Questions about my next tube amp project, 18 watt design.

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TriodeLuvr
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Re: Questions about my next tube amp project, 18 watt design.

Post by TriodeLuvr »

JMPGuitars wrote:
Thu 04/22/21 7:34 pm
The EF86 18Watter is awesome, and it still has the Marshall sound, but also touches on the Vox sound.
I'm a BIG fan of the EF86, but I'm surprised by its following for musical instrument amps. It's one of the lowest distortion small-signal pentodes ever made. Perhaps it's tendency toward microphonics at mV signal levels is a contributor to the unique sound.

Jack
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Re: Questions about my next tube amp project, 18 watt design.

Post by JMPGuitars »

TriodeLuvr wrote:
Thu 04/22/21 9:43 pm
zaphod_phil wrote:
Thu 04/22/21 2:35 pm

Yes, the signal path becomes different when you insert a reverb stage
The reverb stage in mine isn't inserted, it's in parallel with signal path resistance already present. When the pots are at minimum, it's electrically non-existent.

Jack
That's essentially the idea with mine as well. With the reverb pot off, the PI cap is grounded as it would be in an 18W style single-channel amp. Since that's a known, the difference in sounds for Bieworm's amps, are obviously the different components/cabs/speakers being used.

TriodeLuvr wrote:
Thu 04/22/21 9:56 pm
JMPGuitars wrote:
Thu 04/22/21 7:34 pm
The EF86 18Watter is awesome, and it still has the Marshall sound, but also touches on the Vox sound.
I'm a BIG fan of the EF86, but I'm surprised by its following for musical instrument amps. It's one of the lowest distortion small-signal pentodes ever made. Perhaps it's tendency toward microphonics at mV signal levels is a contributor to the unique sound.

Jack
The EF86 can produce very nice distortion in the preamp, but the tendency is to find the lowest microphonic samples of the tube. If you take a look at the sample of my "EF86 Xtra" circuit, it's actually fairly high gain (with a parallel 12AX7 following it). That said, I may want to try building a HiFi version with them eventually, I know they're quite popular for that.

Thanks,
Josh
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Re: Questions about my next tube amp project, 18 watt design.

Post by JMPGuitars »

Raezzordaze wrote:
Fri 04/23/21 7:05 am
JMPGuitars wrote:
Thu 04/22/21 7:34 pm
You sound like what you want is the Superlite TMB. It's a great amp, designed by Zaphod_Phil. I put up new versions of the docs recently. It can be double or single input.
That does look almost exactly like what I want! The only thing I think I might change is the diode rectifier to an EZ81. How well does that amp break up? I'm not exactly looking for heavy metal gain, but something that can do Angus AND Malcolm reasonably well. :twisted:
You can do that with the EZ81, or you can make it switchable between the two. Build it, you'll love it. It has a great range of dirt, and the break up is delicious.

Thanks,
Josh
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Re: Questions about my next tube amp project, 18 watt design.

Post by Bieworm »

IME that EZ81 adds nothing beneficial to these amps . The only time I could hear it was there was when it cr@pped out on me, crackling and popping. It took me 3 nights of troubleshooting before I traced it back to the rectifier. It was a new build with all new tubes, so of course I searched for the issue in the circuit.
I'm never using those again.

And... every single tube-o-phile needs only 1 guess on what brand it was 😉😉😉
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Re: Questions about my next tube amp project, 18 watt design.

Post by JMPGuitars »

Bieworm wrote:
Fri 04/23/21 8:51 am
IME that EZ81 adds nothing beneficial to these amps . The only time I could hear it was there was when it cr@pped out on me, crackling and popping. It took me 3 nights of troubleshooting before I traced it back to the rectifier. It was a new build with all new tubes, so of course I searched for the issue in the circuit.
I'm never using those again.

And... every single tube-o-phile needs only 1 guess on what brand it was 😉😉😉
That's why I suggest making it switchable. You can test for your own ears/fingers whether or not you prefer the tube rec...and even if you do, it's nice to have a backup if the tube fails.
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Re: Questions about my next tube amp project, 18 watt design.

Post by TriodeLuvr »

JMPGuitars wrote:
Fri 04/23/21 6:11 am
I may want to try building a HiFi version with them eventually, I know they're quite popular for that.
Josh, my primary hi-fi amp is an EF86-6V6 SE that I built about 15 years ago. I also have a much larger HK Citation V, but it rarely gets used. The little amp is just too good. :)

Jack
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Re: Questions about my next tube amp project, 18 watt design.

Post by JMPGuitars »

Raezzordaze wrote:
Fri 04/23/21 12:56 pm
I forgot to ask, what program do you use to do your layouts JMP? I tried using DIYlayout creator but it doesn't produce anything near that clean looking, and doesn't seem to have many custom files around for it.
I use Visio, but none of that is stock. I designed every part that goes in the layout drawings.

Thanks,
Josh
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Re: Questions about my next tube amp project, 18 watt design.

Post by JMPGuitars »

Raezzordaze wrote:
Fri 04/23/21 7:12 pm
OOoh wow, a little bit outta my league then lol.
lol, my other job is design. I might get a little OCD about that sorta thing. ;)
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