High gm version of 12AU7

[rongon]

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.

 

[DualTriode]

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

 

[HollowState]

Why has no one mentioned the 5965 ?

 

[rongon]

Why has no one mentioned the 5965 ?

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.

--

 

[ruffrecords]

What about 5687?
Same height as the 12AU7 but with a slightly different pinout.
Vh= 12.6 V, mu = 17, gm = 8 ma/V

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

 

[AllenB]

I haven't used this for a few years as it doesn't work on a Mac, but if I remember correctly it would be perfect for this search.

TDSL has a parametric search function which I've found helpful in odd situations.

 

[DF96]

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?

 

[SY]

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.

 

[ruffrecords]

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?

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

 

[ruffrecords]

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.

I need only a few but this design will be for DIYers so here could be a demand for quite a few.

Cheers

Ian

 

[smoking-amp]

12FV7 it's taller though

 

[jhstewart9]

12FV7 it's taller though

Is there an example of your final design on DIY so that we can see it?

 

[ruffrecords]

Is there an example of your final design on DIY so that we can see it?

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