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Old 6th February 2009, 11:05 PM   #1
Brit01 is offline Brit01  United Kingdom
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Default Stereo Buffer with a single twin triode

I'm looking to build a stereo buffer amp but possibly with just 1 twin triode such as a 6N6P.

I heard that crosstalk is not really an issue so I would like to see if I can use 1 triode to handle the left and right signals.
Input source will be a standard CDP and the buffer will be used with a SS power amp.

CDP>Buffer>Power amp.

Simple self bias cathode follower is on my mind here. But how to design this with the left and right signals is puzzling me a little. Please take a look and let me know.
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Old 7th February 2009, 12:38 AM   #2
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Wow, that circuit is mouth watering...TWO caps in the signal path...for a buffer preamp that's rarely needed nowadays...you had me at "Hello"

Maybe try this page http://www.lampizator.eu/UPGRADE/upg...to%206H6P.html and this circuit http://www.lampizator.eu/UPGRADE/new%20CF%206H6P.mdi

IMHO if you going to build this at least put a CCS in place of the cathode resistor.
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Old 7th February 2009, 01:09 AM   #3
SY is offline SY  United States
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Quote:
But how to design this with the left and right signals is puzzling me a little.
Judging from the schematic, you don't seem puzzled.
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Old 7th February 2009, 01:25 AM   #4
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You can eliminate the caps. on the I/P side, if you use a bipolar PSU.

Constant current sink (CCS) loading is an excellent idea. While a SS cascode or pentode is "best", even the comparatively simple 10M45S will be better than a resistive load.

I agree with SY, in that your schematic makes sense. What is it about stereo that's got you worried?
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Old 7th February 2009, 12:17 PM   #5
Brit01 is offline Brit01  United Kingdom
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Quote:
Wow, that circuit is mouth watering...TWO caps in the signal path...for a buffer preamp that's rarely needed nowadays...you had me at "Hello"
Had a feeling that leadbelly would chime in first. Lol
Yes I wasn't sure about the caps.

What software did you open this with?



Quote:
IMHO if you going to build this at least put a CCS in place of the cathode resistor
I need to look into this as I'm not too familiar with CCS. Any references to circuit ideas would be great.

Quote:
I agree with SY, in that your schematic makes sense. What is it about stereo that's got you worried?
Most of the designs seem to use 2 separate tubes, one for each channel. If there is no crosstalk involved I'd like to use the 2 triodes in one tube.
Do I need a twin triode with a screen to implement this design? The article that leadbelly included states there are 2 types of 6N6P.
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Old 7th February 2009, 12:36 PM   #6
SY is offline SY  United States
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Quote:
I need to look into this as I'm not too familiar with CCS. Any references to circuit ideas would be great.
Here's one:

http://syclotron.com/?page_id=8
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Old 7th February 2009, 01:13 PM   #7
Brit01 is offline Brit01  United Kingdom
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Thks Sy.


But I'm trying to keep the circuit as simple as possible without sacrificing performance too much.
This is getting a little too complicated.
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Old 7th February 2009, 01:37 PM   #8
SY is offline SY  United States
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My solution was a bit complicated, but the CCS use was what I wanted you to see. You could use an input cap in place of my transformer coupling if you want to keep a single supply.
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Old 7th February 2009, 01:39 PM   #9
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Here is a similar circuit ( with obvious mistakes !! )

Uses a CCS in the cathode

(available from Ebay seller Audiotek *** - a wellknown scammer)


Andy
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Old 7th February 2009, 01:41 PM   #10
Brit01 is offline Brit01  United Kingdom
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Just released that was your web site and designs!

Bit slow on the take up this morning.

Nice work Sy.
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