I'm wanting to whip up a classic but simple valve microphone pre amp. You know, input transformer, phantom power, quiet power supply, maybe output transformer. Nothing fancy. But my google-foo is failing: I can find this thread but not much else. I was expecting that there'd be sites dedicated to repairing/contrasting classic designs but I'm just not finding them.
Any suggestions?
Any suggestions?
There's quite a few on diy audio just search. Balanced in, balanced out? The best tube is probably ecc88 for noise. Transformer step up at input ECC88 gain stage followed by ECC88 cathode follower and output transformer. There are lots of other options including nuvistor tubes, and differential amps.
Thanks folks, some interesting suggestions there. However I've misstated quite what I'm looking for: perhaps I should have described it as a "input stage providing microphone phantom power". So I'm really looking for a studio preamplifier circuit (perhaps a single channel from a desk) from perhaps the late fifties or sixties with an input transformer then valve amplification.
Why? I'm following the trail left by R. O. Hamm, 1973 21(4) JAES to get an input stage that overloads sensibly.
I've already got a few jfet units and have done more op-amp circuits than I care to count and have done a range of diode limiter circuits. I know what these sound like.
I know how to design such a circuit but am hoping that there's a "classic" circuit to copy, as half the work will be sorting out the power supplies to get a decent noise floor. I'm also assuming the actual vintage units will be "collector$$$ item$$$" by now.
Why? I'm following the trail left by R. O. Hamm, 1973 21(4) JAES to get an input stage that overloads sensibly.
I've already got a few jfet units and have done more op-amp circuits than I care to count and have done a range of diode limiter circuits. I know what these sound like.
I know how to design such a circuit but am hoping that there's a "classic" circuit to copy, as half the work will be sorting out the power supplies to get a decent noise floor. I'm also assuming the actual vintage units will be "collector$$$ item$$$" by now.
The Altec 1567A is a true classic mixer. Or just use one channel.
http://altec.bayoucables.com/Altec-1567A-MixerAmp.pdf
http://altec.bayoucables.com/Altec-1567A-MixerAmp.pdf
Thanks folks, some good leads there. I've also found lots of interest around Bill Putman's Universal Audio 610.
Found a few
https://vdocuments.mx/universal-audio-610-a.html?page=1
Found a few
https://vdocuments.mx/universal-audio-610-a.html?page=1
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