Introduction From Newbie

[NickC]

Greetings!

Figured I'd introduce myself. Also want to say thanks for this excellent amp forum. I've learned a lot, and need to learn a LOT more.

I am an amateur amp-tinkerer. Had a couple of years formal electronics education primarily focused on vacuum tubes (yes, a few decades ago).

I'm basically a guitar player that had to learn to repair/mod gear for myself and band-mates out of necessity. Until last year I had never built a tube amp from scratch. I had a Sovtek MIG50 that was due for a cap-job. While I was in there I decided to mount the pots on the chassis and fly the leads to the board. I've worked on Fender amps with eyelet boards and am comfortable in that environment. I don't like working on PCBs, and in the case of the MIG50 it turned out to be a disaster. The flimsy solder pads were lifting off the board very easily. Out of disgust and desperation I elected to jettison the PCB and rebuild on a sturdy G10 turret board of my own contruction. The project went through several phases where I tried adopting aspects aspects of a JTM45, and finally married the MIG50 circuit with a Deluxe Reverb transformer set to tame the overall volume (50 watts is too much for the clubs I play). Since a picture is worth a thousands words ..... I'll spare you reading much more by including a few.

Here is a "before" shot:
http://homepage.mac.com/swamptone/Sovte ... Before.jpg

Here is the "after" shot (confirms my amateur standing):
http://homepage.mac.com/swamptone/NickTek-Guts.jpg

An iteration of the main board (before changing out iron, which required rectifier change):
http://homepage.mac.com/swamptone/NickTek-50-Board.jpg

Here is a top shot showing Deluxe Reverb iron:
http://homepage.mac.com/swamptone/NickTek-Top2.jpg

The amp works well, has decent tone, and is reasonably quiet even when dimed. The volume level fits my needs. Someday I'll revisit a few "issues" that cropped up during the build. But I can say with some assurance I'll think long-and-hard before I ever again attempt to reverse-engineer another tube amp with scant documentation out there. Fools rush in where heroes fear to tread. Yep, that's me!

I've learned a lot from this forum. Wish I'd found it sooner. Again, sincere thanks to all for sharing your knowledge and love of tube-circuits. I am grateful.

Nest Wishes,
Nick

[M Fowler]

Nick, welcome aboard and you did a great job on that Mig 50.

Mark

[xtian]

Welcome!

Post your location in your profile; always fun to know if we have neighbors.

[NickC]

Welcome!

Post your location in your profile; always fun to know if we have neighbors.

Thank you!

I updated my profile with location. I'm in upstate New York .... not far from Syracuse.

[M Fowler]

Oh crap those New Yorkers are the worst!

Just kidding of course



Mark

[Ripthorn]

NickC, I am just north of Syracuse about 5 or 10 min. Nice to have someone in the area.

[NickC]

Oh crap those New Yorkers are the worst!

Just kidding of course



Mark

If it's any consolation .... I'm originally from Atlanta ..... but also lived in New Orleans, Detroit, Northwest New Jersey, Athens, and Charlotte. Before I left home at 18, the family had moved 19 times.

Sometimes I wake up in the middle of the night and don't know where I am.

[NickC]

NickC, I am just north of Syracuse about 5 or 10 min. Nice to have someone in the area.

Well met sir!

I do the day-job commute into downtown, but reside in Liverpool.

Lets see .......... 5 or 10 minutes north could place you near St. Joseph's Hospital some days ..... or anywhere between Mattydale and Rt. 31 on other days. In any case, north of the thruway .... you're in the infamous snow belt. We both know how much fun that is.

[Structo]

Hi Nick,
Nice job on fixing up the Mig.

It's a lot of fun working on tube amps.
Even though I have poked around in amps and electronics for years, I still find it amazing when we can take a box of parts and make it do something that we intended.
Like make music.

Welcome aboard!

[daydreamer]

Wow, great job.
I used to have one of these amps, loved it. Don't miss it as much now that I've seen what you had to go through to fix it up!!. Member Selloutrr was educating me about these the other day, mostly bassman/JTM45 clone; I'm going to be studying those photos of yours now!!. Thanks for posting this, really educational.

Andy

[NickC]

Wow, great job.
I used to have one of these amps, loved it. Don't miss it as much now that I've seen what you had to go through to fix it up!!. Member Selloutrr was educating me about these the other day, mostly bassman/JTM45 clone; I'm going to be studying those photos of yours now!!. Thanks for posting this, really educational.

Andy

Thank you!

I made some mistakes in the board layout (from a wire-dress point-of-view). I also made quite a few changes to placement .... for instance, the bias circuit cap/diode/resistor was originally in the upper-right-hand quadrant of the board .... later moved near the rear fuse area. There is a chassis mounted bias pot under the bias board (not visible in picture).

You can see the bias pot in this picture (many changes since then .... the can cap as found in a JTM45 power supply was removed since amp was still too loud .... the PT shown is a MM MIG50 type .... later removed):
http://homepage.mac.com/swamptone/NikTekChassisMods.jpg

This shot shows the top chassis with Triad choke when I experimented with the JTM45 type PS:
http://homepage.mac.com/swamptone/NikTe ... ations.jpg

Other differences/changes:

Original bridge rectifier removed and replaced with 1N4007 diodes (full wave) ..... Deluxe Reverb PT required the change.

Speaker outputs removed for 4 & 16 ohm taps .... present OPT only supports 8 ohm load.

I ganged the guitar inputs together, now just a single guitar input jack. Both channel volumes still operate independently and can be blended to taste.

I removed the 240V AC power option.

A couple more photos angled left and right:

http://homepage.mac.com/swamptone/NickTek-Right.jpg

http://homepage.mac.com/swamptone/NickTek-Left.jpg

If I can be of any help to anyone regarding a MIG50, let me know. I'm happy to share what I learned from the project.

[NickC]

Before embarking on a rebuild of the MIG50 ..... I restored a 1966 Blackface Bassman head. Then mounted it in a combo cab with a 15".

http://homepage.mac.com/swamptone/Blonde_On_Blond.jpg


I changed the bias and NFB to classic blackface specs and recapped it (there were bulges on the original PS caps ... caught it just in time):

http://homepage.mac.com/swamptone/Bassm ... Modded.jpg

http://homepage.mac.com/swamptone/A-Bas ... icCaps.JPG

[surfsup]

nice work dude! I second the comments about the forum. Great info here from some great guys!

[Structo]

I love that Bassman!

Fender blondes are some of the best looking amps ever.

Not a bad looking Strat either.

[lzzrdgrrl]

I guess this counts as an intro thread. Maybe a sticky should apply it to the top of the board.....

I'm one of the few on my side of the field that got an interest in collecting radio equipment. The local consignment shop had me sorting and collecting parts for a time simply to help clear the aisles. So, I know parts. I discovered that some of the stuff from tag sales and flea markets could be cleared for higher profit if broken down and reduced to the more valuable components - like chicken.... .....

I live in the twin cities area in Minnesota. I've always wanted to build my own equipment but am not the best self-motivator. I've looked at several online communities and chose this one....

I have a couple of wee vintage PA amps with 6v6 outputs. They might do for about 10 watts but I like them for the cuteness....XDDDD......

Cheers......