n0nspaz
Rookie Solder Flinger
Posts: 2
Likes: 0
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Post by n0nspaz on Jul 5, 2012 18:01:46 GMT -5
hi guys
need help with some onboard electronics.
circuit path idea is: strat pickups-indiv vol pots-Fetzer Valve Rev preamp with PN4118 fet-passive or active HPF, mid cut, LPF- source follower buffer for 600R-1k Output impedance driving a 10k (line level) load
transistors still confuse me though i am studying. any reccomends for the eq or buffer sections? looking for a transparent buffer, not active (additive) eq. cuts only is fine. i have a bunch of diff fets, 201,202,mpf102, 2n5469, 4117, 4118....
and plenty of resis/caps/chokes here to play with.
thanks. i hope that was clear. take care all
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Post by newey on Jul 5, 2012 18:39:38 GMT -5
NS-
I'm not the guy to ask about a buffer/preamp or transistor questions, so I'll leave that for others to address, just wanted to welcome you.
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Post by 4real on Jul 5, 2012 19:02:12 GMT -5
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Post by reTrEaD on Jul 7, 2012 5:06:26 GMT -5
If you want the least amount of interaction between volume controls, you could use a buffer after each volume control, then mix the three signals together at the input of a fourth buffer. Then your eq and perhaps a master volume?, then an output buffer to drive the cable. JohnH is our resident expert on FETs. He has a lot of first-hand knowledge from tweaking circuits to get the most out of them. The FET buffer/cable thread linked to above, would be a great place to start. I also recommend reading guitarnuts2.proboards.com/index.cgi?board=fxschemes&action=display&thread=4987Best of luck. |
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Post by JohnH on Jul 7, 2012 9:17:31 GMT -5
For your output buffer,the buffer circuit in the thread linked by 4real ,with 22k source resistor will drive a line input. For your first stage,you might want a bit of gain,and the fetzer valve circuit is good. It's similar to the gain stage that I show.
The action of your tone controls is difficult to predict when after a buffer. You can model it, and I recommend that with 5spice, but you should also build it on a breadboard to test how it sounds and try different component values.
Also, you can and should, test your fet circuits with the actual fets you have. All those that you listed can be made to work the j201 will give most gain (in the gain circuit). But you must play with the biasing resistors to get the right voltage at the output. This will be about 5.5v for either circuit. In the gain circuit, this means adjusting the ratio of the source and drain resistors to suit. For the x1 buffer with no gain, its the two resistors at the input.
John
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