new here and seeking info

[ModdersAnon]

Hello all,
I was doing some research on tube biasing and retrofitting better pots and jacks to my Sovtek Tube midget....and wound up here. seems to be a treasure trove of info. looking forward to getting into this project. I've owned this amp for about twelve years and love the sound. but the cheap hardware leaves much to be desired....crappy pots and plastic input jacks.

One thing I can't stand is paying someone to service vehicle/amp/guitar, etc. Had varying luck with this in the past. The guys that are really good usually command a premium(something I really don't have) and the guys that seem like a deal are generally hammer mechanics.

I love modding my stuff. Can't leave it alone. lol

Sovtek behind some junk



My other amps and several of my guitars



None of the amps have stock speakers, the Pro junior has better tubes than stock junk. several of my guitars have pickup upgrades.

The TSL 601 is special. was in a fire, doused with water and still works! speaker and grille cloth were rotted out. replaced speaker and added a Led Zepp T-shirt for grill cloth, and she's still going strong ten years on.

not guitar/amp related, but since I love modding, Daytona 675 streetfighter project




PS: if I seem ignorant of electrical jargon/concepts, its because I am. haha I know a little bit, trying to learn more as I go.

[soundguruman]

I have been using Precision Electronics Canada Pots in MIGS.
These pots have a great super-even taper (reverse log / audio) that maintains adjustment all the way from top to bottom, and an extended rotational range of 130 degrees. These things blow away consumer grade controls, it's like night and day.

As you can see, the circuit board and hardware will need a bit of tweaking, to shim the pots to the correct height.

and the faceplate needs to be drilled out a few thousandths of an inch, but not a whole lot...
Then, you will need to use 1/4 shaft knobs, I prefer the Fender type, because you cannot use knobs with brass set screws. The shaft of the pot is stainless steel, and you must use knobs with steel set screws, not brass.
These type of pots can be had for about $10 each, but some vendors have been selling them for quite a bit more.

The jacks should be replaced with CLIFF (Marshall type) OR if you want to use steel jacks, you are going to need insulators, to prevent the jack from grounding to the faceplate. (this produces a ground loop- BUZZ)

But the end result being, that there is actually hardware holding the pots solidly to the chassis, and the shaft of the pot is no longer (flopping about) at the mercy of the environment.

There are also BOURNS pots, conductive plastic, with 1/4" steel shafts, that will solder right onto the board, However, you will probably find that nobody stocks the values, and they have to be custom ordered and configured. The Bourns pots also have hardware (threaded bushings) to attach the pot solidly to the chassis. The Bourns pot does not have the 130 degree rotation, and does not have the special taper, to allow smooth adjustment all the way from top to bottom.

Actually, people would be surprised to find that the MIG (other than the controls) is a pretty solid guitar amp. It's built really strong, and has nice beefy transformers. It also invites rather easy modifications. I kinda like it myself....

[ModdersAnon]

Thanks for that info! I believe it was a previous post of yours popped up on the search engine that led me here. Before any work happens, I'm gonna do some reading....There's a book "inside tube amps" by Torres that I've seen noted several times. seems like a good place to start. Any other recommendations?