• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

37 / 6080 pre-amp

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I want to build a pre which is a 37 connected to a 6080 CF.

No holds barred pre. Cost not really an object.

Should I DC couple them, cap couple them? Seperate or same PS?

Run the 37 at 135v, 4ma, 9v bias (battery).
Run the 6080 at 140v, 40mA, unsure on bias (recommendations?).

Probably MV rectifiers (which ones?) and regulator tubes (?).

Power Supply ideas?

Thanks!!!!
 
Ok.

Well, unless you need to drive a mile of cable, I think a lower current CF tube would be easier to implement - considering the current draw of the 6080.
Now, I myself am building a 6080 SE amp currently, and I have them biased down to 50mA, which is reasonable - but in order to do that, they need the grids at -125V! So, that's a monstrous amount of signal voltage needed.

These are the issues when using the regulator tubes.

Anyway, I would think for any normal preamp operation and cable length that you could use something a lot easier to work with - like a 12BH7, etc. This will still give you a good 10-15mA of current, and a reasonably low Zo. ;)

Joel
 
gain

I need 2 stages for voltage gain. I want around 5-10 for voltage gain, but have a nice meaty output stage... specifically to potentially drive some nasty input capacitance on my MOSFET amp.

Thats why I was thinking of a 2 stage amp.

Unless I use a high mu tube WOT..... hmmm....

I always liked the sound of the 37 though.
 
analog_sa said:
Just curious, why do you need a CF? They have a controversial reputation soundwise to say the least. With a single 6080 in common cathode you'll get plenty of drive and low output resistance. Do you really need two stages?

I agree. Nothing wrong with CFs , but IMHO
it's easier to get good sound without them.

I you need a lot of gain,
an alternative would be 37- 6080 in cascade.
Separate power supply for the 37 and the 6080.

cheers ;)
 
Hi Richard

If I were to build this, I would breadboard the power supplies and
the line-stage, with lots of room around the components,
so it is easy to change things .
Then try out different valves and configurations, and use what
sounds best to you. You learn a lot about your own preferences
this way.
Now, I have never used the 6080 , so it would be wrong of me to
suggest operating points, Joel might give you a hint, since he is building
with them at the moment.
My own preference is as high a voltage as I can with the components I have on hand, and then adjust the sound with the current , but this is just a taste thing.
Since you are designing it yourself you can build what sounds good to you. ;)

Cheers :drink: ;)
 
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