 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
24.15.32.233
In Reply to: RE: Sub 12AT7 for 12AX7? posted by greg7 on April 18, 2012 at 10:09:44
Didn't you get my reply to your email?
Also, please read the very recent post I linked to below.
Follow Ups:
Thanks, Jim. No, unfortunately I never did get your email (which is why I ended up posting here). Maybe I should check my account settings for current email address and so forth.
I sent it right after you wrote, so do check. The jist of it was it's safe, to swap, but unlikely to have much of an audible effect on gain.
Greg, I've always liked the 5751 sub in the 12AX7 spot, than the 12AT7. May want to try one.
If too much gain is the issue, the 12AY7 (6072) esp in the input stage, as Jim said, is a great choice. Drops the OD point noticeably in many amps.
This sub will work, but not in all cases. Depends on circuit.
In a Fender VibroChamp, subbing a 12AT7 for a 12AX7 changes the downstream voltage and the vibrato/trem almost disappears. I tried this last week.
May not be relevant to orig posters question, but does remind one that different circuits have different rules...and therefore generalizations as to which tubes are "best"....are just that: broad generalizations.
jstrm
That's an interesting result you got. I've never tried a 12AT7 (in the input stage), but have used 5751 in VC's with no issue to the "vibrato/tremolo" stage. But, the v/t stage needs a 12AX7, for sure.
I'm not that big on subbing types to compensate for overall design issues. Dang amps today have too much gain setup on the input stage. Even crazy DIY designs (like many 5E3 Deluxe kits) do not follow original tweed specs. If you set the front end up like it was originally designed, a 12AX7 works fine.
BTW... there is a great modification that can be done to the VC to set it back to 5F1 standards, yet keep the vibrato section. I like the tone of input stage better, with this mod (lower plate voltage on the input) and less feedback. Then, with a good 12AX7, like a Raytheon, man the amp sings at "10."
Have a good weekend!
i know that delivered from china some years ago in a special case the SAME small tube type was just labeled AS REQUIRED: 12AX7... AT7 or ...AU7! they did not care for electric paramters at all! very crative...
N.
Post a Followup:
| FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
||||||||||||||
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]