neutralzz 0 Report post Posted December 12, 2009 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. Share this post Link to post Share on other sites
heady 0 Report post Posted December 13, 2009 (edited) Power brother! Wow, a tube amp built on a literal breadboard! Respect. Edited December 13, 2009 by heady Share this post Link to post Share on other sites
bevan 0 Report post Posted December 14, 2009 wow nice work man! Share this post Link to post Share on other sites
neutralzz 0 Report post Posted December 14, 2009 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
loop_ 0 Report post Posted December 16, 2009 (edited) design a pcb and make a kit! p2p is too chim for the bulk of us! Edited December 16, 2009 by loop_ Share this post Link to post Share on other sites
neutralzz 0 Report post Posted December 16, 2009 design a pcb and make a kit! p2p is too chim for the bulk of us! 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 Share this post Link to post Share on other sites
Cloud 0 Report post Posted December 16, 2009 mind sharing the schematics ? this seems very interesting Share this post Link to post Share on other sites
neutralzz 0 Report post Posted December 17, 2009 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
user 0 Report post Posted December 18, 2009 Looking foward for that.. 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
neutralzz 0 Report post Posted December 18, 2009 Looking foward for that.. 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
user 0 Report post Posted December 19, 2009 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
neutralzz 0 Report post Posted December 19, 2009 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
neutralzz 0 Report post Posted December 19, 2009 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
neutralzz 0 Report post Posted December 19, 2009 (edited) c3g, in background.. the cheap 5AR4... an expensive pair of babies (i'm a fan of lundahl trafos) the ugly looking circuitry.... allen bradley resistors... i might bypass the grid suppressor resistor if needed.. hopefully it doesnt oscillate a tiny little power supply for the c3g eeek.. not another 2A3 amp... TlKyHD2zNEM first test on the amp.. luckily nothing blew up... Edited December 19, 2009 by neutralzz Share this post Link to post Share on other sites
user 0 Report post Posted December 20, 2009 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