Thank you for sharing Chuck, anything and everything regardless if I totally understand it or not is always a learning experience to be added to my mental hard drive. Much appreciated brother.
I've read that Marshall bought the circuit boards from a a bad supplier. They were defective in that they were conductive. Too bad. Because when these are working properly they sound really good. I believe Marshall was competing with Mesa and Soldano back then and they wanted to have an amp that had all kinds of features and channels. Personally I think there's too much going on in there. I don't care for the effects loop, the shift or the reverb. I have two TSL60s. Both of the biases seem to drift. But they usually drift down and back up slowly while playing. Marshall recommends 80 mV for both EL34s. I bias them to 72 mV. Then they drift a little bit down usually. And then drift back up. They may go as low as 65 mV. But after about an hour they drift back up to 72 mV or so. So far no runaway bias drift. I love the way these amps sound. If I knew how to do it I'd make an amp based on the TSL60 head. I leave the reverb, the deep, the shift, the clean and crunch channels and the effects loop off of it. I would make it a point to point or a tagboard amp. And I would use the best parts available. I might even leave the standby switch off if I believed it wasn't needed.
I believe standby switches are necessary, even though most people do not understand the reason or how to use them properly. I am thinking about a video explaining this position based on facts not forum fodder. Thanks for watching.
Hello charlie. I was just now again thinking about a distortion pedal that I used to own back in 1988. It was a DOD distortion pedal. It had 4 control knobs was black and grey. It's just like the layout of an integrated tube fx 100 just not the color (of course). Do you remember this pedal or where I could check on 1. I remember liking the distortion it had better than the others I had owned and played through at that time. Can't find one anywhere. I see others stating 808 distortion but not same pedal at all.
I just bought a JVM205H for $850 in great condition. I'm coming across videos like this and wondering if there's gonna be issues with mine down the road. Any thoughts. Thanks for the vids!
Mine needs the newer revision 20 motherboard. Where are you located? I was going to have Lyle from Psionic fix it, but I don't know his schedule. The board is $209 and I think Lyle told me roughly $250 for labor. Let me know 👍
@@guitarc.p.r.9675 It's a '98 that blew a mains fuse a few years ago. Have had it in storage and I know about the conductive boards and bias drift with these early units. You're right, it could be a blown transformer for all I know. I even had a new set of Wing C EL34's in it too... those might be fried too. I'm in Minnesota, so W. Virginia wouldn't be any further than Lyle in Tennessee. Do you have a website?
My point was the board may be repairable. Chances are pretty good your transformer is ok. Tubes not so much, especially if it red plated. I do not have a website, but my contact info is in the about section of the channel. You can reach me directly by email, or Guitar C.P.R. Facebook.
Replacing the board does not guarantee conductivity issues later. I go with the problems I know exists in the old boards not what we do not know in the new ones. If I can correct the problem in the old boards I do. As I said in the video, I have only had to replace one board in all the TSL and DSLs I have worked on.... many of them are running perfectly years later. Marshall is not the only company to have board issues. The big problems are PC design programs do not know or understand the difference between paths, just rational layout to them, and imported boards. If you want to discuss this in depth, email me at the address in the about section or at Guitar C.P.R. Facebook.
Those boards become conducive over time. Known fact. It's a damn shame that Marshall doesn't care about the customers that buy their crap. I'll never buy a Marshall unless it's old. Terrible design flaws in the beginning.
I agree. At the risk of initiating an on line riot, As I said I have a problem with printed circuit boards for all the high voltage, high current circuits in an amp. Power tube sockets, screen, heater, and output transformer leads should not be on a PC board, especially cheap boards. Preamp circuits especially in high gain, channel switching amps however need the PC boards for size, stability and low noise. Some experts will argue this, but I have seen it for decades. Now to be fair, it is not just Marshall, I have had the same issues with a lot of other manufactures as well. Thanks for watching.
Thank you for sharing Chuck, anything and everything regardless if I totally understand it or not is always a learning experience to be added to my mental hard drive. Much appreciated brother.
I've read that Marshall bought the circuit boards from a a bad supplier. They were defective in that they were conductive. Too bad. Because when these are working properly they sound really good. I believe Marshall was competing with Mesa and Soldano back then and they wanted to have an amp that had all kinds of features and channels. Personally I think there's too much going on in there. I don't care for the effects loop, the shift or the reverb. I have two TSL60s. Both of the biases seem to drift. But they usually drift down and back up slowly while playing. Marshall recommends 80 mV for both EL34s. I bias them to 72 mV. Then they drift a little bit down usually. And then drift back up. They may go as low as 65 mV. But after about an hour they drift back up to 72 mV or so. So far no runaway bias drift. I love the way these amps sound. If I knew how to do it I'd make an amp based on the TSL60 head. I leave the reverb, the deep, the shift, the clean and crunch channels and the effects loop off of it. I would make it a point to point or a tagboard amp. And I would use the best parts available. I might even leave the standby switch off if I believed it wasn't needed.
I believe standby switches are necessary, even though most people do not understand the reason or how to use them properly. I am thinking about a video explaining this position based on facts not forum fodder.
Thanks for watching.
Hello charlie. I was just now again thinking about a distortion pedal that I used to own back in 1988. It was a DOD distortion pedal. It had 4 control knobs was black and grey. It's just like the layout of an integrated tube fx 100 just not the color (of course). Do you remember this pedal or where I could check on 1. I remember liking the distortion it had better than the others I had owned and played through at that time. Can't find one anywhere. I see others stating 808 distortion but not same pedal at all.
Sorry I do not. I did not pay much attention to pedals at that point, other than what I had to deal with selling at the music store.
@@guitarc.p.r.9675 ok thanks charlie.
I just bought a JVM205H for $850 in great condition. I'm coming across videos like this and wondering if there's gonna be issues with mine down the road. Any thoughts. Thanks for the vids!
Probably a good chance of it.
Mine needs the newer revision 20 motherboard. Where are you located? I was going to have Lyle from Psionic fix it, but I don't know his schedule. The board is $209 and I think Lyle told me roughly $250 for labor. Let me know 👍
I am in West Virginia. Are you sure you need a board?
@@guitarc.p.r.9675 It's a '98 that blew a mains fuse a few years ago. Have had it in storage and I know about the conductive boards and bias drift with these early units. You're right, it could be a blown transformer for all I know. I even had a new set of Wing C EL34's in it too... those might be fried too. I'm in Minnesota, so W. Virginia wouldn't be any further than Lyle in Tennessee. Do you have a website?
My point was the board may be repairable. Chances are pretty good your transformer is ok. Tubes not so much, especially if it red plated. I do not have a website, but my contact info is in the about section of the channel. You can reach me directly by email, or Guitar C.P.R. Facebook.
@@guitarc.p.r.9675 Isn't it recommended to replace these old boards with the newest revision 20 board to ensure no conductivity issues?
Replacing the board does not guarantee conductivity issues later. I go with the problems I know exists in the old boards not what we do not know in the new ones. If I can correct the problem in the old boards I do. As I said in the video, I have only had to replace one board in all the TSL and DSLs I have worked on.... many of them are running perfectly years later. Marshall is not the only company to have board issues. The big problems are PC design programs do not know or understand the difference between paths, just rational layout to them, and imported boards. If you want to discuss this in depth, email me at the address in the about section or at Guitar C.P.R. Facebook.
Nice amp! It just needs a boost pedal.
Can you give it just a little more gain? :)
Those boards become conducive over time. Known fact. It's a damn shame that Marshall doesn't care about the customers that buy their crap. I'll never buy a Marshall unless it's old. Terrible design flaws in the beginning.
I agree. At the risk of initiating an on line riot, As I said I have a problem with printed circuit boards for all the high voltage, high current circuits in an amp. Power tube sockets, screen, heater, and output transformer leads should not be on a PC board, especially cheap boards. Preamp circuits especially in high gain, channel switching amps however need the PC boards for size, stability and low noise. Some experts will argue this, but I have seen it for decades. Now to be fair, it is not just Marshall, I have had the same issues with a lot of other manufactures as well. Thanks for watching.