very risky move guys, the circut was there for a reason the older amps had better transformers and was ok down to 90 volts these chinese transformer can't handle it. that's why it's there. you can by pass the relay sure and it will work. but if you have a plate resistor or tube failure which happens every few years, there is no longer any protection and what happens is boards, transformers and other vaulable circuts to burn . not a good idea at all. mine has done it also when it see around 112 volts or 130 volts. I go and grab my voltage stabilizer and use it much safer.
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Johnk_10's SVT VR relay mod.
- Thread starter Rickett Customs
- Start date
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
I recall hearing that Loud had their own version of the bypass mod. The protection circuit causes more problems than it helps. They don't have an issue with it.
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
I realize this is 3 years old, but I'm having the issue with my SVT VR.
Is there a specific reason for the Y cable adapter, or could you just solder the wires directly to the board?
Thanks...
Is there a specific reason for the Y cable adapter, or could you just solder the wires directly to the board?
Thanks...
I posted in the other thread, about this, but, thanks to the help that John posted, seeing his blog page & this thread, & reading Jerrold's initial post, explaining what he saw, I bought a head, in "faulty" condition as not working. I brought it home & did the mod. I used a piggyback faston connector M/M/F.
I didn't even have to pull the chassis out. I just stood the head on it's side & leaned the chassis out enough to expose the power switch board. I pulled the 2 wires, installed the clip, jumpered the wires to the piggyback connector & done. Took me about 5 minutes. It took me longer to bolt the chassis back to the head cab, getting the screws lined up, etc...
I didn't have to clip the plastic ties.
So, thanks!
everything added together for me to clearly understand, going into this.
here's the piggyback adapter I found, at Pep Boys, thanks to a user in the other thread.
for $3.50, you get a pack of 10. a 35¢ part...
I didn't even have to pull the chassis out. I just stood the head on it's side & leaned the chassis out enough to expose the power switch board. I pulled the 2 wires, installed the clip, jumpered the wires to the piggyback connector & done. Took me about 5 minutes. It took me longer to bolt the chassis back to the head cab, getting the screws lined up, etc...
I didn't have to clip the plastic ties.
So, thanks!
everything added together for me to clearly understand, going into this.
here's the piggyback adapter I found, at Pep Boys, thanks to a user in the other thread.
for $3.50, you get a pack of 10. a 35¢ part...
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You can say that now because they've been in the wild for 40-45 years and any issues with them have by and large been fixed by now. But while the Magnavox heads were and continue to be excellent, it wasn't all kumquats and Cool Whip with that era, either.
Thank you John K for precise instructions. I picked up a svt-vr last week. it needed some work. new plate resistors and i also replaced the 220 ohm resistors on the output board, 2 of the 12au7 tubes and 2 of the 6550's were bad. It is running good now. set bias and balance and did your mod this evening. Reason being is that I had a svt classic a couple of years ago that would trip into standby. That was the main reason that i got rid of it. I plan on keeping this amp for a long time and i wanted to say Thank you!
