Finished my first build this week

[glpg80]

I did reflow everything after I got it all working and modded with the JEL spec. One question, I did that mod and installed coax on the input and gain pot, input is grounded to the ground lug of Jack, and gain pot is grounded to back the pot, one side only on each. I seem to now have a ground loop. And I didn’t before with the standard pvc wire. Any idea what I should look at to remedy it?

Try placing a 0.01uF cap from the ground lug of your input jack to chassis ground.

If that doesn’t work try changing the coax ground to ground as close to the grid as possible and not at the jack.

 

[Chubbs]

Two things on the coax. Make sure you didn’t cut through that clear insulator. Also if you haven’t, move that 68k grid to the tube socket.

 

[ibzprestige]

Try placing a 0.01uF cap from the ground lug of your input jack to chassis ground.

If that doesn’t work try changing the coax ground to ground as close to the grid as possible and not at the jack.

I will give that a try, thanks!

Two things on the coax. Make sure you didn’t cut through that clear insulator. Also if you haven’t, move that 68k grid to the tube socket.

I will double check on the insulator, I do have continuity with chassis ground to the hot wire on the input, I’m guessing that’s not normal.

I did move the grid on the tube socket, should I put a grid resistor on both V1 grids?

 

[Chubbs]

I will give that a try, thanks!


I will double check on the insulator, I do have continuity with chassis ground to the hot wire on the input, I’m guessing that’s not normal.

I did move the grid on the tube socket, should I put a grid resistor on both V1 grids?

Sounds like you might have nicked it, that stuff is really hard to strip correctly. I’d almost recommend peeling it vs using wire cutters.

You should only need a grid resistor on the first stage.

 

[jchrisf]

I ended up doing this spec last night. It sounds really great. Definitely recommend trying it out.

Where did you buy your parts?

 

[jchrisf]

Thanks and yep!



Thank you! I’d be lying if I said I didn’t already have parts coming for a new build, hahaha

What's next?

 

[ibzprestige]

Where did you buy your parts?

What's next?

Mouser mostly. I’m going to do a jmp 2203 next with some tweaks, maybe add another gain stage.

 

[MadAsAHatter]

Congrats on a successful build. What are you going to do for the shell?

 

[ibzprestige]

Congrats on a successful build. What are you going to do for the shell?

Thank you! I am waiting on one from sourmash

 

[MGL AmpWorks]

There's a mistake in the MojoTone layout and in your amp. The 2nd cap after the two .022uf caps in the tone stack should be a .1uf, not another .022.

 

[ibzprestige]

There's a mistake in the MojoTone layout and in your amp. The 2nd cap after the two .022uf caps in the tone stack should be a .1uf, not another .022.

this circled one ?

 

[MGL AmpWorks]

this circled one ?

View attachment 299337

Yes, correct!

 

[ibzprestige]

Yes, correct!

Thank you, I will try swapping that out. What kind of difference would that give? Do you have any recommended tweaks to try or usually prefer stock form?

 

[JackBootedThug]

I don't understand any of this but I think it's fuckin awesome!!! Good job ibz!!!

 

[jchrisf]

Thank you, I will try swapping that out. What kind of difference would that give? Do you have any recommended tweaks to try or usually prefer stock form?

Did you switch it?

 

[ibzprestige]

Did you switch it?

Yes, nothing really notable in tone changed. But it is what these amps run stock so I will leave it. I did the JEL mods and like them and my sourmash headshell came in and it’s a perfect fit, drilling the chassis holes was a little stressful hahaha.