Recently an output tube went bad on my HXDA 30, and I had the opportunity to try some different tubes out. It was pretty interesting, so I thought I'd post a few thoughts and descriptions of how the sound changed.
I run this amp into a PRS Big Mouth birch ply 2x12, loaded with PRS-modded Vintage 30s. It's a very sweet combination with the HXDA. I had previously installed NOS Mullard preamp tubes in the amp.
The amp came loaded with Winged C EL34 output tubes, and I stuck with them until a couple of weeks ago when one of the tubes went bad. I like the Winged C tubes, but they're not made any more. Suddenly these very recent tubes are "NOS" and fetch prices that are comparable to vintage NOS tubes from the 70s. Feh. They're nice tubes, but not all that. If I'm paying NOS prices, I'm going with 70s tubes, at the latest.
I had bought a couple of matched sets of 70s NOS Siemens EL34s, made in Germany (probably by RFT in what was formerly East Germany, but I lack sufficient info to know for sure) and was saving them for just such an occasion. These tubes have an excellent reputation for vintage tone.
First, however, I tested the amp with a pair of the JJs that I'm told come stock on recent HXDAs (again, this is just what I've heard). Then I installed, and of course biased, the NOS Siemens after about a week with the JJs.
Here's what I found; this is admittedly subjective, I made no measurements:
In this particular amp, with this cab and my PRS guitars ('15 McCarty, '16 PS 20th Ltd, '14 McCarty Singlecut, '15 30th Anniversary CU24), the Winged Cs had a rich bottom end and lower midrange, and a sparkly top end. I would call the Winged Cs a "warm sounding" tube because of this balance. The tube has good midrange and upper midrange clarity, and is easy to drive into distortion. There is a very controllable "bloom" as the volume increases, and the amp loaded with this set sounded great.
The JJs are a little cloudier in the midrange and upper midrange, and a little less controlled in the low end, but they're still rich sounding tubes. I had to increase the presence and treble, as well as the balance between the treble gain and the bass gain blend, to get things closer to the Winged Cs. Once I did that, I liked playing the amp with them, and admittedly, we are talking about small differences between these two tube brands. I was actually surprised that I liked the JJs, because other JJ EL34 tubes in different amps I've tried didn't thrill me. These were pretty good. Goes to show ya, every amp and tube combination is a little different. They overdrive pretty easily, maybe even a little more quickly than the =c= set.
The NOS Siemens are tighter in the bass and low mids, with more midrange clarity, and definitely more sparkle than the JJs and Winged Cs. I'd say they have excellent definition, and after I got the amp set up the way I like it, I found that I really like these tubes. I found that with the other tubes I liked to set up the amp with the first two HX/DA switches set to the DA position, and the third switch set to HX. With the Siemens, I have so far preferred the amp in all HX mode on all 3 switches. It sounds fine the other way, but I missed some of the really nice detail that I get with this set of tubes set all HX when I tried other positions, especially with the guitar volume rolled back and the amp set pretty clean. They have a bit more headroom than the = C = set, and even more than the JJs. I liked that, because I can get the amp to do more things from clean to mean with this set of tubes. And while I prefer the HX settings, I do like these tubes with the other settings, so there's a lot of versatility.
The caveat here is that yes, we're talking about subtle differences. At first, it's hard to figure out what's different when swapping these EL34 output tubes, but as one plays, the ear becomes acclimated to what to listen for, and it's not difficult to reach conclusions about which tubes do what, and which tubes one prefers.
Anyway, it's been a fun thing to run the amp with these NOS Siemens, and they're staying in the amp. I have a spare set of the Siemens, and will probably buy more, because...of course I need a lifetime supply (given my age, a lifetime supply would be...um...not that many sets.
The JJs will be emergency tubes.
I run this amp into a PRS Big Mouth birch ply 2x12, loaded with PRS-modded Vintage 30s. It's a very sweet combination with the HXDA. I had previously installed NOS Mullard preamp tubes in the amp.
The amp came loaded with Winged C EL34 output tubes, and I stuck with them until a couple of weeks ago when one of the tubes went bad. I like the Winged C tubes, but they're not made any more. Suddenly these very recent tubes are "NOS" and fetch prices that are comparable to vintage NOS tubes from the 70s. Feh. They're nice tubes, but not all that. If I'm paying NOS prices, I'm going with 70s tubes, at the latest.
I had bought a couple of matched sets of 70s NOS Siemens EL34s, made in Germany (probably by RFT in what was formerly East Germany, but I lack sufficient info to know for sure) and was saving them for just such an occasion. These tubes have an excellent reputation for vintage tone.
First, however, I tested the amp with a pair of the JJs that I'm told come stock on recent HXDAs (again, this is just what I've heard). Then I installed, and of course biased, the NOS Siemens after about a week with the JJs.
Here's what I found; this is admittedly subjective, I made no measurements:
In this particular amp, with this cab and my PRS guitars ('15 McCarty, '16 PS 20th Ltd, '14 McCarty Singlecut, '15 30th Anniversary CU24), the Winged Cs had a rich bottom end and lower midrange, and a sparkly top end. I would call the Winged Cs a "warm sounding" tube because of this balance. The tube has good midrange and upper midrange clarity, and is easy to drive into distortion. There is a very controllable "bloom" as the volume increases, and the amp loaded with this set sounded great.
The JJs are a little cloudier in the midrange and upper midrange, and a little less controlled in the low end, but they're still rich sounding tubes. I had to increase the presence and treble, as well as the balance between the treble gain and the bass gain blend, to get things closer to the Winged Cs. Once I did that, I liked playing the amp with them, and admittedly, we are talking about small differences between these two tube brands. I was actually surprised that I liked the JJs, because other JJ EL34 tubes in different amps I've tried didn't thrill me. These were pretty good. Goes to show ya, every amp and tube combination is a little different. They overdrive pretty easily, maybe even a little more quickly than the =c= set.
The NOS Siemens are tighter in the bass and low mids, with more midrange clarity, and definitely more sparkle than the JJs and Winged Cs. I'd say they have excellent definition, and after I got the amp set up the way I like it, I found that I really like these tubes. I found that with the other tubes I liked to set up the amp with the first two HX/DA switches set to the DA position, and the third switch set to HX. With the Siemens, I have so far preferred the amp in all HX mode on all 3 switches. It sounds fine the other way, but I missed some of the really nice detail that I get with this set of tubes set all HX when I tried other positions, especially with the guitar volume rolled back and the amp set pretty clean. They have a bit more headroom than the = C = set, and even more than the JJs. I liked that, because I can get the amp to do more things from clean to mean with this set of tubes. And while I prefer the HX settings, I do like these tubes with the other settings, so there's a lot of versatility.
The caveat here is that yes, we're talking about subtle differences. At first, it's hard to figure out what's different when swapping these EL34 output tubes, but as one plays, the ear becomes acclimated to what to listen for, and it's not difficult to reach conclusions about which tubes do what, and which tubes one prefers.
Anyway, it's been a fun thing to run the amp with these NOS Siemens, and they're staying in the amp. I have a spare set of the Siemens, and will probably buy more, because...of course I need a lifetime supply (given my age, a lifetime supply would be...um...not that many sets.
The JJs will be emergency tubes.
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