Bad OT question

[studiodunn]

So I just finished this VH3 (headfirst) build and once I got it fired up It sounded bad. There tone was nasty and notes had the dreaded blocking distortion/crackle that got worst the harder I played.

I put the guitar through the loop and same thing, so this ruled out all but 2 tubes. i changed them and no improvement. Next I went to power tubes, no change.

I then decided to swap OT primaries on the tubes. To my surprise, no better or worst. No hum, no squeal, no bueno. Is this a sure sign that the OT has an issue?
The amp sounds like an amp running without one side of the Push / Pull - from what I've read

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[xtian]

Can't guess without a schematic.

[ViperDoc]

Just on quick examination, your flying bare PT 6.3V heaters look like they’re frighteningly close to your PT screen resistor leads.

I once had an OT primary that used different colors and had my primary CT connected to a PT plate. Disconnecting and testing the primary resistance helped me connect it properly, problem solved.

[maxkracht]

I would rule out wiring errors and faulty tube sockets first. Looks like a fairly complicated build, lots of places to make an error and it only takes one. Bad output transformers are fairly rare, especially when they are new. If there isn't heavy negative feedback, you won't get squeal, so that doesn't necessarily mean anything. I see what looks like resistors to measure bias. Is each half conducting? Are the plate and screen voltages about the same on each side?

If you really think the OT is bad, here's another test. https://www.premierguitar.com/the-super ... mer-tester

[studiodunn]

Just on quick examination, your flying bare PT 6.3V heaters look like they’re frighteningly close to your PT screen resistor leads.

I once had an OT primary that used different colors and had my primary CT connected to a PT plate. Disconnecting and testing the primary resistance helped me connect it properly, problem solved.

THANK YOU! I'm an idiot and had the CT going to the tube. Amp works perfectly now. Thank you, thank you, thank you.

[ViperDoc]

THANK YOU! I'm an idiot and had the CT going to the tube. Amp works perfectly now. Thank you, thank you, thank you.

Excellent. Now I can see the brown lead on the supply node in your picture. My OT had a Dagnall red-brown-white orientation I wasn't used to where the white was the PCT, not the red. Took me a while to figure it out. I will admit I've hooked future OTs up without checking, but it always pays to be sure.

Nice fix. Now enjoy that amp!

[maxkracht]

Should put some of that silicone sitting above your bench on the tilted filter cap. It will eventually rattle loose if you leave it like that.

[studiodunn]

Should put some of that silicone sitting above your bench on the tilted filter cap. It will eventually rattle loose if you leave it like that.

Wes indeed. I'll go through and silicone things once I am done tweaking.