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See my previous post below...

Posted by Kico (A) on March 18, 2006 at 06:53:40

In Reply to: penta kt88sc question posted by earnie3 on March 18, 2006 at 05:47:26:

Six weeks ago, I ordered a quad (not matched) of these with the solid plates for my "triode" connected Citation II.
Before ordering, I spent at least thirty minutes on the phone with Peter Russell, their Chief Technical Engineer; he's a very knowledgeable person and definitely a "tube head". He told me a great deal about their production facilities in China, the clean rooms and quality control methods. The factory makes tubes for several vendors and not just the 6550's. These are modeled after the GEC and he thinks they sound even better than the original. Now, since I don't own any original GEC, I can't make a direct comparison, but I can compare with NOS Tung-Sols and my Jim McShane Type I Ei KT-90's. He (Peter) also says running in UL mode at 425V on the plates… in AB1 their good for 50W each…hmmmm…I do wonder about that one!

Construction…these tubes seem to be well made, uniform bottles which are solidly attached to the base. Interior elements, plates and micas are straight and uniform among the quad. Pins are solid and straight; the getter flashing is good and is remarkably uniform in my quad. Another thing I noticed is these tubes have a real “heft” to them.

Electrically…with the individual bias pots on the Cit II set at minimum, current on all tubes was within .335MA of each other after a one hour warm up…this really surprised me for non-matched tubes, I later set the bias for 85MA and it’s remained stable since. There are no red plates or other anomalies that I’ve noticed.

Sound… I’ve found these tubes do need a long break in—mine didn’t come into their own until after 100 hours or more; they’ve settled in now though and are still improving; the tubes are dead silent. Are they a Tung-Sol, well no, but they’re sounding pretty darn good; I think a very choice for every day use. So far, the biggest difference is in the midrange, not as silky smooth/mellow as my TS’s, but a good tight and plentiful bass exists; it has a clean crisp top end with plenty of detail, sound-staging is good, with excellent dynamic detail across the audio spectrum and a wide soundstage to boot. Also, at this bias they seem to have a bit more headroom than the Ei KT-90’s or the TS’s; all-in-all, a very listenable tube in my setup.

For a $20 tube I think its going to be hard to beat in my current system. So, if you’re looking for a modern day KT88 that's a very, very good all-rounder, this could be the one.

As for reliability…we’ll see. (an addition here) The reliability has been excellent. I have ordered, and am using, four quads from Penta with no a failures; I believe the long term relibilty will be very good.


Regards,
"Kico"

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