Crucial tone caps 6G4A

Jasonpatrick

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Hey all, I’m just curious on the super 6G4A schematic, which tone caps would you say are the most important in regards to signal and sound. Yes I know other things play bigger roles and sum of parts yada… just wondering.
 

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Phrygian77

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An important part of that tremolo are the cathode bypass caps. So, make sure you don't over size them. There's two different versions, one uses a 4uF and the other a 2uF. I'd still make the 25uF on the oscillator itself a 50uF.
 

slider313

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Follow the wiring on the layout going to the bass and treble controls. Those are the caps that shape the tone.
 

Jasonpatrick

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An important part of that tremolo are the cathode bypass caps. So, make sure you don't over size them. There's two different versions, one uses a 4uF and the other a 2uF. I'd still make the 25uF on the oscillator itself a 50uF.
Oh yeah, already learned that fun tasty morsel. Someone had replaced the 4uf with a 25uf lol.. trem thumped so badly and only worked at the full range of the knobs. Tried the 2uf which the early ones used but still had a slight thump all the way through knob setting, ended up using a 4.7 and it works fine now.
 
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Jasonpatrick

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Follow the wiring on the layout going to the bass and treble controls. Those are the caps that shape the tone.
Thanks for reaffirming my suspicions! I have to order one dumb bias pot so I was contemplating adding on to the order some Jupiters and switching out some of the yellow Malloys. Probably wouldn’t make much of a tone difference but I can’t think of anything else I need haha 🤷‍♂️
 

schmee

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Follow the wiring on the layout going to the bass and treble controls. Those are the caps that shape the tone.
This ...AND if there is a small cap leading from pin 2 of the PI tube, that one makes a difference. They seem to run .001uf to .05 uf.
(Cant read your schem too small to expand clearly.)
 

Jasonpatrick

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This ...AND if there is a small cap leading from pin 2 of the PI tube, that one makes a difference. They seem to run .001uf to .05 uf.
(Cant read your schem too small to expand clearly.)
Thanks! Was wondering about that one. Mines a little ceramic guy but I’ve seen one where they crammed in a sozo cap all willy nilly (photo included of Willy nilly)
 

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Phrygian77

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Oh yeah, already learned that fun tasty morsel. Someone had replaced the 4uf with a 25uf lol.. trem thumped so badly and only worked at the full range of the knobs. Tried the 2uf which the early ones used but still had a slight thump all the way through knob setting, ended up using a 4.7 and it works fine now.

Yeah, the tremolo controls the bias of that stage, so too large of a cap and the low frequency bias voltage AC signal just gets bypassed to ground. The same applies to Vibro Champs.
 
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David Barnett

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This ...AND if there is a small cap leading from pin 2 of the PI tube, that one makes a difference. They seem to run .001uf to .05 uf.
(Cant read your schem too small to expand clearly.)

Fender often used a ceramic cap in this location. The input impedance of the LTP is so high that the cap would have to be fairly tiny to be the dominant pole for the amplifier. But it's a spot where a "funky" cap can add some texture.
 

JRapp

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I have a few well-made tweed clones (a 5E5A Pro and a high-power Twin) and I get as close to the original tone stack components as I can. All my old Astrons are a bit leaky, so I've gone with Sprague BBs recently and they are pretty close with less noise. Yes, you can find all those E series values...
 

slider313

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I recently removed all the yellow Astrons in my September 1960 Super. They lasted longer than expected. I went with a mix of Sozo blue, yellow and yellow Jupiters. The phase inverter cap is the original ceramic disc .001 which I believe, in this position, is a big part of the Fender sound. I've tried other types in this amp, my '61 Deluxe 6G3 and my '64 Vibrolux Reverb and nothing sounds "right" to me except a ceramic disc cap.


001.JPG

015.JPG
 

bebopbrain

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It is easy to make a capacitor with aluminum foil and waxed paper. Maybe DIY artisanal caps sound best.

My spouse buys distilled water in soft plastic milk jugs. I try to explain that when water hits the plastic it is, for practical purposes, no longer distilled. Some things are better unsaid.

A capacitor is like a storage jug, but for electrons (or charge or amp seconds or coulombs) instead of water. The number of electrons per volt is written on the side in microfarads. The original caps were called Lyden jars (not to be confused with John Lydon). Now, why would one electron storage jug (storing the same number of electrons) sound different than another?
 

slider313

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A capacitor is like a storage jug, but for electrons (or charge or amp seconds or coulombs) instead of water. The number of electrons per volt is written on the side in microfarads. The original caps were called Lyden jars (not to be confused with John Lydon). Now, why would one electron storage jug (storing the same number of electrons) sound different than another?

Materials used to make a capacitors have an affect on their sound. In theory all .01 capacitors should sound the same. It all depends on its placement in the circuit. Polystyrene, polypropylene, metal film, film and foil, ceramic, etc. all impart some of their properties into the signal path. Try replacing all the blue molded Ajax caps in a black panel Fender with Sprague orange drop 715P's and see if you hear a difference. ;)
 




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