Carver m400t amplifier repair final

[@blackhorserepairs]

Awesome video! I wish every device came with schematics taped to the back of the cover like they used to 😃 keep up the great work!

[@jerryking2418]

Very educational. Thanks.

[@RoyalTech_2024]

You should make a video on STK IC amplifier

[@davet3804]

I have never seen this fault in a resistor! Well spotted , I would have pulled the transistor and gone down a rabbit hole for sure.I also love keeping stuff out of land fill .

[@andymouse]

Great work and yeah bizzare failure, you don't see that much....cheers.

[@dougfarrell5091]

Hi John. I have been watching your videos. They have been very educational and enjoyable. I don't know if you will see this note. since it is 10 days out since you created it. I watched your "Who am I" video and you mentioned that you did not think you were a good presenter. I disagree with you on this questi😅n completely. Most presenters that I have watched know their subject well, as you do but go through their presentations so fast I have a hard time comprehending what their talking about. I find myself having to repeat their vids over and over again. With your slower and detailed way of covering the focus of an idea or subject, I have no problem following you. Thank you for creating these enjoyable videos....Doug

[@JohnAudioTech]

Thanks Doug!

[@dougfarrell5091]

You are very welcome John. I am going through all of your videos and learning so much about audio and enjoying your lectures. I have been working on learning more about audio electronics and thinking about designing a mixer with tone controls. I ran across a set of speakers at good will store that contained 5 of them and I think I will have to build something to control them because nothing came with the speaker set to plug them into for stitching the sets of them on/off the volume, and tone. How would you interconnect them...Doug

[@aaronstodolka3438]

Thx.

[@rickodetrader]

Hi John. Great videos very inspirational, they are making me want to investigate audio more and build/repair amplifiers. Now if I can ask a question- what makes a really good amplifier? As in what makes some amps sell for $200 and some for $20000. Is it low thd or is that a sales gimmick? A flat frequency response? not sure where to focus my attention at this point. Thank you and keep up the good work, really cool stuff you are doing here

[@JohnAudioTech]

There are really top notch amplifier designs out there that can be home built reasonably. After getting a power transformer and a case, you can end up spending ~$500. A company trying to turn a profit might require $2000 using quality materials. Does it sound better than a lower cost amp with similar specs? I don't think so. There is almost never any proof to back up the claims. The audio industry is filled with a lot of "snake oil" products and claims. A $20,000 amp is esoteric audio to me. Made for people with more money than sense.

[@rickodetrader]

Thank you John, I had a bit of a suspicion that was the case. I think your videos are where I'll focus my attention. You go into a lot of detail from what I've seen so far which is really good. Thanks for the reply great job !

[@overbuiltautomotive1299]

yep A+@@JohnAudioTech

[@TrevorsBench]

1000va input seems excessive for a amplifier putting out 370w. The amplifiers efficiency seems quite low. I don't see a lot of heatsinking for those power levels. I wonder if this is normal, I suspect not

[@JohnAudioTech]

I'd say it is normal. Watt draw is ~750. The regulated and bridge rectified power supply makes PF low. The class G design allows it to run much cooler with "normal" music dynamics, but at high levels with a lot of continuous bass tones, the amp will run hot.

[@pedropianista]

I think that .....Installing a power transformer capable of offering 1000 watts in secondary voltage guarantees almost zero voltage variation to the circuit when it is close to full power. These details help clean the final sound and the stability of the electronic circuit parameters.

[@HillsWorkbench]

@@JohnAudioTech I remember having one of these on the bench over at PAS and testing it against the PAS 800. Distortion wasn't bad but between the amp and our power conditioner, there were a lot of grunts and groans from the transformers. I was able to pick the PAS 800 over the Carver consistantly under ABX listening testing. I guess they accomplished making a faily small amp for the output without expensive heat sinks at the cost of added complexity. A modern class D achieves those goals at less cost. From the name I had imagined some crazy magnetic device, kind of disapointing all the way around. I'm thinking those resistors were just defective, moisture was able to penetrate them maybe. Reliability suffers as complexity increases.

[@JohnAudioTech]

@@HillsWorkbench These aren't my cup of tea either. Just an audio appliance that needs repaired. I sold the other one for $400. This is the "t" version and is in clean shape, so well worth the time and effort. I'll give it several hours of listening to be sure it is reliable and then sell it.

[@nicoras8803]

That Carver is a terrible, messy design inside, not friendly to work on.

[@jakubczajka4275]

Monstrosity!