Jump to content
Sign in to follow this  
neutralzz

Another POST tube amp

Recommended Posts

built a c3g amp in triode mode based on the datasheet specs

 

the sound? superb! no wonder pre-amps of reference standard uses these tubes, i.e. ypsilon, ayon etc, yamamoto uses c3m to drive their 300b in their A11 amplifier.

 

whole amp was rigged out of spare parts here and there, including an el'cheapo power supply and simlim tower parts.. nothing audiophillic as it was just a prototype to see if tube sounds good before using good parts etc. the only expensive thing was the blackgate cap on the cathode because i couldnt rummage out anything of the value required out of my stash except the gates

 

coupling cap to output is cheap german mkp capacitors etc, total wiring with up-occ copper (leftover from old project), original NOS siemens socket as i couldnt find other cheap loctal sockets in singapore thus had to sacrifice my NOS stock.

 

IPB Image

 

IPB Image

 

IPB Image

Share this post


Link to post
Share on other sites

Power brother! Wow, a tube amp built on a literal breadboard! Respect. :thumbup:

Edited by heady

Share this post


Link to post
Share on other sites

thanks.. prototyping right now..

 

intending to vary the anode load and the bias, if it goes well, it could very well be a aural master piece, with the cheapest of parts the whole amp only costs a hundred over dollars, but some people say its 心里障碍for something that cheap to sound ok/good, so i might build a 1k+ part cost version of this.

Share this post


Link to post
Share on other sites

design a pcb and make a kit! p2p is too chim for the bulk of us! :grin:

 

actually dont need PCB bah..its quite simple a design plus normal PCB copper is not quite "audio grade"

 

i'm planning to rebuild it soon, and might adopt the typical "vintage amp" layout which is much easier

 

something like this of the mullard 20 watts will look neater

IPB Image

Share this post


Link to post
Share on other sites

mind sharing the schematics ? this seems very interesting

 

ah.. i was going without a schematic actually.. just following the curves on http://www.4tubes.com/DATASHEETS/SCANS-Original/C/

 

i.e. rk 180 ohm that goes onto the kathode

 

idle current at 17ma and with my current cheapo toroidal trafo of rectified voltage 220v+ which suggests a plate load resistor of 13k (i'm using something lesser than that now cuz i've yet to hit koba/slt to pick up more components)..

 

and triode strapping.. just a grid stopper of 500ohms or 1k on the grid to reduce oscillations, and a anode load of 10k between anode and ground, capacitatively coupled to output with cheap 10uf 400v caps

 

i'll draw it out soon.. its a lot simpler than it sounds....

Share this post


Link to post
Share on other sites

Looking foward for that.. :thumbup:

The simpler the better for beginner like me..

Do like to build a very low cost amp with only SimLim Tower parts..

What is the meaning of POST? Can I use it as a normal headphone amp after a DAC?

Does it involve high voltage(240V or larger than 100V) besides the transformer part?

 

Share this post


Link to post
Share on other sites

Looking foward for that.. :thumbup:

The simpler the better for beginner like me..

Do like to build a very low cost amp with only SimLim Tower parts..

What is the meaning of POST? Can I use it as a normal headphone amp after a DAC?

Does it involve high voltage(240V or larger than 100V) besides the transformer part?

 

yes it is operating at 220-300v depending on the transformer you use, that is the only high voltage part but its not much of a hazard if you wire it carefully and accurately.

 

POST tubes are german tubes that was used for communication back then... and the d3a, c3g series are 3rd generation post tubes, so superbly made that the tubes are self supporting, i.e. mica spacers do not touch glass envelop.. for low noise etc.

 

yes input is typically RCA so if your DAC output is to normal RCA interconnect, it can be used.

 

more information here

http://www.jacmusic.com/nos/C3g-C3m-info.html

Share this post


Link to post
Share on other sites

yes it is operating at 220-300v depending on the transformer you use, that is the only high voltage part but its not much of a hazard if you wire it carefully and accurately.

 

POST tubes are german tubes that was used for communication back then... and the d3a, c3g series are 3rd generation post tubes, so superbly made that the tubes are self supporting, i.e. mica spacers do not touch glass envelop.. for low noise etc.

 

yes input is typically RCA so if your DAC output is to normal RCA interconnect, it can be used.

 

more information here

http://www.jacmusic.com/nos/C3g-C3m-info.html

 

Thank you..learn something..

So is it easy & cheap to get post tube in Singapore? The C3 tubes from Valvo, Siemens and Telefunken looks very expensive and very hard to get..

Share this post


Link to post
Share on other sites

Thank you..learn something..

So is it easy & cheap to get post tube in Singapore? The C3 tubes from Valvo, Siemens and Telefunken looks very expensive and very hard to get..

 

actually i dont get mine from jac music

 

i have friends in germany so they source for me, the price they get it at is actually a fraction of the online price

 

in singapore so far i only saw aural designs starting to pick up post tube amps, i.e. i saw a c3m pre-amp a couple of weeks ago, but generally not that many people in singapore use them.

 

the other hard to get thing is the socket, which is loctal, and not octal, i get either the NOS siemens one or in my latest shipment cheap ones from china which are a few dollars each

 

another challenging thing about all tube amps is just eliminating hum.. and some solutions can be pricey...

Share this post


Link to post
Share on other sites

IPB Image

 

forgive my shabby drawing.. this was drawn up based on the spec sheets and it works well, very good linear gain in triode mode

 

i've currently done up a 2a3 power amp using c3g to drive in this similar fashion and it drives exceedingly well.

Share this post


Link to post
Share on other sites

IPB Image

c3g, in background.. the cheap 5AR4...

 

IPB Image

 

IPB Image

an expensive pair of babies (i'm a fan of lundahl trafos)

 

IPB Image

the ugly looking circuitry.... allen bradley resistors... i might bypass the grid suppressor resistor if needed.. hopefully it doesnt oscillate

 

IPB Image

a tiny little power supply for the c3g

 

IPB Image

eeek.. not another 2A3 amp...

 

TlKyHD2zNEM

first test on the amp.. luckily nothing blew up...

Edited by neutralzz

Share this post


Link to post
Share on other sites

Good case work..It looks it need a lot of measuring and drilling work to do..

 

Yes..Looks like the tube and socket don't come cheap and easy..

The resistors looks big size for higher wattage..

So the schematics is for one stage amplification for one channel? Rectifying to DC required from transformer?

 

The amp have 4 transformer, and the five tubes..So it is just series the different amplification stages? Drive speaker driver just for testing?

 

Sorry newbie here..

Share this post


Link to post
Share on other sites

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
Sign in to follow this  

×
×
  • Create New...