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I'm just getting into my first attempt at building an amp and have what will be an 18 watt sIII splayed across my desk. I've wired the heaters, and am now populating the board. I've a couple quick questions (so far - i'm sure there will be more). If mine works out half as good as some of yours I'll be thrilled. Lots of inspiration here.


Anyway-

First, the little yellow capacitors; I'm assuming the black line on the end designates the polarity, correct? The drawing doesn't seem to indicate which way they go in so I've just been following other peoples pics.

two, the manual says when wiring the IEC, that (L) or hot side goes to the lug on the SIDE of the fuse holder, but my drawing and some of the pics posted here suggest it goes to the lug at the END of the fuse. Which is correct?

Lastly, do the dotted black lines on the drawing designate a specific type of wire or is it the same as the rest?

cheers

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http://thepopmodule.com

Hi! Wecome aboard!
The band on the caps marks the outside foil conection. It doesn't really matter which way they are installed BUT some people claim it makes subtle differences, I think as far as noise is concerned. I think Phil or Coco documented which way round they prefer on a Triwatt so you might do a search for that and get some ideas. On the caps to ground the band will go to the ground side
The dotted line indicates the wire is on the back side of the board. Any of the supplied wire will do.
As for the fuse holder....I don't know if it matters. Technically it's the same.
Stew

found this
viewtopic.php?t=760&highlight=foil

hey thanks. that helped a lot.

Ok, now I'm wondering about the boost circuit on the board.

Stephen has it ghosted out on the schematic but I'm assuming its important if I want my boost switch to work.

The problem is I don't have an additional 22uf cap (I've been using the 223k ones elsewhere but there were only 3 in the kit) I do however, have an additional black 25uf 50V cap that I can't seem to locate where else it will go. Can I use it here instead of the 22uf noted on the schematic?

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Oh for sure! 22..25 no big deal. Just mind the polarity on these elecrolytics .

Stew

Hey Thanks again - I just used the 25u cap.

Does anyone have a decent pic of what is happening with the coax cable at the volume pot? I'm assuming either the inner cable or the shielding goes to the 1st lug and the other goes to the 2nd on the other side of the resister but I'm not sure which.



cheers
M

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http://thepopmodule.com

It doesn't even need to be 50V. Anything rated 6V or above will work fine on a typical preamp cathode. You can also experiment with lower values, anywhere in the 25uF to 0.68uF to tailor the bass response of the boost. Lower values will give less bass. Higher ones will give more.

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Great tones come in small glass jars!

The center conductor goes to the center lug on the pot. The shield is twisted together and soldered to the left lug which is at ground potential along with the left on the "mid" pot and the left terminal on the "volume" pot.
Stew

Cheers again Stoo.
I actually got quite a bit accomplished this afternoon.

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http://thepopmodule.com

Man who would want less bass than 22uf? I use that and this thing is still a treble monster. I suppose thats part of the marshall vibe but i run bass at 7 mid at 5 treble at 3 with this thing... guess is depends on speakers/ tubes too... I just swapped a JJ out for a TS in V1 and it made a world of difference, cold and piercing to warm and detailed, quite a bit more distortion too. A sovtek was even better than that JJ. But im still trying to tame the brightness a bit.

So Am I to understand that elsewhere on the drawing where the shielded cable is shown (the jacks for example) the thick line is the cable and the thin line is the shielding?

just double checking
cheers
M

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http://thepopmodule.com

Yes .. that is a good observation. If you look you can see that several points are tied together then a wire goes to the ground buss which ties it all ( including the sheilds) to ground.
Stew

man, that was tough squeezing 2 ground wires, the resister lead and the shielding onto that one lug on the gain pot. It was tight and then I worried that I used too much heat and damaged the resistor, I'm having difficulty getting a decent reading across the resister now but when I check I get either 0.01 M ohm which is like 10 k (I think) or 34 K neither is the 100k its supposed to be.

would this have something to do with it now being connected to all that other stuff? I think I have an extra 100 k resistor and am wondering if I should start over.

thoughts?

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http://thepopmodule.com

Ya. If you plug a cable into the jack and measure the other end of the sheilded cable in the amp you should see the 1 meg.

Hmm, not sure I follow. This is the 100 k resister on the gain pot on the TMB channel. I haven't finished wiring the jacks yet.

Cheers for all your advice stoo, I'm a complete novice at this stuff.

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http://thepopmodule.com

Ya that 100k has a pot tied across it so your readings on the end of the sheilded cable will vary. When the shielded cable gets too hot the center will melt through the insulation and short against the shield so if you don't have zero ohms your probably OK.
Stew

cool.

cheers

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http://thepopmodule.com

well, i finally had some hours to get back at this project, and have finished wiring up the jacks as well as the transformers.

I was wondering if someone could just give a quick glance at what i've got so far. I was particularly curious if the wires from the OT transformer are cool going perpendicular under the board as I have it before the 90 degree bend to the ohm selector and output jack -- or -- should i try to keep them along the outside edge of the chassis.



also, could someone double my input leads to V6 here?




Thanks again for eveyone's support; this forum really is gold.

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http://thepopmodule.com

OT leads look good.

If the 68K connect and go to pin 2 & 7, they look good. Check the solder joint at the socket.

Be sure the combo input jacks are are wired according to this: viewtopic.php?t=1523

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

We're getting close now. (I'm likely the slowest person to ever build a trinity amp) but my speaker finally arrived today so hopefully - time allowing - i can finish it up by the weekend. I've no doubt it's been worth the wait... I've one more rudimentary question (to add to my list of rudimentary questions already asked.) that is: What gauge wire should I be using to wire my speaker or does it matter much?

cheers guys.

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http://thepopmodule.com