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Hey folks,

After completing Fortis's TMBV6 a couple weeks ago, I decided it was time to rebuild my sIII and while I was at it, I decided to mod it to the V6 version. After getting some parts shipped from our pal Coco this week I was ready to dig in.

The sIII was my very first amp build, and looking at the thing now after building a number of others with all the stuff I've learned here and on other forums, it was pretty laughable really. It did sound very good, but there were some artifacts in the tone that I was never quite happy about. It was also a bit noisy thanks to simply horrendous lead dress (well, by my somewhat anal standard at least). I thought it was just the way it was until I built the TMB-V6 for Fortis. Even at retarded gain & volume it was still pretty quiet. When I heard the more laid back open vibe with 6V6's the decision was made. Time for a rebuild.

I did not re-build the board. I did replace all the wiring though, and I touched up some soldering. Basically I just added the V6 components. I pulled the wiring on all of the tube sockets except for the rectifier. I had to move a couple of sockets anyway for make room for the 6V6's so I took the time to clean things up while I was at it.

So, having received the parts on Wednesday I went to work. Three nights later (was at a halloween party last night) I have a fully functional amp again. Sounds 100% better than the old build. The nasty lead dress was just making a mess of the tone. It's now much quieter & is much more detailed tonally. It even sounds kind of jangly with the 6V6's on the normal channel - even with my stock SG. I do need to re-tube it...it's basically loaded with old junk I had lying around at the moment.

Sorry - I don't have any pics of the re-build. I'll do that when I re-tube the thing.

Now for the next project...re-building a Valve Jr with a boatload of mods...

Congratulations on the re-build. Now you have two amps in one - probably more once you get the hang of it! Not a bad deal at all.

Those nasty artefacts you worked on initially are gone now??

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

Yep - rather different character depending on the output tubes. I ordered some Tung-Sol 6V6's & a couple of Mullard re-issue 12AX7's for it today. I expect they'll be here before the weekend (gotta love the Tube Store's quick turnaround). Should be interesting. I expect the normal channel to have a very Fender-ish vibe with those.

And yes, the artifacts I was wrestling with when I originally built it are gone (and thanks for your patience with all those e-mails back then, BTW!). I don't know if it was the lead dress, a bad solder join, or a combination but it's nowhere to be found now. I'm thinking it had to be lead dress since I re-soldered the entire board a couple of times and it didn't help.

It was better or worse depending on tubes, but I suspect the character of the tubes was masking the issue to some degree, not fixing it. It sounds great now with the EH EL84's (didn't replace them - didn't need to). I do have a NOS RFT rectifier in there now, and it seems a little smoother. Guess there's a slight voltage difference & maybe a little more sag. I do have a defective 6V6 and that's why I ordered the Tung-Sol's. It sounds nice, but drops out occasionally & goes slightly microphonic at times. No issues on the EL84 side.

And a pic of the re-built innards. I really should tidy up the AC side too, but it isn't causing issues at the moment. This is before I zip-tied anything...



The wire I've been using is 20/22 gauge stuff I got from Metroamp when I built my 2204. The sleeve is just a tad more bulky than the wire Coco uses! Note that I ran out of green wire for the pre-amp grounds...had to use brown. You have no idea how much that bugs me!!! That and the over/under I did with the input jack cables. I didn't even notice that until after everything was done. Note I used the two-conductor shielded cable for the jacks again...

How about a close-up of the 6V6 cathode bias points you attached to the board. I thought it was pretty slick the way you did that.

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

Thanks! Ask and ye shall receive...



I mounted two tag strips on the end of the board & bent the unused tabs down & over. I had planned to use a turret strip but I didn't have any kicking around.

So, cool. How did you insulate the tags from grounding out? The tags close to the mounting bolts.

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

They're not close actually - just looks that way in the picture. And that end of the tag strip has plenty of space between the mounting on the strip & the edge. Even if the strip did twist a little it would still just be the fiberglass hitting the mounting bolt underneath the board. The strip is mounted a little below the board - you can see the overlap if you look closely.