Problem with Integration upgrade [resolved]

[cpditter]

Terminal 53 is 166v

[Paul Birkeland]

How about the voltage at X on each side of the PC board?

Your C4S current sources are working properly, as we see about 40mA of current being pulled across the power supply resistors.  The only real issue that I think you're having is that the four zener diodes on the PC board don't appear to be pulling down the regulated rail.  Measuring the voltage between them will provide another helpful data point.

[cpditter]

x on the B side is 53.6v

x on the A side is only reading a few 3-4mv

[Paul Birkeland]

So x on the B side being 53.6V would suggest that Ob should be around 107V, which is what we are aiming for.

X on the A side being 3-4mV means either those zener diodes on that side aren't well soldered or maybe (but less likely) the ground jumper isn't well connected. 

[cpditter]

OK, I'll resolder that Zener diode and resolder the ground wire and then check again...will do in the a.m. when I am fresh!
Thanks again for sticking with me on this...

[Paul Birkeland]

It's also worth double checking that all the zener diodes have the correct part number written on them.

[cpditter]

Good morning

I desoldered the ground jumper and the zener diode joints.  That resulted in both readings at x now being 53-54v

My other reading:

still at 122 and 123v on the transistor pins and

Term 56 126v

Sorry I could not verify the values on the zener diodes without unsoldering them all...

[cpditter]

Correction on last post line 1, meant to say resoldered, not desoldered.
thx

[Paul Birkeland]

still at 122 and 123v on the transistor pins and
Term 56 126v

Both x pads being 53-54 is a good sign.  That's half the zener stack on each channel.  The voltage at the metal tab should be about 2x that.

What voltages do you get at OA and OB? Can you reflow the center leg of each MJE5731A and reheat both ends of each zener diode connected to OA and OB?

[cpditter]

Hi

OA and OB both reading 107v

[Paul Birkeland]

OA and OB are connected to the metal tab of the MJE5731A, so I'm not sure why you have a different voltage there.  It may be that getting good probe contact on the metal tab is a bit of a problem in your case for some reason.

Either way you're OK to continue with the build.

-PB

[cpditter]

Thanks!

[cpditter]

Hi:

The rest of the build went fine...up and running, will give it a good listen tonight.

Thanks again for the assistance...guess my soldering skills (which are probably not great to start with) were really rusty when I started this process

[Paul Birkeland]

I'm glad to hear you got it up and running!

[cpditter]

Hi:
I've now listened to my Reduction with the newly-added Integration upgrade for about two days...

What I'm hearing so far is this:

Overall noise floor is reduced...not that it was bad before but definitely very quiet now.

Gain is noticeably higher so I'm listening with the volume at a lower setting than previously...used to be a very dramatic difference between phono and a line source like my CD player...now that difference is much less.

Can't say I'm hearing a big difference in bass response per se...but, some of the lower end like kick drum seems tighter and just pops out of the mix better I feel.

Thanks again for the help on the build