Another linestage......

kianbach · 26th June 2005, 03:41 PM

Will THIS work and if not why not?

SY · 26th June 2005, 03:52 PM

The plate of the first stage is at AC ground.

kianbach · 26th June 2005, 04:01 PM

Explain please I'm a newbie

moamps · 26th June 2005, 04:58 PM

Quote:

Originally posted by kianbach
Explain please I'm a newbie

The anode resistor on the input tube is missing.

Regards,
Milan

kianbach · 26th June 2005, 06:01 PM

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 · 26th June 2005, 06:36 PM

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 · 26th June 2005, 06:52 PM

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 · 26th June 2005, 08:10 PM

Quote:

Originally posted by kianbach
..... 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
Rc=Vgc/Ia=100ohm (in your schematic 390ohm),
Ra=(Vcc-Va)/Ia=150/0,01=15kohm (dropper in your schematic).

Regards,
Milan

kianbach · 26th June 2005, 09:29 PM

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

kianbach · 28th June 2005, 01:11 PM

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.

26th June 2005, 03:52 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	The plate of the first stage is at AC ground. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

26th June 2005, 06:36 PM	#6
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	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...? __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

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26th June 2005, 04:01 PM	#3
kianbach diyAudio Member Join Date: Apr 2005 Location: anglesey	Explain please I'm a newbie

26th June 2005, 06:01 PM	#5
kianbach diyAudio Member Join Date: Apr 2005 Location: anglesey	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?

26th June 2005, 06:52 PM	#7
kianbach diyAudio Member Join Date: Apr 2005 Location: anglesey	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.

26th June 2005, 09:29 PM	#9
kianbach diyAudio Member Join Date: Apr 2005 Location: anglesey	Thanks for your help.Will the second stage be OK as is or do I need to change anything?

28th June 2005, 01:11 PM	#10
kianbach diyAudio Member Join Date: Apr 2005 Location: anglesey	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.

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