No love for the KT 90?

I believe that most vendors will cyro-treat a large batch of tubes. And after the treatment, will re-test each tube and reassemble them into matched pairs/quads.

Q: How many tubes are enough?
A: One more than you already have.

skriefal wrote:I believe that most vendors will cyro-treat a large batch of tubes. And after the treatment, will re-test each tube and reassemble them into matched pairs/quads.

Which closes the circle ...

My concern with cryo is that the process DOES apparently change the electronic characteristics of the tube, so that leaves us with the question as to whether the "improvement" is actually an improvement over the original factory matching. A lot would depend on how inclusive the post-cryo testing is.

deepee99 wrote:Q: How many tubes are enough?

You're saying I should just get a set of each to put the question to rest?
(Way to enable my addiction, you dirty rat, you ...)

You're saying I should just get a set of each to put the question to rest?
(Way to enable my addiction, you dirty rat, you ...)

Well i do have more than one tube Amp...............more like 8 to day...........But the more tubes the better...
If you keep the B+....at 480V.....i have not lost an tubes in years.........thay i did not DroP..
Hehe....It happen.....but in my MK3s i have ran one ea KT90 an one KT88 an got great sound!
An even with one amp......most people cant just chang the outputs AMps... Tube amps 2014....Heh

Have fun your only here for a Min......



Thanks for the site Bob........




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I'd like to hear Jim McShane weigh on the cryo business. Opinions range from that it's the greatest thing since sliced bread to that it's snake oil. It would be nice to hear from somebody who knows what he's talking about.

one thing I noticed when I got cryo KT120's for one of my clients amps was that they looked 'aged' on the inside. All the plates were kind of pitted and I also saw some silver flakes inside all of them, like it came from the getter.
Sound wise, for the short period I had them running, I could not hear any differences between those and non cryo'ed KT120's.

Ok, I've been reading this thread with interest but with a little skepticism. I'm certainly a tube noob and I am assuming that the original tubes in my dad's ST70 are going to have to be replaced (once I finish the rebuild). So my question is this: all other things being equal, what makes one tube sound different from another? coatings? physical spacing? differences in ear drums? or the ever present risk of "I paid more for these tubes so they MUST sound better"! Also (since the last time I heard this amp play I was a kid) what modern tube represents a good VALUE and sounds as close to the original tubes as possible? I want my dad's amp to be the baseline sound so I have a point of comparison if/when I build a new kit amp with all of the possible upgrades. BTW I hope my choice of using an 80/40/30/20 quad cap won't alter the original sound too much as I'm trying to keep this amp's signal path as close to original as possible.

n3ikq wrote:Ok, I've been reading this thread with interest but with a little skepticism. I'm certainly a tube noob and I am assuming that the original tubes in my dad's ST70 are going to have to be replaced (once I finish the rebuild). So my question is this: all other things being equal, what makes one tube sound different from another? coatings? physical spacing? differences in ear drums? or the ever present risk of "I paid more for these tubes so they MUST sound better"! Also (since the last time I heard this amp play I was a kid) what modern tube represents a good VALUE and sounds as close to the original tubes as possible? I want my dad's amp to be the baseline sound so I have a point of comparison if/when I build a new kit amp with all of the possible upgrades. BTW I hope my choice of using an 80/40/30/20 quad cap won't alter the original sound too much as I'm trying to keep this amp's signal path as close to original as possible.

sound is EXTREMELY subjective as you may well imagine.
But yes, different model power tube do sound different, no doubt about that. To my ears, Kt88' as well as KT120's have more bass and seem to be able to handle a wider frequency range than say EL34's.
For driver tubes, I prefer the sound of 5963's instead of a lot of 12AU7's as driver tubes, I also like the sound of the 6SN7's and 6SL7's as driver tubes, I use those in the ST120's and M125's.

I am assuming your ST70 has the older smaller power transformer, as I would suggest trying the KT88's, but the smaller transformer will REALLY struggle with those, not really helping in the overall sound, so you would not get the full benefit of using KT88's in your ST70.

Keeping things original can be good and/or bad. In case of an old tube amp, I would upgrade as much as I can, the difference in sound is SO much better and will astound you!

Not all tubes of the same type are created equal. Heavier structure, modified elements, assembly details, metal alloys and even the glass used, can have major effects on the end product ... no shortcuts to quality here.

I did get the TADs in yesterday's mail. First thing I noticed is they are HEAVY compared to my Psvane KT88's. Those are also rated quite high, so that should give some indication as to the quality of the TADs. Plugged them in - biased right up, and stayed steady after idling for several minutes. Fired up the system and played a rather eclectic selection I like to use for testing purposes and they really held their own against what I'm used to hearing out of the KT120's. Strong bass was always a major factor in what I liked about those. The TADs are easily as strong on the bottom, and have greater definition and impact. We're talking some serious PUNCH here. Vocals and mids are pleasant, and the top is all there.

*No changes other than the bias, which I set to 55mV vice the 60mV used with the KT120's.

Keep in mind we're talking fresh out of the box here ... I expect some improvement over time, but truth be told, won't be seriously disappointed if they stay just as they are.

If I had a complaint (and I do so love to complain), I noticed the top spreader that centers the internal structure in the glass is slightly off center on one of the tubes. I might have to get all anal retentive about that and request an exchange. Or not. Doesn't seem to make any difference in what I'm hearing ...

Oh ... and the boxes are overlarge - I imagine to fit their tallest tubes. Not an issue except that the tubes had a good inch of headroom to slide back and forth inside during shipping. I DID drop a note to TAD about that ... either a plastic peanut or a wad of bubbles could prevent that easily. They did triple box the shipment ... no complaints there.

In the 90s...i had a Jadis Defy7.....I got 15 KT100s the Defy needed 12 tubes an came stock with GE 6550s
An then maybe 2004-6 i got the  EI KT90s...the sound of the KT100-KT90s Had a littel stronger uper mid an diff bass than the KT88s.........What you say about the new Kt88 an the KT120 sound is about right...in the end the KT88 for me... takes the day for power an tone....in my amps the 6550 can be vary sweet......it all about the uper mid an top end with 6550s....the KT88 can sound like a Big 6550 with more power an big bass...THE KT90-100-an maybe the KT120-50...amps may need to be setup a littel diff....in time well see.....but in the tube amp i have the the biger tubes are Darker sounding......................well to me...i have not got into the KT120s...Golden Gate 88 just look fun....
Thanks for any an all info pic....of tubes....


Thanks for the site Bob.....

sKiZo wrote:Not all tubes of the same type are created equal. Heavier structure, modified elements, assembly details, metal alloys and even the glass used, can have major effects on the end product ... no shortcuts to quality here.

I did get the TADs in yesterday's mail. First thing I noticed is they are HEAVY compared to my Psvane KT88's. Those are also rated quite high, so that should give some indication as to the quality of the TADs. Plugged them in - biased right up, and stayed steady after idling for several minutes. Fired up the system and played a rather eclectic selection I like to use for testing purposes and they really held their own against what I'm used to hearing out of the KT120's. Strong bass was always a major factor in what I liked about those. The TADs are easily as strong on the bottom, and have greater definition and impact. We're talking some serious PUNCH here. Vocals and mids are pleasant, and the top is all there.

*No changes other than the bias, which I set to 55mV vice the 60mV used with the KT120's.

Keep in mind we're talking fresh out of the box here ... I expect some improvement over time, but truth be told, won't be seriously disappointed if they stay just as they are.

If I had a complaint (and I do so love to complain), I noticed the top spreader that centers the internal structure in the glass is slightly off center on one of the tubes. I might have to get all anal retentive about that and request an exchange. Or not. Doesn't seem to make any difference in what I'm hearing ...

Oh ... and the boxes are overlarge - I imagine to fit their tallest tubes. Not an issue except that the tubes had a good inch of headroom to slide back and forth inside during shipping. I DID drop a note to TAD about that ... either a plastic peanut or a wad of bubbles could prevent that easily. They did triple box the shipment ... no complaints there.

So, what's the latest impressions on the TADs?

sKiZo wrote:I'd forgotten about the Golden Gate KT88 Super Tube.



Posted up about those a couple years back over on AK and only thing I got back was
.
.
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(yup ... pretty much nothing)

They've been around for a while, and GuiGuang gets real decent reviews for sound quality and durability. And, like ... they're super! You'd think there'd be more folk using them at $100 a quad?

Have to keep them in mind as another option.

You can get them for $90.72 a quad and FREE shipping! https://www.tubesandmore.com/products/T-KT88-GG

poconoman wrote:

So, what's the latest impressions on the TADs?

Impressions? Well ... I scratched my name into them ... not!

Probably about a hundred hours on them now, and they're still holding their own against the KT120's I've been used to. Definitely tightened up across the spectrum for better detail.

Problem being - I'm a habitual tube roller and always looking for better. Since installing the TADs, I've also changed rectifiers (GZ37, but the NATO version) and drivers. Tried a few combos on those, and am currently using a Tele 12AU7 in the center and Westinghouse Star 5363's in the sides. My house voltage is also down from what it was so I've taken the bucker out of line.

So, are the improvements all TAD? Who knows" But I LIKE it!

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Speaking of Golden Gate ... did some digging and found out they're made by Guiguang in China. Which apparently was bought out by Psvane a few years back. Fun fact ... the name literally means "light bulbs from GuangXi province". Apparently, the road's been rocky for them and ya takes your chances - which could explain the price. Also possible that the tubes are actually the best ever made and will make your farts sound like a symphony, but ... just sayin', as they say.

Here's an interesting (but dated) write up.
http://psvanetube.com/wordpress/who-was-guiguang/

Still might be interesting to pick up a set for an audition. Seems to me Tubes & More has a real decent return policy.

Interesting discussion on the development of the Kt-90 here:http://www.diyaudio.com/forums/tubes-valves/24313-electro-harmonix-kt90.html

Specs for the EI Kt-90 here:http://www.eierc.com/rc/KT90.htm

I know I like mine, powerful clean bass, lucid mids, sweet highs.

Great link! I'm on page three and had to stop to clean the blood off the monitor ... getting kinda heated!

One interesting tidbit I found ...

Recommendations for running the KT88 in an o/p stage are that the anodes be orientated 90° from each other and tubes be 4” apart on the horiz. The GEC spec stipulates that the envelope temperature not exceed 250°C.

Often wondered why push/pull sockets are mirrored ...

"Recommendations for running the KT88 in an o/p stage are that the anodes be orientated 90° from each other and tubes be 4” apart on the horiz. The GEC spec stipulates that the envelope temperature not exceed 250°C."

Looks like someone didn't get the memo:
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