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Eddie Current Aficionado Feedback Mod

Discussion in 'DIY' started by purr1n, Jan 5, 2021.

  1. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Pyrate BWC
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    Trying to help @fastfwd here on implementing the feedback mod. Unfortunately, I do not have schematics or the amp in front of me so I cannot say for certain, but these are guesses. If anyone has an Aficionado and can open up and confirm parts and values, that would be appreciated. The following is what I know of the amps. Some parts could be there, some parts may not be. Parts values can change over time from batch to batch.

    upload_2021-1-5_19-14-34.png

    upload_2021-1-5_19-16-23.png
    • Tip: for models without the feedback mod, the tertiary winding outputs are taken to the RCA outs on the back of the chassis
    • Note: I marked 6SN7, but this is incorrect. It should be WE396A.
    The main difference is what's off the cathode. There is no cathode bypass cap on the non-feedback version. The feedback resistor values are a guess. I think Craig may have backed off the feedback even more where the 698 ohm is closer to 1k. Doesn't matter a lot, but this is something you can play around with.
     
    Last edited: Jan 5, 2021
    purr1n, Jan 5, 2021
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  2. purr1n

    purr1n Desire for betterer is endless.

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    May be a useful community project to trace the circuits to these amps as Craig is semi-retired now.
     
    purr1n, Jan 5, 2021
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  3. dncnexus

    dncnexus Friend

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    I am not really knowledgeable in tracing circuits, but am receiving the Aficionado tomorrow that has the feedback mod. I can try to open it and take pictures if that would help at all.
     
    dncnexus, Jan 5, 2021
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  4. gaspasser

    gaspasser Flatulence Maestro

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    This may help. Here is a decent internal shot of my old Aficionado with feedback mod switch.

    105DB57B-31F0-41B9-BDA9-2BDDA2D6DBE6.jpeg
     
    gaspasser, Jan 5, 2021
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  5. fastfwd

    fastfwd Friend

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    Thanks, @purr1n. As I mentioned privately, it makes me nervous to poke around inside a mystery tube amp with a scope probe -- but I'll definitely share any circuit tracing that I do manage to perform.

    @Gaspasser, I actually downloaded that photo back in August and compared it to my amp, but there were enough little differences between our builds that I couldn't isolate the feedback mod. You also had a power LED (or lamp) on the amp itself, right? That's another mod I want to make, because my power supply is hidden, so I don't see its power light and I occasionally forget to turn it off.

    @dncnexus, photos would be great -- when you have time, and only if it's not too much trouble. Thanks very much for the kind offer.
     
    fastfwd, Jan 6, 2021
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  6. thoth

    thoth Acquaintance

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    @gaspasser Can you please make a photo of the switch wirings? I'm considering to implement the mod in Studio Jr.
     
    thoth, Aug 31, 2023
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  7. gaspasser

    gaspasser Flatulence Maestro

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    Unfortunately I’m unable to help you because I no longer own this amp.
     
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    gaspasser, Aug 31, 2023
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