Hello-
I apologize if this is a little off-topic but I cannot get the info I need from phone calls or searches. A friend brought over one of the Martin B-20WN custom made guitars. This is a special edition made in the late 1990's with a pickup that was supposed to be sonicly equivalent to the original Baldin Prismatone; only 100 guitars were made. My friend played it through a tube amp I just finished building. The amp had the traditional dual input jacks (pair of 68K grid stopper resistors and 1 meg grid leak) wired for high/low as in many Fender tube amps. The guitar sounded better on the input jack acting as a 3 dB attenuator (one 68K in series, the other 68K to ground). Evidently this pickup has fairly high output. It is a passive pickup. I am searching for technical information about this Fishman pickup used in these special edition guitars. I called Fishman but was unable to get info. I am planning an amplifier build for this guitar and would like to know the appropriate input circuit to use. Thanks all.
Amplifier Input Circuit for Martin B-20WN
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Reeltarded
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Re: Amplifier Input Circuit for Martin B-20WN
In my mind, it was plugged into the expected circuit.
Oh. I see. A direct box with a PA head is the appropriate amp.
Oh. I see. A direct box with a PA head is the appropriate amp.
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
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Stevem
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Re: Amplifier Input Circuit for Martin B-20WN
Well if you want to do something simple and then at least get a feel for what would work best then just play the guitar while hooked up to a voltmeter set for ac volts.
Beat on the guitar hard to get a peak reading .
In general I find with tube guitar amps that .150 volts put to its input is more then enough to drive the amp to max output and of course full on clipping.
If your building a amp just for this guitar which sounds like it's fitted with a hot pickup then just bias that first gain stage to need maybe .300 volts to drive the amps output stage to max wattage.
The RCA tube book (RC30) which can be had in reprint has a good section on preamp sections and the components and power supply voltages needed to attain a given level of signal output.
Just the info in that section along is worth the cost of the book if you ask me!
Beat on the guitar hard to get a peak reading .
In general I find with tube guitar amps that .150 volts put to its input is more then enough to drive the amp to max output and of course full on clipping.
If your building a amp just for this guitar which sounds like it's fitted with a hot pickup then just bias that first gain stage to need maybe .300 volts to drive the amps output stage to max wattage.
The RCA tube book (RC30) which can be had in reprint has a good section on preamp sections and the components and power supply voltages needed to attain a given level of signal output.
Just the info in that section along is worth the cost of the book if you ask me!
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Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!