Wish 6CA7 Plexi with s/n # 12301 specs ….

R.D.

R.D.

Fractal Fanatic
I’m renewing my “wish” for a 6CA7 Plexi w/ the following specifications ….

  • 6CA7 Output Tubes
  • Sylvania 12AX7 Preamp Tubes
  • 50K mid-pot
  • Split cathode on V1a (250µF/820Ω) and V1b (.68µF/820Ω)
  • All coupling caps: 0.022µF
  • 470K mixer resistors
  • 500pF red tubular mixer bypass cap
  • Fat Cap mod: .68µF and 250µF on V2a
  • Tone stack: 33k/560pF Lemco combo
  • 100K NFB resistor from 4Ω tap
  • 220K bias splitter resistors
  • 0.1µF cap on presence control
  • 0.022µF output couplers
  • Heyboer Transformers (Dagnall clones)

Power filtering:
  • [2] 100µF F&T ( mains )
  • [2] 32µF F&T ( screens )
  • [1] 100µF LCR ( phase inverter )
  • [1] Dual 33µF x 33µF F&T ( preamp )

And finally …, the ability to switch between a PP & SE power section configuration ….

@FractalAudio – I know that you typically like to have a physical amp to measure and verify everything. But, you do have at least a few FAS style amps that I’m guessing might not actually exist to be measured ?

Based on your past comments and the information in the Wiki …, I think that we have models w/ the majority ( if not all ) of these specs already ( ? ) …, they just aren’t all contained in the same amp ....

Would it be possible ( and would you be willing ) to re-work the FAS Brown w/ the above specifications ?

Respectfully submitted ….
 
R.D. said:
I’m renewing my “wish” for a 6CA7 Plexi w/ the following specifications ….

  • 6CA7 Output Tubes
  • Sylvania 12AX7 Preamp Tubes
  • 50K mid-pot
  • Split cathode on V1a (250µF/820Ω) and V1b (.68µF/820Ω)
  • All coupling caps: 0.022µF
  • 470K mixer resistors
  • 500pF red tubular mixer bypass cap
  • Fat Cap mod: .68µF and 250µF on V2a
  • Tone stack: 33k/560pF Lemco combo
  • 100K NFB resistor from 4Ω tap
  • 220K bias splitter resistors
  • 0.1µF cap on presence control
  • 0.022µF output couplers
  • Heyboer Transformers (Dagnall clones)

Power filtering:
  • [2] 100µF F&T ( mains )
  • [2] 32µF F&T ( screens )
  • [1] 100µF LCR ( phase inverter )
  • [1] Dual 33µF x 33µF F&T ( preamp )

And finally …, the ability to switch between a PP & SE power section configuration ….

@FractalAudio – I know that you typically like to have a physical amp to measure and verify everything. But, you do have at least a few FAS style amps that I’m guessing might not actually exist to be measured ?

Based on your past comments and the information in the Wiki …, I think that we have models w/ the majority ( if not all ) of these specs already ( ? ) …, they just aren’t all contained in the same amp ....

Would it be possible ( and would you be willing ) to re-work the FAS Brown w/ the above specifications ?

Respectfully submitted ….
Click to expand...
Slippery slope you've got there :)
Why that particular combination and not the other 43,638?
 
Pardon my ignorance, but isn't the Plexi Brown tone stack supposed to be modeled after EVH's Plexi? Would changing the tone stack in the 6CA7 to Plexi Brown be close? Yes, I know it doesn't do the PP SE thing.
 
ocaptainjr2 said:
Pardon my ignorance, but isn't the Plexi Brown tone stack supposed to be modeled after EVH's Plexi? Would changing the tone stack in the 6CA7 to Plexi Brown be close? Yes, I know it doesn't do the PP SE thing.
Click to expand...

No ..., not really ..., from the Wiki ....
  1. "The Brit Brown was built by ear."
  2. "Brit Brown is my personal take on what the ultimate "Brown" Plexi should sound like. It's based on a 100W SLP with Arredondo mods and a few little voicing tweaks."
 
R.D. said:
No ..., not really ..., from the Wiki ....
  1. "The Brit Brown was built by ear."
  2. "Brit Brown is my personal take on what the ultimate "Brown" Plexi should sound like. It's based on a 100W SLP with Arredondo mods and a few little voicing tweaks."
Click to expand...
Again, I may be misunderstanding, but I read it as being independent of the Brit Brown amp model. The Cliff quote #2 about the 100W SLP was from Firmware 18'ish. Edit....Firmware 18 of the Axe-Fx II.

From the 28.01 Release Notes: Added “Plexi Brown” tone stack based on EVH’s amp with a 50K mid pot.
 
R.D. said:
I’m renewing my “wish” for a 6CA7 Plexi w/ the following specifications ….

  • 6CA7 Output Tubes
  • Sylvania 12AX7 Preamp Tubes
  • 50K mid-pot
  • Split cathode on V1a (250µF/820Ω) and V1b (.68µF/820Ω)
  • All coupling caps: 0.022µF
  • 470K mixer resistors
  • 500pF red tubular mixer bypass cap
  • Fat Cap mod: .68µF and 250µF on V2a
  • Tone stack: 33k/560pF Lemco combo
  • 100K NFB resistor from 4Ω tap
  • 220K bias splitter resistors
  • 0.1µF cap on presence control
  • 0.022µF output couplers
  • Heyboer Transformers (Dagnall clones)

Power filtering:
  • [2] 100µF F&T ( mains )
  • [2] 32µF F&T ( screens )
  • [1] 100µF LCR ( phase inverter )
  • [1] Dual 33µF x 33µF F&T ( preamp )

And finally …, the ability to switch between a PP & SE power section configuration ….

@FractalAudio – I know that you typically like to have a physical amp to measure and verify everything. But, you do have at least a few FAS style amps that I’m guessing might not actually exist to be measured ?

Based on your past comments and the information in the Wiki …, I think that we have models w/ the majority ( if not all ) of these specs already ( ? ) …, they just aren’t all contained in the same amp ....

Would it be possible ( and would you be willing ) to re-work the FAS Brown w/ the above specifications ?

Respectfully submitted ….
Click to expand...
Maybe the easiest way for Fractal to fulfill our wishes is if they do the new Friedman Arredondo amp?
 
R.D. said:
I’m renewing my “wish” for a 6CA7 Plexi w/ the following specifications ….

  • 6CA7 Output Tubes
  • Sylvania 12AX7 Preamp Tubes
  • 50K mid-pot
  • Split cathode on V1a (250µF/820Ω) and V1b (.68µF/820Ω)
  • All coupling caps: 0.022µF
  • 470K mixer resistors
  • 500pF red tubular mixer bypass cap
  • Fat Cap mod: .68µF and 250µF on V2a
  • Tone stack: 33k/560pF Lemco combo
  • 100K NFB resistor from 4Ω tap
  • 220K bias splitter resistors
  • 0.1µF cap on presence control
  • 0.022µF output couplers
  • Heyboer Transformers (Dagnall clones)

Power filtering:
  • [2] 100µF F&T ( mains )
  • [2] 32µF F&T ( screens )
  • [1] 100µF LCR ( phase inverter )
  • [1] Dual 33µF x 33µF F&T ( preamp )

And finally …, the ability to switch between a PP & SE power section configuration ….

@FractalAudio – I know that you typically like to have a physical amp to measure and verify everything. But, you do have at least a few FAS style amps that I’m guessing might not actually exist to be measured ?

Based on your past comments and the information in the Wiki …, I think that we have models w/ the majority ( if not all ) of these specs already ( ? ) …, they just aren’t all contained in the same amp ....

Would it be possible ( and would you be willing ) to re-work the FAS Brown w/ the above specifications ?

Respectfully submitted ….
Click to expand...
Where are these specifications from, and are the values nominal or by measurements? Just to clarify if this is something Cliff can trust
 
Chiguete said:
Maybe the easiest way for Fractal to fulfill our wishes is if they do the new Friedman Arredondo amp?
Click to expand...

Except Eddie's original Plexi didn't have ANY of Jose's mods done to it ! That was later ....
 
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JDR3009 said:
Without wanting to sound confrontational, even if you get that exact, extremely specific and also still somewhat incompletely specced amp, what’s going to be the excuse when it still doesn’t sound like Van Halen I?
Click to expand...

I put together a preset ( here - https://forum.fractalaudio.com/threads/van-halen-i-preset.212097/#post-2671417 ), that for me is probably about 90% there .... But something about the gain structure and the character of the "distortion" still isn't quite right ....

I don't know enough about the "engineering" of it to know if it's the missing spec. or the PP vs SE power amp section, or a combination of ALL of that ?

I'm hopeful that if @FractalAudio can put the missing pieces together that it'll get me the last 10% that I'm looking for ?

I've been a Fractal User since 2011 with almost every platform that Fractal has put out ..., I love, Love LOVE the entire ecosystem and just want to get as close to that tone ( my "holy grail" ) as I can without resorting to other methods !
 
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km 202257 said:
Where are these specifications from, and are the values nominal or by measurements? Just to clarify if this is something Cliff can trust
Click to expand...

These specifications are pretty much unanimously agreed upon between Dave Friedman, John Suhr, George Metropoulos and Jim Gaustad ....

Dave & John worked on Eddie's amp at different times ..., and along with them George Metropoulos is one of the premenent Plexi experts in the United States today ! Finally, Jim Gaustad has just been V.H. tone chasing since he first heard Eddie back in 1978 !
 
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R.D. said:
These specifications are pretty much unanimously agreed upon between Dave Friedman, John Suhr, George Metropoulos and Jim Gaustad ....
Click to expand...
And references to the source: URLs, books that support the consensus between those engineers?

As a follow-up: I agree that these specs should be reflected to the models if it's correct, in a situation where IK has released TONEX Brown Sound 78/79 and Fractal still want to claim competence in authenticity in recreating Brown Sound. I just worry if your information is ignored from Fractal just because of lack of citation which provides verifiability.
 
km 202257 said:
And references to the source: URLs, books that support the consensus between those engineers?

As a follow-up: I agree that these specs should be reflected to the models if it's correct, in a situation where IK has released TONEX Brown Sound 78/79 and Fractal still want to claim competence in authenticity in recreating Brown Sound. I just worry if your information is ignored from Fractal just because of lack of citation which provides verifiability.
Click to expand...

It's all out there on the interwebz ..., YouTube, ToneTalk, Jim Gaustad, iK Multimedia etc; etc; ..., I don't feel any pressure to cite it here ! If you want to double check me on it, feel free to search it up ....

If @FractalAudio decides not to "grant this particular wish" ..., it would more likely be because there's no source amp that he can actually measure and verify ! Especially the PP vs SE part of the argument. I will readily admit ..., that part of the tone equation is 100% speculation and can not be verified. I think that based on what we do know about Eddie's personality and the situation he grew up in, that logically the speculation has merit .... But that's my opinion and it may ( or may not ) be shared by others ?

To that I say "fair" and I move on ... !

Cliff has said time and again that he is striving for 100% accuracy with his modeling approach ! And I completely respect and support that ! And I realize that unfortunately there's no simple way to apply that ethos to this endeavor. Beyond his time and effort .... Cliff has invested A LOT of capital in obtaining source amplifiers to measure and verify against ! He's even mentioned that from time to time ...,

the physical amps ....
1.) don't have the components that the schematic diagrams say they should have ....
2.) based on the components they do have don't exactly measure they way he expects ....

And the only way to get an amp that he could measure ..., would be to take one of his already sourced amps and change out the component values to match Ed's # 12301 ..., or buy yet another amp to do the same ....

That's why I asked for a re-work of an FAS model. Those are his idealized versions of certain amps .... I'm guessing that those models don't have "real" amps to measure and verify against either ?

Look ..., I wouldn't blame him if he decided it's a fools errand and/or a rabbit hole that he does not want to go down.

I'm O.K., with and will respect his decision on the matter ....

But that said ..., it doesn't stop me from asking either ;) ....
 
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If you're 90% of the way there as you said, the other 10 is likely you (your gear and your playing). Also, I'm pretty sure tagging Cliff in every post is not necessary
 
I know nobody wants to hear it but these small changes barely matter, any Plexi in the AxeFx will do.
Eddies tone was all in his fingers. ie. excellent sense of rhythm and flawless playing.

PS.
Sorry, for being a wet blanket, I don't like when people poopoo my requests either. 😅
 
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