Latino ST120, if you could just have one set of output tubes, what would they be?

I'm not into hype, I'm into sound. I'm currently running matched Ruby KT88's in my ST120. My pre-amp tubes are NOS Bugle Boys. It sounds very good coming from my Cornwalls.

I'm thinking of getting another set of output tubes just to have, really can't imagine a lot of improvement from what I have. Craig at NOS Valves told me to spend my money on the best pre-amp tubes and get some good output tubes. I've got Mullard's and the Bugle Boys for my pre tubes & I'm now thinking about getting some extra output tubes as the Ruby's are all I have.

What say ye & why?

Hi jhoman

I an running a ST-120 built 8/09

(2) VALVE ELECTRONIC CV 4024
(1) TELEFUNKEN ECC801S
(1) WEBER COOPER CAP WZ68
(4) TUNG-SOL KT-120
I have had GOLDLIONS and SOVTEK output tubes the GOLDLION'S did not last and the SOVTEK did not sound as good.
I find the KT-120 sound best to me and have been in the system for over a year of very long hard playing.
Plus adding the ECC801s was like adding 3D to your T.V. (A Lotta Depth )

avi.inc wrote:Hi jhoman

I an running a ST-120 built 8/09

(2) VALVE ELECTRONIC CV 4024
(1) TELEFUNKEN ECC801S
(1) WEBER COOPER CAP WZ68
(4) TUNG-SOL KT-120
I have had GOLDLIONS and SOVTEK output tubes the GOLDLION'S did not last and the SOVTEK did not sound as good.
I find the KT-120 sound best to me and have been in the system for over a year of very long hard playing.
Plus adding the ECC801s was like adding 3D to your T.V. (A Lotta Depth )

My only complaint with the GL's.


Steve

In my VTA ST70 I first ran the Sov Tek KT88's. Then, on Bob's recommendation, switched to Gold Lion KT66's for an improvement.

Then at the suggestion of JunkyJan (form member), Gold Lion KT88's for a BIG improvement again.
I've probably got several hundred hours on them, and haven't lost a tube.

Right this minute I'm running Tung Sol KT120s in my ST-120 and VERY pleased. I can't speak to life yet as they're still plugging away.

I started out with a quad of Ruby Tubes KT88s but found that I liked what I heard using the KT120s better. Was the difference "night and day"? No. Not at all. Very subtle but as I have swapped back and forth I've come to the conclusion that there will most likely be KT120s in my amp for as long as I own it.

My first ST-120 had Valve Art KT88s in it. I thought those were very nice but again I can't speak to life as I didn't own that amp for very long.

So... To answer the original quetion... I'd have to say Tung Sol KT120s.

If the VA KT88's do as well as their EL34B's, you might want to give them a try.


Steve

Hi All:
This is becoming another interesting thread. We have members who like most everything in there but it seems like the KT-120's have the edge as a reliable KT-88 substitute.
I have used them for over a year daily without issue and love them. I feel they are the equal to any KT-88 I have tried (Gold Lions and Sovtec) they run beautifully at a nominal bias for the typical KT-88 designed amp but sadly at less than their full potential. What a shame we can't realize their maximum power in these amps.
Therefore I would like to now ask two questions:

(1.) Whether or not Bob feels that the KT-120 is here to stay?
and
(2.)if he would now be interested in doing an amp with a little more wattage based on these tubes?
I love the ST-120 format in fact a new amp could almost be a big brother to these amps with a very similar format. Kind of like the GTO which was a souped up Pontiac tempest that turned out to be a real star.

Of course that would mean going back to the drawing board for some R&D and no doubt yet another transformer with a little more wally and voltage but I am sure the way the ST-120 has been received and its widespread use as a KT-88 substitute in many other amps it may be financially viable and make some sense.
I for one would be one of the first to take the plunge if Bob puts the quality and workmanship behind it he has with his other amps. Anybody agree?? Bob??
Baddog1946

OK… I’ll be the first to chime in and say no thank you to a redesigned ST-120 for the sake of a few more watts. Think about this for a minute. You’re talking a new power transformer and new output transformers for what? Another eight or ten watts? Do the math. You’re talking an additional one or two maybe 3 dB when it’s all said and done. In my eyes it’s not worth the effort. If you want to move to the “next level” using KT120s then build a pair of the M-125 monoblocks.

In my case I use a pair of very efficient speakers. As in close to 102 dB@1W. As near as I can figure my ST-120 with KT120's installed runs at somewhere in the neighborhood of 1/16 of a watt or less most of the time. That gives me plenty of “headroom” for transients.

Considering that the KT120s that are currently installed are grossly over-rated and grossly under-utilized to me that adds up to very long life. I can’t speak for anyone else here but my very first choice for a tube amp is one that I don’t have to worry about any kind of failure for a very long time. I just want my system to play music for as long as possible with as little fuss as possible. A few more watts just doesn't mean that much to me. Especially if it comes at the cost of reduced reliability.

Hi Jhoak:
You are right, of course I was referring to the M-125's but wrote down st-120 for some mindless reason.I must be getting senile. I agree with you 100% about the ST-120 being at its development limit. Apologies to all but the questions about a new amp for the KT-120's are still of interest to me (Bob).
Wow I gotta go, I think I need to take some vitamin B.
BD

IMHO driver tubes make more of a difference (even the side ones) than the output tubes. Also i think there is a synergy between middle driver tube and the outside tubes which shouldn't be discounted. That being said i've only run KT-120s as outputs on this. I think they sound great and no failure issue (only 6 months so far). I've read they should have longer life than KT-88 and 6550s in this duty. Time will tell.

avi.inc wrote:Hi jhoman

I an running a ST-120 built 8/09

(2) VALVE ELECTRONIC CV 4024
(1) TELEFUNKEN ECC801S
(1) WEBER COOPER CAP WZ68
(4) TUNG-SOL KT-120
I have had GOLDLIONS and SOVTEK output tubes the GOLDLION'S did not last and the SOVTEK did not sound as good.
I find the KT-120 sound best to me and have been in the system for over a year of very long hard playing.
Plus adding the ECC801s was like adding 3D to your T.V. (A Lotta Depth )

It's been over a year ,still same setup no problems.

Merry Christams to all members of the forum:
It's interesting this thread re-surfaces again and again, it seems like this is a recurrent question we all have to ask ourselves from time to time when our tubes get a little long in the tooth. Sadly all tubes go to heaven at some point.

Since the last time around I have put a lot hours on my Tung Sol KT-120's and they seem to be bullet proof as well as sounding great.
I have two ST120's and I use one of them as a test-comparison amp, the other one runs the KT-120's all the time. I have tried Gold Lions, Sovtek and JJ KT88 recently.

I found the Gold Lion and KT120's on a par soundwise but sadly I have to say the Gold Lions do not seem to live long. I now have a set of three as one of them just flamed out a couple of weeks ago out after what I guess would be less than 100 hours.That also seems to be the opinion of more than a few other members.

My observation here is the VTA/Latino ST-120 amps are on the cutting edge of perfomance for a design that first appeared over 50 yrs and it has undergone a lot of tweaks and performance improvements. Although Roy and Bob always use top quality parts and oversize things for safety sadly the new generation of tubes are not the equals of the kt88 tubes 50's and 60's.
We may be pushing the performance limits of these new generation tubes in the ST-120 which is not a criticism of the amp as much as of the quality of newer tubes.

Other tube amp designs use whatever KT88 tube with seeemingly no long life issues but I have not heard another amp their equal at anywhere near their pricepoint. So I am sticking with the ST-120 hands down. But my guess is that newer tubes get a serious workpout with the ST-120 circuit.
Therefore I think that the best tubes for an ST-120 would be the most robust types available (KT-120) to get the advertised lifespan out of them in this amp.

The KT-120 is still the king of the hill in this respect. They are designed to run at higher voltages than the ST-120 has and can dissapate up to 60 watts each which is more than enough for an ST-120.
Even though Bob said at one point it was not worth doing an amp just for them I think he may already have one.

There are some sweet sounding tubes out there I could probably be happy with soundwise but I for one cannot afford the attrition rate of the acclaimed Gold Lions for example so its KT120's for me all the way. They sound great and live long in my experience.

I have been running the same EH 6550's in my ST120 since I had it built in Feb of 2010.

I bought the tubes from Jim Mcshane and they are actually nearing the 3.5-4k hours mark!!!

Alas, it is time to be installing some new tubes...this time EH KT88's from McShane.

-Vic

I currently like the Penta Lab KT-88s. About a year now with no issues. I also like the KT-120s but while sounding a little more "ballsy", the gave up a little on the top end I thought. In a blind test, I'm sure I couldn't tell 1 from the other. Both are new tubes and seem plenty tough for our application.

I have been operating my ST-120 since built about a year ago with the SOVTEK KT-88s. I decided to try a set of GoldLions and swapped them out yesterday. I was skeptical about noticing any difference but what was very apparent was that I lost the low end of the music. (using Klipsch RF-7s) Is that typical for the GoldLions? I don't believe I have read anything indicating such a change.

thevic24 wrote:I have been running the same EH 6550's in my ST120 since I had it built in Feb of 2010.

I bought the tubes from Jim Mcshane and they are actually nearing the 3.5-4k hours mark!!!

Alas, it is time to be installing some new tubes...this time EH KT88's from McShane.

-Vic

Amen to Jim McShane. A great guy. I've bought both -88s and -120s from him, no problem in my Latino M-125s.

My only grief has been with the Weber solid-state rectifiers, which I must have gotten a bad batch of. Pair I'm using now have been in there for months with no worries, but I had four melt-downs prior to that.

Running the Weber rectifier since build in june of '12 along with kt120s no problem. Driver tubes very subjective. After pios broke in, i've liked long black plate rca 12bh7a in all three positions. I've had a Daystrom Mullard , a bugleboy also, and brimar 12au7 which i've liked in the middle between the rcas. I've found the outside drivers effect the middle. There is a synergy if you will between them. While changing the middle changes sound the most, different middle drivers sound better with different outside drivers IMO.