TMB tremolo part deux

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Re: TMB tremolo part deux

Post by JMPGuitars »

Bieworm wrote:
Sat 05/09/20 4:19 am
https://www.dropbox.com/s/vwcaxvfws1fsu ... p.m4a?dl=0
This is one badass amp!!!
Agreed! That amp sounds awesome. Nice work. congrats
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Re: TMB tremolo part deux

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Josh, I was testing stuff with a 5W 24V zener between the rectifier and the first filter cap.
B+ dropped as expected. But the voltages on the PI did too..as expected...
What is your opinion on that?
Took it a little further by parallelling another 8.2k from B+ point B to C, ending up with 4.1k. That helped some, but the powertubes went lower in plate and grid voltages.
Just testing here...
Is there any way I can get the PI back up to spec without the 4.1k tweak?
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Re: TMB tremolo part deux

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I like the red voltages. Go back to that, and see how it sounds.
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Re: TMB tremolo part deux

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Josh, I was wondering... the cathode caps and resistors of V2.. are they responsible for the huge boost in overdrive? I have yet to find a TMB that drives so hard as this one.. that is the only part that I can't find in other TMB designs.. on the trinity SIII those caps aren't there.. only a 2.7k and a 56k to ground. Where did you get your inspiration for that? Just trying to understand it...
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Re: TMB tremolo part deux

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Bieworm wrote:
Sun 05/17/20 4:43 am
Josh, I was wondering... the cathode caps and resistors of V2.. are they responsible for the huge boost in overdrive? I have yet to find a TMB that drives so hard as this one.. that is the only part that I can't find in other TMB designs.. on the trinity SIII those caps aren't there.. only a 2.7k and a 56k to ground. Where did you get your inspiration for that? Just trying to understand it...
Ha, you need to look at the bigger picture. That V2 isn't in the circuits you're referring to. That tube is increasing the gain, and driving the tone stack.

The amps you're comparing to are 2 channel amps with the same amount of preamp tubes, but the first 2 preamp tubes are only used 1 per channel in them.

I was also going to experiment with a 12AT7/ECC81 in the V2 position if I think the gain is too much when I build mine. You can try that if you want.

Thanks,
Josh
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Re: TMB tremolo part deux

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JMPGuitars wrote:
Sun 05/17/20 6:37 am
Bieworm wrote:
Sun 05/17/20 4:43 am
Josh, I was wondering... the cathode caps and resistors of V2.. are they responsible for the huge boost in overdrive? I have yet to find a TMB that drives so hard as this one.. that is the only part that I can't find in other TMB designs.. on the trinity SIII those caps aren't there.. only a 2.7k and a 56k to ground. Where did you get your inspiration for that? Just trying to understand it...
Ha, you need to look at the bigger picture. That V2 isn't in the circuits you're referring to. That tube is increasing the gain, and driving the tone stack.

The amps you're comparing to are 2 channel amps with the same amount of preamp tubes, but the first 2 preamp tubes are only used 1 per channel in them.

I was also going to experiment with a 12AT7/ECC81 in the V2 position if I think the gain is too much when I build mine. You can try that if you want.

Thanks,
Josh
FWIW I already tried an old US JAN 5751 and it's still a lot of gain. But hey.. I like the amp more and more. I even get some Slayer tones out of it... no wonder , Slayer plays JCM800's

The OD is hands down one of the best I ever had. I just can't imagine there is NO clean in this amp that is useable.. is there by chance a hypothetical way to skip 1 preamp stage, switchable? That would mean I have no need for a boost pedal anymore
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Re: TMB tremolo part deux

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Bieworm wrote:
Sun 05/17/20 7:13 am
FWIW I already tried an old US JAN 5751 and it's still a lot of gain. But hey.. I like the amp more and more. I even get some Slayer tones out of it... no wonder , Slayer plays JCM800's

The OD is hands down one of the best I ever had. I just can't imagine there is NO clean in this amp that is useable.. is there by chance a hypothetical way to skip 1 preamp stage, switchable? That would mean I have no need for a boost pedal anymore
Have you tried.....lowering the volume on your guitar?
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Re: TMB tremolo part deux

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JMPGuitars wrote:
Sun 05/17/20 8:21 am
Bieworm wrote:
Sun 05/17/20 7:13 am
FWIW I already tried an old US JAN 5751 and it's still a lot of gain. But hey.. I like the amp more and more. I even get some Slayer tones out of it... no wonder , Slayer plays JCM800's

The OD is hands down one of the best I ever had. I just can't imagine there is NO clean in this amp that is useable.. is there by chance a hypothetical way to skip 1 preamp stage, switchable? That would mean I have no need for a boost pedal anymore
Have you tried.....lowering the volume on your guitar?
Certainly, but it kills treble. And treble bleed mods are not the ideal solution neither
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Re: TMB tremolo part deux

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Bieworm wrote:
Sun 05/17/20 9:52 am
Certainly, but it kills treble. And treble bleed mods are not the ideal solution neither
I use a treble bleed volume pot in all the guitars I build or upgrade these days. They work great. I use a 150K resistor and a .001uF cap in parallel across the volume pot lugs 1 and 2 (lug 3 is ground). It's super simple for you to add this to your guitars.

Having a more functional volume pot will give you more interactive control with all your touch-sensitive amps. It's absolutely worth it. It doesn't matter if you have to do it to 10 guitars, you enjoy tinkering. ;)

I'll have more opinions on the amp circuit in probably a month or so after I build mine. I could build it now, but I'd rather wait to build it in a better chassis when my chassis guy is ready to make more.
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Re: TMB tremolo part deux

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JMPGuitars wrote:
Sun 05/17/20 9:58 am
Bieworm wrote:
Sun 05/17/20 9:52 am
Certainly, but it kills treble. And treble bleed mods are not the ideal solution neither
I use a treble bleed volume pot in all the guitars I build or upgrade these days. They work great. I use a 150K resistor and a .001uF cap in parallel across the volume pot lugs 1 and 2 (lug 3 is ground). It's super simple for you to add this to your guitars.

Having a more functional volume pot will give you more interactive control with all your touch-sensitive amps. It's absolutely worth it. It doesn't matter if you have to do it to 10 guitars, you enjoy tinkering. ;)

I'll have more opinions on the amp circuit in probably a month or so after I build mine. I could build it now, but I'd rather wait to build it in a better chassis when my chassis guy is ready to make more.
It will sell good for sure! There are a lot of people waiting for that amp. Some might not even know it yet.
Ok I will try the TB mod. Same values with 1M pots?
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Re: TMB tremolo part deux

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Josh.. I was experimenting with the amp with 12at7 and 5751 in V2. The OD on low volume disappears. I'm still deciding if I like it better.. it looses its Mojo a bit. The at7 is some Chinese tube that I have for a very long time..unused. and the 5751 is an old JAN. It feels as if the ideal tube is somewhere between those two and the JJ12ax7S that 's been in there all the time. Do you have a suggestion what types and brands I should definitly try?
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Re: TMB tremolo part deux

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Re: TMB tremolo part deux

Post by JMPGuitars »

That's with the 2.2K resistor on V2 cathode 1? Post the demo publicly, it sounds awesome. I think I'll update the schematic with that value, and leave a note if people want more gain to lower that a little.
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Re: TMB tremolo part deux

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JMPGuitars wrote:
Sat 05/30/20 7:58 am
That's with the 2.2K resistor on V2 cathode 1? Post the demo publicly, it sounds awesome. I think I'll update the schematic with that value, and leave a note if people want more gain to lower that a little.
Yes that is a 2k2 cathode resistor on the first triode of V2. It magically added even more touch sensitivity that while clean sounds are obtained with lighter touching the strings, there is some decent gain on tap when strummed harder. You know I have the part of voltage devider that goes to ground with a 500k audio pot and 10k resistor in series. The pot was set at vol 4 for the recording. Didn't measure the resistance...
https://www.dropbox.com/s/k4rlwdg0c64a9 ... 2.m4a?dl=0
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Re: TMB tremolo part deux

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Hey I have an idea...
What if I wire a parallel resistor on the 2.2k CR V2 cath 1 that can be brought in by footswitch... that would give me an OD pedal.. if I wire a 5k pot + switch in a pedal to do so then I would be able to dial in the amount of OD...
Is this a good idea, that being the cathode and all...?

Maybe try a 3k resistor first, that would bring me in the ballpark of 1.5k , just like it initially was with the OD on the preamp. I have a dual footswitch that on 1 side controlls the tremolo, the other side might be used for engaging the OD via the 3k resistor. It means it would share ground with the tremolo switch, but we'll see if that's a problem when doing the alligator clip tryout. The input jack for the footswitch is a stereo jack already, so... quick testing is easy enough
Last edited by Bieworm on Tue 06/02/20 5:06 am, edited 2 times in total.
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