5E3 coupling cap question

Discussion in 'Amp Tech Center' started by klobasa, May 8, 2019.

  1. klobasa

    klobasa Tele-Meister

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    Whats the tonal difference between these two coupling cap options in a 5E3 circuit:

    1. Reduce the first two coupling caps (maybe .022uf) and keeping the other two later at the signal chain at .1uf

    2. Reduce all the coupling caps .047uf

    I just made those .022uf and .047uf values, I don't know it these two combinations would give the same bass response or not. But I would like to know what is the difference between changing all the caps to slightly lower value vs. changing only the first two caps to much lower, but keeping the other .1uf caps.

    Thanks...
     
  2. Uncle Daddy

    Uncle Daddy Tele-Holic

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    I tried changing them all to 0.022, and things started to get a bit thinner, losing what makes the Deluxe what it is. Settled for 0.02 on the first stages, and 0.01 on the later. Doesn't make a huge difference to single coils.
     
  3. klobasa

    klobasa Tele-Meister

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    It seems that The Edge 5E3 has reduced PI coupling caps (.02) but the V1 caps are stock.

    How would the amp be different if V1 caps would be .02 and PI caps stock?
     
  4. Wally

    Wally Telefied Ad Free Member

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    Uncle Daddy, I have to think that you meant to type ‘.1’ there for the PI coupling cap’s, correct?
    Klobasa, as you may have found, reducing the capacitance at either or both of those points reduces low end. You might even get far off into it by remembering that there are .033mfd and .068mfd caps as well. I have never felt the need to change those values...ommv, obviously. I like having a bass cut control on my guitar so as to control low end...especially when pushing power chords hard.
     
  5. robrob

    robrob Poster Extraordinaire Ad Free Member

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    The Lead Channel mod changes only the first coupling cap to .0047uF. The other channel stays Fender stock. The small coupling cap removes excess bass but the large stock coupling caps that follow allow intermodulation distortion to fill in some bottom end. The more distortion you generate the more the bottom end fills in.

    If you change all the caps you keep the bottom end trimmed and thinned all the way to the speaker. If that's how you want to voice the amp then that's fine.
     
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  6. klobasa

    klobasa Tele-Meister

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    Thanks. My amp has .022 V1 and stock .1 PI coupling caps. I know that the .022 caps cut bass, but I still wonder how would the amp be different if the caps would be the other way around (like in The Edge 5E3) or if all four caps would be of similiar value that cuts the same amount of bass.

    Does it not differ if the bass is cut in preamp or in PI?
     
  7. AJBaker

    AJBaker Friend of Leo's

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    I'm curious as well: I have a 5e3 clone that came with the Edge mods. I like the sound, but I wonder if I'm missing out on something, or if I'd be better of cutting the bass at V1 instead of the PI.

    I'll be following this thread.
     
  8. Wally

    Wally Telefied Ad Free Member

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    So, now.....who wants switchable coupling cap capacitance in both places? Rotary switches for at least three if not more choices??
     
  9. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Keep in mind the phase inverter input coupling cap can be much smaller than other coupling caps due to the PI's high input impedance. A 1000pF coupling cap can pass all guitar freqs with most PI circuits.
     
  10. jman72

    jman72 Tele-Afflicted

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    Not sure, but I have 0.022 in the first three and 0.047 in the last two and I love it. But exactly what is different from the stock other than generally tighter bass I can't say.
     
  11. klobasa

    klobasa Tele-Meister

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    Hmmm...so if only the PI caps are reduced the bass response does not change from stock?
     
  12. robrob

    robrob Poster Extraordinaire Ad Free Member

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    Pretty much. Fender blackface head amps have a 500pF phase inverter coupling cap to trim a little bass to keep the sealed back cabs from booming.
     
  13. klobasa

    klobasa Tele-Meister

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    I'm wondering why do people then often chance the PI caps to smaller value... I was also going to try it, but I guess not anymore :)
     
  14. P100

    P100 TDPRI Member

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    Actually as it was mentioned, heaving rotary switch to increase/decrease capacitance of V1 stage would be a great idea. You may set "fatness" of an amp easily. Hint - mount those selectable caps in serial with already existing one and add some "bleeding" resistors to get rid of pop-click sound during switching. Also, compare 5D3 schematics with 5E3 regarding caps values.
     
  15. klobasa

    klobasa Tele-Meister

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    I agree, I am actually tomorrow pickup up a new VOX / Matchless style amp that has rotary cap switch. I have had similar cap switch before in one amp and it was very usefull.
     
  16. P100

    P100 TDPRI Member

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    There's also another possibility to mod standard 5E3 if there's no place for additional pot - use stereo Tone pot where the second section would be responsible for increasing/decreasing resistance of a parallel cap from v1. Not sure how it would work with only 1 tone control, but this approach was used in a Marshall Silver Jubillee for Bass control. Did not have occasion to play one, but I remember reading that Bonamassa stated that it's the only amp that allows him to set bass to 10 and it still sounds nice - that might be the key.
     
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