I think ECC813 = US industrial type 6463
http://www.op316.com/tubes/mw/image/6463.pdf
I think it's another tall one, though.
6350 looks like another equivalent, but again is in a taller bottle.
http://www.op316.com/tubes/mw/image/6463.pdf
I think it's another tall one, though.
6350 looks like another equivalent, but again is in a taller bottle.
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Slice the pi.
Hello Ian,
Keeping in mind that mu = rp * gm. Holding mu constant while increasing gm means that rp will need to decrease proportionally as much as gm is increased. Changing rp will have an effect on output impedance.
DT
Hello Ian,
Keeping in mind that mu = rp * gm. Holding mu constant while increasing gm means that rp will need to decrease proportionally as much as gm is increased. Changing rp will have an effect on output impedance.
DT
5965 is like a better version of 12AV7, which is sorta/kinda in the 12AT7/ECC81 ballpark. That's got higher mu (about 40, I think), so would give double the voltage gain. Other than that, yeah, that's a good one.
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The 5687 is a definite contender. I have already tried a couple and they perfom better than the AU7 but not as well as I hoped Pinout differences are mnor and I can easily accomodate them.
Cheers
Ian
TDSL has a parametric search function which I've found helpful in odd situations.
Attachments
It was by using TDSL that I was reminded of the ECC804.
Presumably the OP has an idea of what gm he has in mind, or is it that the more the better?
Presumably the OP has an idea of what gm he has in mind, or is it that the more the better?
Do you need large quantities or is this a one-off? If the latter, I have in mind something with a mu of 30, gm of 9-10mA/V, and similar operating currents. 12V heater, same size envelope and pinout.
What I really need is lower ra but tubes are not generally specified by that parameter. For a given mu, the higher gm is the lower is ra, hence my request. An ra of 2K or less at 10mA would be fine which implies a gm of 10mA/V.
Cheers
Ian
In the end I used the 5687. The circuit was designed to be configurable to be either a mu follower or an SRPP, with optional shut derived shunt applied NFB.
Cheers
Ian