I bought a matched quad of KT-88s and a pair of 300B-Zs from Grant Fidelity to put in a Quad II-forty pair of monoblocks (for the KT-88s) and a Manley 300B Neoclassic preamp respectively.
There was an extended break in time for the 300B-Zs in the Manley, but within hours they were far better than the EH 300Bs supplied as stock tubes with the preamp. The experience that I've had with the tubes has been extremely positive. They are very fine devices and the sound is gorgeous. There is an extended thread here on Audiogon re the Shuguang Black Treasure 300B-Zs in similar Manley gear to mine, so I won't be repetitive.
The experience I had with the KT-88s was quite similar to the previous posts in this thread, but the break in period was considerably briefer. I found the differences after 50 hours to be quite minute and I had to listen to CDs and repeat tracks or sections to discern a difference.
For the KT-88s, I replaced Genalex Gold Lion KT-88 reissues. There was no contest. The Shuguangs represented a significant and discernable upgrade and, even taking into account the premium price, they were cheap. A friend of mine replaced Mullard EL-34 reissues with the 6CA7 and his experience paralleled mine: an initial break in period of 50-60 hours and the difference was pronounced and quite wonderful.
These are marvellous valves and worth the cash.
There was an extended break in time for the 300B-Zs in the Manley, but within hours they were far better than the EH 300Bs supplied as stock tubes with the preamp. The experience that I've had with the tubes has been extremely positive. They are very fine devices and the sound is gorgeous. There is an extended thread here on Audiogon re the Shuguang Black Treasure 300B-Zs in similar Manley gear to mine, so I won't be repetitive.
The experience I had with the KT-88s was quite similar to the previous posts in this thread, but the break in period was considerably briefer. I found the differences after 50 hours to be quite minute and I had to listen to CDs and repeat tracks or sections to discern a difference.
For the KT-88s, I replaced Genalex Gold Lion KT-88 reissues. There was no contest. The Shuguangs represented a significant and discernable upgrade and, even taking into account the premium price, they were cheap. A friend of mine replaced Mullard EL-34 reissues with the 6CA7 and his experience paralleled mine: an initial break in period of 50-60 hours and the difference was pronounced and quite wonderful.
These are marvellous valves and worth the cash.