• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

DIY Stereo Amp


2016-03-29 9:08 am
Can anyone point me in the right direction, im new to tubes and i want to build something using some C3C pentode tubes i have, (I have four of them) they have a 4Volt filament. Im interested in trying to build a stereo Amplifier of some description using the C3C tubes as output tubes but feel Ive already hit a brick wall as the filaments they have are not the common 6v or 12volt and trying to find a suitable power transformer is impossible. Has anyone got a source for a suitable transformer or can help me work around this problem?
Im a complete Newb to all this but studying like mad to understand vacuum tube theory. my goal is to understand and design a circuit to make a semi-decent working amp for running a CD player or Ipod (a circuit that doesnt require pre-amplification) I may build a dynaco st35 initially to help grasp the concept then start working on the weird C3C design idea after (hopefully) gaining some knowledge with the dynakit. I hope you guys can offer me some support with this. Cheers, Harry
Don't just limit yourself to power transformers to supply heaters, let alone thinking in the 6V and 12V heater tap realms. The world of SMPS is amazing and will save you bundles of precious money. Good thing that C3C is indirectly heated so you can just wire the heaters in series and power them using a 15VDC switch-mode power supply. 4x4 = 16V and 15V is less than 10% from 16V so you should be okay. The tubes will last longer too with slightly lower heater voltage.. Here's a 15VDC 2A power supply for just 6 bucks on Ebay.
15V Power Module Supply Isolation Bare Plate 431 Precision Voltage Regulator 2A | eBay

Sorry, i can't help with designing amp around C3c as i can't find a complete datasheet for it.
As my command of German is (at best) mediocre, take what I say with considerable amounts of salt. My understanding of the C3c datasheet is that plate dissipation is limited to 2 W. You will need 100 dB. sensitive horn speakers with those tubes or you are building a headphone amp.

Check out Jeff Yourison's 6Y6 amp, as a good deal of working with that tube also applies to C3c.