JTM45 build, static

[ColeC]

I am getting pretty much only static sound out of my JTM45, if i crank the loudness 1, i can barely hear my guitar, my EQ controls actually change the sound of the static. I will put the link to a video of it below. Any help would be appreciated!!

https://www.youtube.com/watch?v=P7r9AlVtmr4

Edit: Should probably mention i have EL34`s in it. 12ax7 pre's, GZ34 rec, 1Kohm screen, the resistor on the bias pot was switched to 47K to match the el34`s.

[Jazz P Bass]

It's a new build?

Has it ever worked?

[ColeC]

Brand new build, has never done anything but this noise

[big_teee]

Did you do any preliminary voltage testing with the tubes out?
Like checking the primary and secondary voltages, 6 vac heater voltage?
Then check the Voltages with just the rectifier tube in.
Make sure you have the straps on the preamp tubes like the amp layout.
Be careful these voltages can kill you!
T

[ColeC]

I did, but i have made some corrections so I will double check my voltages now and post as soon as I finish.

[Chuck H]

Sounds like a problem with the signal path and probably DC on the pots (at least). Almost certainly a wiring error (or errors). It's not a real complicated circuit. If you can post gut shots (in high res and from angles that show the whole circuit) we may be able to spot them. The amp could actually be dangerous (to you and itself) to power up right now!!!

[ColeC]

I do have one shot currently Simple File Sharing and Storage.

I will get some more soon, let me know if you spot anything in the meantime.

[Chuck H]

Ok, well, thanks for that. Good pic. Tidy build. Unfortunately all the connections are made under the board where we can't see them. So never mind about more pics. I didn't look it over too close though because I can't download the image from that site (just the url) and I got tired of grope sites popping up.

[big_teee]

I built one with the wires on the bottom.
Much harder to trouble shoot.
Now I put all the wires and straps on top.
Not as pretty and neat, but much easier to tell what you got.
Here is a scratch board & amp I built a couple years back.
Which shows it all on the top.
This was taken before I was finished and fully tested.
T

[Chuck H]

I learned to mount everything accessible in my mod years before I ever built my first complete amp. Now, with scratch designs I try to keep the layouts tidy by making sure all terminations are at the edge of the board. Sometimes I also hide the grounds under the board so any ground leads just lip the edge of the board. When I do that I always include a couple of extra ground leads from the buss attached to nothing, so they can fished out and used for mods or repairs if needed. Whenever I want to run a lead under the board ('cause I don't want to look at it) I still solder to the top and lip over the board edge or sometimes I'll drill a hole to run it through. But yeah, I learned long ago NOT to make any connections under the board. When you do that it's pretty certain that you're going to have to unsolder a bunch of crap and lift the board, possibly repeatedly, for troubleshooting, voicing or modification.

[ColeC]

Damn, so there's really not much else to go on at this point unless I unsolder the board?

[Chuck H]

Well there's still voltage testing. That might lead to some isolation of the problem/s... Before you have to unsolder the board to make corrections And since you can't be sure things are working correctly without putting the amp back together, you may want to rewire for top mounted leads to avoid having to pull the board repeatedly if affecting repairs takes several efforts.

[ColeC]

Well, i just went to do some testing for grounding and resistance and such, and found that im not getting any readings throughout most of the resistors currently on my turret board. Could the have been fused when my OT primaries were switched on first startup or maybe from excessive heat on setting the board?

[Chuck H]

Well, i just went to do some testing for grounding and resistance and such, and found that im not getting any readings throughout most of the resistors currently on my turret board. Could the have been fused when my OT primaries were switched on first startup or maybe from excessive heat on setting the board?

I'm a little unclear on the details of what you're describing, but no. Nothing that's happened has homogenized your components into one.?. There must be some error with your meter or method.

[ColeC]

Was just measuring wrong, meter is fine haha