Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan, G

[some_dude]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

The JJ ECC803 does have a spiral filament. However, I don't know if it's problematic in cathode followers like the Russian made, New Sensor spiral filament 12AX7's. My understanding is that the issue isn't that spiral filaments inherently cant handle the voltage. RCA manual spec is 200V heater to cathode (but not sure that's spiral filaments). It's that those Russian made tubes spiral filaments cant, although new sensor claims that it's spiral filaments in general. The Russian new sensors with spiral filaments don't come remotely close to meeting that spec. But some people have reported no issues, so it's probably dependent on the specific tube (luck?) and the voltage in the specific amp/circuit. New sensor recommends the older 12AX7WA, WB or WC. I think the JJ ECC83's are know to work fine there and the Chinese made tubes as well.

EHX used to be standard issue in new Mesa's until around 2008. Back in 2006 I started seeing a number of complaints about Mesa's being dead either on or shortly after arrival. Apparently New Sensor changed their specs and didn't tell people. Mesa switched to JJ and I haven't heard of a similar issue since.

 

[Orville]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

EHX used to be standard issue in new Mesa's until around 2008. Back in 2006 I started seeing a number of complaints about Mesa's being dead either on or shortly after arrival. Apparently New Sensor changed their specs and didn't tell people. Mesa switched to JJ and I haven't heard of a similar issue since.

I am not sure but I think my TA-30 came with Mesa branded JJ 12ax7's. I have a long plate Sovtec ( new) and some short plate 12ax7's I pulled from my old MarkIII that have nothing on the glass. The 12ax7's from the TA-30 have shorter plates than any other 12ax7 I have. Well, to be specific the insulating spacers are the same length, but that block part in the middle is noticeably shorter. The no label 12ax7's work fine, I think I was just experimenting back in the day when I swapped them out.

 

[FuseG4]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

People say a lot to avoid long plate tube in v1 for combo amps cuz of a tendency to get microphonic but out of the Chinese, sovtek, and JJ tubes I have on hand the sovtek LPS has the best bass response so I use it for v1 and really dig it.

 

[dystrust]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

EHX used to be standard issue in new Mesa's until around 2008. Back in 2006 I started seeing a number of complaints about Mesa's being dead either on or shortly after arrival. Apparently New Sensor changed their specs and didn't tell people. Mesa switched to JJ and I haven't heard of a similar issue since.

That would explain why my more recent EHX tubes can't seem to handle being in my Jubilee's cathode follower. Sure would've been nice to know that.

People say a lot to avoid long plate tube in v1 for combo amps cuz of a tendency to get microphonic but out of the Chinese, sovtek, and JJ tubes I have on hand the sovtek LPS has the best bass response so I use it for v1 and really dig it.

Unless you're playing with a lot of preamp gain you're probably fine. I've heard that long plate tubes can develop mechanical noise in combo amps, but I don't know what specifically would cause that? Maybe proximity to the speaker or being mounted in a different orientation from most heads?

 

[Orville]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

So I rolled some tubes, and ended up with the Mesa 12ax7's that were in the amp when I bought it. I think they are JJ's. The Sovtec LPS in the PI was okay, but for my ears it did flatten the amp a bit- as in flat sounding in the negative way. I liked it more in V1 but still went back to the Mesa 12ax7.
So now I am looking at power tubes. I think I'll start a new thread. Bottom line for me was the Mesa 12ax7's were quiet and had some nice gain and punch.

 

[some_dude]

Re: Mesa Trans Atlantic 30 preamp tube functions ( V1,V2, ect) Moderators: Guitarzan

So I rolled some tubes, and ended up with the Mesa 12ax7's that were in the amp when I bought it. I think they are JJ's. The Sovtec LPS in the PI was okay, but for my ears it did flatten the amp a bit- as in flat sounding in the negative way. I liked it more in V1 but still went back to the Mesa 12ax7.
So now I am looking at power tubes. I think I'll start a new thread. Bottom line for me was the Mesa 12ax7's were quiet and had some nice gain and punch.

The TA-30 is EL84?

The stock ones are Electro-Harmonix EL84EH, which are arguably the best current production EL84 on the market.