The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Fri Oct 20, 2017 9:16 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 3 posts ] 
Author Message
 Post subject: 7025 WA tubes in TA-30
PostPosted: Thu Feb 16, 2017 2:45 pm 
Offline
Bottle Rocket

Joined: Sun Sep 25, 2016 10:07 am
Posts: 1
Two of my friends are using 7025 WA tubes in their amps instead of 12AX7's. I'd like to try some in my TA-30 but wondering if I need to change all six or just V1, V2, and V3? I'm looking for a little warmer, fuller sound from the Vox and the Tweed voices. Currently all six preamp tubes are Mesa.


Top
 Profile  
 
PostPosted: Thu Feb 16, 2017 2:55 pm 
Offline
Mark IV
User avatar

Joined: Wed Sep 08, 2010 4:12 pm
Posts: 629
Location: Petaluma, California
7025's were a low noise 12AX7, however later the 12AX7-A was introduced with the same low noise construction - deeming the 7025 designation obsolete.

_________________
MESA/Boogie - Product Specialist/Customer Service - http://www.mesaboogie.com/support/index.html


Top
 Profile  
 
PostPosted: Fri May 26, 2017 8:15 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2493
Location: North Carolina
Not sure about the TA amp. There are some 12AX7 tubes that will provide a change in character. All depends on the circuit of the preamp for the tube position you change. I found the Mesa SPAX7 seems to have a bit of roll off on the top frequencies. It is essentially the same tube a the 12AX7A stock tube.
There are some other variants in the 12AX7 family, short plate like the Mesa tube generally have the least influence from mechanical vibration. Medium plate tubes like the 7025 (generally the Chinese variant has a medium plate) also the Tung Sol, Mullard CV4004, EH12AX7, Svetlana (all from the same company but difference character in tone ) to the long plate Mullard RI 12AX7, as well as the JJ ECC803s. Warmer tubes would be the Mullards or the ECC803s but that all depends on the tuning of the circuit the tube is in.

Believe it or not the Mesa stock tube is dark sounding in one amp (Roadster) or the RA on the clean channel but bright and grinding on the hi/lo as well as balanced and masterful with the TC-50 and JP-2C. Tonal character you will hear from the tube is dependent on the circuit that is using it. In some cases you may not even notice a difference.

_________________
Current amps:
TC-50, JP-2C, MK V, Roadster, RA100
Old friends I sometimes miss:
Mk III (blue stripe), Mark IVb-WB


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group