More tranny trouble? [solved]

[Karl5150]

Sorry for the confusion
The noise does NOT follow the tubes
The noise stays in the Right channel, NOT the originally miss-wired channel
With the new tubes the #s are:
MJE...transistors -103/102V
2 - 71V
18- 69V
26 - 69V
31 - 70V
 Thanks again, I'll try and slow down to be sure what I write is as clear as possible.

[Doc B.]

OK, so we can eliminate the tubes and the repaired left channel miswire as the source of the noise. Since it is in one channel it is not a problem in the power supply. the next step might be to swap the C4S load connections from side to side and see if the noise follows the C4S components. I have gotten far enough away from working on the physical layouts of the kits that I will let PB weigh in on what terminals this swapping involves.

[Paul Birkeland]

I still strongly suspect a cold solder joint in the right channel.  The fact that it takes time for this to develop is all the more convincing.

To eliminate it as a source, you can swap the C4S boards between channels, just to be sure.

-PB

[Karl5150]

Thank you guys for your patience with this, I know I haven't been as careful and clear in my reporting of the issues.
1) before the upgrades the S.E.X and the Reduction worked well. Beautifully.
2)  after transistor issues the C4S S.E.X. worked well with the stock Reduction.
3) MY miss-wire on the Integration C4S started this thread.
4) After ascertaining the noise that developed was only in the right channel of the Reduction I swapped   C4S boards.

Here is where I'm at now:
The C4S board that was in the noisy right channel is now in the left and it works fine - quiet, musical.
There is nothing from the right channel, no hum, hiss, noise....no sound. (Switch RCAs out of the Reduction end and no sound from the left speaker- it is not the amp.)
I checked the wiring (multiple times), swapped tubes, swapped 1 end of in and out RCAs (1 set at a time), changed RCA cables, I even checked resistance between RCA in and out, both channels read the same.... but there is no signal from the right channel of the Reduction.

Both tubes and all 16 LEDs glow. Integration voltages as in previous post.
I ran through the resistance check and the voltage check from the Reduction manual and for now I will only report the abnormalities:

1) Overall the voltages are lower, but in the ballpark.
2) 43, 49 & 54 show OL not 0 ohm in the resistance check and show fluctuating <1V not zero volts in the voltage check.

I hope this is enough for some help, thanks again in advance.

[Paul Birkeland]

OK, nothing from the right channel is very, very helpful!!!!

Download a 60Hz tone and play it into your Reduction at a very low level.  Set your meter for AC voltage and connect the black probe to ground.

Measure the AC voltage at terminals:

2
6
10

If you can reach it safely, also check the AC voltage at the RCA jack input.

[Karl5150]

Here goes:

2 - With no tone - 143
     With 60Hz tone - 143 to 170+ as input moved from min up

6 - With no tone - 0
     With 60Hz tone - 0 to 0.6 as input moved from min up

10 - With no tone - 0
       With 60Hz tone - 0 to 30 as input moved from min up

I did not do an input level sweep on the RCA pin because of its location, but a static check matched the signal on the left side.
2, 6 & 10 AC voltage readings mirror the left channel equivalents at slightly higher levels.

Karl

 

[Karl5150]

Those are the # on the "ACV" scale set at 200 (I did 'em again cause you got me scared )
I got a low level "sinus 60Hz -10dB" tone running thru my nuforce microDAC2.
They do vary depending on the volume the computer feeds the DAC, it defaults to 100%
Those # are way different than DC values.

[Grainger49]

Then you might be reading them wrong.  146V AC in the Reduction would be only at a transformer output to the high voltage rectifiers.

I don't have the reduction or the manual.  But 143V AC is not going to happen in the signal path.  Could it have been 143mV AC?

When you have a meter with different ranges start with the highest range and move downward on the ranges till you have a reading of at least 50% of that range.  A reading of 0.6V or even 30V on the 200V range is unreliable.

[Karl5150]

Unfortunately the AC voltage on my meter only reads 200 and 600V scales. 
The meter reads 122.4 from the wall outlet and a third check shows the same #s reported, similar on both channels.
DC reads down to mV, maybe I'll try and pick up a meter that reads AC in the mV range too.
Thanks for the heads up

[2wo]

Before you condemn your meter, look again. I bet there is a little mv indicator somewhere along the bottom. easy to miss...John     

[Paul Birkeland]

Those are the # on the "ACV" scale set at 200 (I did 'em again cause you got me scared )
I got a low level "sinus 60Hz -10dB" tone running thru my nuforce microDAC2.
They do vary depending on the volume the computer feeds the DAC, it defaults to 100%
Those # are way different than DC values.

100% out of the computer is too high, try 2%.

What I am looking for is for you to feed a fixed 60Hz tone into the Reduction, then to measure the AC voltage at those points without adjusting the level coming in.  If you adjust the level coming in, then you need to start over.

-PB

[Karl5150]

Will do
The DAC also has a pot, should that also be set to the minimum?
I have access to a meter that reads AC in mV.
At 100% the test tone only showed a steady output of about 10% on the level meter built in to the volume display on the computer.
As an aside, I'm sure this is frustrating for all on the help end of the forum, just for different reasons than it is for me on the build end, but for me it is much more of a learning experience than the original builds, which went so well.
Thank you for all your time.

[Paul Birkeland]

You can measure the signal coming out of your digital setup by measuring hot to cold on each RCA plug. Do your best to set those to 2-5mV. 

-PB

[Karl5150]

Got 4mV from the DAC measured on the open end of 0.6m interconnects, plugged them into the Reduction and got:

2 - 2.9V AC
6 - 100mV AC
10 - 2.9V AC
I hope these #s make more sense.
Thanks

[fullheadofnothing]

It seems, in my limited experience, that you are putting an AC voltage into a tube, and getting a higher voltage on the other side(it goes from 4mv at the grid of the first triode to 100mv at the anode of the first /grid of second triode, then to 2.9V at the anode of the second triode). In other words: an amplifier...

What is the AC voltage at the center pin of the output jack in this test scenario? If you're losing voltage between 10 and the pin, you've found your bad solder joint.