Hey all,
I'm reconfiguring a Berlant Series 30 record electronics package for use as a mic/line/DI amp. I've got the mic side of things working, and now I'm on the instrument input/DI side. If you look at the attached schematic, I've got the guitar input going in to what used to be the playback electronics (V6 at bottom left, a 12ax7), as of now the only addition is a 1Meg resistor on the input jack and 1000uF cathode bypass caps on both 12ax7 triode stages. Voltages seem to be holding steady, I've swapped tubes and it doesn't seem like that's the issue. Anyway, have a listen to the mp3 in the attached .zip file and tell me whats going on. Is this some sort of extreme blocking distortion? The click you hear is the initial pick attack, then the body of the note sort of rides back up and is all nasty-like. I'll gladly get more info (voltages, etc..) if you'd like.
Thanks in advance to anyone with an insight.
I'm reconfiguring a Berlant Series 30 record electronics package for use as a mic/line/DI amp. I've got the mic side of things working, and now I'm on the instrument input/DI side. If you look at the attached schematic, I've got the guitar input going in to what used to be the playback electronics (V6 at bottom left, a 12ax7), as of now the only addition is a 1Meg resistor on the input jack and 1000uF cathode bypass caps on both 12ax7 triode stages. Voltages seem to be holding steady, I've swapped tubes and it doesn't seem like that's the issue. Anyway, have a listen to the mp3 in the attached .zip file and tell me whats going on. Is this some sort of extreme blocking distortion? The click you hear is the initial pick attack, then the body of the note sort of rides back up and is all nasty-like. I'll gladly get more info (voltages, etc..) if you'd like.
Thanks in advance to anyone with an insight.
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Moved this to Instruments and Amps per forum policy.More likely that someone here will be able to help you. 😀
First comment is those 1000uF cathode bypass caps are about 10 - 20X too large, and second there is probably too much gain and the input stage is overloading.
Note that the circuit shown for V6 is a tapehead amp complete with very high voltage gain, and playback EQ. This is unsuitable as wired for use with a guitar pick up.. Take a look at the first stage of the mic amp and do something similar here. Using an active pickup may require a two jack set up with a "passive" and "active" jack a la Fender..
Note that the circuit shown for V6 is a tapehead amp complete with very high voltage gain, and playback EQ. This is unsuitable as wired for use with a guitar pick up.. Take a look at the first stage of the mic amp and do something similar here. Using an active pickup may require a two jack set up with a "passive" and "active" jack a la Fender..
Hi, I appreciate the schematic, helps me work on mine.
My concern is why you would modify it though, i mean, Ampex, Berlant, Magnecord, Crown, etc were made for the vintage mics, and aren't that great for mic preamps, I have a tube recording studio and have restored Ampex,etc for Tape recording, but would not Dare use these preamps for mics, MY in house ones are so much better sounding. And offer more features.
-Chris
My concern is why you would modify it though, i mean, Ampex, Berlant, Magnecord, Crown, etc were made for the vintage mics, and aren't that great for mic preamps, I have a tube recording studio and have restored Ampex,etc for Tape recording, but would not Dare use these preamps for mics, MY in house ones are so much better sounding. And offer more features.
-Chris
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