36 Watt EL34 Superlite TMB

Double-Bubble! Place for discussing the 36W version...

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Re: 36 Watt EL34 Superlite TMB

Post by colossal »

crgfrench wrote:
Tue 09/03/19 8:25 am
...so, since Josh's tail resistor is 15k, this amp might benefit from the 82k load resistor. Perhaps?
Possibly. Josh's posted voltages indicate a good DC balance, but the AC balance is another story. EL34s require a little more of a push than EL84s too.
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

crgfrench wrote:
Tue 09/03/19 9:16 am
Sonically, probably would sound about the same either way.

To make a long story short, "nevermind".
Exactly! The intrigue of any theoretical discussion has to outweigh my laziness. Since any potential reward is likely unnoticeable, I'll let somebody else experiment if they want to. ;)
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Re: 36 Watt EL34 Superlite TMB

Post by crgfrench »

I realize this may seem OCD but you could optimize it with a Dale 68.1k and a Dale 22.1k in series, for a nearly perfect balance, just sayin'...
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Re: 36 Watt EL34 Superlite TMB

Post by colossal »

Dumble used a trimmer pot in the middle of the pair of PI plate loads and attached B+ to the wiper. The Inverting side might get 91k and balance trimmer at 10k. The AC balance is set by dialing the trimmer and using a scope with a target of about 6V difference being desirable. Some imbalance is desirable for tonal consideration. The 18W PI is more center biased than a Plexi PI too and that will change the sound as well.
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

I have a difference of 2 VDC at the plates, all else matching. I could swap the tube and probably get 10 or 15V difference at the plates, or an exact VDC match.

Theory is great, but tube variance is reality. If you want to tweak that to make your OCD happy, you'll want to do it like colossal said re: dumble, and rebias every time you change the tube. I could see some people being entertained by that...but I'd rather play if I ever get any free time. ;)
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Re: 36 Watt EL34 Superlite TMB

Post by crgfrench »

colossal wrote:
Tue 09/03/19 10:49 am
...The AC balance is set by dialing the trimmer and using a scope with a target of about 6V difference being desirable...
I would take a very similar approach:
The AC balance is set by dialing the trimmer and using a stratocaster with a target of the juiciest tone and sweetest sustain being desirable...
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Re: 36 Watt EL34 Superlite TMB

Post by colossal »

crgfrench wrote:
Sat 08/31/19 11:41 am
Josh how did you decide on the 1kuF value of the output cathode bypass cap?
I am bumping this as I'm interested as well. Josh, did you try A/Bing the stock cap and a 1kuF or just go with the big one to get more of the fixed bias stiffness right from the start?
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

colossal wrote:
Tue 09/03/19 1:21 pm
crgfrench wrote:
Sat 08/31/19 11:41 am
Josh how did you decide on the 1kuF value of the output cathode bypass cap?
I am bumping this as I'm interested as well. Josh, did you try A/Bing the stock cap and a 1kuF or just go with the big one to get more of the fixed bias stiffness right from the start?
I've built many superlites. I've built them with 100, 250, 1000, and 2200uF caps. They all sound good, but I think I remember liking the 1000 more... Who knows, it's been a long time since I thought much about that cap. I actually drew that circuit a couple years ago, and I'm not getting any younger. ;)

But also keep in mind that my build has a 5AR4 tube rectifier, and I have a dropping resistor on the B+, so it's not going to sound too stiff anyway. If anything I miiiiight have been thinking about how it affects the bottom end.

Thanks,
Josh
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Re: 36 Watt EL34 Superlite TMB

Post by colossal »

JMPGuitars wrote:
Tue 09/03/19 1:51 pm
I've built many superlites. I've built them with 100, 250, 1000, and 2200uF caps. They all sound good, but I think I remember liking the 1000 more... Who knows, it's been a long time since I thought much about that cap.
I know I tried a 1000uF cap once, but it was so long ago I can't quite remember its effects. I want to say I remember it affecting the feel of the amp and I preferred the stock 47uF cap better. Oh, and I meant stock 18W, not a Superlite...
JMPGuitars wrote:
Tue 09/03/19 1:51 pm
I actually drew that circuit a couple years ago, and I'm not getting any younger. ;)
Man, none of us are {=[
JMPGuitars wrote:
Tue 09/03/19 1:51 pm
But also keep in mind that my build has a 5AR4 tube rectifier, and I have a dropping resistor on the B+, so it's not going to sound too stiff anyway. If anything I miiiiight have been thinking about how it affects the bottom end.

Thanks,
Josh
For sure. The screen supply dropping resistor will dump some voltage on big transients, giving some great sag and compression. That's why we love these amps! Very easy under the fingers and they sustain forever.
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

I was playing earlier on a Lite 2b(ish) variant today, with a 250uF cap on the cathode. The amp sounded a little farty playing in the lower register, and especially with my looper pedal playing backing tracks. I rebiased the amp, swapped the 250uF for a 1000uF cathode cap, and it sings now.
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Re: 36 Watt EL34 Superlite TMB

Post by bvayling »

JMPGuitars wrote:
Sun 08/11/19 8:32 pm
Here's a mediocre demo of my 36 Watt EL34 Superlite TMB.

2:54 reverb turned on (with the reverb off, the reverb portion of the circuit essentially doesn't exist)

4:39 bridge pickup switched to single coil

Bright/Thick Switch:
5:04 = thick
5:26 = off
5:42
= bright

https://youtu.be/PeRZXThV54s

Thanks,
Josh
Hey Josh, nice sounding rig. I love how you’ve got it constantly on the edge.
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Re: 36 Watt EL34 Superlite TMB

Post by Bieworm »

bvayling wrote:
Thu 04/16/20 11:04 pm
JMPGuitars wrote:
Sun 08/11/19 8:32 pm
Here's a mediocre demo of my 36 Watt EL34 Superlite TMB.

2:54 reverb turned on (with the reverb off, the reverb portion of the circuit essentially doesn't exist)

4:39 bridge pickup switched to single coil

Bright/Thick Switch:
5:04 = thick
5:26 = off
5:42
= bright

https://youtu.be/PeRZXThV54s

Thanks,
Josh
Hey Josh, nice sounding rig. I love how you’ve got it constantly on the edge.
EL34s are nice and mighty tubes!!! It's on my list to go for an EL34 build in the future. Bluesbreaker style...
With winged "C"s... Bogner squeezes 80 watts out of 2 winged C Svetlanas on the Shiva.
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

Thanks, I'm a big fan of this amp. I think whoever builds the new docs version of it will enjoy it even more. Circuit and layout improvements since I made that demo.
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Re: 36 Watt EL34 Superlite TMB

Post by zaphod_phil »

JMPGuitars wrote:
Sun 08/11/19 8:32 pm
Here's a mediocre demo of my 36 Watt EL34 Superlite TMB.
https://youtu.be/PeRZXThV54s
All I can say is Wow, that amp has tone to die for!!! 8O I was just blown away by the sounds in that clip. Great range of clean to dirt tones. Lead notes were nice and thick too. I liked that the dreaded reverb :lol: was nice and subtle, and didn't overpower the whole sound of the guitar and amp. I have to say it nicely enhanced the clean lead notes in that section.

I wasn't so keen on the jazz chords section, but the amp still performed really well. My musical tastes cover the range from Bach to SOAD, but I really can't take jazz or opera :lol:

I hope you get to sell lots of these!
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Re: 36 Watt EL34 Superlite TMB

Post by JMPGuitars »

zaphod_phil wrote:
Sat 04/18/20 2:51 pm
All I can say is Wow, that amp has tone to die for!!! 8O I was just blown away by the sounds in that clip. Great range of clean to dirt tones. Lead notes were nice and thick too. I liked that the dreaded reverb :lol: was nice and subtle, and didn't overpower the whole sound of the guitar and amp. I have to say it nicely enhanced the clean lead notes in that section.

I wasn't so keen on the jazz chords section, but the amp still performed really well. My musical tastes cover the range from Bach to SOAD, but I really can't take jazz or opera :lol:

I hope you get to sell lots of these!
Thank you!

I'll make sure to make a heavy reverb jazz only demo, while very poorly singing opera. :lol: ...I know what you mean though, I can't deal with 99% of country music.
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