I am a long time solid state type that has recently dipped a toe into tube gear. I first bought a Conrad Johnson Premier 14 preamp which pleased me (it is a line stage, as I use a separate phono stage). I thought that given that it uses tubes that are modestly priced, I would have a shot at some modest tube rolling to see what differences I could hear, if any.
The stock CJ tubes are 6FQ5A / 6GK5 and the factory likes to supply GEs. I obtained NOS and used with good test results to audition, with no expectations at all.
Results:
Hitachis sounded a bit inferior and closed in
Mullards sounded about the same
RCAs sounded significantly better and more open
Interesting! When I bought a CJ Premier 11a power amp (which I decided I liked more than I did the sound of the Rowland 5 in the main system, although the latter had better bass slam), I decided to do a bit of tube swapping on it. The amp uses four 6550 output tubes which were new when I bought the amp and I decided to leave them alone, a pair of 5751s and a pair of 6CG7s.
I swapped out the 5751s for some Raytheon JAN-5751 black plate windmill getter tubes with excellent results (I’d borrowed a pair from a friend to try before buying) and then added a pair of US Sylvania 6CG7s which also made a small but distinct improvement in sound.
Thus endeth my tube swapping for the time being. I am happy with the results and have thought of eventually trying the same thing on the output tubes. I’ve seen good reviews of Tungsols and of some KT-88s that I gather are direct substitutes. But before getting into that, I thought I’d ask if anyone else had any preferences as far as 6550s go?
And to what degree is the experience with one amp likely to be the same with another? Or are tube results dependent on which amp you are using them in (in which case I doubt I'll find many people with identical tubes/amps to offer advice). All advice gratefully received.
The stock CJ tubes are 6FQ5A / 6GK5 and the factory likes to supply GEs. I obtained NOS and used with good test results to audition, with no expectations at all.
Results:
Hitachis sounded a bit inferior and closed in
Mullards sounded about the same
RCAs sounded significantly better and more open
Interesting! When I bought a CJ Premier 11a power amp (which I decided I liked more than I did the sound of the Rowland 5 in the main system, although the latter had better bass slam), I decided to do a bit of tube swapping on it. The amp uses four 6550 output tubes which were new when I bought the amp and I decided to leave them alone, a pair of 5751s and a pair of 6CG7s.
I swapped out the 5751s for some Raytheon JAN-5751 black plate windmill getter tubes with excellent results (I’d borrowed a pair from a friend to try before buying) and then added a pair of US Sylvania 6CG7s which also made a small but distinct improvement in sound.
Thus endeth my tube swapping for the time being. I am happy with the results and have thought of eventually trying the same thing on the output tubes. I’ve seen good reviews of Tungsols and of some KT-88s that I gather are direct substitutes. But before getting into that, I thought I’d ask if anyone else had any preferences as far as 6550s go?
And to what degree is the experience with one amp likely to be the same with another? Or are tube results dependent on which amp you are using them in (in which case I doubt I'll find many people with identical tubes/amps to offer advice). All advice gratefully received.
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