18W Tremolo TMB Xtra Gain build

[Bieworm]

Hey dudes..
Building a new Tremolo TMB, but with the option of cascading the parallel triodes of stage 2. I drew it using ZP's cascade switching from the Downloads.. the 20k trim pot + 200k series resistor will be an A250k pot. Relays switching first Tremolo and cascade

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[JMPGuitars]

That should be interesting.

[Bieworm]

It also sports the transformer with 2-9-18w switching. So this could be the ultimate Tremolo TMB

[robthemac]

It also sports the transformer with 2-9-18w switching. So this could be the ultimate Tremolo TMB

Which transformer is this?

[Bieworm]

It also sports the transformer with 2-9-18w switching. So this could be the ultimate Tremolo TMB

Which transformer is this?

It's the PWAM01 from Ampmaker UK

[robthemac]

It also sports the transformer with 2-9-18w switching. So this could be the ultimate Tremolo TMB

Which transformer is this?

It's the PWAM01 from Ampmaker UK

Yikes. Pricey. Useful though.

[Bieworm]

Which transformer is this?

It's the PWAM01 from Ampmaker UK

Yikes. Pricey. Useful though.

I am Europe based. It doesn't cost me 100€ to get 2 transformers delivered at my house.. that's very cheap

[robthemac]

€376 for a transformer? I'm in the backblocks of the ass-end of the world and that still seems expensive.

http://test2019.primarywindings.com/pro ... ma-6-3v3a/

[geoff 1965]

Crossed wires somewhere here Rob!
I bought one from ampmaker for about £50 but he just passes you onto the transformer makers direct now. I’ve tried going onto primary windings site but keep getting blocked with spam warning.
Try going through www.ampmaker.com or ask if he can help you his name is Barry.

[robthemac]

Crossed wires somewhere here Rob!
I bought one from ampmaker for about £50 but he just passes you onto the transformer makers direct now. I’ve tried going onto primary windings site but keep getting blocked with spam warning.
Try going through www.ampmaker.com or ask if he can help you his name is Barry.

Very helpful, cheers!

[Bieworm]

Ok!! Now we'll see what the fuss is all about with the Celestion G12H30 55Hz heritage series. I bought a used one yesterday..
I also expect a delivery on Feb 26th of 3x early 70's G12H30 75Hz ( 2 creambacks and 1 greyback).. made a very good deal with those. Somebody was cleaning our his workshop

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[Bieworm]

Current situation of the build
B+ switching works! Relays switching works too!

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[Bieworm]

Well, I put the 55Hz G12H30 in my 6G3 build. I must admit it's a LOT better than the 70th anniversary series!! It's warm and fat sounding, very nice highs and VERY efficient. I'm taking that amp to practice this evening and will see if it is all that in a band situation. I found this amp pretty good at home, but kinda lifeless in live setups... even (especially) with an Alnico Cream, which should be the cream of the crops of current Celestion production. I'm curious if it will deliver tonight...

[Bieworm]

Ok!!! Here are the first sounds from this build!!!
I have a nasty buzz I have to find and fix. It sounds like you take the guitar off the instrument cable, wit the cable plugged into the amp. Grounding issue somewhere I guess.

Edit: problem solved. Grounded the unused toggle switch connections of the relays board. Didn't realize that was a thang. ..

https://www.dropbox.com/s/kdz7j9w6v9ci1 ... 0.m4a?dl=0

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[Bieworm]

Almost ready!!! One backpanel to go. Oh, waiting for my new batch of logos...

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[JMPGuitars]

I'm probably going to make a Tremolo TMB Xtra...and because I'm cuckoo, I'm going to fit it on a much smaller PCB.

[Bieworm]

I'm probably going to make a Tremolo TMB Xtra...and because I'm cuckoo, I'm going to fit it on a much smaller PCB.

This one is pretty Xtra!! Going to have to swap the 1M Xtra gain pot to 500k or even 250.. it oscillates after 9.00

[JMPGuitars]

I'm probably going to make a Tremolo TMB Xtra...and because I'm cuckoo, I'm going to fit it on a much smaller PCB.

This one is pretty Xtra!! Going to have to swap the 1M Xtra gain pot to 500k or even 250.. it oscillates after 9.00

That doesn't surprise me. I think doing the Xtra mod OR the 1M pot would probably work, but both is a little cuckoo. The point of it being 250K in the first place was to avoid driving into blocking distortion.

[Bieworm]

I'm probably going to make a Tremolo TMB Xtra...and because I'm cuckoo, I'm going to fit it on a much smaller PCB.

This one is pretty Xtra!! Going to have to swap the 1M Xtra gain pot to 500k or even 250.. it oscillates after 9.00

That doesn't surprise me. I think doing the Xtra mod OR the 1M pot would probably work, but both is a little cuckoo. The point of it being 250K in the first place was to avoid driving into blocking distortion.

I can understand why. But although the 250k in your Tremolo TMB has a better sweep I like the 500k in the prototype better. It adds more than just some gain. The tone is somewhat sweeter. In this build I copied that.
It's really nice! The 2-9-18W switch and the gain boost switch are really making it very versatile

[Bieworm]

Ok did some tweaks since the Xtra gain knob is giving oscillation/blocking distortion when dialed up too high.
on the schematic I initially had (see numbers)

1. nothing
2. pot A1M
3. 33k

I tried a 250k pot, but it still gave me much blocking distortion when dimed, so I added a 470k resistor in series between the .022uf cap an the pot.

1. 470k resistor
2. pot A250k
3. 33k

I still have some of the ugliness left.. here's things I could try:

A. put in a 100k of 50k pot?
B. put a 270k resistor in parallel with the pot?
C. put an even larger resistor in series instead of the 470k?
D. put an extra voltage divider before the 470k / A250k divider? This seems silly
E. is upping the 33k grid stopper going to do anything but darken things?

schema 18W cascade reverb tremolo execution rev01.png