The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Sat Dec 15, 2018 8:08 pm

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Tue Jan 24, 2017 5:24 am 
Offline
Mark I

Joined: Thu May 29, 2008 10:44 am
Posts: 28
Location: Perth, Australia
Just wondering if anyone has experimented with using 12at7's in a dual rectifier..
Either replacing V1,2&3 or replacing just one..
Given they are a lower output,
I'm wondering if they would tame the fizz and gain or just push it back further requiring you to turn up the dials?
Any thought or experiences?

_________________
Mesa DR, TC G Maj, Berg F/Sw, PRS Cu24, EJ Strat, Ibanez RG7620 w EMG 707 781, fender HRDlx


Top
 Profile  
 
PostPosted: Sat Feb 04, 2017 8:50 am 
Offline
Triple Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 3088
Location: North Carolina
Yes, I have used an NOS (RFT as well as JAN-GE) in my Roadster. I only ventured into the V1 or V2 positions. Never try a 12AT7 in a cathode follower circuit as it will not work well. I was impressed with a NOS JAN version of the 5751 in V2. Actually sounded much better than using current 12ax7's.


Top
 Profile  
 
PostPosted: Wed Oct 24, 2018 10:25 am 
Offline
Mark I

Joined: Thu May 29, 2008 10:44 am
Posts: 28
Location: Perth, Australia
Thanks for the reply bandit,.. Last year.. Oops.. It's been a while on here..
I ended up changing V12&3 to At7's and it tamed the amp pretty nicely.. It's a subtle change didn't really drop the volume much but tamed the gain a little.. I get a little more range from the gain before it hits the fizz spot..
Still frustrating though.. I've now tried different power tubes, preamp tubes, pickups, volume settings, tone settings, mic placements.. and still when the gain control gets to the point where any sort of usable gain and sustain gets introduced, the high frequency fizz comes in at the same time.. I'm now thinking it must be a bias thing..

_________________
Mesa DR, TC G Maj, Berg F/Sw, PRS Cu24, EJ Strat, Ibanez RG7620 w EMG 707 781, fender HRDlx


Top
 Profile  
 
PostPosted: Sat Oct 27, 2018 9:30 am 
Offline
Triple Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 3088
Location: North Carolina
I have not done this with the Roadster yet (however I have had done so but did not impress me so I forgot about it), but have with the JP-2C. 12AT7 in the phase inverter position. Another tube you can try out is the JAN/GE 5751. Has more gain than a 12AT7 and is closer to the 12AX7 characteristic just lower gain.

I would also keep one of the tubes in V1 or V2 as a 12AX7 and see if the 12AT7 in V1 or V2 makes much of a difference. Stock tube in the cathode follower position is best. I have tried the Chinese tubes there as well. I actually preferred the character when using a JAN/GE 5751 in V2 and a stock tube in V1 (reference to the Roadster). I think the standard Dual recto is a bit different than the Roadster.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 4 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 5 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