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Hey all, I have been hanging on to a TFM-25 as a first owner with the original box and stryofoam (much to wife's discontent ) for past 30 years - Got a kit for rebuilding from eBay that likely spent too much on. Gonna replace the caps and do the 4/15/92 service bulletin upgrade. Wish me luck! Cool site - read a couple cool threads already! Brian

@otisboss Wow. So much to unpack. @jazzman53 is a huge fan of the TFM-25. His posts are excellent and can be used as good guidance. I wouldn't be too worried about knockoff caps. Nichicon and Chemcon are good brands. I would hold off on shot gunning all the parts you have into the amp. I'm a big fan of first diagnosing and fixing any problems before carpet bombing the amp with new parts. Truth be told, the binding posts and RCA connectors in the TFM-25 amp are fine. Changing them may look nicer and feel better, but unless there are problems, the stock components should be good. @Circuits & Concepts is an excellent and reputable source of packaged components. Mouser and Digikey are good sources for individual components. So sorry that the upgrade information is scattered. This might be an opportunity for you to create a consolidated thread for others. We are an all volunteer site, supported by donations. Sometimes folks get fired up and post excellent DIY tutorials. Sometimes somebody gets motivated and consolidates fragmented info. It all depends on the membership. This is your chance to create a timeless contribution to the Carver community. Depending on what you find after an initial test and survey of your amp, you may want to consider sending it to a pro. It's not a bad starter amp to learn on, but you can dig a big hole if you are not careful. We are usually very responsive to questions you may have and can help, but diagnosing an amp via photos and messages only goes so far. Greg, the head honcho of Nelion idoes excellent refurb work. You can contact him directly here @Nahash5150 or via his Sound Room and even his web site. nelionaudio.com Good luck and keep up posted.

Welcome to the site Brian! Les @Circuits & Concepts is a member here and a valuable source for parts. I’ve purchased several power supply kits from him a and have been very happy with them. I did a couple TFM-25 rebuilds a few years ago, chronicled here: There is a pic of all the caps I removed. And pics of the “upgrade” parts I.e. binding posts, etc. The pic of the removed caps just happens to show the values. When you dive into this, start a new thread. Add pics, chronicle your work, ask for help if needed. You’re in good company here… 😎

Thanks wrf. I got it in 1989 when heading off to college (Marquette University) playing through some old AR-35BXs that have been lost to time. I loved the speed and punch of that set up. And it got loud! Later, the TFM25 was weak and or cutting out in one channel and that is when it got boxed. It is in mint condition externally, but obviously I will need to look carefully inside. I have some experience with electronics, pretty nifty with a soldering iron, and enough sense to be careful of dangerous voltages. I did intend a cover off inspection first, then to fire it up with a dim bulb test and see if anything appears grossly off. I will definitely be checking those items you mentioned above. I looked through the TFM-25 library at many of the issues - service 2 resistor and transistor replacement, comments on capacitor replacement (and failures to discharge caps!), and input regarding replacement of output relays. Unfortunately, I did not do all this research before sourcing a "rebuild kit" from HiFiAudio on ebay - it includes a near-full cap set, several transistors, and a number of diodes, . . . but not the resistors for service bulletin-2. Also, seems to be lacking caps C451 and C510. Instructions for the capacitors is fine, but absent for the transistors or diodes. AFTER researching, I see that Les (@circuits&concepts) has a power supply capacitor rebuild kit - now I am wondering the quality of components I purchased (kicking myself). I did see Jazzman's list of parts for the TFM-25 rebuild - excellent resource, thanks! So any info on HifiAudio's TFM-25 kit, anybody? I do see some Chemicon and Nichicon smaller caps, but not clear if the larger ones are real or knock-offs? Any advice for identification, testing, ??? (Can't post pics quite yet, too new!) Since I have yet to even start, would it be worth sourcing those 6 power supply caps to be sure??? https://www.ebay.com/itm/222548677988?hash=item33d0ef5564:g:S1wAAOSwjk9ZRGza&amdata=enc%3AAQAIAAAA4L2l75jzTqzkVA5oZTwh8wDvHjNVTWvRk5K6cen%2BPAxYDPGbXj9fASMAhY32Wy%2BVV9nUeoyCGiCoguuWJ5xPpeuACP9t0XMzJu1xcVLcsH90T98i%2B58M5QJymVcNrb9Dph1fCgEIL4vbPijkDuArtUfnBG6w1Ef2%2BaAP1ZUm2Rm%2BLVkGqiehZ0Ix9jykr7cYnTzLQ%2FV65045zApgnmULptnySATCydDAPCvGT0xT76GYkl%2FItWzyF82T%2F1CQDjPrdYxmBv6LIphRdu4ja0cqnc3KzDRLxXQzAiZbQhYF6lpe|tkp%3ABk9SR76Lgb-aYw Also, when replacing binding posts and/or RCAs, any preferred manufacturer? If there are obvious 'upgrades' for these amps it would be great to have it spelled out clearly rather than strewn over a multitude threads 'to discover' - For example, I have a couple cars that lend themselves to upgrade paths and there are some nicely codified threads on EvoM.net and S2k.com that review typical upgrade path - instead of wider tires, 18" rims, improved turbos, discussing benefits and tradeoffs expected with the upgrade in question; Maybe I missed a similar 'recipe' for the TFM-25 in my initial foray. If planning for upgrading performance (not just spending $ on fancier parts) what replacement caps would be recommended (and the like) - saw this for a tube amp I'm building, basic set, higher level, top tier. The future paired speaker would be a modest KEF floorstander, yet unpurchased. I have some various bookshelf speakers to play via digital and analog sources in the meantime. Thanks again any and all - happy to get in touch with my OCCD!!! Brian

I can attest to the quality of the Nelion Audio @Nahash5150 work, It is top notch. My son and I have entrusted him with several prized pieces of equipment. They have come back to us ready for the task of some great performance. Here is his listing for the TFM-25/24 restore, and his warranty tells you volumes about the quality of his work. https://nelionaudio.com/index.php?/services.html/carver/carver-amplifiers/carver-tfm-2524-restore-r9/ Good luck.

Hello everyone, I've known and admired Carver from at least the late '70s. Wonderful innovative equipment, way ahead of its time. When I started out in this hobby in the 70s, that was cutting edge technology for audio. I built two mono amplifiers & a Hafler pre-amp from kits. When I went shopping for a tuner in my local Hi-Fi shop, I compared several tuners. Denon and Carver. Denon sounded more like a typical tube sound. The Carver TX-2 was more accurate to my ears. So I bought it. Few years later I was reading a diy magazine and high-speed diodes for power supplies. Grabbed my attention. I put them into the tuner. Not sure if it made any difference though. Recently I tried picking up FM signal where I live now. It's a poor reception area but I had a very good indoor VHF TV antenna. No output, no signal strength on the meter. Yesterday I brought it over to someone's house that had excellent reception. Hooked it up to the original sansui receiver. The output jack board was loose and I must have shorted it with my modern RCA cables. I opened it up and tried to hold the board so I could plug in. I think it's shorted everything out. What looks like the fuse smoked and burnt. I immediately shut it down. So I came back to the site to find a service manual. I'm going to repair it myself. I think I'll be able to do it with a simple fix. I'm looking forward to digging deeper into this community's interests.

Welcome to the site @otisboss. I assume you have found our library. There is an excellent service manual for the TFM-25 there. The service bulletin understates the potential damage on the PCB. In extreme cases, the board under the resistors and transistors targeted by the service bulletin can become severely burned and even damage the traces on the back of the board. Be careful. It's easy to cause further damage when removing components in this area. Inspect the back of the board carefully for overheated solder joints and weak traces. Is the amplifier currently operating properly? If not, I would recommend doing a bit of diagnostic work BEFORE the recap and service bulletin work. It's always good to know what's broken before unleashing a bunch of parts on an amp. That way you can set expectations. Rarely does a shotgun of new parts solve an unknown problem in an amp. Even if the amp is working properly, I would recommend a quick health check prior to replacing the parts. Power supply voltages, bias setting, DC offset etc. That way if there are problems later you know if the new parts caused the problem. Good luck. The TFM-25 is a fine amplifier and well worth the updates.

I've listened to both transistor and tube amps over the years It has always been my perception that the distortions produced by tubes are primarily even order harmonics. In the same proportion vacuum tube distortions seem to be much less objectionable than the odd order harmonics present in most transistor designs. That is why tube amps with one percent distortion at rated power often sound much better than transistor amps with .1 % distortion. Agree with what's been said by Ar9Jim and Bob. Delivering enough power at the frequency extremes is more of a problem than distortion is for tube amps designs. The 180 amps I have sound better on the less negative feedback setting than on the higher feedback setting even though technically you will have slightly more distortion. Less complex tube circuits tend to sound better and are more stable than complex designs...there is less to go wrong when driving real-world speaker loads.