Greetings,
I friend of mine who was moving abroad gave me a box of approx 100 Brimar ECC81 valves tht he picked up in a car boot sale years ago. I know practically nothing about valves but am keen to make a few circuits with them, maybe a phono preamp. Are these valves suitable? any info would be appreciated.
Thanks,
tuathal
I friend of mine who was moving abroad gave me a box of approx 100 Brimar ECC81 valves tht he picked up in a car boot sale years ago. I know practically nothing about valves but am keen to make a few circuits with them, maybe a phono preamp. Are these valves suitable? any info would be appreciated.
Thanks,
tuathal
These are a very nice version of the 12AT7. They're probably not the best choice for a phono amp, but they'll do very well in line amps and input stages or power amps.
Hey, I'd say that with a hundred of them for free, they're ideal for anything!
If you were really keen you could make an entire amplifier solely out of ECC81. It's not as linear as some valves, but it has good mutual conductance and a useful anode dissipation, so you could make an RIAA stage using them, a cathode follower line stage (if needed). Power amplifier could use common cathode input stage DC coupled to concertina phase splitter feeding six triodes per side with a 4ka-a output transformer ought to be good for 5W. A stereo amplifier would ths use about 22 ECC81, so you've plenty for a revalve. For more power, simply parallel more ECC81 in the output stage, although you'd probably need to drive them from cathode followers because of the increased Miller capacitance.
If you were really keen you could make an entire amplifier solely out of ECC81. It's not as linear as some valves, but it has good mutual conductance and a useful anode dissipation, so you could make an RIAA stage using them, a cathode follower line stage (if needed). Power amplifier could use common cathode input stage DC coupled to concertina phase splitter feeding six triodes per side with a 4ka-a output transformer ought to be good for 5W. A stereo amplifier would ths use about 22 ECC81, so you've plenty for a revalve. For more power, simply parallel more ECC81 in the output stage, although you'd probably need to drive them from cathode followers because of the increased Miller capacitance.
Hi,
Not related to Tim de paravicini by any chance?
David Manley of VTL used (abused😉 ) the AT7 extensively in phono pre's, input valves, splitters etc....
Lucky you, Brimars and a box of a hundred too...equals the lottery in my valvebook.
Cheers,😉
Not related to Tim de paravicini by any chance?
David Manley of VTL used (abused😉 ) the AT7 extensively in phono pre's, input valves, splitters etc....
Lucky you, Brimars and a box of a hundred too...equals the lottery in my valvebook.
Cheers,😉
phono pre for beginner
Thanks for the replys, anyone know of any websites with phono pre designs suitable for valve ameteur. How much are these valves worth?
Thanks for the replys, anyone know of any websites with phono pre designs suitable for valve ameteur. How much are these valves worth?
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