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post #1261 of 1688
There is a problem, i can't adjust B+, i get 107V on B+ without the tubes, but the P1P trimpot have absolutely no effect on B+
post #1262 of 1688
Thread Starter 
Quote:
Originally Posted by capernicus View Post
Attachment 27974

Here are my op amp voltages as looking at them from the top down. (Click on image to view)
Many apologies for the delay. I am traveling far too much lately.

Only two of these voltages are correct. Try replacing the opamps to see if you get any better results. If there are still problems we can debug from there.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1263 of 1688
Thread Starter 
Quote:
Originally Posted by FairyTales View Post
There is a problem, i can't adjust B+, i get 107V on B+ without the tubes, but the P1P trimpot have absolutely no effect on B+
First, verify all of the components in the HV section of the PS. This is R4P, R5P, and R6P. Also measure all three pins on the TL783.

Your HV regulator is probably bad, but let's do some testing before you replace it.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1264 of 1688
Thread Starter 
Are there other posted problems that have not been addressed?
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1265 of 1688
Quote:
Originally Posted by runeight View Post
First, verify all of the components in the HV section of the PS. This is R4P, R5P, and R6P. Also measure all three pins on the TL783.

Your HV regulator is probably bad, but let's do some testing before you replace it.
Hey Runeight thanks for for the help (again), here are the measurements you asked for.

R4P: 200 ohms
R5P: 8.2KOhms
R6P: 2.73 Kohms

For the TL783 i have (no quite sure if it is what you're looking for )
1.27vdc between out and adj
34vdc between in and out
35vdc between in and adj

Thanks
Arnaud
post #1266 of 1688
Thread Starter 
OK. Can please measure the regulator pins with respect to ground.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1267 of 1688
Thread Starter 
Also, R6P is in parallel with at 10k pot. Please take a look at the resistor markings to be sure that R6P is actually 30k and that the pot is 10k.

Thanks.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1268 of 1688
Quote:
Originally Posted by capernicus View Post
These voltages were measured from the top with one probe on the board GND and the other probing each leg of the opamp where they exit the housing of the part.
Runeight, any ideas on what might be causing my op-amp voltages to be so far out of whack?
post #1269 of 1688
Thread Starter 
The first thought is that the opamps are toast. What are you reading for the DC voltage at R10 (on each channel) with respect to ground??
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1270 of 1688
Thread Starter 
Or maybe the opamps are in backwards????
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #1271 of 1688
Quote:
Originally Posted by runeight View Post
Also, R6P is in parallel with at 10k pot. Please take a look at the resistor markings to be sure that R6P is actually 30k and that the pot is 10k.

Thanks.
Values on the regulator are from left to right (to the ground)
70.3VDC
71.8VDC
101.7VDC

R6P is 30K and the pot is 10K.

In case you missed my initial question, the amp stops randomly for a few seconds from time to time (your hear the click from the relay), and this behaviour only appeared recently. Regal did suggest to reduce B+ by 10V, which leads to the problem of not being able to adjust B+. Just to sum it up.

If the regulator is fried could it be the reason why the amps stops from time to time?

Thanks
post #1272 of 1688
Quote:
Originally Posted by FairyTales View Post
Values on the regulator are from left to right (to the ground)
70.3VDC
71.8VDC
101.7VDC

R6P is 30K and the pot is 10K.

In case you missed my initial question, the amp stops randomly for a few seconds from time to time (your hear the click from the relay), and this behaviour only appeared recently. Regal did suggest to reduce B+ by 10V, which leads to the problem of not being able to adjust B+. Just to sum it up.

If the regulator is fried could it be the reason why the amps stops from time to time?

Thanks
I can't explain how the ADJ (middle) is higher than the output. You can check the pot by turning it and seeing if the resistance changes just to rule that out, but I think you need a new regulator.

Yes without the regulator working correctly the amp will experience voltage drops-outs which will trip the E12.
post #1273 of 1688
grr.. so FedEx lost my Mouser package so I'm still waiting on the parts

...murphy's at work, FML
post #1274 of 1688
Quote:
Originally Posted by runeight View Post
Or maybe the opamps are in backwards????
so this is an interesting thought, which way is the right way? If I am looking at the board with the parts on top, the power supply in the back and the pot in the front right, I have each of the opamps such that the text on the parts is right side up - is this the right way?

I suppose since I am about to order new opamps I could go turn them around and see what happens...
post #1275 of 1688
Quote:
Originally Posted by capernicus View Post
so this is an interesting thought, which way is the right way? If I am looking at the board with the parts on top, the power supply in the back and the pot in the front right, I have each of the opamps such that the text on the parts is right side up - is this the right way?

I suppose since I am about to order new opamps I could go turn them around and see what happens...
I did just double check my op amp installation with the part placement drawing and it does appear that I put them in correctly - with the notch on the left side.

I'll place the order for the new op amps and give an update once I get them in.
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