Wow. What a great channel. I'm still rocking my RedKnob that I bought 35 years ago but am about to get it on my bench and look for problems (my speed is looking for cracked solder joints to start) but will look at those ceramic caps and see if I can find replacements.
Wonderful video ! I have the same amp but it went three times out of order... The last issue is still not identified, I hope I'll fix it, it's the best amp I've tried
I am trying to bias this amp i can get the balance to 0 but the im getting -40dc on the other pot with my taiwanese digital multimeter. Could i have an issue here?
Love the video! I have the same amp and for the longest of times I’ve been thinking on replacing the PS caps. Strangely enough, mine only has one of the high-power resistors, might as well replace it like you did and put the one that’s missing.
Someone may have already modified it to a traditional dropper resistor instead, like I was talking about. The value of the remaining resistor should be much higher than on the schematic if this is the case.
In this case I mean that the bias supply voltage was fluctuating due to the pots which form the voltage divider which supplies the variable voltage needing cleaning. In general, if I say "bias instability" I mean that the dissipation of the output valves is fluctuating somewhat. Could have various reasons for that, including just the output valves being on the way out.
@@BradsGuitarGarage yup, the whole sub board was scorched and burnt. Happened before it ever hit our bench and was working for ages before coming in for other issues.
Thanks mate really enjoyed this video hopefully I can set my bias now after seeing this, thank you Champion.
Great video, I have one of these on my bench right now for recap and power up for 1st time in 10 years.
Wow. What a great channel. I'm still rocking my RedKnob that I bought 35 years ago but am about to get it on my bench and look for problems (my speed is looking for cracked solder joints to start) but will look at those ceramic caps and see if I can find replacements.
Enjoyed seeing this one again. Great playing. Love The Shadows.
Thanks for following, mate!
Love mine best amp i have own at least half a dozen valve amps .
Great video, so much info etc..Love the Shadows vibe at the end...Thanks for sharing your knowledge...Ed..UK..😀
I need to get those riffs down.
I used to play that perfectly as a 15 year old.
mighty twins
7:56 That's exactly the sort of repair I would have done ... when I was fifteen years old.
These are the kind of guys that make better margins than me.
@@BradsGuitarGarage Margin, smargin. Do proper work and charge more than the hacks.
Lovely video, thansk! How do you think it compates to a bf twin reverb sound wise?
Wonderful video !
I have the same amp but it went three times out of order...
The last issue is still not identified, I hope I'll fix it, it's the best amp I've tried
I am trying to bias this amp i can get the balance to 0 but the im getting -40dc on the other pot with my taiwanese digital multimeter. Could i have an issue here?
Love the video! I have the same amp and for the longest of times I’ve been thinking on replacing the PS caps. Strangely enough, mine only has one of the high-power resistors, might as well replace it like you did and put the one that’s missing.
Someone may have already modified it to a traditional dropper resistor instead, like I was talking about. The value of the remaining resistor should be much higher than on the schematic if this is the case.
Brad, what do you mean by bias instability? you mean the bias voltage was drifting or what
In this case I mean that the bias supply voltage was fluctuating due to the pots which form the voltage divider which supplies the variable voltage needing cleaning.
In general, if I say "bias instability" I mean that the dissipation of the output valves is fluctuating somewhat. Could have various reasons for that, including just the output valves being on the way out.
I had the same issue on one ages ago that set fire to the board. Seems to be a common issue.
The bias sense resistor?
As you'd know that would be the valve causing that, perhaps the stock resistor wasn't a flame retardant type.
@@BradsGuitarGarage yup, the whole sub board was scorched and burnt. Happened before it ever hit our bench and was working for ages before coming in for other issues.
They were designed to be biased cold and sound best that way.
Yeah, crossover distortion sounds fabulous.
@@BradsGuitarGarage
F9aSCo_MXhk
Fixing and playing one live for over 25 years I might have picked up a few things.
Brad please quote me a price for the Fully Schmicko mod to my Plexi clone.
$3000.
Rivera from Rivera amps designed the amp while working at fender early 80s?
Nope, this was done after Riveras time. His last amp was the last of the perfboard amps before they went full PCB.
I had one thought it was junk
Maybe it was junk. This one isn't though.