CapnDenny1
Student Of The Blues
Last spring I got an amp into the shop. A Peavey Musician Series 400 Mk III. It was a 400 watt solid state guitar amp. The guy brought it in and said it was his dad's amp, and it had been in storage, and was broke when they got it out.
Most amps I fix turn out to be fairly easy. They still require some work, and skill in diagnosing the problem. But these old solid state high powered amps have a whole bunch of expensive transistors all tied together and fed back around to the circuit. The failure of just about any part in that loop usually results in most of the high powered transistors getting blown. If you replace them and try again they will usually blow again, so it's important to figure out what is really causing it.
I worked and worked on this one. i even built a light bulb limiter to try and prevent blowing the power transistors. It has 8 of them! But even after 20-40 hours of working on it I could not find it.
Well I had other amps to fix, and then my knees started hurting really bad, and I couldn't go down the stairs to work. I ended up putting a stair lift in. But I was pretty much at a loss of what to do. I sought advice from the real amp guru's. I suggesting just shot-gunning it, replace all the parts in the hopes I would replace the bad part. One of the guru's agreed, but another took objection to that and more or less shamed me into needing to find THE ISSUE, and just replacing it.
It went on into September. I did do some work on it. The owner had worked on it, and he had swapped the + and - voltage regulators, and the wire attachment connectors had started to fail, so I fixed all that. But still could not find the issue. So about the last week of September the owner called me, and said I had till the end of the month, and if I didn't have it fixed by then we would have to consider other options.
I understood, so as a last chance I went ahead and replaced all the small electrolytic caps in the power amp circuit. Guess what? It fixed it. I don't even know which one it was, since I changed about 10 of them at once.
I was so excited I called the customer, and told him his amp was ready, and I beat his deadline bu a day! He said he would come by soon. A month later I sent another reminder, and he thanked me for my work, and he would be there soon. Finally I sent him an email a couple days ago asking if he still wanted the amp. He said yes. I reminded him the charge was $125, 3 hours labor and $50 in parts. I had probably 40-60 hours in it, but just because I am stupid is no reason for him to have to pay. Most shops just say NO on these amps.
So of course once the amp was fixed I tested it. It has a very unique feature that it has both reverb and a phaser control. That and 300 watts at 2 ohms! So i played through it and it sounded really really good! The reverb was very nice, and the phaser control had a really nice sound to it. And the 300 watts gives it like unlimited headroom. I mean sky high headroom. I was half hoping he said he didn't want it.
But yesterday he came and picked it up. He even tested it before he left. I guess he didn't trust me? Anyway it passed the test, and again I was reminded of how nice it sounds. He paid me $140, and at first I was going to say no, but 40-60 hours, yeah I'll take your $140.
So I was wondering what it was worth, so I did some searching. Couldn't find many with the phaser control. Most of the 400 series amps from Peavey are either PA or bass amps. But lo and behold last night I found this.
https://reverb.com/item/31168339-peavey-musician-mark-iii-bass-guitar-head
So I went ahead and bought it. It is in even better shape cosmetically than the one I worked on, and is supposed to be fully functional. I have a spare 4x12 Ampeg speaker cab that I bought with my Ampeg full stack. But with both speaker cabs stacked and the head on top, I couldn't reach the controls from my chair, and I can't stand for long.
So don't tell anybody, but this tube amp cork sniffer has found a solid state amp that really caught my ear. A late 70's Peavey boat anchor! But man it sounds sweet!
Most amps I fix turn out to be fairly easy. They still require some work, and skill in diagnosing the problem. But these old solid state high powered amps have a whole bunch of expensive transistors all tied together and fed back around to the circuit. The failure of just about any part in that loop usually results in most of the high powered transistors getting blown. If you replace them and try again they will usually blow again, so it's important to figure out what is really causing it.
I worked and worked on this one. i even built a light bulb limiter to try and prevent blowing the power transistors. It has 8 of them! But even after 20-40 hours of working on it I could not find it.
Well I had other amps to fix, and then my knees started hurting really bad, and I couldn't go down the stairs to work. I ended up putting a stair lift in. But I was pretty much at a loss of what to do. I sought advice from the real amp guru's. I suggesting just shot-gunning it, replace all the parts in the hopes I would replace the bad part. One of the guru's agreed, but another took objection to that and more or less shamed me into needing to find THE ISSUE, and just replacing it.
It went on into September. I did do some work on it. The owner had worked on it, and he had swapped the + and - voltage regulators, and the wire attachment connectors had started to fail, so I fixed all that. But still could not find the issue. So about the last week of September the owner called me, and said I had till the end of the month, and if I didn't have it fixed by then we would have to consider other options.
I understood, so as a last chance I went ahead and replaced all the small electrolytic caps in the power amp circuit. Guess what? It fixed it. I don't even know which one it was, since I changed about 10 of them at once.
I was so excited I called the customer, and told him his amp was ready, and I beat his deadline bu a day! He said he would come by soon. A month later I sent another reminder, and he thanked me for my work, and he would be there soon. Finally I sent him an email a couple days ago asking if he still wanted the amp. He said yes. I reminded him the charge was $125, 3 hours labor and $50 in parts. I had probably 40-60 hours in it, but just because I am stupid is no reason for him to have to pay. Most shops just say NO on these amps.
So of course once the amp was fixed I tested it. It has a very unique feature that it has both reverb and a phaser control. That and 300 watts at 2 ohms! So i played through it and it sounded really really good! The reverb was very nice, and the phaser control had a really nice sound to it. And the 300 watts gives it like unlimited headroom. I mean sky high headroom. I was half hoping he said he didn't want it.
But yesterday he came and picked it up. He even tested it before he left. I guess he didn't trust me? Anyway it passed the test, and again I was reminded of how nice it sounds. He paid me $140, and at first I was going to say no, but 40-60 hours, yeah I'll take your $140.
So I was wondering what it was worth, so I did some searching. Couldn't find many with the phaser control. Most of the 400 series amps from Peavey are either PA or bass amps. But lo and behold last night I found this.
https://reverb.com/item/31168339-peavey-musician-mark-iii-bass-guitar-head
So I went ahead and bought it. It is in even better shape cosmetically than the one I worked on, and is supposed to be fully functional. I have a spare 4x12 Ampeg speaker cab that I bought with my Ampeg full stack. But with both speaker cabs stacked and the head on top, I couldn't reach the controls from my chair, and I can't stand for long.
So don't tell anybody, but this tube amp cork sniffer has found a solid state amp that really caught my ear. A late 70's Peavey boat anchor! But man it sounds sweet!