Help- Another Resistance/Voltage Failure

[diggs5]

I'm trying to get my Quickie with PJCCS up and running.  I put them together at the same time, but based on the voltage checks, I think the PJCCS is ok.  I'm a complete beginner to assembling a kit like this so I am lost as to what to do next with my problem.

Resistance checks ok except terminal 1 on the rotary switch which read 1.03K

Voltage reads:

PJCCS
IA/IB    37    37
A6/B6  24.5  22.8
A5/B5  1.77  1.78

Quickie
Terminals
1,6    24.65    22.83
4,9      1.7        1.8
5,10      0           0
C,D       3.3       3.3

Since all the voltages seemed consistent with each other (although different than published levels) I decided to hook it up to some old gear and see what happens.  "A" side has almost no sound (very faint), "B" output is loud but also has a loud deep hum.  The selector switch makes a very loud popping noise when changed.

I tried swapping tubes and making sure that everything else was working properly (cables, amp, etc), but nothing.

Based on other posts I really tried to diagnosis it myself, but I'm sorry to say that I was not successful and I probably did more harm than good when I tried to redo solder points (I'm not very good at soldering, very little practice).

I've had a lot of fun doing this so far so hopefully someone can point me in the right direction.  Thanks in advance!

[Paul Joppa]

The voltages are good, indicating that the tube portion of the circuit is operating correctly. The popping on switching indicates the output is good - though I have to ask whether it make a noise on both channels. Assuming it does, then the problem is most likely to be in the input wiring - the RCA jacks, selector switch, and volume control.

Since you have hum, there is most likely a problem with the ground wires in that area.

Poke around at the connections, and refer to the pictures in the manual to check (again! I know you've done it before...) to make sure that everything is wired correctly and the solder joints are solid. If that doesn't lead you to an answer then we'll come up with some more specific diagnostic questions.

Don't worry about the hum until we get both channels working; that may solve the hum problem as well. Even if it doesn't, one thing at a time - helps maintain focus!

[diggs5]

Thanks for the quick response!

I have no idea which thing fixed it, but after re-soldering a couple connections its up and runnin!!!

But i still have that crazy ground hum (and popping when switching). Any suggestions on a starting point?  I basically walked from every ground connected point and re-soldered them. It gets more noticeable when I'm touching either knob if that makes a difference.

I read in another post about solder dripping down and shorting out the rca input/output jack.  Could that have cause it?  I only ask because i noticed a small amount on one input jack that i removed but i suppose it could have gotten inside.

Thanks for your help!  Even w the hum it sounds great!!!  Still havin fun.

[diggs5]

One more update if it helps...

When i touch the top of the tube on side A the hum gets a lot worse.  Touching side B has no affect.  I switched tubes and it stayed w side A.

Once again if it matters, I know ground hums can be tricky.

Thanks.

[Paul Birkeland]

It's possible that your source is looking for a ground reference.  Run a wire from the chassis of your source to one of the shells of one of the RCA jacks. 

You can also try connecting a wire between the chassis of your amplifier and the shell of one RCA jack.

[diggs5]

Didn't do much to help.

I did check resist again and my OP was incorrectly stated.  Rotary switch 1 was 103k not 1.03k.  Also now switch 4 reads 103k which it did not read that way the first time.  I'm not sure if it matters but I guess fyi if it helps a diagnosis.

Could there be anything wrong with one of the tube sockets or either switch and if so how could I test them?  BTW I doubt thats the case over my soldering job, but since I've re-soldered everything with no change I thought I would ask.  Thanks.