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Hoffman Amps Forum image Author Topic: 6SJ7  (Read 13480 times)

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Offline rzenc

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6SJ7
« on: July 30, 2013, 04:22:19 pm »
Hello!

I'm about to build a new project and the schem calls for it. I have never tried this tube and was wondering if you guys have experience with it?

I also don't have any on tubepiles and will need to buy some. Do you have a suggestion regarding manufacturers?

Are you aware of possible substitutes/electrically equivalent?

All input greatly appreciated!

Best Regards
R.

Offline DummyLoad

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Re: 6SJ7
« Reply #1 on: July 30, 2013, 08:08:37 pm »
RCA 5693 is an industrial direct replacement. 6J7 is the predecessor with lass-steep slope and arguably better for audio; my favorite 6J7 is the RCA. 6SJ7 are can be/become quite microphonic. i'd suggest you shock mount the socket with some rubber o-rings or something similar. the 6SJ7GT-MR by tung-sol is a glass version with a mesh plate and they are VERY rare and difficult to shield, but damn they sound nice in a guitar amp, if you can find a working copy at a decent price, you won't be disappointed. next on the favorites list is the 5693 the RCA and national union 6SJ7 are desirable as well.

some say that 6SJ7 is/are similar to the EF86. if i need a pentode front end for a guitar amp - the EF86 is my go-to tube. i

haven't fooled around enough with 5879 to form an opinion, except that they can be very microphonic. 

another cool pentode is the EF40, however it has a rim-lock base and they are hardly a mainstream socket, + becoming increasingly difficult to find.

we can't forget the workhorse 6AU6 - a decent tube, but can have too much gain in some circuits. the 6AK5/5654 is another with similar characteristics to the 6AU6, some forum members here have made statements as to liking the 5654 over all.

--pete 

Offline DummyLoad

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Re: 6SJ7
« Reply #2 on: July 30, 2013, 08:11:36 pm »
almost forgot... avoid the 6SH7.

--pete

Offline rzenc

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Re: 6SJ7
« Reply #3 on: July 31, 2013, 10:30:44 am »
Thanks for all the info Pete!!

It's going for a rack mounted bass preamp that I want to try. Schem attached. Sent ya pm.

Best Regards

R.

Offline DummyLoad

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Re: 6SJ7
« Reply #4 on: July 31, 2013, 04:35:19 pm »
replied to your PM... plan looks nice. definitely lots of contouring possibilities there...    :icon_biggrin:

respectfully,

--pete

 


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