My 124# is up and running!!!!! A few issues?

[echo44]

Ok so I built a Tubes up version as I used a chassis from RJ?

First major issue all the number rotary knobs work in reverse?
In other words when the knobs are rotated all the way clockwise they are
at their lowest values?

His chassis came with a filament on off light and their is no light happening, is that because it should be a diode?

so I haven't wired the pedal jack yet but did wire the OD and PAB switch
The OD switch works yet the ratio and level don't seem to do anything?

The good news I haven't biased the amp yet just put the knob in the middle
loaded it up wis some cheap ass tubes rather than my vintage tubes yet it still sound great. I hope someone has a simple solution for the knobs or i will have to live in backwards land.

Thanks!!

[xtian]

Oh, noes. You wired the pots wrongly. Easy fix. May also solve your OD controls.

The good news I haven't biased the amp yet

That's good news? Dude. Bias it.

[echo44]

I am pretty sure they are wired correctly I will post a picture.
Now the OD problems have changed? The Level and Ratio work(although backwards, I think this has to do with the amp being built tubes up yet
the knobs are upside down as I wired it as a tubes down)
Now when I switch on the OD I get a tremolo type sound with an occasional
loud cut in? I probed for shorts with a wooden stick yet didn't find any? Could this be a bad V2? The non OD channel sound fine

[amplifiednation]

Well did you install the pots upside down? I bet you didn't. If you reversed the wiring they will work in reverse

Posts some pics, can probably figure that one out pretty quickly

[echo44]

i will post some pics in a few min
in the meantime trying to trouble shoot the OD channel not working correctly
i followed the signal at v2 pin 1 the voltage is 343 is this two high? same on v2 pin 6 343. on v1 pin 1 the voltage is 233 and 6 is 237 these were all measured with od on?

[echo44]

the pots

[amplifiednation]

the pots

Yeah you shouldn't have reversed the wiring of the pots. You need to switch pin 1 and pin 3 on all those pots. That may be why your ratio/volume isn't working. Did you make a new layout to follow for this?

[M Fowler]

This is a HRM but reverse layout and maybe helpful.

[echo44]

Thanks,
When I get a chance I will rewire the pots
In the meantime on the OD channel the ratio and level work
but you have to rotate the knobs in reverse.

My big issue is when in the OD channel the sound is garbled almost sounds like a tremolo and than as you increase volume you get cutoff and it pop in and out. Any suggestions? Here are my voltages on V1 and V2
I tested the v2 tube in a tube tester and it seemed ok.

V1 pins 1=235, 2=0001, 3= 1.58, 6=238, 7=.001 8=1.55

V2 pins- 1=347, 2= 0, 3=4.5, 6= 345, 7=.01, 8=4.7


Thanks again for everyones help

[bluesfendermanblues]

Thanks,
When I get a chance I will rewire the pots
In the meantime on the OD channel the ratio and level work
but you have to rotate the knobs in reverse.

My big issue is when in the OD channel the sound is garbled almost sounds like a tremolo and than as you increase volume you get cutoff and it pop in and out. Any suggestions? Here are my voltages on V1 and V2
I tested the v2 tube in a tube tester and it seemed ok.

V1 pins 1=235, 2=0001, 3= 1.58, 6=238, 7=.001 8=1.55

V2 pins- 1=347, 2= 0, 3=4.5, 6= 345, 7=.01, 8=4.7


Thanks again for everyones help

Those voltages are way too high!

Do you have the FET board installed? - if not or if you don't want it, you have to add a 150k resistor at the end of the PSU chain....at the node feeding V1 and V2.

[amplifiednation]

Your voltages are much too high. V1 should be around 185 or 190, V2 around 200, V3 just under 300. I think it might help if you posted all readings, including power tubes and your main stages, B1 - B5. Your amp isn't going to work right with B2 voltage in the mid 3s.

Good news is you are passing signal, the power stage is much easier to sort out since there aren't as many parts

[amplifiednation]

And post more pictures!!

I might be wrong but I don't think the cathodes should be anywhere near 4v either. I want to say they are around 1.5v or 1.3v for all four pre amp stages. Need to find voltage sheets... If the grid is too negative in respect to the cathode the tube will pull lots of current.

[echo44]

I will post some more pics tonight when I get home from work.
definitely think the voltage is causing V2 to cut out as I did an experiment
before work today, i switched in the OD channel on and got the usual cutout
garbly sound. I than lowered my volume knob on the guitar and the sound became low volume but clear. I assume than this is not a short problem but related to the voltage.

I measured the voltage on the power tubes and it is exact 440V therfore the problem must be between b3-b5?

I will measure all the b+ volatge when I get home

Thanks again for all the help !!!

[echo44]

Ok so I went and measured the B+ to find out why the tube plate voltage on the 12ax7 are so high

B1 = 473
B2 = 470
B3 = 466
B4= 406
B5=400

wall voltage in the amp = 122 volts AC

will post some pics of my power supply soon

[echo44]

pics of my power supply