• 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.

6V6 line preamp

Jump to Latest
S

stajo

Member
Joined 2011
It is very hard to see on schematics because the 6V6 in this application is working so low compared to its capacity and normal operating area that it is almost impossible to judge from the loadline on paper. But your measures on the scope shows good results.

I wonder how Salas came up with this idea, cause its a bit odd but showes good results.

At this currents a 1660 gaped for 18 mA (wich I happen to have somewhere) would be happy.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
stajo said:
It is very hard to see on schematics because the 6V6 in this application is working so low compared to its capacity and normal operating area that it is almost impossible to judge from the loadline on paper. But your measures on the scope shows good results.

I wonder how Salas came up with this idea, cause its a bit odd but showes good results.
Click to expand...

The blue rectangle point is what George has now. The red point is what we use when B+ is plenty. When assuming that the reissue tubes are staying roughly on that old GE map of course. Each valve is consuming 3W when on the blue, 4W when on the red. We go a little >200V >4W usually for the red, but I centered it for clarity.
 

Attachments

  • Snap 2013-03-23 at 12.21.20.png
    Snap 2013-03-23 at 12.21.20.png
    122.6 KB · Views: 439
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
stajo said:
And heres Georges approximate loadline. I put some marks around where the tube operates with 2 V RMS in.
Click to expand...

Correct load line. Its a a bit of a niche for long life cool tubes not pushed for current which is usually a noisier situation. Being output tubes they are designed for high swings so when in a line pre we can keep them even more linear.
 
S

stajo

Member
Joined 2011
vgeorge said:
TSSA and Baby Huey. Brings the best out of them.
Have not listened much yet, but the sonic signature is more or less the same.
I think it would be ideal for F5 though, or other low gain amps with highish input impedance.
Click to expand...

So I dont intend to be a partybuster here but the Baby Huey has sensitivity enough for line level input. Just for scientific reason it would be interesting to compare your impression on what some would call the best preamp in the world. None at all. You had a TVC dont you?
 
vgeorge

vgeorge

Member
Joined 2004
goldenview.gr
My phono stage has about 0,3V output, so some gain is required. Tried it with a buffer, but was marginal. If you wanted to rock a little bit sometimes, or with lower level recordings, no chance.
With cd you should be ok.
Also I use the TSSA which has around 20dB sensitivity, and there is a must.
As I was thinking to apply some GNF to the power amp - as an experiment, maybe I like it more - this would drop the sensitivity a little more, so some gain is necessary in this situation too.
 
You must log in or register to reply here.
Top Bottom