What to do with C3g tubes

[AJMARS]

I did a two stages SE amplifier using a C3g (triode connected) and a 211 or TM100 or MC1/60 or RS237 power triode (I have the 4 options).... and I am really happy with it.
The C3g can deliver 60 V peak signal on the grid of the "big" triode with 2 V at the input (my CD and RIAA stage can deliver more than 2V) at quite low impedance (about 2500 ohms).

Here is a little view of the amplifier...

An externally hosted image should be here but it was not working when we last tested it.

The amplifier is built in 3 parts, two mono blocs for the power triodes and one stereo input stage (here with the C3g)
I did made a lot of tests as input stages, EC86, E81L, ECC35 + VT52, 6SL7 + 6A3 (or 6B4G)... le C3g is the one I prefer.
I will try a E80L as pentode.

André

 

[adalin]

I was sorting some boxes with tubes today and came across what I thought was C3g tubes but they where to my surprise C3m tubes, the marking on the boxes was faded.

I came to think about this thread and decided to expand it to C3m territory

I built a experimental preamp with C3g and it worked.
But then I forgot about it, until now.

So what can one build with C3m tubes?

Preamp or use it as a driver tube perhaps?

 

[kevinkr]

C3M can be used for all the same applications as the C3G in my very limited experience. I had both at one time and now only have C3G here.

 

[RajkoM]

Man has a lot of the best small signal tubes in the world, and wondering what to do with them

 

[adalin]

Well its not as I dont know what kind of tubes they are.

I know how good the curves look in both pentode and triode mode.

But there is not a lot of information about practical use and I want to collect that information here.

Because both c3g and c3m are masterpieces in their own way.

And I like all the pictures people have posted so far.

 

[RajkoM]

But there is not a lot of information about practical use and I want to collect that information here.

It will not be so.
On the net you have a ton of information about practical use C3g and C3m tubes in audio.

 

[pauldune]

That picture of the cut open c3g
I want to build something with it, just for looks only
It is soooo beautiful...

 

[wicked1]

What causes the blue glow in that particular picture? Some gas in the tube, or is the mica or something fluorescing?

 

[adalin]

Its not gas, I have seen the effect in all the c3g tubes I have re-based so its probably stray electrons hitting the mica or something similar.

and yes there is a lot of schematics on the net with c3g and c3m driving 300B and similar, but its still nice to discuss them further and to experiment with CCS and led bias and chokes ect ect

 

[adalin]

I stripped a C3m tube and put it in my AVO and there is a trace of blue glow on the mica in these tubes also, not as clear as the C3g tubes though

 

[euro21]

A few months ago I (re) built an amp for my friend.

C3g, IR+Red LED bias, gyrator loaded, cap coupled to "powerdrive", 300B SE, Transcendar 5k:8 OPT.

Very balanced sound, but a bit insensitive (due to the high DCR of OPT).

 

[pauldune]

You mounted them in an octal base; could you explain how you did that?

 

[euro21]

These are old Siemens loctal sockets (black bakelite?). I bought these a few years ago in hamfest.

 

[adalin]

A led bias, nice

I like the russian loctal sockets because it puts no stress on the pins, But I do have a bunch of old german sockets with a grounding collar around the socket that fits the C3g perfectly, they are nice and high quality.

 

[soulmerchant]

I stripped a C3m tube and put it in my AVO and there is a trace of blue glow on the mica in these tubes also, not as clear as the C3g tubes though

oh that mesh plate... get the heater supply right and you are in for a real surprise...

 

[RajkoM]

oh that mesh plate... get the heater supply right and you are in for a real surprise...

It is not mesh plate. It is mesh connected to cathode in C3m.

 

[zflazar]

Line-amp with Lundahl 1660 4:1 Output and TVC as Input.
In Triode-mode because "euro21" is right - in Pentode Ri is way to high.
Sound is fantastic.
For optical reasons you can cut with a sharp knife or a very fine saw the alu-case and you will see the nice glow of the heaters.

Hilmar

Hilmar, did You use the Lundahl 1660/18mA version ?

Zoltán

 

[Leucate]

PCM5142 based on C3m:

An externally hosted image should be here but it was not working when we last tested it.

 

[motorbreath]

Sorry to revive this older thread , but since i'm in the process of starting a C3G line preamp built, i am looking for a schematic of a line preamp, using the C3G as the only gain stage and GZ34 rectifier for stable power. Anyone knows of a schematic for this? I am planning of using no volume at all, and transformer wise i think 8K/600Ohm split would be ok, with 60mA as a max?
cheers all

 

[Datun Walnut]

So I got a large amount of C3g tubes and Im looking for projects that fits this tube perfectly

So what can you really do with these tubes?

They are really great tubes, the curves look beautiful and the build quality is superb

I feel bad to let them waste away on a shelf

so enlighten me!

I've you were thinking of selling a pair, I'd love them.
I've been told they a great in littledot amplifiers