For my first attempt at tube DIY I want to make a simple low voltage buffer for my cd Player. The DAC has a 2.4V p-p balanced output, although I can easily change this to a unbalanced o/p if required.
I want a good, simple, reliable circuit that will operate at no more than about +/-35V with a low input impendance and no output transformer.
Can anyone recommend something.
Kind regards
Paul
I want a good, simple, reliable circuit that will operate at no more than about +/-35V with a low input impendance and no output transformer.
Can anyone recommend something.
Kind regards
Paul
Why not an SRPP with a 6GM8 / ECC86 ?
As per "Tube CAD", allows for about 10mA plate current, gain should be around 17 dB with no cathode bypass and output Z less than 2K.
Moreover, with symetrical supply, the output could easily be set at ground potential, eliminating the need for any output cap.
Yves.
I agree with Geek, use transistors.
http://www.borbelyaudio.com/adobe/ae699bor.pdf
Page 3 shows some simple JFET buffers with performance measurements.
http://www.borbelyaudio.com/adobe/ae699bor.pdf
Page 3 shows some simple JFET buffers with performance measurements.
"...... that will operate at no more than about +/-35V with a low input impendance and no output transformer.
Transistors."
Ha Ha, Aren't you people supposed to be trying to convert everybody to the wonders of tubes!
As this will be my first tube project I wanted something simple to build and fault find if it goes wrong. Thats the idea of low voltage and no transformer. If it goes wrong I wont cry over all that cash thats gone up in smoke!
I thought I would sample some of that valve sound in a little way first of all to see what the fuss is about.
For the others thanks for the leads, Say you havent got any circuits to post. I have found some but have no idea if they are reliable.
Transistors."
Ha Ha, Aren't you people supposed to be trying to convert everybody to the wonders of tubes!
As this will be my first tube project I wanted something simple to build and fault find if it goes wrong. Thats the idea of low voltage and no transformer. If it goes wrong I wont cry over all that cash thats gone up in smoke!
I thought I would sample some of that valve sound in a little way first of all to see what the fuss is about.
For the others thanks for the leads, Say you havent got any circuits to post. I have found some but have no idea if they are reliable.
If you're going to the bother of using tubes, go to the bother of using reasonable voltages for them. If you insist on limiting yourself to 30 volts, the tube choices are awfully slim- Nuvistors are logical, but darn hard to source, microphonic, and expensive.
A 100-200V supply isn't all that expensive or difficult.
A 100-200V supply isn't all that expensive or difficult.
This is a great sounding little one and hard to overdrive 
http://geek.scorpiorising.ca/contrib/Geek/12AU7-SRPP.png
http://geek.scorpiorising.ca/contrib/Geek/12AU7-SRPP.png
I like tubes if I'm looking for voltage gain, especially for small input voltages, like phono preamps, or if the output needs large voltage swings at modest currents, like electrostatic headphone drivers.
If i'm looking for a buffer, with no voltage gain, some current gain, with line-level signal voltages and supply voltage less than 100V I find that transistors, especially jfet input and bipolar output, work well and have little sonic coloration if biased class A.
If i'm looking for a buffer, with no voltage gain, some current gain, with line-level signal voltages and supply voltage less than 100V I find that transistors, especially jfet input and bipolar output, work well and have little sonic coloration if biased class A.
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