First sounds of the 18W TMB tremolo build

[JMPGuitars]

I am going to the something..
Remove the shielded wires from V1 pin 1 and 7 and hook some regular wires on it. Then I can rule out of the shielding isn't touching anything it shouldn't. I don't think it does, but hey..
BTW I connected both shields to the ground at the tube area, not at the board area... is that ok?

That's fine. Shielded wire is always connected only on one end, and that's what's important. It also might not be completely necessary there, I copied the suggestion from a different layout. If it gets noisier without it, obviously it was helpful. But either way, you'll need to be careful of the positions of the wires, as they can cause squeal if in a bad position.

Verify the components and values and connections, and make sure nothing is connecting that shouldn't be.

You can also try different tubes there. In the past people have mentioned getting tremolo working specifically based on tube swapping.

[Bieworm]

I am going to the something..
Remove the shielded wires from V1 pin 1 and 7 and hook some regular wires on it. Then I can rule out of the shielding isn't touching anything it shouldn't. I don't think it does, but hey..
BTW I connected both shields to the ground at the tube area, not at the board area... is that ok?

That's fine. Shielded wire is always connected only on one end, and that's what's important. It also might not be completely necessary there, I copied the suggestion from a different layout. If it gets noisier without it, obviously it was helpful. But either way, you'll need to be careful of the positions of the wires, as they can cause squeal if in a bad position.

Verify the components and values and connections, and make sure nothing is connecting that shouldn't be.

You can also try different tubes there. In the past people have mentioned getting tremolo working specifically based on tube swapping.

Josh, the tremolo design was incorrect. I copied the design from the ceriatone classic 18 watt. I will draw it for you in a moment. It's a few tweaks and moving connections. I am gonna measure the voltages first. But I rewired it and BAM!!! Tremolo!!!

15857622781673709113844528969912.jpg

Look at that!!! Voltages are nice IMHO

Listen:
https://www.dropbox.com/s/yp2gp6khutfph ... g.m4a?dl=0

[JMPGuitars]

Voltages are MUCH better! Post another sample of the tremolo with the gain up (no pedals).

I'll review the changes.

Thanks,
Josh

[Bieworm]

Voltages are MUCH better! Post another sample of the tremolo with the gain up (no pedals).

I'll review the changes.

Thanks,
Josh

Voila!
https://www.dropbox.com/s/fp1oirkkkxaw0 ... e.m4a?dl=0

[Bieworm]

Oh damn... I was playing with the lightbulb limiter in the powerchain. Voltages are a little higher...

2nd readings:

1585767372463190337033392033956.jpg

[JMPGuitars]

Your voltages are definitely better than what they were. Though I'm not surprised that you should still drop your B+.

Thanks for finding those errors! I've updated the docs, and they should be all good now. Please verify.

It's funny, there was only 1 real error in the schematic, but it was an easy one to make (the missing jumper). That stupid backwards pot is because the schematic I referenced didn't label the pin numbers in their schematic. They're totally ambiguous otherwise.

Thanks,
Josh

PS. Post more demos! I want to hear the trem with different levels of gain.

[JMPGuitars]

Side note: you should always reference both the schematic and layout. If you highlighter tested against both, you would have found my mistakes faster.

[Bieworm]

Side note: you should always reference both the schematic and layout. If you highlighter tested against both, you would have found my mistakes faster.

I find schematics very confusing. Layouts are as-built plans. Much easier for a novice like me

Will make some more recordings tomorrow. It's late over here...

But I'm glad it's sorted out now with the trem. Stuff like that eats my nights rest...

The good part of these errors help me to understand that system. I previously did a trem conversion on my vibro king. From **** opto to bias vary...I learned a lot during that nightmare and got a little into amps that way

[JMPGuitars]

I find schematics very confusing. Layouts are as-built plans. Much easier for a novice like me

Will make some more recordings tomorrow. It's late over here...

The good part of these errors help me to understand that system.

Yeah, mistakes are usually the best teachers. Unfortunately...and I've learned a LOT.

Print both the schematic and layout. Highlight each part / connection as you match them up together. Start at the input and work from there. It will help you understand the docs and circuit better.

If you get comfortable reading the schematic, it's actually a lot easier to understand what you're looking at than the layouts. Layouts are just as you said, a guide for where to put stuff.

Thanks,
Josh

[crgfrench]

Sorry to jump in after the fact, I just wanted to say that tremolo sounds great!

[Bieworm]

Sorry to jump in after the fact, I just wanted to say that tremolo sounds great!

That is correct!!! There are only some little tweaks left to get this amp in pole position and you can start building your own clone

[Bieworm]

Your voltages are definitely better than what they were. Though I'm not surprised that you should still drop your B+.

--> you think it's necessary? I've read that these higher B+'es are no problem.. what is the downside of this? Why is it so important? I'm a novice

Thanks for finding those errors! I've updated the docs, and they should be all good now. Please verify.

--> Verified and qualified!!!

It's funny, there was only 1 real error in the schematic, but it was an easy one to make (the missing jumper). That stupid backwards pot is because the schematic I referenced didn't label the pin numbers in their schematic. They're totally ambiguous otherwise.

--> in f*nders they are often in the form of reversed audio pots (for the powertube bias vary that is...)

Thanks,
Josh

PS. Post more demos! I want to hear the trem with different levels of gain.

[JMPGuitars]

--> you think it's necessary? I've read that these higher B+'es are no problem.. what is the downside of this? Why is it so important? I'm a novice

They're not a problem in that range. Especially not if you're running a solid state rectifier. However, the ideal B+ of 345VDC (+/- 5V) is based on the characteristics of the 18 watt amp. Too high a B+ gives more headroom, and a less gain. Too low a B+ gives more gain (but likely muddy), and less headroom.

If 361VDC is your B+, it's really a question of whether or not you like the sound. It sounds great in your demo to me. If you want a hair more dirt, then drop it. If you like it, keep it as it is.

I have an amp I recently finished that has a switchable rectifier between solid state and tube. The Tube rec's B+ is 345. The SS rec B+ is 365. Both sound great, but there is a difference. I decided in that case not to match them, because the switch is useless if they both sound exactly the same. I'll probably post a demo comparing them at some point.

Thanks,
Josh

[Bieworm]

--> you think it's necessary? I've read that these higher B+'es are no problem.. what is the downside of this? Why is it so important? I'm a novice

They're not a problem in that range. Especially not if you're running a solid state rectifier. However, the ideal B+ of 345VDC (+/- 5V) is based on the characteristics of the 18 watt amp. Too high a B+ gives more headroom, and a less gain. Too low a B+ gives more gain (but likely muddy), and less headroom.

If 361VDC is your B+, it's really a question of whether or not you like the sound. It sounds great in your demo to me. If you want a hair more dirt, then drop it. If you like it, keep it as it is.

--) that's the "problem" ... Even though I have max headroom with that B+ value, I would like the grind to start a little later. Now the grind starts immediatly. Is there a way that I would be able to
- controll the amount of early preamp drive with a pot?
Or
- tweak the gain in an early stage on component value area.
I don't know if the grind is there before the PI.. otherwise MV post PI would be a solution. But that's adding various components with the risk of adding noisy stuff. A resistor or cap tweak would be less risky IMHO

Anyway, it's dat from doubt this amp has the potential to be a very versatile yet simple amp with all the necessaries such as TMB and Trem. A reverb is going to be the next journey. I have a sockethole spare since it's SS rectified + there are 3 unused inputs where there's the option to put controllpots . So a reverbtranny ,a pan and some wiring...

I have an amp I recently finished that has a switchable rectifier between solid state and tube. The Tube rec's B+ is 345. The SS rec B+ is 365. Both sound great, but there is a difference. I decided in that case not to match them, because the switch is useless if they both sound exactly the same. I'll probably post a demo comparing them at some point.

Thanks,
Josh

[JMPGuitars]

--) that's the "problem" ... Even though I have max headroom with that B+ value, I would like the grind to start a little later. Now the grind starts immediatly. Is there a way that I would be able to

You can try replacing the Volume pot with an A1M pot instead of the A500K. I dunno if that would make much difference, but it might give you some more play before all the dirt kicks in.

You can also reduce the preamp gain. You could try dropping the V2 plate resistor from 100K to 82K and see where that puts your voltage and sound.

Two things:
1. This is not a F*nder, and it's not supposed to be that clean. Your demos started off sounding very clean to me, with excellent tone. I wouldn't change it personally.
2. This is a touch-sensitive amp. You can play lighter, or roll off the guitar volume a little bit to clean up the amp. And you can turn up the guitar volume or play harder to get more dirt. I'd experiment with this before you do anything else. And post a demo of doing this. - no pedals, no touching the amp, just adjust the guitar volume knob and see what happens.

Thanks,
Josh

[Bieworm]

--) that's the "problem" ... Even though I have max headroom with that B+ value, I would like the grind to start a little later. Now the grind starts immediatly. Is there a way that I would be able to

You can try replacing the Volume pot with an A1M pot instead of the A500K. I dunno if that would make much difference, but it might give you some more play before all the dirt kicks in.

You can also reduce the preamp gain. You could try dropping the V2 plate resistor from 100K to 82K and see where that puts your voltage and sound.

Two things:
1. This is not a F*nder, and it's not supposed to be that clean. Your demos started off sounding very clean to me, with excellent tone. I wouldn't change it personally.
2. This is a touch-sensitive amp. You can play lighter, or roll off the guitar volume a little bit to clean up the amp. And you can turn up the guitar volume or play harder to get more dirt. I'd experiment with this before you do anything else. And post a demo of doing this. - no pedals, no touching the amp, just adjust the guitar volume knob and see what happens.

Thanks,
Josh

Well to try the plate resistor... it's very tight to try that without burning caps.
Is there any harm in placing a parallel resitor of 470K ..the total resitance is normally around 82K then?
In fact..I have the cap to ground on the spot of the initial schematic, right next to the phase inverter area.

parallel resistor plate V2.png

[JMPGuitars]

That's fine. Try it out and see how it goes.

[Bieworm]

That's fine. Try it out and see how it goes.

It worked with the resistor. On 82.4K the sound is still driven, but with light pick attack it cleans up nicely!! Exactly what I wanted! Seriously!!! With the 100k it was untameable ..even with light picking or rolling back the volume on the guitar.

Here is the voltage chart:

15858490971142987693071219809203.jpg

I have a recording:
https://www.dropbox.com/s/k8skj0rgslu54 ... r.m4a?dl=0

Unfortunately my wife started complaining about the noise. So the trem samples on various volume settings will be for later.
Man this amp kicks.

Today I ordered my stuff for the making of the combo shell.. hope I can find wood somewhere. Shops are closed with the virus measures...But the tolex etc. is on its way. Even found some NOS Russian mil spec EL84's (6P14P) for 12$ each

[JMPGuitars]

That sounds great! And your V2 voltage looks good. I might switch that or add a note in the docs. It's hard to tell since your PT situation is odd.

[Bieworm]

That sounds great! And your V2 voltage looks good. I might switch that or add a note in the docs. It's hard to tell since your PT situation is odd.

Yes.. better wait until someone more conservative decides to build it. Wait... conservative? This amp? Naaaaa

I really believe this amp would sell good man!
Everyone is always trying to get drive on low volume..adding VVR's or attenuators... this one don't need that. It's easier in dialing in than the classic 18W, that's for sure

Build one.. you need to own one, seriously!