**Please contact me BEFORE BUYING so that I can determine your exact needs.**
*Turn-around time for this Upgrade is typically 1-2 weeks once I begin your project. However, because of the popularity of my upgrades, I currently have 14 projects lined up. So if you are willing to wait your turn in line, I would be happy to put you on my \'Wait List\'. As I move through the list, I will let you know when to ship me your amp so I canbegin work on your amp. I also will send you regular progress updates so you can see how things are coming along.I will also advise you if anything unexpected reveals itself. I ALWAYS open,andinspectyour ampwhen I first receive it BEFORE doing anything. I check the fuses,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 notify you if I find anything that we don\'t already know about.If 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. 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 life-long passion of mine.
Here\'s what you will get:
You will get your DH-500 Amplifier Power Supply rebuilt with (2) new 24,000uF 100V Nippon Filter Capacitors and a new, higher current 35 Amp Rectifier Bridge. If your 500 is a very early version, it may not have an Inrush Limiter as do the later versions. I will also add that if yours does not have one. This listing is for PARTS AND INSTALLATION AND CALIBRATION. I will also calibrate the DC-Offset and Bias 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 noiseinduction.I HIGHLY recommend having this PS rebuild done if you still have the original 30+ year old caps installed. If your Power Supply is not solid, notbalanced orsagging, your sound quality will suffer and may even cause premature failure of the output MOSFETS! If you plan on doinganyupgrades and plan on keeping your amp running properly for the next 30 years and sounding its best, do the Power Supply rebuild.
I can also upgrade the Power Switch from the 10A original to a new Lighted 16A version. I have started to routinely replace these, but it is a recommended option and is only $25 additional and includes a fresh 1KV Disc Capacitor across it and an Inrush Limiter for a softer start which extends the life of your new Switch and Rectifier. Early version 500\'s did not have these, but when Hafler saw several Switches failing prematurely because of the Inrush of current damaging the contacts, they began to routinely add them in later versions.
As part of my upgrade service, I will clean your Input and Output Connectors, Frame & Heat Sink. Once completed, I put each amplifier through 2 hours of rigorous \'in-system\' testing to make sure everything sounds just right.I will also make sure you have the correct 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. Only make 1/2 amp increases at a time to avoid damaging your speakers. The DH-500 is capable of a 30 Amp output which would destroy almost any speaker, so choose wisely.Want more from your amp?Here\'s what you COULD get:
If you have a DH-500 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 QUA-CO Audio\'s UltimateAudiophile Upgrade Kitto get you to that next level. I exclusively install Ed\'s upgrade parts and kits. I have had nothing but FANTASTIC results using his upgrade kits. These upgraded Hafler Amplifiers have NEVER sounded better! See my other listings for Installation of the QUA-CO Audio PC-1 Driver Board Upgrade Kit if you really want a major amplifier upgrade. After listening to my first fully modified DH-500 that 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 QUA-CO had truly designed something really special. Ed spent many years working as the Amplifier Project Manager at Hafler, but his own PC-1 Driver Boards that he designed to work specifically in 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.Testimonials:
Jim,
I\'d like to give you a heart-felt thanks for what you did for my DH500. It\'s taken some time to fully appreciate...
Right out of the box I noticed that the amp made my JBL 4412\'s sing, a strange word but that sums it up. Back in it\'s youth the DH500 sounded great, and I have no way to do a side by side between 1988 and 2018, but this made me very happy. Unfortunately this exacerbated problems I was having with poor room acoustics and lead to a major re-organization of my audio space- a big, time-consuming project. That finished, I brought my parametric EQ into my preamp EPL along with a new 31 band Graphic EQ and mostly fixed the problem.
I\'ve spent many hours at this point sitting on the couch at the focal point of the 4412\'s, listening very carefully. I\'ve concluded that the \"imaging\" of the soundstage in the \'reborn\' DH500 is almost certainly better than it has ever been. I say this becauseI\'m hearing things I\'ve never heard before on CD\'s that I know well. Specifically, I can hear little tweaks on the board by the sound engineer changing the location of the musicians within both 3D image-space and sonic layers of frequency space ever so slightly to great musical effect. Of course this is both a blessing and a curse - some recording engineers have the gift and some don\'t. It\'s a whole new dimension to the music.
I hate to admit this, but I was a bit hesitant to ship my amp off to a complete stranger. I am grateful that you took the time to get me on board. You, my friend, and the engineer that designed the driver boards, are the real deal, true afficionados pushing the audiophile envelope to new heights.
Thanks and God Bless you and yours,
Jerome S.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. Case
Ashland, Ohio\"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 myMcIntoshMC2100. The work was flawless and the DH-220 sound\'s great. I can honestly say that I cannot tell the difference, sideby 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 . 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.\"
Other Upgrades Available:
I can also install a new set of 12 (6 \'matched\' pairs on the DH500) for $290. I only use the Exicon MOSFETS also available from QUA-CO. All 6 pairs of MOSFETS are closely \'matched\' and sound every bit as good,if not better, thanthe originals (NLA) as they are faster offering better transient response. If you decide to have my complete set of upgrades (Power Supply, PC-1 Boards and New MOSFETS),you will have one of the finest sounding stereo amplifiers one can own! Your fully upgraded DH-500 will complete with amplifiers costing more than $5000. Take the time to read the new and improved specs provided by the PC-1 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 response 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 at335 watts into 8 ohms instead of the 270 watts from original PC-10 or PC-19.
DH220,DH200, P220 & P230:Clipping now occurs at150-160 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 withpolypropylene\'s.
F. Vital \'Star Grounding\' realized with pictorial showing proper wiring arrangement\"
IMPROVED SPECIFICATIONS:
Signal to Noise Ratio, unweighted:
Exceeds 100 db referred to100 watts into 8 ohms. 103 dB Typical
Typical THD at100 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:
4.8 Hz to 225 kHz at 1 watt- 3 db,
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. QUA-CO uses only the highest quality components and closely \'matches\' all semiconductors to ensure that the best specifications are achieved.
Better Architecture + Better Components = Better Sound.Add professional, hand-build construction, custom installation and you\'ve got a truly high-end audiophile grade amplifier!
I have been working directly with Ed, the designer at QUA-CO Audio and exclusively use his Hafler upgrade kits and parts. Message me with any questions about the other available upgrades.
Shipping: (Please Read Carefully)
You MUST make sure that your amplifier is packaged properly as they can weight upwards of 50 lbs.!I suggest having it double boxed. It would be a shame to have it damaged in shipping.I will be usingYOUR packaging to return ship your amp once completed.Buyer assumes all responsibility.
Please include a PREPAID UPS GROUND RETURN SHIPPING LABEL in the box along with your ampso that there is no delay in returning your amp to you once completed.
Buyerpays ALL Shipping Costs,to and from meand will specify shipping method if other than UPS Ground.Estimated shipping cost each way: $28.59 - $66.23 (cost varies by buyer\'s location).
Payment:
I currently will be accepting PayPal only.
Thanks for looking.
