audio-talk

Been Google 'ing KT66 circuits due to thinking about this project.

Came across our Mike's little experiment.

20th April? good exercise in patience.

Looks like the one you have on order. The other one is too high. Only way I can see to use it would be with the 5u4 choke input but with a small first cap somewhere around 2uF to tweak up the voltage, again this type of thing you adjust on test by paralleling small value polyprop's until the desired...

To Simon: I don't know, might be a power output stage thing.

If you use one of the chokes for the output stage and a 5r4gy rectifier you will end up with about 370v B+ I have assumed a 100 ohm dc resistance for the chokes. Then you have a loss across the OPT typically 5v. Talking triode mode, your cathode bias with our rough guessed supply voltages we'd proba...

slowmotion wrote: (I like the 813 triode better than 845.

I agree if we are taking Chinese 845.

I didn't draw it right. It is where the 250I resistor is.

I didn't draw it right. It is where the 250I resistor is.

I expect that the James transformers would be higher quality. Hammond are good but made as a budget item.

I can't send the pdf until I am home.

Yes the concept is good. The em7 has more gain in the 1st section which is advantageous for single VA (voltage amplification) stage designs. The CCS is advantageous but non essential if simplicity matters. Mike has direct coupled two consecutive stages. It may be better for Collin to play safe with ...

Sorry about the garbage I have a peculiarity going on with Windows 8 that it is jumping my typing into strange parts of the text and even I can't easity unravel it. I think my fingers must brush a key which shiftes the position of the typing but I can't make out what that key combination is. anyway ...

Collin has asked for schematics for " 6EM7s as drivers into ether 6l6 /5881 /KT 66/807s? " As there is now a wealth of knowledge and experience on here about using the 6em7, I thought that it would be good to openly discuss it and facilitate contributions from others experienced in using t...

Back to the circuit, I have put a 6em7 (pin1,2,3) cathode follower in between the two valves. As discussed the purpose was to provide an infinite load to the 110k output impedance of the 6sj7 rather than the 250k pot which would have lost me considerable gain. Direct coupled to the 6sj7, on the outp...

That's a big claim to make. They didn't use Black Gates. What speaker/s are you going to hang off the end of it? I can't claim to make a better combo, just a head amp. Can't afford the proper genuin speakers used those days. just a fun project for myself. other aspects of life raise their head for ...