Another linestage......

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kianbach

Will THIS work and if not why not?

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SY

The plate of the first stage is at AC ground.

moamps

kianbach said:

The anode resistor on the input tube is missing.

Regards,
Milan

kianbach

What sort of value should I use?

Is there a formula to work it out apart from Ohm's law for dropping voltage?

I've got some 6k8 and 10k resistors.Would either of these do?

SY

I don't mean to be rude, but you're asking a lot of questions about arrows and you haven't yet defined the target. What are you trying to accomplish? Gain, source Z, load, distortion, signal-to-noise...?

kianbach

Well,I've got an SRPP 6SN7 linestage atm and am looking for more gain and/or a different sound.A few months ago I tried Joel's 12AY7/6SN7 circuit but with ecc81 and 6N7 and liked the sound of it but was thinking of having 1/2 the B+ for the 1st stage and direct-coupling between stages,hence this sorry attempt at designing my own.I was hoping someone could point me in the right direction,I need to drive a SRPP 6SN7/2A3 SE power amp.

moamps

kianbach said:
..... I tried Joel's 12AY7/6SN7 circuit but with ecc81 and 6N7 and liked the sound of it but was thinking of having 1/2 the B+ for the 1st stage and direct-coupling between stages.....I need to drive a SRPP 6SN7/2A3 SE power amp..

Hi,

Use 300V B+ for ECC85 (omit OA2 and 0.1uF),
Va=150V, Ia=10mA, Vgc=-1V,
then

Regards,
Milan

kianbach

Thanks for your help.Will the second stage be OK as is or do I need to change anything?

kianbach

Well it's built and running!Sounds nice,plenty of gain,Drives my 2A3SE no probs.Ear bleeding volume from my Lowther Acoustas.
Values as follows::

B+ 300v
Ecc85 anode R = 15k
Ecc85 cathode R = 220r
6N7 cathode R = 23.5k(47k x 2)

total current draw 25mA from a 100mA tranny.

NICE!
Will post Picks soon but it looks rough as it's on my experimantal/Frankenstein chassis.

amperex

Sucks

Move one to a quality design...........

kianbach

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