I recently obtained a lightly used Mesa Boogie Royal Atlantic head. Sign off date was February 27, 2012. Almost 2 years in age. The amp was well maintained and the tubes were worn out (not surprised). On the same day the amp arrived, I also got my shipment of SED =c= EL34. I bought them primarily for the Mark V. I did have a chance to try them in the V before committing them to the RA. In honesty, they sounded like the TAD6L6GC-STR (almost), they did not have as much grunt as the EH EL34 after they burned in. However, the SED =C= EL34 performed unbelievably well in the RA100.
The RA100 had a few changes in the preamp as well. Most of the tubes were Mesa brand except for V5 which was a JJ labeled tube. For start, to wake up the Hi/Lo gain channel and to smooth up the tone, the GOLD Tung Sol 12ax7 really made a difference. I installed the standard Tung Sol in V2. Left the original 12aT7 in V3. For the clean channel, I tried a few different tubes but what really made a difference in V4 was a JAN/GE 5751. Tone controls were less neutral with the lower gain tube. Improved brightness which was lacking, and the bass was more defined and not soft. V5 I used a vintage Mesa Chinese tube from the 90's that I had (tube has the square getter). For the reverb which is essentially a driver tube I made use of the Penta Labs 12ax7 tube (which is also Chinese). Along with my tube order, I also got a new Sovtek 12ax7LPS (matched triodes) for the PI (V7).
Impressions, I just could not stop playing the amp. Power soak tone also changed with the new (or in some cases old) tubes. Hi/Lo channel has improved bass response. Not as relaxed as it was with other tubes. The treble is sweet and not so dominant as it was. The Tung Sol tubes offered a perfect blend of tone from low to the high end. Since I am using the V30 that I had in storage for a very long time, they really sound great with this amp, now better with the tube roll. I would say this amp sounds better than any of the recordings on the Mesa Web site. For 70's through 80's rock this amp can't be beat. I thought the Mark V was killer but the RA100 makes ACDC, Led Zepplin, and even Scorpions type music sound more like it should. When it comes to getting the Deep Purple tone, the Mark V seems to handle that very well.
I would definitely recommend a JAN/GE 5751 for V4 (1st and 2nd gain stage for the clean channel), Tung Sol Gold 12ax7 for V1. I think I need to get a new 12aT7 for V3, I seem to have a slight bit of hum in the amp. I will try a different tube in there just to see if I can remove it. It may be motor noise from the fan, I believe it can be turned off so I will check that out. The hum was there with the original tubes, so that has not changed with the new tubes. Only tube not changed was V3. Also the noise goes away when the power soak is turned on. It is not bothering me since it is low level noise which becomes unnoticeable when you are playing. I could also defeat the reverb and see if it goes away. When I got the amp, the reverb cable was unconnected. I installed white cable towards the rear, black towards the transformer (next to the hidden reverb kill jack).
The RA100 had a few changes in the preamp as well. Most of the tubes were Mesa brand except for V5 which was a JJ labeled tube. For start, to wake up the Hi/Lo gain channel and to smooth up the tone, the GOLD Tung Sol 12ax7 really made a difference. I installed the standard Tung Sol in V2. Left the original 12aT7 in V3. For the clean channel, I tried a few different tubes but what really made a difference in V4 was a JAN/GE 5751. Tone controls were less neutral with the lower gain tube. Improved brightness which was lacking, and the bass was more defined and not soft. V5 I used a vintage Mesa Chinese tube from the 90's that I had (tube has the square getter). For the reverb which is essentially a driver tube I made use of the Penta Labs 12ax7 tube (which is also Chinese). Along with my tube order, I also got a new Sovtek 12ax7LPS (matched triodes) for the PI (V7).
Impressions, I just could not stop playing the amp. Power soak tone also changed with the new (or in some cases old) tubes. Hi/Lo channel has improved bass response. Not as relaxed as it was with other tubes. The treble is sweet and not so dominant as it was. The Tung Sol tubes offered a perfect blend of tone from low to the high end. Since I am using the V30 that I had in storage for a very long time, they really sound great with this amp, now better with the tube roll. I would say this amp sounds better than any of the recordings on the Mesa Web site. For 70's through 80's rock this amp can't be beat. I thought the Mark V was killer but the RA100 makes ACDC, Led Zepplin, and even Scorpions type music sound more like it should. When it comes to getting the Deep Purple tone, the Mark V seems to handle that very well.
I would definitely recommend a JAN/GE 5751 for V4 (1st and 2nd gain stage for the clean channel), Tung Sol Gold 12ax7 for V1. I think I need to get a new 12aT7 for V3, I seem to have a slight bit of hum in the amp. I will try a different tube in there just to see if I can remove it. It may be motor noise from the fan, I believe it can be turned off so I will check that out. The hum was there with the original tubes, so that has not changed with the new tubes. Only tube not changed was V3. Also the noise goes away when the power soak is turned on. It is not bothering me since it is low level noise which becomes unnoticeable when you are playing. I could also defeat the reverb and see if it goes away. When I got the amp, the reverb cable was unconnected. I installed white cable towards the rear, black towards the transformer (next to the hidden reverb kill jack).