Is Doc a Saint or .... ??

Is the choke you used in place of the 270 ohm resistor the Triad C7X I have a couple in my parts box and was wondering?
 
Very tidy build. I hope i am wrong about this, but i don't like the look of that choke so close to the output transformer.  It may work fine, but i wouldn't be surprised if it created a lot of noise on that channel..
 
JamieMcC said:
Is the choke you used in place of the 270 ohm resistor the Triad C7X I have a couple in my parts box and was wondering?
Click to expand...

Yes, it is - and it is an experiment.  If I get some noise it should be an easy thing to just pull it and put the resistor back in.  That's one of the reason's I decided to try it - easy access.

And I'm on temporary hold.  One of the volume switches is missing one bottom lug so that's on the way back to BH land so I can get a new one.
 
mcandmar said:
Very tidy build. I hope i am wrong about this, but i don't like the look of that choke so close to the output transformer.  It may work fine, but i wouldn't be surprised if it created a lot of noise on that channel..
Click to expand...
Its core is oriented at 90 degrees to the output transformer, which should be helpful in terms of noise mitigation.  This is hypothetically a much better place to put the choke compared to mounting it above one of the output transformers.
 
Actually, the coil axis of the choke is the same as the output transformer, so there may be some hum coupling. Not easy to predict the magnitude though.

You can listen to the speaker to determine whether the noise is acceptable, and whether it is noticeably different from the other channel.
 
I meant as shielding - just wrap that sucker up with aluminum tape and ground one end.

Still not good?
 
So does PJ. You would potentially need magnetic shielding for what we are talking about with this choke (coupling), not electrostatic. That means mu metal, molyperm, steel, soft iron, etc.
 
AHHH!!!!  sry....

I think we'll just use plan A - if it hums either find the words or remove it.

Output wiring:
 
Got home from deployment a few days ago, and I finished the Mainline yesterday.  Doc, you nailed it with this one.  First track I listened to was Pink Floyd - Echoes.  When that crescendo started building in the 15-20 minute mark, I had the biggest s**t-eating grin on my face. 

I think my headphone system has finally reached end-game status.  Thanks BH!
 
Wow Nick, thanks so much for the kind words! And thanks for your service!
 
Rocketman248, thanks for your service.  Much appreciated!

Next step is board mounting.  Thought I'd throw this in before that starts.



If everything checks out this could be done tomorrow.

 
It almost checked...HELP!!

Resistance checks all good.

Initial voltage checks all good but the inside set of LED's on the A side came up slowly.  Turned it off and realized I needed to set the voltages.

Terminal 20 is at 220v and the inside LED's (closest to the OT-3's) are not lit.  The other pair are lit.  It will not adjust.

The other channel is perfect - adjusts just fine.

I put in a new 12AU7 and switched the other tubes to the other sides.  All heaters glow.

Remeasured volts.
KReg on A side is 3.8 volts - everything else is per spec.
 
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