2. amps-preamps
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Alternative to 12AX7-EH tube needed...new to tubes

I purchased a new to me preamp a couple of weeks ago and would like to replace the tubes. I am a first time tube owner and would appreciate any and all advice. It's an Aronov and is connected to a McIntosh 752.

I would like to lower my noise floor and reduce how hot the signal is on my preamp out. Basically, I want to be able to turn the gain on my amp back up.

Would a Sovtek 5751 be a good alternative?

I want to keep my highs detailed, lows fat, and the mids rich and full.

Thanks.
techguy0192
10 responses Add your response
hifigeek1
770 posts
 
I've always found U.S. 5751's to be a bit noisy and microphonic. How are the JJ's 5751's vs. the JJ ECC803s? Anyone??
jedinite24's avatar
jedinite24
1,503 posts
 
Does anyone have any updates regarding the Sovtek 5751 tubes? Has anyone used it with their amps and care to share their thoughts? I enjoy 5751 type tubes (currently JJ 5751, previously NOS GE black plate 5751) in my Jolida amp. I was thinking about trying something different with these Sovteks.

Thanks and advise when you can.
racamuti's avatar
racamuti
362 posts
 
I don't think that you will realize very much gain reduction in your pre-amp by using lower gain tubes, it doesn't work that way. Just use the best sounding tubes and use an inline attenuator between your pre and power amp. Rothwell makes some good ones. Take care and good luck!
techguy0192 OP
4 posts
 
Thanks for all the help.

I'm going to give the 5751 a try.

I love the Aronov, it is a shame they no longer make gear; stopped in 2008.
cyclonicman
693 posts
 
I would definitely try a 5751(GE black plate or Tung Sol))which has a gain factor of 70, while the 12AX7 is rated at 100, so you would have a 30% gain reduction. I think the 12AT7 mentioned by Yogiboy and rated at 60 might be too drastic a reduction at 40% gain reduction. I think this is especially true if the Aronov has a phono stage.
maxmad
182 posts
 
Best pre-amp tubes are made by Telefunkens, may be expensive, but thats what you pay for a quality. I love smooth plated.
yogiboy's avatar
yogiboy
5,624 posts
 
You can reduce gain with 12at7 40%,12au7 80%,jjtesla makes both of them,tube depot is a nice place to start.
blindjim
3,092 posts
 

Both posts here are excellent ideas. Andy @ Vintage Tubes, and Joe's tube lore...

I'm wondering though, why move off of the 12AX 7 TO BEGIN WITH?

There are a lot of these types of tubes around which should meet your needs. Amperex Bugle boy 12AX7's ought to fit very well. Quite extended, dynamic, and very clean & clear window to the music. I use a combo of these and RCA 12AT7s in my preamp.
saki70
907 posts
 
Go to "Joe's Tube Lore" at Audioasylum.com . He has done a rather exhaustive study on input tubes and has compared most all of the different types of small tubes .
I found it a nice place to start .

Good luck .
racamuti's avatar
racamuti
362 posts
 
Call Andy at "Vintage Tube Services",or Jim McShane. Both of these guys are the real deal when it comes to recommending and supplying good tubes that are quiet and tested to the max.
Good Luck!!
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