Josh's 18W Tremolo TMB Builds

[JMPGuitars]

No components?

Lol! Nope. They're mostly there now, I'll post more photos later. There was a flaw on the original layout that somebody pointed out to me, which happened after I made the board.

[JMPGuitars]

Here's the board completed (with the old layout flaw also corrected):

JMPGuitars-Tremolo-TMB-Reverb-Build.jpg

I will do a highlighter test before powering up on my variac tomorrow. I'll also test the amp and work out any kinks before I install the FX loop or footswitch stuff.

There's enough visible in this image for anybody interested in my version of the reverb circuit to figure out/comment enough to get me to share it.

Thanks,
Josh

[Bieworm]

Did you fire it up yet? Hope all is ok..

[JMPGuitars]

Did you fire it up yet? Hope all is ok..

Not yet, busy with other work. But I did have time to highlighter test it last night, and it was all good. Though I moved the 4th filter cap to match the layout. I don't think it really mattered where I had it, but I wanted the build to match the layout doc for testing.

If I have time, I'm going to throw in some tubes and fire it up today.

Thanks,
Josh

[JMPGuitars]

Well, unfortunately I'm going to need to drop the voltage more than expected, so it will be longer before I can test this out properly. My B+ is around 383VDC, and I only have a 10V zener after it, so I'm going to have to swap that out with a couple bigger ones.

My voltages in general so far look okay, although some are high (as expected with the high B+). But, my V1 voltages were oscillating on almost all measurements (I'm fairly certain that's not normal even if this is my first trem ). I'm going to put a standard 12AX7 in there, and retake the voltages when the B+ is dropped before I do any tweaking/troubleshooting.

Thanks,
Josh

[Bieworm]

1600916636810861553259522614254.jpg

1600916550070398776885708583747.jpg

16009165850832305563145474326806.jpg

[Bieworm]

I have a 150R after the rectifier diodes. Do you have a resistor there? I only see the diode rectifier straight to the switch...

[JMPGuitars]

I have a 150R after the rectifier diodes. Do you have a resistor there? I only see the diode rectifier straight to the switch...

That 150R you're using is a sag resistor. I'm probably not using one in this, but I'll determine that after playing it.

[JMPGuitars]

Here's a question for you Trem nerds (this is my first tube tremolo build). Do you have to disable the trem to get your V1 voltages? Switching it off is the only way I got stable voltages from the tremolo channel (I jumped pin 7 to ground).

Thanks,
Josh

[Bieworm]

Here's a question for you Trem nerds (this is my first tube tremolo build). Do you have to disable the trem to get your V1 voltages? Switching it off is the only way I got stable voltages from the tremolo channel (I jumped pin 7 to ground).

Thanks,
Josh

What exactly is the problem? Mine works flawless... you mentioned oscillations earlier.

[JMPGuitars]

What exactly is the problem? Mine works flawless... you mentioned oscillations earlier.

I'm not sure yet, I haven't actually connected a speaker yet (I have it connected to a dummy load). The signal was generally clean on my scope with the trem knobs turned down, so I'll be testing V1 section out later.

When you test your trem voltages, do any or all of them fluctuate while the tremolo is active? Or did you test with the trem disabled (via the footswitch, or by manually grounding it out)?

[Bieworm]

What exactly is the problem? Mine works flawless... you mentioned oscillations earlier.

I'm not sure yet, I haven't actually connected a speaker yet (I have it connected to a dummy load). The signal was generally clean on my scope with the trem knobs turned down, so I'll be testing V1 section out later.

When you test your trem voltages, do any or all of them fluctuate while the tremolo is active? Or did you test with the trem disabled (via the footswitch, or by manually grounding it out)?

I only tested with the trem disengaged by footswitch. I don't have the equipment to measure the fluctuating trem while enabled. It just works great.. better than the modern classic Fwiw..

[JMPGuitars]

I only tested with the trem disengaged by footswitch. I don't have the equipment to measure the fluctuating trem while enabled. It just works great.. better than the modern classic Fwiw..

Okay, cool. That's what I was asking. So that means I should be good, and only need to focus on my voltages.

Scoping was clean, and the tremolo was audible in the speaker motor, so it sounds like everything probably works.

[JMPGuitars]

Mine works flawless...

IIRC, didn't you use a 4.7K resistor between B and C because you didn't have an 8.2K?

Well, that's going to be permanent. 4.7K gives better voltages down the line, but I will likely have a couple more small changes depending on how it sounds once I connect a speaker.

EDIT: I just saw your note on your voltage charts. 4.7K is definitely a winner. I think I also suggested 82K for the V2 plates? Is that what you stuck with? That's where I'm about to head to next.

Thanks,
Josh

[Bieworm]

Mine works flawless...

IIRC, didn't you use a 4.7K resistor between B and C because you didn't have an 8.2K?

Well, that's going to be permanent. 4.7K gives better voltages down the line, but I will likely have a couple more small changes depending on how it sounds once I connect a speaker.

EDIT: I just saw your note on your voltage charts. 4.7K is definitely a winner. I think I also suggested 82K for the V2 plates? Is that what you stuck with? That's where I'm about to head to next.

Thanks,
Josh

Yes the 4k7 was required to get the voltage line corrected. It is still there
On the v2 plates the 100k is parallelled with a 470k, so yes.. that's about 82.
You do remember I also have that gain/edge pot ? And some tweaks on the cathodes of V2?

[JMPGuitars]

Yes the 4k7 was required to get the voltage line corrected. It is still there
On the v2 plates the 100k is parallelled with a 470k, so yes.. that's about 82.
You do remember I also have that gain/edge pot ? And some tweaks on the cathodes of V2?

Yeah, that's what I thought. I vaguely remembered pretty well.

I'm actually thinking I'll drop the 4.7k slightly lower to see if that reduces the need for further tweaks down the line. Maybe 3.3K. I'll see what I have.

What are your V2 cathode resistor values? I put 2.2K and 680Ω in the docs.

I dunno if you've looked at the docs recently, but I already implemented a gain pot.

Thanks,
Josh

[Bieworm]

Yes the 4k7 was required to get the voltage line corrected. It is still there
On the v2 plates the 100k is parallelled with a 470k, so yes.. that's about 82.
You do remember I also have that gain/edge pot ? And some tweaks on the cathodes of V2?

Yeah, that's what I thought. I vaguely remembered pretty well.

I'm actually thinking I'll drop the 4.7k slightly lower to see if that reduces the need for further tweaks down the line. Maybe 3.3K. I'll see what I have.

What are your V2 cathode resistor values? I put 2.2K and 680Ω in the docs.

I dunno if you've looked at the docs recently, but I already implemented a gain pot.

Thanks,
Josh

I have a mini switch that toggles 2k2 or 1k5 across the .68uf CBC.

I have thought about lowering the 4k7 too at some time... but didn't because my PI voltages were kinda spot-on.
Watch out for the voltages on V1 being high enough or the trem won't start immediately when switched. That 4k7 cured my trem instantaneously. Also, I had a Tung-sol 12ax7 as V1.. that didn't oscillate immediately. The EHX did it just fine. The TS is great in V2

[JMPGuitars]

I have a mini switch that toggles 2k2 or 1k5 across the .68uf CBC.

I have thought about lowering the 4k7 too at some time... but didn't because my PI voltages were kinda spot-on.
Watch out for the voltages on V1 being high enough or the trem won't start immediately when switched. That 4k7 cured my trem instantaneously. Also, I had a Tung-sol 12ax7 as V1.. that didn't oscillate immediately. The EHX did it just fine. The TS is great in V2

I went with 2.2K for the B to C resistor. I used this variable resistance box to find the sweet spot:

variable-resistance-box.jpg

Now my voltages are looking really good:

JMPGuitars 18 Watt Tremolo TMB Reverb Voltage Test Chart - 001.jpg

The only thing off far enough that I might change it is pin 6 on the reverb tube, but I want to listen to it first before I consider any changes.

This is what the build looks like right now:

JMPGuitars-Tremolo-TMB-Reverb-Build3.jpg

Thanks,
Josh

[Bieworm]

I have a mini switch that toggles 2k2 or 1k5 across the .68uf CBC.

I have thought about lowering the 4k7 too at some time... but didn't because my PI voltages were kinda spot-on.
Watch out for the voltages on V1 being high enough or the trem won't start immediately when switched. That 4k7 cured my trem instantaneously. Also, I had a Tung-sol 12ax7 as V1.. that didn't oscillate immediately. The EHX did it just fine. The TS is great in V2

I went with 2.2K for the B to C resistor. I used this variable resistance box to find the sweet spot:
variable-resistance-box.jpg


Now my voltages are looking really good:
JMPGuitars 18 Watt Tremolo TMB Reverb Voltage Test Chart - 001.jpg


The only thing off far enough that I might change it is pin 6 on the reverb tube, but I want to listen to it first before I consider any changes.

This is what the build looks like right now:
JMPGuitars-Tremolo-TMB-Reverb-Build3.jpg


Thanks,
Josh

You're the master Josh!!!
Your layout is the work of a meticulous librarian!!!

[JMPGuitars]

You're the master Josh!!!
Your layout is the work of a meticulous librarian!!!

lol, thanks.

I'm not done yet, but I posted a quick demo on my instalame: https://www.instagram.com/p/CF44OVBHaho/

Thanks,
Josh