Adding tube to Audiosector GC

marcus7601 · 13th June 2008, 11:45 AM

I am looking into a way to add a 6N1P (6922) tube into a already finished Audiosector 3875 gainclone. I have very little knowledge of tubes and i dont want to break up the gainclone pcb i already have assembled.

Is there and easy way to add a tube on the input of the GC?

To be honest i dont care much about improving the sound quality, i just want to fiddle around with my first tube project.

I am using 35V rails to my GC and i now that there are projects that uses this with LM3875 and 6922 tubes but i want to use the audiosector kit i already have.

Please help a newbie!

ionomolo · 13th June 2008, 01:28 PM

Yes, there is:

http://www.customanalogue.com/diytub...lone/index.htm

If the amp is AC-Coupled noninverting connect the cathode of the tube directly at the input and check if placing something like the 1n5 cap removes some noise.

The 1n5 cap is imprescindible in the inverting amp as it is to make the noise gain of the amplifier independent of the source impedance.

marcus7601 · 13th June 2008, 01:56 PM

Hmm...can you be more specific?

Which part of the schematic from the link should i use to then connect to the input of my gainclone?

ionomolo · 13th June 2008, 02:49 PM

The tube, the input (resistor + pot) network and the cathode resistor (4 parts).

If your amplifier is DC coupled (does not have a resistor and a cap at the input) you should use a capacitor and a resistor to connect the tube

leadbelly · 13th June 2008, 03:47 PM

A 6N1P is NOT equivalent to a 6922, no matter what the eBay sellers say. If you want to use low voltage rails I recommend you use a ECC88, 6922, or 6N23P.

Nordic · 13th June 2008, 04:19 PM

add 6DJ8

A nice High voltage supply can be made with a 2x24V PCB mount transformer and a greinacher voltage doubler useing caps from a dead PC PSU...

flubug · 13th June 2008, 05:07 PM

What's the problem with using the 6N1P?

leadbelly · 13th June 2008, 05:33 PM

Quote:

Originally posted by flubug
What's the problem with using the 6N1P?

It's not a low voltage tube and will add lots of distortion with the suggested +/-35V rails.

flubug · 13th June 2008, 06:00 PM

QUOTE: It's not a low voltage tube and will add lots of distortion with the suggested +/-35V rails.

Thanks for the warning! You probably saved me a lot of grief.

marcus7601 · 13th June 2008, 09:03 PM

Thanks for the tips but i will use my 6N1P for testing and maybe later change to better tube.

I cant seem to find schematic to audiosectors gc to check the ac-coupling. Anyone knows where to find it?

13th June 2008, 11:45 AM	#1
marcus7601 diyAudio Member Join Date: Jun 2006	Adding tube to Audiosector GC I am looking into a way to add a 6N1P (6922) tube into a already finished Audiosector 3875 gainclone. I have very little knowledge of tubes and i dont want to break up the gainclone pcb i already have assembled. Is there and easy way to add a tube on the input of the GC? To be honest i dont care much about improving the sound quality, i just want to fiddle around with my first tube project. I am using 35V rails to my GC and i now that there are projects that uses this with LM3875 and 6922 tubes but i want to use the audiosector kit i already have. Please help a newbie!

13th June 2008, 03:47 PM	#5
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	A 6N1P is NOT equivalent to a 6922, no matter what the eBay sellers say. If you want to use low voltage rails I recommend you use a ECC88, 6922, or 6N23P. __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

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13th June 2008, 01:28 PM	#2
ionomolo diyAudio Member Join Date: May 2007 Location: Los Angeles	Yes, there is: http://www.customanalogue.com/diytub...lone/index.htm If the amp is AC-Coupled noninverting connect the cathode of the tube directly at the input and check if placing something like the 1n5 cap removes some noise. The 1n5 cap is imprescindible in the inverting amp as it is to make the noise gain of the amplifier independent of the source impedance.

13th June 2008, 01:56 PM	#3
marcus7601 diyAudio Member Join Date: Jun 2006	Hmm...can you be more specific? Which part of the schematic from the link should i use to then connect to the input of my gainclone?

13th June 2008, 02:49 PM	#4
ionomolo diyAudio Member Join Date: May 2007 Location: Los Angeles	The tube, the input (resistor + pot) network and the cathode resistor (4 parts). If your amplifier is DC coupled (does not have a resistor and a cap at the input) you should use a capacitor and a resistor to connect the tube

13th June 2008, 04:19 PM	#6
Nordic diyAudio Member Join Date: Sep 2005	add 6DJ8 A nice High voltage supply can be made with a 2x24V PCB mount transformer and a greinacher voltage doubler useing caps from a dead PC PSU...

13th June 2008, 05:07 PM	#7
flubug diyAudio Member Join Date: Mar 2004 Location: Atlanta	What's the problem with using the 6N1P?

13th June 2008, 06:00 PM	#9
flubug diyAudio Member Join Date: Mar 2004 Location: Atlanta	QUOTE: It's not a low voltage tube and will add lots of distortion with the suggested +/-35V rails. Thanks for the warning! You probably saved me a lot of grief.

13th June 2008, 09:03 PM	#10
marcus7601 diyAudio Member Join Date: Jun 2006	Thanks for the tips but i will use my 6N1P for testing and maybe later change to better tube. I cant seem to find schematic to audiosectors gc to check the ac-coupling. Anyone knows where to find it?