JM Signature Build

[BarryW]

Here is my attempt put one of these together. As in the past, I can't even begin to thank the folks on here enough from whom I've received so much help. Special mention to Taylor and Mark Fowler for sharing! I have learned so much from the various forums here. My wreck is one of the best amps I've ever played, and I have high hopes for this one as well. Hopefully I'll get my quality inspection done soon and get this fired up. Hybrid 70s 50w build is next . . .

[dorrisant]

Lookin' good.

Tony

[dreric]

Nice, need to get mine going!

[M Fowler]

Nice looking build.

[BarryW]

Thanks for the nice comments. And it's alive! I'm on a roll, three in a row powered up first time without a hiccup. Not sure I have the bias range right, extreme range is 40mv at about 413v, I'll get into it more thoroughly over the weekend and check all the voltages. I don't seem to have much of anything going on the bass pot, I'll have to check that. Wow, sounds REALLY sweet - reverb quiet, rich and just wonderful. Thanks!

[M Fowler]

Great news.

Make sure the bass pot is wired correctly I miswired mine at first and had little to no bass.

[BarryW]

yup, found it - I had omitted the jumper between the left and right sides on the Bass switch. It didn't make sense to me at the time so I left it off, but obviously I was wrong. Works now! This thing just sings, I can see what everybody was talking about. Absolutely wonderful cleans!

[beasleybodyshop]

Looks good!

[Blindog]

Nice job!

Mark

[dorrisant]

yup, found it - I had omitted the jumper between the left and right sides on the Bass switch. It didn't make sense to me at the time so I left it off, but obviously I was wrong. Works now! This thing just sings, I can see what everybody was talking about. Absolutely wonderful cleans!

Can you post a close-up picture of the bass pot and switch? I have looked through all the drawings and pictures I have and I get the feeling I have left something out...

Tony

[BarryW]

the schematic shows the switch
https://tubeamparchive.com/download/file.php?id=30388

and beasleybodyshop's draft layout shows the pot correctly (I think it's missing the one jumper on the switch tho):

https://tubeamparchive.com/download/file.php?id=37515

This is my pic before I added the jumper across the top two poles of the bass switch (thumb):

[IMG:160:120]http://i13.photobucket.com/albums/a264/barrywol/amp%20builds/Custom%20Signature%20Reverb/th_4DEDFB29-591E-4452-B2BD-3FCB14A5BAE7_zpsbsl2f9f4.jpg[/img]

yup, found it - I had omitted the jumper between the left and right sides on the Bass switch. It didn't make sense to me at the time so I left it off, but obviously I was wrong. Works now! This thing just sings, I can see what everybody was talking about. Absolutely wonderful cleans!

Can you post a close-up picture of the bass pot and switch? I have looked through all the drawings and pictures I have and I get the feeling I have left something out...

Tony

[M Fowler]

Not connecting pot pins 1 and 2 together was my problem.

[BarryW]

mine still doesn't have pins 1 and 2 together, I think I did that intentionally but I can't recall why right now. I'll have to try that when I get back to town after the new year -

Not connecting pot pins 1 and 2 together was my problem.

[dorrisant]

Mine seems to be connected as in the schematic from above. Does this pic show it correctly?

Tony

[M Fowler]

My photos of the bass pot/switch in my two amps are hard to follow and not as neat as others.