The Original RX is a great and underrated jem of an amp!
It's one of Doc's earlier designs, and as much as I like the ES, I like the Original equally.
To me it's just raw, and as you know having one it gets really hairy...
THE most percussive / responsive amp I've ever played other than the Z wreck... um n' it's LOUD.
If you want to tame the raw-ness somewhat / hair just a bit, and either get more clean headroom or smooth it out some there are several things you can try...
For pre amp tubes… I'm liking a 5751 in V1 to smooth it out some... try several different ones (
especially nos, but current ones aren't bad either) as different brands may react a little different and you may prefer the sound of one brand over another...
Also another big difference can be made with the Tube rectifier, I'd try a few good NOS ones and can give you more clean headroom / change the feel or tone some too... as with the 5751, try a few to see which you like the best. For current production Tube rectifiers I like the JJ 5AR4 / GZ-34.
Changing these two tubes seem to make the biggest difference for tube swapping.
As far as power tubes, the old GT rating of 5 or 6 is a nice middle of the road EL-84, Doc used these rated ones for a reason and to me they are just about perfect.
You can use a lower rated EL-84 power tube for some earlier break up or a higher rated EL-84 for some more head room… but it does change the feel of the amp some, Now you may like the change, I prefer to use the #6 EL-84’s and change the V1 or Rectifier instead.
and another thing to try is different speakers...
the Greenbacks or the G12 H30 are both really excellent with this amp... and if you like the Greenback style, but want a little more clean headroom, some “slight” chime / nice high’s… try a ceramic 50 watt Weber Silver bell (
also a G12 65 would probably work well for a higher wattage greenback but haven’t tried it with this amp). A Weber Blue dog or a Celestion Gold will bring out the Chime more and voxy side if that’s what you’re wanting… Celestion Gold would be very nice.
Just depends on what you’re looking for, and a higher wattage Alnico (
like the Silver bell or Tone Tubby) will smooth it out some too and take away some of the Ceramic’s bite.
Anyway YMMV,
that's some of my thoughts (
maybe ALL of my thoughts lol) and especially depending on the guitar and style you play... I prefer single coils / bluesy rock so most of this is based on that perspective. Humbuckers and p-90's may vary.
Have fun and let us know what YOU end up trying and what you like best...
Jason