by past customer KptKrunch – owner of Grant Fidelity A-88 tube amp:
Original post on audiokarma.org:
http://www.audiokarma.org/forums/showthread.php?t=241929
“Well – I didn’t do the exhaustive listening session I planned – didn’t need to. I put my GF A-88 amp in UL mode, put on some PJ Ten Redux, and listened to the first 5 tracks with all the stock Shuguang tubes for the GF A-88. Music seemed very forward, Eddie Vedder sounded reproduced, not at all natural. In fact, I didn’t like the vocals much at all. The highs, cymbals in Alive for example, were very loud and distracting from the rest of the music. The Guitar sounded harsh. I then powered the amp off, waited a few minutes, and swapped out the stock KT-88’s with the Shuguang Treasures (tubes were really hot though let me tell you).
Listened to the same tracks again. Oh, forgot to mention, the A-88 is a manual bias amp, with the voltage recommended to be between .53 and .57 for the stock, and around .45 to .50 for the treasures. I set it to .55 for the stock (as that is how I had it before) and biased the Treasures to .50.
Ian told me that getting the Treasures (I also have the TJ Full Music 12AX7’s but more on those later) would be more of an upgrade than a tube roll per say. Of course he’s going to ‘say’ that, he’s a salesman, right? And those tubes aren’t cheap. I took it with a grain of salt.
Well, there was about a 5 minute delay as I mentioned I had to let the power drain from the amp and the tubes needed to cool a bit before I could take them out. Once I did the switch and started up TEN again – there was a definite difference. I wish I could have two amps running and just use a switch but even with a 5 minute delay I could hear it. The music had much more weight to it. Bass was a little less though, but it was heavier. Not sure if that makes sense, but that’s what I picked up. Also the highs were much smoother with the treasures. With the stock tubes the highs were on the harsh side, which is saying a lot as I’m using Totem Hawks right now and they are not a forward/harsh speaker. Overall I would say the amp sounded richer, smoother, without losing any detail at all. Even the cymbals on Alive which were far too in your face with the stock tubes were not nearly as present but you could still hear them loud and clear.
I next swapped out the stock 6SN7’s with my NOS 1958 Sylvinia black bottoms. This really ‘lushed’ it up I found. Again, I could hear a difference right away (note: Treasures stayed in). This sounded like I switched it over to Triode mode actually, bass was softer, but still present, cymbals were now hard to discern on Alive, in fact you had to now strain to hear them, but guitar sounded really sweet.
Last but not least, with the NOS 6S7N’s and the Treasures still in, I swapped the 12AX7 Shuguang stock with the TJ Full Music 12AX7 tubes. Same 5 tracks again.
Detail is all back to where it should be, those TJ’s sure woke up the 6S7N’s, but the lushness did not leave. Cymbals were back though still not as ‘there’ as they were with the stock 6SN7’s, but you didn’t need to strain to hear them and they did not detract from the music at all.
This is the way I’ve been listening to this A-88 amp for the past 65 hours (which in real time is 5 months) and all I can say is each swap offered a definite improvement and I’m happy to hear it. I was worried I wouldn’t hear anything.
Furthermore, Ian is 100% accurate when he told me this would be more of an upgrade than a tube roll per say. It really does sound like a different amp, a much better amp (and I’m not meaning to say it sounded like a slouch to begin with, but I realize why I felt the stock tubes sounded like they did when I first started this).
Now the scary news, I spent as much on all these tubes as I did on the original purchase price of this amp. Hard to believe but it’s true. Was it worth it? IMO – yes, definitely. I now have an amp that cost me with the upgraded tubes approx $1500.00 that I would gladly put up against any other tube amp out there. Not saying it would beat them (the more expensive ones that is) but I’d bet it would very close. I don’t think I could find a tube amp for $1500 that would beat this current setup.
Very happy indeed. IMO the treasures are well worth the expense.”
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*(hopefully that won’t stop), so I would like to share my experience with other tube lovers. I used to have Golden Dragons (I think marked Hot Rod) then Svetlana 300 B, which I thought are much better than dragons, but Black Bottles are something special.. Too sad that there is no information for them on the net, except on the distributor site (it is Grant Fidelity from whom I bought them)…