Bearfoot - Model H  [traced]

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WhiteKeyHole
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Post by WhiteKeyHole »

Can I get the Dale resistor values? Thanks!

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Post by WhiteKeyHole »

Also, could I get some information about the gain and tone potentiometer wiring? I have my assumptions down now but would like to be sure.

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Post by WhiteKeyHole »

Never mind, missed the pictures somehow. Sorry.

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Post by culturejam »

WhiteKeyHole wrote:Can I get the Dale resistor values? Thanks!
The 5-bands are Vishay CCF-55 series. I love those! I use them in a lot of my builds.

Yes, I know that's not what you were asking about, but I just had to comment. :thumbsup

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WhiteKeyHole
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Post by WhiteKeyHole »

Thanks. What's the resistor just above the 4n7 capacitor? Is "R4" 22K?

That should be it, thanks for all the help.

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Post by WhiteKeyHole »

As always, there may be revisions.
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Jack Deville
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Post by Jack Deville »

Re: schematic above:

I don't think the connections on Q3 and Q4 are correct.
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Post by WhiteKeyHole »

Yeah, I think it's suspect. Went by what I can see, though.

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Post by WhiteKeyHole »

He uses them in the same way in the Fire Red Fuzz,

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Post by WhiteKeyHole »

Wait, never mind. Why don't you think it's correct? Makes sense to me...

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Post by Jack Deville »

:scratch:
N channel JFETs' drain and source tied together?
Drain and source to ground at Q3, bypassed entirely at Q4?
Explain how this makes sense.
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Post by RnFR »

yeah, that doesn't look right. maybe check the pinouts?
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Post by WhiteKeyHole »

I did check the pin arrangement, would be foolish not to. Anyway, seems like a diode to me. Gate being the anode, drain/source being the cathode. To quote Wikipedia, "The gate(G) (control) terminal has doping opposite to that of the channel, which surrounds it, so that there is a P-N junction at the interface."

What am I missing? How else are you going to use a JFET as a diode?

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Post by WhiteKeyHole »

Other than using it as a current source.

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Post by WhiteKeyHole »

:x :x :x

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Post by RnFR »

easy buddy. I stand corrected, you can do it that way. but I'm used to seeing it one of these two ways, usually the one on the left.

http://www3.hi.is/~voe1/Posted/jFET_clip_cir.jpg
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Post by WhiteKeyHole »

J1 and J2 are, basically, the same configuration found in the Model H. J3 and J4 are the other method I mentioned, the JFETs are configured as current sources (regulators, limiters, what have you).

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Post by culturejam »

RnFR wrote:easy buddy. I stand corrected, you can do it that way. but I'm used to seeing it one of these two ways, usually the one on the left.

http://www3.hi.is/~voe1/Posted/jFET_clip_cir.jpg
I thought the same thing at first about having the drain and source tied together, but apparently it works that way as well as a diode. :hmmm:

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Post by WhiteKeyHole »

Yeah, R15.

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Post by earthtonesaudio »

A JFET wired like that makes a "low leakage" diode. You'll sometimes see them used in low-drift peak detectors or sample/hold circuits.
rocklander wrote:hairsplitting and semantics aren't exactly the same thing though.. we may need two contests for that.

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