounds and instruments. I will have you do the same reconstruction to my other 500 at a later date.Kind Regards,Pierre Jim,Thank you for the work on my DH-200, now QC-280. I still can't fathom the difference that you've built into this amp, It's too much (in a good way)! I've only played the amp for an hour or so and am floored by the bass response. I could go on, but you know what you built for me, so I won't. Suffice to say, I am one very happy customer :) Update: Thank you again for the upgrade work on my 'QC-280', it's so clear. And seems to appear more transparent and more dynamic every day (maybe the speakers are finally getting run in too? who knows!). I'm having to weed out the 'not so well produced' sources, not necessarily a bad thing. This amp is deep (as in, way down the audiophile rabbit hole!!). Regards, Mark. Hi Jim,I wanted to send you an update on how the Hafler 500 (QC 600) has been performing. It's been a couple of months since the upgrade and I am really enjoying the amp. The Solstice speakers are moderately efficient so it doesn't take much form the QC 600 to shake the house. What I have really noticed is the increase in sound stage, the clarity of the individual instruments, especially with Hi-Res sources. Bass response is fast and punchy way different than the Adcom amp I used to own. It has been a blast to listen to my collection of music and hear parts of the recordings that I was not able to discern before. The amp runs super quiet thanks to your work getting the fan to run correctly. I was really impressed with how fast you responded to questions I had and the level of detail to questions and to the repair process itself. I wanted to let you know how pleased I am with the process and the end result. Your attention to detail is tremendous and your fees are really reasonable!Best Wishes,Dave B. Hey Jim, been meaning to send you a line or two with my thoughts about the "new" DH200/QC280. 😁I've been giving it some very serious listening sessions since discovering I'd wired the right speaker out of phase. 😝 In a way I'm glad I messed up, I can be confident I'm listening objectively and not hearing what I want to hear.So what I'm hearing is nothing short of spectacular! The combination of the Hafler and Infinity's is incredible. As you pointed out these speakers have the reputation of being amp-killers. Paired with an amp that took measures to prevent speaker-killing and I think we have a thing of beauty. The amp has the balls to push the speakers and they have the balls to take all it can dish out. I haven't come close to pushing either but enjoy the pure, clean power while listening 'comfortably loud'. I have no doubt the sound will be just as pure at ear-splitting levels as well.Like you said, some music is better produced than others and I find myself cringing a tad from time to time, but when you hit a well produced song it is absolutely thrilling. I listen to just the Infinity's on 2 channel most of the time, but occasionally I'll kick it into full 9 channel wall of sound and it's really something.I'm totally happy that I went ahead and had you do the full mod on my amp. It was totally worth every cent not only to have an absolutely top notch power-amp, but the nostalgia factor of having the core of my 30 plus year old hi-fi system back can't be measured. I don't think a modern 2 channel amp can come close to the old Hafler's for the price of this upgrade. This is as close to the warm sound of a tube amp as anybody can possibly hope to come.I look forward all week to my weekend listening sessions.Thanks Jim!Theo Hi Jim,I wanted to give a few impressions after having the amplifier on for over 200 hours. I want to first state that I have mainly used tube amps in my main system (Marantz 8B, Eico HF 81 Sam Kim mod, Dynaco St 70, Dynaco ST 35 power supply upgraded and others). With that said, I have a bias and a love for the midrange, especially vocals and strings, a good and properly working tube amp can bring. My favorite, the ST35 is only 16 or 17 watts, but the EL 84 tube is fast in the transients and has airy highs and a good foundation for bass. I have used my Hafler XL280 in my main system and my 2nd system uses an old NAD 3020 amplifier which had been serviced recently. My impressions will now focus only on the QC-280 with only a few comparisons to the other amps.Associated Equipment: conrad johnson PV5 (Bill Thalmann mods) pre-amp; Sound Dynamics RTS 9 speakers, Linn Lingo turntable with Dynavector 10X4 cartridge, Thorens TD 147 turntable with Audio Technica AT33 mono cartridge, Marantz SA8001 CD player and a Yamaha T85 tuner.Break in period observations: the amplifier did not ever get hot to touch throughout the burn in period. I could place my hand on the top and touch the cooling fins without any problems. A 40 watt light bulb gets hotter to touch than the amp. When the amp was first on for an hour and listening to the tuner, I could tell the sound was clean, dynamic and in control with orchestral music. The floor noise was clean. As time passed, at 50 hours I could hear a change in the soundstage getting wider and going outside the speakers with music I was familiar with. At 100 hours, using the same music, I felt the soundstage reached its potential and I could get a better sense of the front to back depth. I could easily hear the space of the recording venue. Likewise, it took the bass the same amount of time to sound its best in terms of detail and solidarity. I have found this with my tube amps when they haven't been played for long periods of time. Yes, IMHO, break in is important before judging an amp. Impressions: after 150 hours of break in, I found this amp to be dynamic, able to resolve musical details and was in control of the music at all listening levels. Complex passages and the many instrumental soloists playing at the same time found in Decca's Gerhard "The Plague" by Antal Doriti or London's "Messiaen" by Antal Dorati proved to be no problem for this amp. Individual instruments were easily heard and no smearing of the instruments was evident. It was easy to hear a soloist in a choir as the choir harmonized in the background (evident in the soundtrack "Glory" with the Harlem Boy's choir). You can hear cello soloists breathing and in the case of Glenn Gould, hear his humming as he played the piano (sometimes annoyingly). Microdynamics are good when going from a soft to loud passages. Musical lines are easy to hear. The only area I found not as pleasing as my trusty ST 35 tube amp was getting the nth degree of musicality in the midrange. This is not a criticism, but maybe a bias. What I mean is that on unamplified music like Yo Yo Ma playing his cello or a violinist like Heifetz, I can hear and in a physical sense the bowing of the strings as they play. On piano music or hearing drum cymbals, the decay of the notes is more pleasing to my ear and realistic on a tube amp. The QC-280 gets to 90% of what I sense and enjoy. Is it more correct?, I don't know. But with the bass, there is no comparison. This amp brings a solidarity in the bass foundation that I have never heard. There is detail and a "correctness" of how it presents itself. It is my speaker that is the limitation as it only goes down to 35 Hz. Drum whacks are realistic and quick. No boomy bass here. My last point is that regardless of the listening level, this amplifier controls the music, whether it a singer and a guitar or a 100 piece orchestra. Usually when you play music loud (which I seldom do), it just breaks up and gets distorted. Not this amp.In closing, this amp has the 'WOW' factor. What I mean is when you are playing the stereo system and listening from a different room and either I or a friend says "Wow, that really sounds good", the amp has done its job. Jim, a job well done and a true bargain for having done this under $1,000 to boot. This isn't my Hafler XL280. Thanks (and I'm sorry I babbled on too much.)John H. Jim,I wanted to tell you your work is impeccable and nice to see those skills of yours. Thanks so much for all of your help. When I get customers wanting there Haflers upgraded, your the man and I'll send them to you.Thanks again,Alan Jim and Ed ,First thing, Thank You for a great design Ed, and Jim your expert work and grand service. The sound emitted from this upgrade is truly noticeable first track !! The clarity jumps front and center! Taj Mahal honestly could have been just across the room, so much “like you are there!” experience. I am just amazed how the instruments from front to back are clear, clean with no drop off for background passages, crisp not muddled. Silent passages are just that, dead silence, that stood out. The openness of the sound this puts out is truly a joy to experience! Seems even better as days go by😃. After listening to full compliment of Pink Floyd “Wish You Were Here”, I felt like my lower jaw needed pushed back up!!! That pretty well sums it up there!!!! Could not be happier, Thank You both , Rob "Absolutely professional! Perfectionistic! Great communication! Amp sounds great!" "Excellent service! Jim goes out of his way to be helpful and meet your needs!" "Had a chance to test out the amp, and it sounds AMAZING! Thank you for all the work. Starting with great communication throughout with progress updates, the attention to detail and letting me know of unforeseen issues with advice on remedies, taking the time to repackage the amp for shipping just because it was in my best interest. And finally, the craftsmanship that went into putting it all together. Initially I was apprehensive about spending the money on an old piece of electronics, but after having had a chance to really listen to the results, it was the best money I've spent on audio gear in years!" "I have not been ignoring you in responding to the work (magic) you performed on my DH-220. I wanted to let it settle in before I wrote back to you. My intent was to use the Hafler as my backup amp to the MC2100. So, along with the Nippon Cap & 35A Rectifier Power supply upgrade, Polypropylene cap upgrade kit, we talked about installing Input Level Pots located in the rear of the top panel so I would have the same ability to balance the speakers as I can with my McIntosh MC2100. The work was flawless and the DH-220 sound's great. I can honestly say that I cannot tell the difference, side by side, between the MC2100 and the DH-220 now. Instead of a backup amp, it is my first chair. Thank's again for the great work. My new Hafler will probably out live me. Money well spent. - All the best, Bob H." "Thinking my DH-220 was dead, I began shopping for a replacement amp. Nothing I came across would fill the nostalgia flicking on my Hafler provided, and being part of a system passed on by my dad I was inclined to keep it. I knew it needed a repair and had almost given up when I came across 7houses on eBay. I sent an email and received a quick reply and then a phone call. I knew I had found the 220's only chance and quickly followed Jim's directions for shipping. He immediately sent pictures and an autopsy report and his suggestions for a repair. Within a couple of weeks the amp was working, together we discussed other potential upgrades and I basically received a NEW Hafler within another few weeks- Completely upgraded, sure to last another 30 years, and most importantly sounding great! I have spent the weeks since receiving the amp listening to most of my vinyl, locked up for hours on end. My wife is happier, the Hafler is back to doing its thing, and I'm tickled silly. It's beautiful, sounds great and I can't wait to pass it onto my 7 yr. old in a decade or two, perhaps three. Thanks Jim."----------------------------------------------------------------------------------------------------------------------------------------

Price: 185 USD

Location: Brunswick, Ohio

End Time: 2023-10-23T11:40:17.000Z

Shipping Cost: N/A USD