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Got my 18w plexi kit built up. The normal channel works fine, thoughg it is quite bright with my strat, even with the tone all the way down. Turning up the tone also adds some noise whether or not anything is plugged in the input.

However the real problem is that the TMB channel only allows a faint sound to come out. After measuring the voltages on the pins I have found the culprit. V2 Pin 1 has no voltage and pin 8 has 4.5v. Pin 3 has .38v with the boost off, and 310v with it on. All other pins check out fairly close to spec.

So where exactly should I be looking for a my problem? I'm not sure where those pins should be getting their voltage from. Something on the board? Wiring somewhere? I wish I understood schematics better.

Here's my full list of voltages:

AC Mains 122v
B+ No tubes 447v
B+ All tubes 371v

V1
P1 148v
P3 1.1v
P6 154.7v
P8 1.14v

V2
P1 0v
P3 0.38v / 310v
P6 285.5
P8 4.5

V3
P1 205v
P2 60v
P3 94.5v
P6 208.3v
P7 61.2v
P8 94.5v

V4 and V5 (pretty much identical readings)
P3 12.63v
P7 358v
P9 347v

V6
P1 312v
P3 371v
P7 312v

Try a new V2 tube first.
After that check all your connections to that tube socket. Check that you have all the right values to. Basically just check everything associated with V2.

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http://pdfelectronics.com

Found one problem. The shield from the gain control was tied to pin 1 (a little line on the layout resembles the shield). So now I have sound, but it sounds ugly. And I have about half the reccomended voltage at pins 1 and 8. I am going to remove the optional resister from pins 1 and 6 and see what happens. Will report soon.

Oh, and a little reccomendation would be to add numbers to the lugs of the pots on the layout for idots like me who might wire every single pot backwards. I even looked up how to read which lugs are which on a schematic, and looked at the pots on the schematic to make sure, yet still came up wrong. Oh well, too much work to re-do every single tone and volume control...

Don't do that. The composition is optional is optional the resistor is not.

I'd rewire all the controls. It's two wires per control not a big deal. Might as well build the amp right.

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http://pdfelectronics.com

Ok, I swapped out the tube for the one I originally had in there and it's better. Still don't think it sounds right though. I don't have the speaker mounted in a cabinet as I am building it yet, and don't have any speaker cabinets to try it with. So anyway, it's just sitting there on the floor. But the breakup is really hard edged. Overall on both channels it seems bright and hard.

My voltages check out decent now. With 122v mains and 371 B+ here are my voltages again...

V1
P1 142.6
P3 1.08
P6 145
P8 1.13

V2
P1 170
P3 1.73
P6 273
P8 170

V3
P1 198
P2 58.6
P3 91.2
P6 202.2
P7 59.2
P8 91.3

V4
P3 12.3
P7 359
P9 346

V5
P3 12.3
P7 356
P9 346

I think I may have bitten off more than I can chew. It's a big step from pedals and guitars to an amp. Does anyone know if Steven will work on kit amps? It'd be a shame if I can't figure this out and am stuck with a rotten sounding amp.

Shawn

That's your issue. The cab does more than just hold the speaker. No wonder it sounds like shi t now.

_________________
http://pdfelectronics.com

Ok, I'll wait till I get the cab built. I know the cab does more than hold the speaker, just didn't expect it to sound that awful without a cab. Will report back after I get the cab built. Making it out of maple and walnut with a birch ply baffle. Thanks for the help.

Shawn

We can work on kit builds in a pinch if required. Most times, it gets sorted out but test with a speaker in a cab. The voltages look good.
If it sounds bad in a cab, compare the two channels, maybe a tube swap, check for bad solder joints.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yup, you need a cab. Without a cab all the lower frequencies cancel out and you just hear the higher ones, leaving an overall bright/harsh effect.

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Great tones come in small glass jars!

Ok, yeah. Now that I had a chance to listen when I wasn't so exhausted, it sounds fine except for the lack of a cab. When I swapped tubes before as recommended, I had put in a bad tube unknowingly. It squealed with the gain knob and had the wrong voltages. Plus it sounded terrible. Can't wait to get the cab built. Need a router plate for the guide for a dovetail jig I just got.

Will definately have to post pics when completed. And if everything works great, I will probably go in and reverse all the pots and install the vrm I bought with it. Was just too frustrated before to think about redoing that stuff.

Thanks guys,
Shawn