Opinion of Quicksilver KT88 60 watt mono amps

Don't bother. I had a pair back in the early 1990s. If you want 1950s sound, buy them. Poor bass performance. Mid range is nice and highs are a bit rolled off. The stock Chinese KT88 back in the day were junk. I pitched them and replaced them with US made 6550. The GE version was robust, the smaller Sylvania sounded like the original US Tung-Sol, but the Tung-Sol was the best sonically and would last forever in the amps. The amps are not hard on good tubes, and a well made 6550 will work great in them. I had the model that used two 5AR4 on each amp. That is the model you want - if you must get them. While I am not a big fan of the "audio experts" for the "big mags", I will admit that Dick Osler's review in Stereophile (back in the day) was spot-on the mark. Read it before you buy a pair. Just remember this, you are basically buying an amp design from the 1950's. Nothing that special, but they are musical and with good tubes, are very reliable.

Robetozian, what currently available tube amps are not based on a '50s circuit design? I thought most advancements have come from better parts availability, not new designs. I'm asking about tube amps in general, not just Quicksilver.

Tube amplifier circuits have`nt change very much(no need to).Refinement, better power supplies and high quality parts will bring out the very best of these classic circuits. There are many current tube amps with good to excellent bass performance available.Don`t forget transformer quality matters quite a bit.

Pryso,
I agree if there's mid-60's circuit you're lucky:)
Quickies and HH Scott are the most advanced tube amps so far.

Having owned a pair of the original Quicksilver KT88s along with Cary 805C.s, Jolida Music Envoy amps along with a few others here and there I feel that the KT88s are more than just competent. They have exceptional mid range, very detailed Highs without edge and grain and the bottom end is quite capable especially with the right tubes. I am currently running Sophia Blue Bottle KT88 tubes as the ouput tubes, 12ax7s and 5R4U rectifier tubes. I was stunned at the difference the Sophia tubes made. They were expensive but worth every single penny. I have use them to drive various speakers along with the the Carys. They do have their drawbacks, namely the bass. When you compare it to a solid state amp you will not get the speed and attack that comes with solid state. Instead you will get very competent bass that is tuneful, fairly well controlled and with plenty of slam. I have tried numerous solid state amps and always find my way back to tubes. Bojackyour pricing would be on target for the KT88s with mundane set of tubes. Mine wouldn’t leave my hands for less than $1500 with the Sophia tubes.