How is the James stack working for you? I am thinking about using the James for a clean build. What value did you settle on for the mid resistor? Did you find the mid control to be of little value?
Great looking amp and it sounds killer.
It really depends on what you are shooting for. For a clean build, using the values that are stock in the Duncan tone stack calculator, the mid-shift has much more value and usable range. I would use a 500K linear pot . You can see how it affects the mid point by diming the treble and bass in the calculator and then playing with the value of R4. The higher the value of R4, the lower the mid point is. In this amp I built, I already have a very high mid content, so shifting the mid point did almost nothing, barely noticeable.
shane wrote:Thanks for clarifying the tone cap thing, does your gain control come before the James tone stack then?
That last clip sounded absolutely wonderful by the way!
Cheers
Shane
It is very similar to an express circuit:
Input>1st gain stage>coupling cap to gain pot>Tone Stack>2nd gain stage>coupling cap>third gain stage>Coupling cap>PI>coupling caps>Power Tubes.
In the Express tone stack, the stack itself is coupled via the three caps that comprise the TS to block the DC. In a James, you have to add a coupler before the stack due to it having paths to ground for DC.
fusionbear wrote:It really depends on what you are shooting for. For a clean build, using the values that are stock in the Duncan tone stack calculator, the mid-shift has much more value and usable range. I would use a 500K linear pot . You can see how it affects the mid point by diming the treble and bass in the calculator and then playing with the value of R4. The higher the value of R4, the lower the mid point is. In this amp I built, I already have a very high mid content, so shifting the mid point did almost nothing, barely noticeable.
Thanks again for the kind comments, I made one more adjustment. The amp seemed a little too thick, so I made very minor changes. I went from a .027 out of the plate of V1 to a .018. Also I went from the 3900pf treble cap to 3000pf ceramic that I preferred. In the James tone stack, this took out a "smidgen" of lower mids. I got my 6SL7 replacement tubes today and they were a little microphonic too. But, much less than the NOS Tungsol's. So now I have the 6SU7 in V1, The only non-microphonic NOS Tungsol in V2, and the new GE 6SL7GT in V3 (P.I.)
Much happier overall. I will make a new recording, hopefully tomorrow. Suffering from a sinus headache right now....... ugh!
Jeez...this amp sounds REALLY good. I like the #3 clip a lot, and I can understand the 4th one trying to keep peace w/neighbors. I am pretty much waiting for the cops to show up at my door whenever I run amps loud, so I only do it for a few minutes at a time.
768]http://i169.photobucket.com/albums/u223/fusionbear/Wreckish%20Octal%20Build/IMG_0224_zpscxfcbgd5.jpg[/img]