New 6N6P linestage

[Brit01]

Hi all,


Just threw together a new linestage. Got loads of tubes and experimenting with all types of designs.

Sounds very nice indeed. No hum, no noise, very detailed, good punch.

Even thought I'm using a very simple SS power supply, simple CRCRC.

Please have a look at the voltages, values and see what you think. B+ is a little high a think. Current on lower tube is 5.8mA I believe. Could do with raising this somewhat I guess.

Now I'm not too familiar with this design. Your guidance would be appreciated on currents.

[Brit01]

Slight mod to design:

[zigzagflux]

I'd say the voltages look pretty good. Anywhere from 90V to 150V seems to be a popular range for this tube. I run them at 105V in my D/A and 150V in my amp.

I would agree that you might find marked improvement by increasing the current, but this is of course application and topology dependent. By the curves, it shouldn't matter, but subjectively this tube seems to enjoy running at higher currents and lower grid voltages. As a linestage, you might be able to run successfully at a 3 or 4V grid instead of 7. There is typically low grid current up to +0.5V.

Worth a try; just change a few resistors and make sure the PS can handle it.

[Brit01]

Cool!

Made some improvements and changes to values.

Very pleased with the sound indeed.

[SY]

Why the SRPP? A line stage only needs to swing a few volts and the loads aren't horribly reactive. A plain vanilla common-cathode stage with a CF would have lower distortion and less stress on heater-to-cathode.

[Brit01]

Why the SRPP?

Why? Just for experimentation. Trying out all different designs to see how they sound.

Thks for your advice. I'll try out your suggestions for the next one.

A plain vanilla common-cathode stage with a CF would have lower distortion and less stress on heater-to-cathode.

Interested in knowing how the triode strapped pentode would sound in the CF stage of your idea. I have some SV83's which I heard are very linear.

Would this be a good idea?

[SY]

I haven't used those, but I've had excellent results with triode-strapped EF86, 5879, and D3a.

[Brit01]

This is a very crude design.

Just to check how to strap a pentode.

Would this be the correct form?

G2 strapped to anode (with resistor)

G3 strapped to cathode.

Is a cap between the anode of the first triode and G1 of the pentode necessary?

[SY]

For small signal pentodes, I generally tie g2 directly to plate. Usually g3 to cathode, but that could go either way- take a look at the D3a datasheet which shows characteristics with g3 to plate vs g3 to cathode.