I know a guy that used a 1625 and a 25DQ6 as regenerative receivers. Obvious, the power wasted was of no significance for him.
You might see a tiny amount lower Rp with g3 connected to the plate. Probably not even visible with beam plates. The main reason I would keep g3 connected to the cathode would be to prevent secondary emission electrons (from the plate) reaching +g2 (or +g3, and over-heating them). Maybe not an issue for the small signal case, depends on how hard the tube is being run.
Small signal pentode - EL34? You could but.. but.. WHY?!? Sorry, I came to this thread via Google.
Customers who went on about wave shapes and that they turntable 'wasn't running at quite the right speed' we referred to as 'scope jockeys' and they never, never talked about music. It was all about collecting bigger and more boxes. Complete ego and left-brained. Whereas the right-brained people who brought in music where far happier, healthier and wealthier people who also loved photography and movies.
So, NO, you can't messure that!
Customers who went on about wave shapes and that they turntable 'wasn't running at quite the right speed' we referred to as 'scope jockeys' and they never, never talked about music. It was all about collecting bigger and more boxes. Complete ego and left-brained. Whereas the right-brained people who brought in music where far happier, healthier and wealthier people who also loved photography and movies.
So, NO, you can't messure that!
Classic example I think, 6V6 (in triode) is so similar to 6SN7 with mu traded for Zp, except for the increase in 2HD. It gets used in low level gain stages but more obviously presents as a potential driver of more difficult output stages.
I've seen a 300B used as a peramp valve too, it works and sounded 'okay' but its like asking a giant to fix a watch. You'd need a particularly difficulut output Tx to warrant it's use to get the best linearity out of the tube and by then I suspect this output Tx would delimit the quality i.e Generally speaking, good Txs are good conductors and 'shows a high degree of fidelity in regard to the original input source' I think was the quote that started hifi, wasn't it?
You can use power valves as preamp valves but their linearity is seldom better than smaller valves designed for small signals and really, do you want to switch your preamp on and >POP< 'Oh, I need another power valve'.
No? Not a problem? You are wealthy in this incarnation and don't care about the diminishing supply of vintage valves? Okay, then use the 211 which is supremely linear. I've personally seen an Ongaku switch on and one of the valve filaments go. There was a pause before I ask "So how much will that cost?" and the answer was £6,000 and go to the cellar and get another.
And that is why no hifi company worth speaking of uses power valves in preamps.
You can use power valves as preamp valves but their linearity is seldom better than smaller valves designed for small signals and really, do you want to switch your preamp on and >POP< 'Oh, I need another power valve'.
No? Not a problem? You are wealthy in this incarnation and don't care about the diminishing supply of vintage valves? Okay, then use the 211 which is supremely linear. I've personally seen an Ongaku switch on and one of the valve filaments go. There was a pause before I ask "So how much will that cost?" and the answer was £6,000 and go to the cellar and get another.
And that is why no hifi company worth speaking of uses power valves in preamps.
I can't see this "sweet" measurement on test equipment but sure can hear it.
A 6922 tube instead of TA7136P in SX 780 is astounding.
it now drives the tone stack with 126v B+ from voltage tripler.
I also Added Mosfet outputs but the tube is by far the best upgrade.
A 6922 tube instead of TA7136P in SX 780 is astounding.
it now drives the tone stack with 126v B+ from voltage tripler.
I also Added Mosfet outputs but the tube is by far the best upgrade.
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