No ... it just sits on the floor collecting dust
I have yet to pull the legs of the bias circuit. The poor board has been soldered and re-soldered so many times replacing FETs and re-touching all the joints I am afraid to apply heat yet again.
I can't figure out where to go from here based on the information available.
I have only done this twice in 12 years so far, but it might be time for number three. If you send it to me I WILL make it work at no cost to you other than shipping.
#1 was a case where the builder had run about 6 inches of wire from the board to his 300B sockets which were mounted on a slab of marble. The whole amp had turned into a giant oscillator / radio transmitter. I had to add ferrite beads and multiple stopper resistors top calm the beast.
#2 was an SSE which turned out to be not so simple. The troubleshooting thread had grown to a dozen pages or so with several experienced tech trying to solve the dead channel. The builder had drilled out the holes in the PCB to accommodate the fat leads on his specialized coupling caps. This broke the plated through hole connections from the top of the board to the bottom killing the signal.
#3 ???
If this works for you, send me a PM and we will work out the details.
I would prefer the board only. I have several power transformers to use, some OPT's and several sets of old 45's that work. This avoids the expense of shipping a whole amp, but I can deal with the whole amp too, Michigan isn't too far away, so shipping shouldn't be too expensive, but UPS here tends to break things, then claim that they weren't packaged properly.
I have only done this twice in 12 years so far, but it might be time for number three. If you send it to me I WILL make it work at no cost to you other than shipping.
#1 was a case where the builder had run about 6 inches of wire from the board to his 300B sockets which were mounted on a slab of marble. The whole amp had turned into a giant oscillator / radio transmitter. I had to add ferrite beads and multiple stopper resistors top calm the beast.
#2 was an SSE which turned out to be not so simple. The troubleshooting thread had grown to a dozen pages or so with several experienced tech trying to solve the dead channel. The builder had drilled out the holes in the PCB to accommodate the fat leads on his specialized coupling caps. This broke the plated through hole connections from the top of the board to the bottom killing the signal.
#3 ???
If this works for you, send me a PM and we will work out the details.
I would prefer the board only. I have several power transformers to use, some OPT's and several sets of old 45's that work. This avoids the expense of shipping a whole amp, but I can deal with the whole amp too, Michigan isn't too far away, so shipping shouldn't be too expensive, but UPS here tends to break things, then claim that they weren't packaged properly.
It's ALIVE!
Admittedly a rather low Fi setup, especially those trendy Radio Shack speakers from 1980, but it the best that I can do right now. It took me much longer than I expected to find things like my box of 5842's and a suitable set of OPT's, but I found all sorts of missing things in the process like a long lost guitar amp, and some OPT's that I had forgotten about. These things haven't been seen since I lived in Florida, more than three years and two moves ago.
has been playing for a couple hours and there were NO dead parts.
Admittedly a rather low Fi setup, especially those trendy Radio Shack speakers from 1980, but it the best that I can do right now. It took me much longer than I expected to find things like my box of 5842's and a suitable set of OPT's, but I found all sorts of missing things in the process like a long lost guitar amp, and some OPT's that I had forgotten about. These things haven't been seen since I lived in Florida, more than three years and two moves ago.
has been playing for a couple hours and there were NO dead parts.
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It was so obvious that I missed it until I powered it up and starting poking around with a voltmeter and found no drain voltage on the mosfets. There is a wire jumper that supplies this voltage. It was not installed. This was not visible in the photo that you had posted since it is on the other side of the board.
I will unhook and pack the board up and send it back to you tomorrow or Wednesday.
I will unhook and pack the board up and send it back to you tomorrow or Wednesday.
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I did a lot of digging through boxes in the last few days and I discovered what was likely the first ever TSE. I always make home cooked PC boards and test them before I commit a kilobuck to get professional PC boards made. The TSE was my first Tubelab PC board, so it had to be right. There were several iterations as the design was being developed but there were two identical proto boards made to prove out the layout. One of them went into my Lexan TSE. It played flawlessly from the initial build in 2005 until the power transformer fried after the amp got wet during a hurricane several years later. I replaced the proto PC board using parts from the proto board when I changed the power transformer because it had the "green growth" from copper, water, and electricity. The other board was populated, tested, and forgotten. It was in a box with a populated commercial PCB that has obviously been used, but I don't remember where.
The TSE and Tubelab story has been told several times before, but the short version is that I had never planned for the TSE, or Tubelab to be a commercial venture. I worked for Motorola for 41 years. During that time I made PC boards and basic kits for all sorts of stuff from satellite TV receivers (I found one of those boards too) to guitar amps. I also built completed amps, both solid state and tube for friends and paying customers. I built myself a little SE amp just to see what all the fuss was about, then another, then.......until I created the predecessor to the TSE. At the time (early 2000's) Motorola was booming, there were over 5000 employees in south Florida, and quite a few of them had one of my amps (guitar and HiFi). I would make myself one, let someone borrow it, and sometimes it didn't come back, cash came back instead, so I made another.
It got to the point that I couldn't make them quick enough, and another guy offered to help. The bottleneck was the home made boards, so we got 20 or so boards made by a proto board house, but they were expensive. Then someone suggested making instructions so that the technically capable (most everyone I knew) could build them. Someone suggested a web site, and Tubelab was born. Within a a year of Tubelab being launched, the economy would crash (2008) and all those people would be laid off. The SSE was already in the works, but it would be delayed.
I put those jumper pads in there for what was going to be a 3 stage monster SE amp using the TSE as the driver. Unfortunately only one would ever be built, my 845SE which is sitting on the shelf waiting for something between a power supply upgrade, and a total rebuild. There are multiple instances of exposed electricity up to 1050 volts and grandkids come here.....
Those pads actually only isolate the B+ voltage to the mosfets. The limiting factor for B+ on the board is heat and breakdown voltage in the mosfets. This jumper, and the -Vin pad next to the Fred diodes aloe operating the mosfets from an external power supply. I used +/- 150 volts in my 845 SE, and ran the TSE board from an external 500 volt supply.
To run 811A's or other big voltage tubes, build the TSE with enough power supply to generate the drive for the big tubes, then just tie the red wires from your OPT's to a power supply with enough voltage for the big tubes. That supply never needs to touch the TSE board at all!
The TSE and Tubelab story has been told several times before, but the short version is that I had never planned for the TSE, or Tubelab to be a commercial venture. I worked for Motorola for 41 years. During that time I made PC boards and basic kits for all sorts of stuff from satellite TV receivers (I found one of those boards too) to guitar amps. I also built completed amps, both solid state and tube for friends and paying customers. I built myself a little SE amp just to see what all the fuss was about, then another, then.......until I created the predecessor to the TSE. At the time (early 2000's) Motorola was booming, there were over 5000 employees in south Florida, and quite a few of them had one of my amps (guitar and HiFi). I would make myself one, let someone borrow it, and sometimes it didn't come back, cash came back instead, so I made another.
It got to the point that I couldn't make them quick enough, and another guy offered to help. The bottleneck was the home made boards, so we got 20 or so boards made by a proto board house, but they were expensive. Then someone suggested making instructions so that the technically capable (most everyone I knew) could build them. Someone suggested a web site, and Tubelab was born. Within a a year of Tubelab being launched, the economy would crash (2008) and all those people would be laid off. The SSE was already in the works, but it would be delayed.
I put those jumper pads in there for what was going to be a 3 stage monster SE amp using the TSE as the driver. Unfortunately only one would ever be built, my 845SE which is sitting on the shelf waiting for something between a power supply upgrade, and a total rebuild. There are multiple instances of exposed electricity up to 1050 volts and grandkids come here.....
Those pads actually only isolate the B+ voltage to the mosfets. The limiting factor for B+ on the board is heat and breakdown voltage in the mosfets. This jumper, and the -Vin pad next to the Fred diodes aloe operating the mosfets from an external power supply. I used +/- 150 volts in my 845 SE, and ran the TSE board from an external 500 volt supply.
To run 811A's or other big voltage tubes, build the TSE with enough power supply to generate the drive for the big tubes, then just tie the red wires from your OPT's to a power supply with enough voltage for the big tubes. That supply never needs to touch the TSE board at all!
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Now I feel stupid! How did we miss something so obvious when we had both boards side by side? Thanks so much for checking this out!!!! Send me a PM with what I owe ya!
I already have one running with CX345's this one was for my buddy who built one alongside my build. But yes, it sounds great and this one is running 45's.
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