All Questions
Tagged with preamp vacuum-tube
8 questions
2
votes
1
answer
113
views
Tube amplifier preamplifier
I received this little two tube preamp
http://www.gikfun.com/electronic-diy-kits-c-7/6j1-tube-preamplifier-board-20-stereo-multiple-diy-kit-p-730.html
It comes with 9 470uF caps. The symbol on the ...
- 3,661
14
votes
1
answer
369
views
Why is there a winding on a capacitor?
I just came across this tube RIAA preamp on which there is a coil on the input capacitor, can someone please explain what's the reason of such thing? The schematic and the actual circuit bellow.
The ...
- 455
-2
votes
2
answers
2k
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Single double triode vacuum tube for headphone amp at high voltages
I'm planning to build a single double triode vacuum tube as I have seen many schematics even though most of them are low voltage (20-40v). However I didn't seem to find a high voltage single double ...
- 365
4
votes
1
answer
2k
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How do you know if a vacuum tube is going to suffer from AC hum or not?
I know that technically there is little difference between AC or DC heating of the tube - if it gives proper voltage everything is fine... Except the hum:
I have read in various sources that some ...
- 365
0
votes
3
answers
4k
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Running preamp tube filament on 5v?
Is it safe and not harmful to run a preamp tube filaments at 5v? The tube is ECC85. I built a tube preamp in a DIY portable guitar amp. It's very similar to Matsumins valvecaster with a few slight ...
- 365
2
votes
2
answers
2k
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Why are JJ Electronic R.F. preamp tubes preferred over A.F. tubes in guitar amps?
JJ Electronic has both R.F. (radio-frequency) and A.F. (audio frequency) versions of some of their tubes.
Yet in far the most tubeshops for guitar amps they only sell the R.F. versions (ECC83 S - ...
- 125
0
votes
1
answer
5k
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How does one calculate the input impedance of a tube based preamp?
I'm finding tons of information and equations on calculating this for solid state devices, but nothing for good old fashion particle accelerator based amplifiers :P
Currently I'm revamping the K270 ...
0
votes
1
answer
1k
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Need a voltage follower buffer for a tube, how do I calculate and select a mosfet?
I'm finishing up a design here: https://123d.circuits.io/circuits/852190-jan-6418-vaccum-tube-valve-preamp which is a preamp for an instrument.
First, let me know if anything stupid pops out at you ...