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

[Orville]

I want to swap in some of the preamp tubes I have laying around to get the best ( for me) sound out of it. I have some basic questions on functions of the tubes. I am operating under the assumption that since 12ax7s have two sides, the A and B denote the sides and if the schematic says A&B that means the amp uses both sides for that function? I know I can just swap some in and see how they sound but I wouldn't mind knowing what each tube is doing.

Per the owners manual :
V1 A&B - Ch 1 input stage
V2 A&B - Input stage for Ch 2
- 2nd gain stage for Ch 2
V3 A&B - Tone control Driver for Ch1 & Ch2
V4 A&B - driver/ phase inverter
V5A - Loop return stage
V5B - Reverb mixer
V6A - reverb return gain stage
V6B - Reverb Send stage

Question 1 ) If I am on channel 2 does the signal go thru channel 1 tube V1 then to ch 2 v2 tube, or is V1 or V2 only in play when on that channel?

Question 2) The amp has a pull pt on Ch 2 gain to add extra gain. When that is NOT pulled I am only using the A side of the V2 tube?

Question 3) Do all the preamp tubes add gain? For example does the V3 tone control add gain? Does the V5/V6 loop and reverb tubes add to the gain?

Thanks for any help! I have a handful of 12ax7's of different mfg and some older RCA 12ax7s and an AT7 to swap in and I'll let my ears decide, but knowing what each V position does could help me as I swap them around.

[FuseG4]

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

This is difficult, finding Mesa current production schematic is hard cuz they don't publish them.

Generally through based on the info you gave it sounds like channel 1 starts on v1 and channel 2 starts with v2

Question two, many times pull boosts change something about how the tube is biased which increases gain, sometimes it can be done by switching in another tube triode but I can't confirm here.

And question 3 things like the tone stack buffer/recovery won't overdrive as much so any good tube should work.
The fx loop and reverb are the same but here look for low noise tubes of you can

[zionstrat]

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

I want to swap in some of the preamp tubes I have laying around to get the best ( for me) sound out of it. I have some basic questions on functions of the tubes. I am operating under the assumption that since 12ax7s have two sides, the A and B denote the sides and if the schematic says A&B that means the amp uses both sides for that function? I know I can just swap some in and see how they sound but I wouldn't mind knowing what each tube is doing.

Per the owners manual :
V1 A&B - Ch 1 input stage
V2 A&B - Input stage for Ch 2
- 2nd gain stage for Ch 2
V3 A&B - Tone control Driver for Ch1 & Ch2
V4 A&B - driver/ phase inverter
V5A - Loop return stage
V5B - Reverb mixer
V6A - reverb return gain stage
V6B - Reverb Send stage

Question 1 ) If I am on channel 2 does the signal go thru channel 1 tube V1 then to ch 2 v2 tube, or is V1 or V2 only in play when on that channel?

Question 2) The amp has a pull pt on Ch 2 gain to add extra gain. When that is NOT pulled I am only using the A side of the V2 tube?

Question 3) Do all the preamp tubes add gain? For example does the V3 tone control add gain? Does the V5/V6 loop and reverb tubes add to the gain?

Thanks for any help! I have a handful of 12ax7's of different mfg and some older RCA 12ax7s and an AT7 to swap in and I'll let my ears decide, but knowing what each V position does could help me as I swap them around.

Can't answer your questions however I hear TAs are one of the better clean to crunch amps... Can u confirm and describe?

Have a client looking for one right now and details would be helpful.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[Gtrjunior]

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

Can't answer your questions however I hear TAs are one of the better clean to crunch amps... Can u confirm and describe?

Have a client looking for one right now and details would be helpful.

Sent from my SAMSUNG-SM-G920A using Tapatalk

I played in a band with a guy that had the TA-30...it is indeed a great clean/crunch amp.
Unfortunately he had no idea how to work the amp. ☹️

[Orville]

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

Can't answer your questions however I hear TAs are one of the better clean to crunch amps... Can u confirm and describe?

Have a client looking for one right now and details would be helpful.

Sent from my SAMSUNG-SM-G920A using Tapatalk

I haven't had it too long so I am just getting to know it but it does both pretty well.

Channel 1 is the Vox inspired side. It has a switch to go to Top Boost mode. I have never played a vintage Vox Top Boost but have heard my share live and have a friend with a newer AC15. It does capture a Vox -like sound, and sounds great in general, especially in Top Boost. It's not a Vox but gets a chimey sound pretty well. It can be set to overdrive and it's not bad, but I haven't really sorted out that sound so I can't comment too much. Great clean sound.
Channel 2 has some options. A 3 way switch offers a Tweed mode, Hi 1 and Hi 2. The tweed mode, like Channel 1 is a Tweed inspired sound. It captures a tweed-ish sound and will overdrive similar to a Tweed. It's a nice crisp clean sound. Hi 1 is kinda Marshally and Hi 2 is supposed to be in the vein of a old Boogie mark series I think. All the modes sound good. You can get all kinds of clean sounds and the overdrive is pretty British. It will go dead clean to classic rock to early metal dirty. The Hi 2 is a smoother version of Hi 1. I set up a clean sound on ch 1 and a nice dirty sound using Hi 1 on Ch 2. Ch2 in Tweed is pretty nice clean as well and it's not the same clean as Ch 1 so Mesa did a decent job of getting American vs British sounds. In general if you want a clean amp this has some great dead clean sounds in it. The dirt side is great too, wouldn't need pedals unless you wanted to get into some fairly modern metal. I haven't gone there. I also haven't used a lot of pedals with it yet, but my sense is it would take them well, up front.
You have to make sure your client is aware of some of the noise issues with this amp. There are fixes - which I got - but when the FX/reverb switch is enabled depending on some of the amp settings it can be a bit noisy. I can run decent reverb on Ch 2 with a good amount of gain and it isn't bad. I'd have you or your client do some research on this, there is a ton on the web about this. I ultimately plan to use this amp in the old fashioned - pre effects loop days and run stuff thru the front, like Eric Johnson and his old Marshalls and not enable the reverb/loop for Ch 2. For Channel 1 the noise is not bad at any volume. Too bad this issue is an issue at all, because the reverb itself is really nice. Both channels have their own reverb/loop select so you can run 'verb clean and none on Ch 2.

It's a great amp with a number of great sounds overall and could do anything from Jazz clean to early-mid '80s metal with no help. Aside from the noise issues which may not be an issue for your client I'd say just the sound of the amp is damn good. Not vintage point to point but especially on the clean sounds pretty close, and for the money excellent.

[allbutromeo]

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

^^^ Try a 5751 or 12AT7 in V6 and maybe also in V5, this should quiet the amp down when reverb and/or FX Loop is turned on. 5751 tubes are about 70% the amount of gain as a 12AX7 and a 12AT7 is about 60%.

[zionstrat]

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

I haven't had it too long so I am just getting to know it but it does both pretty well.

Channel 1 is the Vox inspired side. It has a switch to go to Top Boost mode. I have never played a vintage Vox Top Boost but have heard my share live and have a friend with a newer AC15. It does capture a Vox -like sound, and sounds great in general, especially in Top Boost. It's not a Vox but gets a chimey sound pretty well. It can be set to overdrive and it's not bad, but I haven't really sorted out that sound so I can't comment too much. Great clean sound.
Channel 2 has some options. A 3 way switch offers a Tweed mode, Hi 1 and Hi 2. The tweed mode, like Channel 1 is a Tweed inspired sound. It captures a tweed-ish sound and will overdrive similar to a Tweed. It's a nice crisp clean sound. Hi 1 is kinda Marshally and Hi 2 is supposed to be in the vein of a old Boogie mark series I think. All the modes sound good. You can get all kinds of clean sounds and the overdrive is pretty British. It will go dead clean to classic rock to early metal dirty. The Hi 2 is a smoother version of Hi 1. I set up a clean sound on ch 1 and a nice dirty sound using Hi 1 on Ch 2. Ch2 in Tweed is pretty nice clean as well and it's not the same clean as Ch 1 so Mesa did a decent job of getting American vs British sounds. In general if you want a clean amp this has some great dead clean sounds in it. The dirt side is great too, wouldn't need pedals unless you wanted to get into some fairly modern metal. I haven't gone there. I also haven't used a lot of pedals with it yet, but my sense is it would take them well, up front.
You have to make sure your client is aware of some of the noise issues with this amp. There are fixes - which I got - but when the FX/reverb switch is enabled depending on some of the amp settings it can be a bit noisy. I can run decent reverb on Ch 2 with a good amount of gain and it isn't bad. I'd have you or your client do some research on this, there is a ton on the web about this. I ultimately plan to use this amp in the old fashioned - pre effects loop days and run stuff thru the front, like Eric Johnson and his old Marshalls and not enable the reverb/loop for Ch 2. For Channel 1 the noise is not bad at any volume. Too bad this issue is an issue at all, because the reverb itself is really nice. Both channels have their own reverb/loop select so you can run 'verb clean and none on Ch 2.

It's a great amp with a number of great sounds overall and could do anything from Jazz clean to early-mid '80s metal with no help. Aside from the noise issues which may not be an issue for your client I'd say just the sound of the amp is damn good. Not vintage point to point but especially on the clean sounds pretty close, and for the money excellent.

Exactly what I needed! Thanks so much and good luck on the tubes.

Sent from my SAMSUNG-SM-G920A using Tapatalk

[some_dude]

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

I want to swap in some of the preamp tubes I have laying around to get the best ( for me) sound out of it. I have some basic questions on functions of the tubes. I am operating under the assumption that since 12ax7s have two sides, the A and B denote the sides and if the schematic says A&B that means the amp uses both sides for that function? I know I can just swap some in and see how they sound but I wouldn't mind knowing what each tube is doing.

Per the owners manual :
V1 A&B - Ch 1 input stage
V2 A&B - Input stage for Ch 2
- 2nd gain stage for Ch 2
V3 A&B - Tone control Driver for Ch1 & Ch2
V4 A&B - driver/ phase inverter
V5A - Loop return stage
V5B - Reverb mixer
V6A - reverb return gain stage
V6B - Reverb Send stage

Question 1 ) If I am on channel 2 does the signal go thru channel 1 tube V1 then to ch 2 v2 tube, or is V1 or V2 only in play when on that channel?

Question 2) The amp has a pull pt on Ch 2 gain to add extra gain. When that is NOT pulled I am only using the A side of the V2 tube?

Question 3) Do all the preamp tubes add gain? For example does the V3 tone control add gain? Does the V5/V6 loop and reverb tubes add to the gain?

Thanks for any help! I have a handful of 12ax7's of different mfg and some older RCA 12ax7s and an AT7 to swap in and I'll let my ears decide, but knowing what each V position does could help me as I swap them around.

1) Modern Mesas generally have two separate preamps in them. One is typically based off the Lonestar and the other is amp specific. It's why there's two separate input stages in your amp. It also means that swapping the V1 won't affect the sound of channel 2 and swapping the V2 won't affect the sound of channel 1.

2) Most likely.

3) No. Some of them are buffers and should ideally be working at unity gain.

[dystrust]

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

Per the owners manual :
V1 A&B - Ch 1 input stage
V2 A&B - Input stage for Ch 2
- 2nd gain stage for Ch 2
V3 A&B - Tone control Driver for Ch1 & Ch2
V4 A&B - driver/ phase inverter
V5A - Loop return stage
V5B - Reverb mixer
V6A - reverb return gain stage
V6B - Reverb Send stage

Question 3) Do all the preamp tubes add gain? For example does the V3 tone control add gain? Does the V5/V6 loop and reverb tubes add to the gain?

If I'm reading that tube chart correctly, I would expect V3, V5, and V6 to have almost zero effect on the overall tone of the amp. V1 and V2 will have a huge impact on the tone with V4 having somewhat less. I'm not super familiar with that amp, so I can't provide any specific tube suggestions.

[FuseG4]

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

also about v3: "tone control driver", if this is a cathode follower, avoid the long plate spiral filament tubes, Sovtek LPS and JJ ECC803 long plates, Mullard RI, those seem to die quickly in that spot.

[dystrust]

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

also about v3: "tone control driver", if this is a cathode follower, avoid the long plate spiral filament tubes, Sovtek LPS and JJ ECC803 long plates, Mullard RI, those seem to die quickly in that spot.

I'm not sure about the JJ ECC803 since AFAIK the only problematic cathode followers are spiral filament tubes made by New Sensor. The Sovtek LPS and Mullard RI would be included in that group, as well as the EHX, Tung-Sol, and Svetlana 12AX7s.

[FuseG4]

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

but yeah some people like hughes and kettner believe that cathode followers are a key tone-shaping stage and to be honest I don't think I've experimented with rolling CF tubes but I'd say go ahead and try your decent tubes there as well in v3 and see if you notice a difference, could be interesting.

[Gtrjunior]

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

I'm not sure about the JJ ECC803 since AFAIK the only problematic cathode followers are spiral filament tubes made by New Sensor. The Sovtek LPS and Mullard RI would be included in that group, as well as the EHX, Tung-Sol, and Svetlana 12AX7s.

This is my understanding as well.

[Gtrjunior]

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

If I'm reading that tube chart correctly, I would expect V3, V5, and V6 to have almost zero effect on the overall tone of the amp. V1 and V2 will have a huge impact on the tone with V4 having somewhat less. I'm not super familiar with that amp, so I can't provide any specific tube suggestions.

Only thing I’ll add here is that the tube in the reverb a lot may affect the tone of the reverb. But I wouldn’t expect it to affect the primary tone.

[hamerfan]

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

Thanks for any help! I have a handful of 12ax7's of different mfg and some older RCA 12ax7s and an AT7 to swap in and I'll let my ears decide, but knowing what each V position does could help me as I swap them around.

RCA 12ax7 are among the finest input tubes, moreso if they carry the 12AX7A designation. Put them in V1 and V2.