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12BZ7/12AX7 vs. 5751

I have a Cary V12 with 12BZ7 tubes in the input. I read an article last night that suggest that the 5751 is interchangeable, just with less gain, and that it sounds significantly better. Has anyone used a 5751 in place of a 12BZ7, or for that matter a 12AX7, and could you comment on any differences/improvements in sound?

Thanks!
grimace
phillyb's avatar
phillyb
401 posts
 
5751 sound thin, if you like a more solid state sound then go 5751's. Joe's Lore is what he heard in his system with his ears and his likes. Nothing wrong with that, but it does not make for in stone what tube is the best for your system and your ear and bias.
facten
2,877 posts
 
surprising comment " i just don't get the whole tune rolling deal" given sounds real audio that you sell tube gear - try it you might be amazed
wolf_garcia
6,695 posts
 
Not getting the "whole tube rolling deal" is like "not getting the whole appreciating differences between things deal." Also, I'm a believer in 7025s as a 12AX7 swap, although results may vary. Is an accurate and full range tube tone a "SS" sound? This term is bandied about by term bandiers suffering from adjective deprivation. I prefer my music to sound tonally correct using my extremely refined ear, impeccable taste, serious demeanor, and finger burning tubes glowing for my amusement and aesthetic needs. Both ears actually, especially when they're clean-ish.
defride
89 posts
 
I can't comment on whether 12bz7 is a substitute for 12ax7/5751 however if it is my advice would be take advice only from those who have experience of your amp or go out and listen for yourself.

For me Sylvania 5751 are excellent, better than any 12ax7 I've tried but in another implementation they may not work at all.

Can be good fun exploring different tubes though expensive and a good measure of frustrating
jedinite24's avatar
jedinite24
1,503 posts
 
Hi Grimace

I have been swapping 12AX7 tubes with 5751 type tubes in a Jolida Glass FX tube DAC. The RCA Grey Plate 12AX7 tubes from the 70s I had in the DAC made the music very forward and cymbals and highs really had some sizzle to them. Music was borderline unnatural sounding. I rolled in some JAN GE 5751 type tubes from the late 80s and it made the music less in your face and calmed down the highs by wide margin.

I'm going to try to find Sylvania 5751s at a good price but they seem to be getting scarce. There are a lot of GE 5751 tubes out there for you to choose from. Lastly some tube sellers have low gain options for 12AX7 tubes BUT from what I've seen these are for newer issued tubes. E.g. Sovtek, JJ, Tung Sol. I don't know if that could be another solution for you.

Good luck.
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