Re: 12DW7's or 7247's

Posted by sgmlaw (A) on June 26, 2002 at 09:51:24

In Reply to: 12DW7's or 7247's posted by Bryon on June 25, 2002 at 17:12:34:

The 7247 is supposedly a premium version of the 12DW7. However, that doesn't always mean that one is better than the other. Don't toss aside a Sylvania 12DW7 just beacuse it's not a 7247. They are generally interchangable.

This is a hybrid tube: half 12AX7, half 12AU7. Avoid haphazard substitutions, such as a 12AX7. The AU7 side current will quickly kill one section. If you must, you can sometimes rewire sockets to use a 12AU7 and 12AX7 in lieu of two 7247s, but this is a significant modification to what may be a perfect classic.

Most vendors (including some experts who advertise here) don't know all that much about this tube, as it is not much used anymore, and not many were made to begin with. The best source for experience is among Far Eastern users of older vintage preamps, who love to roll.

I've got a good collection of these (none are for sale). Among the NOS ones I use in my gear, the Mullards are excellent, especially in a cathode follower design. But TFKs are also terrific, albeit very hard to find. These are the two best in my experience, and a mix of both can be quite outstanding. Don't overlook GEs, which can sound very very nice, with only a slight boominess at times. If your setup is too laid back, this could be the ticket. I have heard good things about the Siemens, but have yet to hear one. Be wary of U.S. made Mullards, which appear to be an RCA type and are very hard to get a quality sound from (but it CAN be done with the right mix, however). RCA also made 7247s under their own brand, and they're not bad. The Sylvania 12DW7 is a good tube, and should be considered if in the sub $10 range. JJ and EI also make a 12DW7, and they deserve some consideration as well, especially the EI.

Good luck!

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Follow Ups Full Thread

Topic - 12DW7's or 7247's - Bryon 17:12:34 06/25/02 (15)

Roll Both types - Joe Rosen 01:02:06 06/27/02 (0)

Re: 12DW7's or 7247's - Uncle Ned 19:38:05 06/26/02 (1)

Re: 12DW7's or 7247's - Bryon 21:45:24 06/26/02 (0)

Re: 12DW7's or 7247's - sgmlaw 09:51:24 06/26/02 (3)

Re: 12DW7's or 7247's - Ivan303 19:06:08 06/26/02 (2)

Who's on first......... - Sam 12:11:50 06/27/02 (0)

Not sure what you're trying to say . . . - sgmlaw 21:07:22 06/26/02 (0)

Re: 12DW7's or 7247's - Ivan303 18:36:33 06/25/02 (7)

Re: 12DW7's or 7247's - Joe Rosen 01:06:39 06/27/02 (6)

Hey, great to hear from you, Joe! - Ivan303 05:59:16 06/27/02 (5)

Re: Hey, great to hear from you, Joe! - Joe Rosen 03:27:21 06/28/02 (4)

Re: Ever try spinning(i.e. indoor exercise bike)during the winter months - Russ57 11:39:17 06/28/02 (3)

Re: Ever try spinning(i.e. indoor exercise bike)during the winter months - Joe Rosen 16:27:35 06/28/02 (2)

Re: Ever try spinning(i.e. indoor exercise bike)during the winter months - Russ57 07:26:56 07/01/02 (1)

Re: Ever try spinning(i.e. indoor exercise bike)during the winter months - Joe Rosen 04:46:37 07/07/02 (0)

Follow Ups

Re: 12DW7's or 7247's - sgmlaw 09:51:24 06/26/02 (3)

Re: 12DW7's or 7247's - Ivan303 19:06:08 06/26/02 (2)

Who's on first......... - Sam 12:11:50 06/27/02 (0)

Not sure what you're trying to say . . . - sgmlaw 21:07:22 06/26/02 (0)

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