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Finished my Trinity Head build.
Instead of going into all the things I love about it, the one thing that stands out right now is that the bass is not tight at all if the bass control is over about 1/4 of the way up. I'm running it through a 2x12 closed back w/vintage 30's at the moment. My other amps have no problems with this cab. I've tried a GZ34 and a 5U4GB. The tranny's are the Matchless originals. This is with a Tele. It's more of a sagging muffled sound when hitting the low E string notes. Sounds pretty normal when the bass control is all the way down but any increase above 1/4 turn and it turns to mush. Any ideas?

One thing to note. The 1200pf coupling cap on the plates of V1 was missing from the kit so I threw a 2200pf cap on there. It was all I had. I don't think this would affect the bass but I'm not sure. Has anyone played with the cap values in the tone stack.....or needed to?

I can't remember the exact equation, but as i remeber it there is a inverse relationship between capacitance and frequency....I think....so you are going to get more bass passed on to the next stage with 2400pf then 1200pf...please correct me if I am wrong.

From the user perspective, I would be interested in knowing where you have the treble set. With treble and bass at high noon, my Trinity has a nice round bottom end. I may move the bass back to 9 o'clock when playing through a neck humbucker .... but I might also move both controls to 3 o'clock in that case too.

Now, admittedly, the design of this amp does allow you to get too much treble or too much bass but in there are a wide range of settings..

Oh...btw...what kind of guitar are you using? What are the rest of the map settings?

Lbet/Tybone

A larger coupling cap will pass more bass, so your substitution definitely would add to your problem.

My Lightning also gives a bit of flab, but only on Humbuckers with the bass control above 1/4 turn. I will be experimenting with values there to see if I can improve that, I'll post results when I get them.

P.

I was testing the amp with a Tele and a Les Paul Custom with Voodoo 59's. I moved the dials all over the map trying different gain and eq settings. Like I said, it sounds really good with the bass almost off.
I'm really liking a 12AY7 (6072) in the phase inverter and the 5U4GB in there.

When I get the cap and put it in, I'll know more about what's really going on.

I looked at the DC30 channel 1 schematic and it uses a 500pf with a 500K volume pot after V1.

OK. I ordered some .001uf Mallory 150's and replaced the .0022uf that I had temporarily in C1. Well it was quite an improvement. Much better. But, I took it a step further and put 2 in series to give me 500pf. Way better bass response. It actually gives the bass control much more usable range and took the low mid mud away.

Another thing I did was to add a 1M resistor across 1 and 3 of the Volume pot and wow, the Volume control has a much more open gain range and it's ALL good. Chimey clean to cranked AC30. Without the 1M resistor, the gain just got too squishy and smeared at the high gain settings.

These mods really made my Lightning what I was hoping for. No mud, plenty of chime and clarity, even at the highest gain settings.

I also went back and forth between the GZ34 and the 5U4GB many times but in the end I stuck with the GZ34. It just had a little better feel to me. The 5U4GB has a tad more clarity but sounds and feels just a bit harder.

I hope someone else will try these easy mods and post back their results.

KevinL, sounds like you solved the problem. One of my customers is also looking for a louder / clean sound option. Would you say that this generally gives you the same volume, but cleaner sound? I know that's what you were looking for. If so, I would want to try it out.

Good tweak! Congrats!

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Stephen
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