Resistance Check oddities

[snm]

I have to order some replacements as I cut the leads and originally installed them pretty close to the terminal strip. I'll report back as soon as I get some replacements put in

[snm]

Ok, with resistors reinstalled:

Terminal 1: ~67-68V
Terminal 2: 229V
Terminal 3: 0V
Terminal 4: 229V
Terminal 5: 83V

This is without the tube installed

With the tube reinstalled, my readings are:
Terminal 1: 57.6V
Terminal 2: 179.2V
Terminal 3: 0V
Terminal 4: 179.1V
Terminal 5: 71.1V

[Paul Birkeland]

Can you carefully measure the voltage at A8?

The 67V seems pretty low, but you could have a 12AU7 with one half that's very potent, or there could be another issue at work.

[snm]

A8 looks to measure out to 1.595V (with both tubes plugged in)

[Paul Birkeland]

How about A3?

Is the jumper installed on the volume pot between the lugs where black wires land?

[snm]

I’m reading 1.588V at A3.

Can you clarify what you mean by the jumper?

[Paul Birkeland]

There should be a bare wire between the upper and lower lugs on the volume pot where the black wires connect.

[snm]

Oh, my apologies. That's installed. Here's a picture for reference:

https://drive.google.com/file/d/1DkNyuo6HC6RzHT0YkimH5LeOLhx0bzWh/view?usp=sharing

[Paul Birkeland]

Does the amp otherwise sound good and work in what would be considered a normal way under these conditions?  Can you post some photos of the 12AU7 you have as well?

[snm]

Here's some photos:
https://drive.google.com/file/d/1WavPdI3cm4lhIitNHnJvoSA0dp9ozpGN/view?usp=share_link
https://drive.google.com/file/d/1ttI2jqRog3ECBBqV5n1_lzI9kbhbcln0/view?usp=share_link
https://drive.google.com/file/d/1PjVoFfVaEBoRWcgbwQAZPz7ra2_nMxBc/view?usp=share_link
https://drive.google.com/file/d/1HTEElxpBPS05NpP2oTBvS3E-fhj1uH-4/view?usp=share_link

The amp sounds fine to me, atleast I haven't noticed anything abnormal, though this is my first tube amp.

[Paul Birkeland]

I would pop the PC board back in and give the amp a listen.  It may just be that your 12AU7 is unusually potent. 

[snm]

Am I fine to listen with the small board only? I haven’t proceeded past testing voltages yet, but wanted to confirm first. Appreciate your help with this!

[Paul Birkeland]

Yes, the amp will work with just the small PC board installed provided the 3K/10W resistors are still present.

[snm]

I've been running the stock Crack for a few days now, without the small board just to see if any issues arise. Only thing I have a question about is the TRS connector. After listening for about ~30 minutes today, I unplugged my headphones and noticed the TRS connector was slightly warm. I assume this is normal?

[Doc B.]

Sure, the whole chassis will be warm after playing for a while. The Brits call vacuum tubes thermionic valves. Emphasis on the 'therm' syllable here. Tubes only work if their heaters are hot, and of course that heat energy transfers into the rest of the amp. The power transformer also gets quite warm.