In trying to tune up my TR Ruby, I've done some Google research and post reading lately. I've developed a couple of thoughts about tube selection for a 'Wreck style amp I thought I'd share.
I came across some oscilloscope traces that show distortion at various points in the amp at different gain levels, and as many have detailed here, it tends to distort in the power stages first, then progressively toward the front end of the amp, with the V1 tube pretty much staying clean the whole way. I had seen some discussion of the 3rd gain stage acting as a "clipper" by being biased cold, but the 'scope traces showed the PI distorting more heavily earlier, and then the V2 distorting more modestly at higher gain levels.
In other amps, I have always put my "best tube" in V1, then a "robust tube" in V2, and usually a Sovtek LPS in the PI slot. After thinking the above through, I rearranged things for the Ruby. I put an old stock Mullard in the PI slot, as in my experience I love the way a Mullard sounds when it distorts. I put an old stock Phillips 7025 in V1, because I want a very clean tube with good articulation and character in that spot. I put a reissue Mullard in V2, as I want a nice distortion character, but as it doesn't add as much as the PI I didn't want to waste a vintage Mullard there. I'll probably experiment more with the V2 spot.
Man, what an improvement! Gobs of thick creamy distortion, very smooth, lots of character, good articulation.
I plan to play around with more tube rolling, but I think the keys, at least to my ear, are to put a tube with great sound when distorted in the PI slot, and a tube that sounds great clean in V1.
The only thing I don't like about this setup is knowing that I'll probably burn up the Mullard a bit quicker. I'd like to find some cheap new tubes that distort nicely - I'll probably try a Mullard RI there soon. I'm also wondering if some tubes are optimal for V2 - it would be nice to find something that distorts nicely when biased cold and stands up well to that condition - probably whatever sounds good in something like a Real Tube pedal.
Apparently, at least in a 'Wreck style amp, power tube distortion is a major factor - I need to figure out which new EL-34s sound best when they distort.
Some thoughts on 'Wreck preamp tube selection...
Moderators: pompeiisneaks, Colossal
Some thoughts on 'Wreck preamp tube selection...
Let that boy boogie woogie.