New production 12DW7 v.s. 7247

[mashaffer]

Just wondering if the new production 12DW7 such as the EH are equivalent to the old 7247 with respect to hum and microphonics resistance.

 

[Eli Duttman]

FWIW, JJ's 12DW7 gets good "press".

Are you overhauling an already existing piece of equipment? In a new build, contain your costs with 'X7s and something else, say a 12BH7. Share bottles between channels.

 

[kodabmx]

+1
The 12DW7 is half a 12AX7 and half a 12AU7 in one envelope. It's also stupid expensive compared to 12A*7...

 

[petertub]

+1
The 12DW7 is half a 12AX7 and half a 12AU7 in one envelope. It's also stupid expensive compared to 12A*7...

Nope. It's about the same price as 12ax7 ( talking about new tubes from JJ )

 

[mashaffer]

The sense I got from data sheets was that the originals were somewhat of an upgrade over the A_7s in noise and microphonics. If so I was curious as to whether the current production were also.

 

[kodabmx]

Nope. It's about the same price as 12ax7 ( talking about new tubes from JJ )

Ya I was talking NOS... I should have said. Still, a Shuguang 12AX7 is about 10 bucks. JJ 12DW7 are going for about $25 at the local shop, and NOS are $42... 6N2P are still only like $2 Funny enough, the only place I have a use for 12DW7 (or 12AX7/12AU7 is for voltage regulation in a phono amp. I don't use those for audio at all!

 

[petertub]

Ya I was talking NOS... I should have said. Still, a Shuguang 12AX7 is about 10 bucks. JJ 12DW7 are going for about $25 at the local shop, and NOS are $42... 6N2P are still only like $2 Funny enough, the only place I have a use for 12DW7 (or 12AX7/12AU7 is for voltage regulation in a phono amp. I don't use those for audio at all!

In my part of the globe the prices of ECC832 and ECC83S (JJ) is

approximate equal. And that is brand new tubes with warranty.

 

[PRR]

The sense I got from data sheets was that the originals were somewhat of an upgrade over the A_7s in noise and microphonics. ...

I never got that idea. AFAIK it was just one X and one U gut in the same bottle, for chassis where you need half an X and a half a U.

Like "meatloaf mix": half ground beef, half ground pork, from the regular bins, pre-paired for your convenience.

Oh... the 7xxx series were supposedly "industrial", which may imply Premium, but AFAIK these were mostly regular-run parts with a little more inspection.

 

[Kay Pirinha]

OTOH, the 7025, whose specs equal those of the 12AX7, is quite another Version, though, with dedicated low hum, bifilarly wound heaters. Hence it equals the European ECC83.
Best regards!