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C3M linestage

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dsavitsk

dsavitsk

diyAudio Member
Joined 2005
diyaudio.ecp.cc
costa23 said:
I wanna build the C3M linestage in triode mode.
Does anyone have the good scheme....
Please.....
Click to expand...

What sort of gain/Zout do you need? I have used them with a CCS load and a parafeed OPT which seems to work well.

commstech said:
why not just use a triode ?
Click to expand...

Because it is a really linear tube as a triode, and because there are few, if any, triodes that have similar specs.
 
C

costa23

Member
Joined 2008
i wanna build this c3m with anode follower (RC) topology.
i will use this preamp with 6sn7-300b single ended (JE lab design).
I've heard that this tube sound great as triode, so i wanna try to build one.
My plan is:

B+ 300V
Vp 150V
Rp 22 K
Ip 7 mA
Rk 0.5 K
Bias -6 V
How about that....

Please help

thanks


Regards,


hendra
 
K

Klimon

Member
Joined 2005
costa23 said:
thanks for your comment
i think the je labs gain is not high enough...
Click to expand...

Unless I'm very mistaken, it should be able to drive the 300b's into clipping.

See here for distortion comparison between c3m pentode and 6sn7 cascade: http://www.pmillett.com/pentodes.htm

Should you be interested, schematics for c3m + 300b amps can be found here:

http://www.fortunecity.com/rivendell/xentar/1179/projects/legacy/Legacy.html

http://www.diyparadiso.com/sedesign1.htm

Edit: Millett's page does not feature the c3m, but the measurements of other high-gm pentodes should give you a basic idea...

Simon
 
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disco

disco

Member
Joined 2006
C3M trioded makes an great driver indeed, just installed one on a 2A3 amp.
Kathode resistor 220 ohm for circa 4V bias, CCS at 18-20mA for 130V plate voltage. Excellent sonics.

edit: in case you need to swing more volts, set Va=200V Vg-=-9V by a resistor of 643 ohm. Ia should be around 12-14mA.
 
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Stixx

Stixx

Member
Joined 2003
original-ton.net
You might as well use the C3G which has the advantage of 6.3V heaters, the same delicate frame grid construction (C3G has it for sure...) and very good sonics, at least in my C3G headphone amplifier.
Going through your numbers for the C3M you will be running 12mA with the 500R cathode resistor (when I am not mistaken) which still is absolutely no problem for both of them...
 
C

commstech

Member
Joined 2002
disco said:
C3M trioded makes an great driver indeed, just installed one on a 2A3 amp.
Kathode resistor 220 ohm for circa 4V bias, CCS at 18-20mA for 130V plate voltage. Excellent sonics.

edit: in case you need to swing more volts, set Va=200V Vg-=-9V by a resistor of 643 ohm. Ia should be around 12-14mA.
Click to expand...

have u tried the C3M in pentode mode driving your 2A3? i prefer the pentode mode as a driver for DHT. In the pentode mode, the mid range blooms gloriously....and the vocals sounds rich, nice ambience to the music. In the triode mode driving DHT, the sound seems to thin out and add some rawness to the higher frequencies.
 
disco

disco

Member
Joined 2006
commstech said:
have u tried the C3M in pentode mode driving your 2A3? i prefer the pentode mode as a driver for DHT. In the pentode mode, the mid range blooms gloriously....and the vocals sounds rich, nice ambience to the music. In the triode mode driving DHT, the sound seems to thin out and add some rawness to the higher frequencies.
Click to expand...

I haven't because of the ancient insight that high Ri has to deal with mr. Miller. :)
You see I'm new to CCS, I'm trying Garys for the first time here.
The mu-output gives low enough output impedance, right?
 
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