Wednesday, 23 September 2020

Solid Gold Fx Rosie

 A silicon tonebender with a nice touch; it has a J FET at the first gain stage. The BC239s could possibly be replaced with BC549 or 2N5088.

 


 



14 comments:

  1. Hell yeah bro! I was waiting for this one! Mine works with bc550.

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  2. Sorry - silly question....would this be an on/on switch?

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    1. SPST can be substituted for a SPDT on/on - just leave the 3rd lug disconnected

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    2. I get so confused with switches! So should it ideally be a 2 lug on/off?

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    3. That's what it calls for, but for what it's worth a lot of retailers don't bother stocking SPST switches because half of a SPDT on/on does the same thing and it's the same cost. Just connect switch 2 to the center, and switch 1 to one of the outer legs (literally doesn't matter which one) and leave the other outer leg disconnected and you're good to go!

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  3. I bought some BC239's to make this, but the hfe's were a bit lower than I expected - around 320. Think I should sub for something higher?

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    1. Try it. Mine were lower gain than that and it sounded amazing.

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    2. Thank you ben I will do that. I've got some reliable j201s for the first time ever so I can make this at last!

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  4. I had a crack at this today and was irked by (very) low level whine. Although it was not always audible it imparted that tone into the guitar sound. Both with j201 and worse with 2n5457. Not my favourite TB variant. (I didn't think to change the trannies🤦🏼)

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    1. Just a thought, does your jfet bias correctly, and do you get decent voltages at the other transistor? I've had problems with circuits using a diode to control the 9v input (perhaps try shorting it). Have you boxed it up? Some high gain circuits pick up all sorts of crap before boxing.

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    2. Hi there. I'm not very good at testing voltages. It was all boxed up. I just put a another circuit in the box 👍

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  5. What is the 50K trim pot for in this circuit? And how should it be set?

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