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Audiophiles,
Considering upgrading the tubes in my Vac 160i integrated amp which comes with Shuguang KT88 SC (quad). Looking for something with the same overall sound signature with better sound quality and reliable if possible.
Can't wait for your suggestions since I'm not that familiar with tubes...
Thanks,
Follow Ups:
Asylums..
I am new here and accidently posted with my email address as username ( moniker )..
Boy - what a struggle to change that. I needed to delete the post and are now reposting it with a "proper" username.
Well - it is not any important message , I just didnt like to see my email address at the top of the post..
------------
In my opinion there is some important issues that needs to be addressed when comparing valves. The tolerance of most valves, referred to the standard valve characteristics as published in the manufacture datasheets are usually up to +/- 20% or more. ( Matching does not change this fact, - a matched pair may be close to one another, but perhaps 15% off the standard/statistical characteristics )
When dropping a set of valves in to a particular amplifier, we expose the valves to the working settings of that particular amp. ( Driver, bias, plate, sg2 Voltages, regulation etc )
Further - but just as important - the OPT turns ratio and the impedance of the loudspeakers are reflected according to these.
Loudspeakers are not 8 Ohms constants. Rather they change according to freq as well as with dynamic signals. A steady signal sine wave freq sweep reveals that the speaker changes impedance as much as -50 to +200%. ( Much more when dynamic music signals are the source )
This means that the output valves will "see" a load changing dramatically following the "chaotic" impedance of the speakers, reflected via the OPT. The particular turn ratio here, as well as the the working settings decides the actual load and the slope to the valves.
The theoretical target load for a set of KT88's, "dialed in" by the amplifier designer, say 5000 Ohms, will as such change from at least 2000 to 15000 Ohms during expose to music. ( or a sine wave freq sweep )
Add to this the merits of the speakers, that will favour some tone characteristics, dump others etc etc...And not least our personal preferences, habitat and so on.
It is in reality an impossible mission to elect an all over best output valve. We can find the ones that suits the particular amplifier design and loudspeakers..
But that is all.
Many years ago I produced some KT88 power amps. ( Mono blocks )
I used British made KT88's. ( Gold Lion, MO-valve )
These were excellent - all of them within 5% straight from the shelves and they did not change much. At the point when I ran out of stock I feared I had to give up this amplifier. I finally got some US made GE 6550A's. They were not as tough, tight ( +/- 20 % ) and die hard as the KT88's, but I modified the circuit, matched the valves and got pretty much the same results as with the MO-valves.
Later I ran out of the GE's - and to make a long story short - I ended with some Svetlana KT88's. ( Thanks to Eric Barbour )
These were however more than +/- 30 % and changed quite a bit during burn in. So matching was vital. Again a little modification was needed in order to get the best out of these Svetlana's.
Sadly they also changed from production series to product series and I finally gave up and discontinued the production of the power amp.
If I today found a set of NOS original MO-valve KT88's and dropped them into that 3'rh generation of this amplifier, it would now be able to get the best out of these wonderful Gold Lion/MO-valve.
I have no experience with the P-Svane KT88, but they sure look good.
What I wish to emphasize with this post is that the choice of valves ( in particular output valves ), depends upon many variables. The design working settings of the amplifier and not least choice of speakers. There is no such thing as an "optimal" specific load point/sweet spot, due to all these variables and unknowns. The best sounding output valves ( tubes ) in one particular set up, are very unlikely to necessarily be the best in all set ups.
In other words it is case sensitive.
A matched pair of valves is good, but it depends as well upon many variables and if we really care about a symmetrical signal through the OPT, it would be a much better approach to make the driver adjustable from an AC point of view just as well.
This is the only certain way to insure the best possible symmetrical signal.
( Personally I do not think this means as much as is sometimes claimed , but that is another story all over )
I am new to this list and may not post the proper way - I am having difficulties sorting the posts in a way I would prefer.
Thanks
- Kurt Lilienthal Steffensen
Kurt Lilienthal
Kurt v L :Have you tried JJ kt-88 ?
As you live in aarhus there is no fuzz delivering them there from sweden ..
Edits: 06/10/14 06/10/14
Hi Tubular...
Thank you for asking, but I am in no need for KT88's.
I discontinued the KT88 amps, many years ago.
It is the person "Wiggy" that asks for advice regarding KT88's.
:-)
Best regards
Kurt Lilienthal
The GLs have settled in quite nicely and now it's time to try the Psvane TII KT88; will order by weeks end. Hopefully, I won't regret it...
Wig
Heard from a good source that I can't go wrong with the KT88Z; TII may be a tad better but it's a toss up so I'll get the Z :)
Wig
Guys,
My KT88Z came in today and have a question on the rating listed on their sides; their all listed as Ia1 26 Ma, what does this represents and I thought the #s would be higher for a KT88?
Thanks,
Wig
My Shuguang KT88Z are very good tubes as most have said, separation of instruments and imaging are so realistic. They sounded good right out of the box and now I'm going through the stages of reduced clarity and focus which started at 60 hours and still present at the 81 hours mark. Hopefully, they will begin to open back up when 100 hours are reached but they have a way to go...
one that is the current build for the tube amp building course taught here in San Francisco at the Randall Museum. (Not to be confused with the original Randall Amp designed by John Atwood)
We did a bunch of tube rolling and the PSVANE KT88 TII pictured above kicked everything else to the curb, all of the other Chinese KT-88 as well as MY NOS Quad of Tung Sol 6550 solid plates, which I thought were a pretty good tube.
OK, my NOS Tung Sol 6550's came in second, but not a very close second.
Ivan
Did you compare the 6550 Tungsols in the same amps?That is important to do..I have the solid black plate Tungsols which are my favorite with the EI KT90s coming in a close 2nd.Now you have me wondering about the PSvanes..I know the internals are Shuggie and the KT88Z is a wondrous tube in its own right.
Honest amplification is better than excessive 2nd order distortion anytime.
Believe the amp to be a later version of the amp pictured above. EF804 gain stage plus 6SL7 phase splitter?
Seem to recall all of the other output tubes that were compared(besides the PSVANE and the NOS Tung Sol, both three hole plate and solid dark plates) were Chinese KT-88 Gold Lion versions.
Surprisingly, the NOS TS three hole grey plates sounded better than the solid plates. Both quads of TS I have had for over 10 years and were NOS/NIB when I purchased them. Max 100 hours use if that as I modified the bias circuit on the PP amp I had at the time to use EL-34 for some reason.
Ivan
That's the synergy of the amp and which tubes it reacts to best.When you said you like the three hole Tungsols better than the solid black plate ones,your black plates may be old and not matched as well as the three hole ones are and that could be the difference or,the three hole versions and the Psvanes might be a more conducive match for that particular amp.
Honest amplification is better than excessive 2nd order distortion anytime.
The solid plates are not black but dark grey(darker than the three hole plates).
Matching tubes is over-rated but these were matched when new 10 years ago and I doubt they have changed much sitting in storage.
Again, less than 100 hours if that.
But yes, I do believe the amp in question was voiced for Chinese tubes.
And Chinese tubes are MUCH better than they were 10 years ago AND, don't forget, the Tung Sol 6550 was never manufactured as an Audiophile tube (mine all likely came from old stock held for years in storage at Hill AFB in Ogden, Utah).
Matching tubes is over-rated
I would agree as long as mutual conductance and current draw are within 15% of each other.
Honest amplification is better than excessive 2nd order distortion anytime.
In the case of my ST-35, there is a common cathode resistor for all for power tubes, so all bets are off here!
Received my GLs KT88 last night and sat down for a quick listen to get an initial observation after 5 hours of running. They are very quiet with better separation and a deeper and wider soundstage but still require many more hours for them to really snap into focus. Great midrange and rich overtones which is a plus since I listen only to cello, violin and acoustic guitar.
More to follow as they get more hours but I'll have 16 hours on them tonight around 9 PM so I'm interested on how they will sound tonight...
Excellent service from Jim and these tubes are solid and biased perfectly.
Listened last night at the 16 hour mark and they were definitely more open and musical but image focus is still vague and not pin point and hopefully this will happen with more time; they're running now and will shut the system down when I hit the hay at midnight...
After a few more hours of listening, pop the KT88SC back in and see how you like the sound. Let us know which tubes you prefer.
I'll be over 50+ hours tomorrow and will advise on which I prefer at this stage...
Guys,
I popped the Shuguangs SC back in last night and got them warm before biasing to get an overall impression of the two tubes. I can say that the GLs are quite special, images are more palpable and the ability to capture subtle ambiance cues is amazing. The SCs are also good but are thinner sounding in comparison.
If your music is missing flesh and bones, give the GLs a try and you'll be impressed...
Funny, I found the Goldlions thick sounding and rolled off on top when they were working in my amp. Guess it depends on the amp and the listener.
Glad they are working out for you.
Nunki,
Are the Black Treasures Z much better the your Penta SC? No thickness at all in my Vac amp, very organic/natural sounding and I'll do more serious listening when I've hit the 100 hour mark.
I'm interested in the Psvane KT88 TII, anyone have a quad matched used set for sale?
Wig
wig,
in my rogue atlas magnum i prefer the pentas over the black treasures. in my welter monos it is just the other way round. but i can stat that the black treasure Z is definitely more accurat, neutral, more "true" than the penta SC. although some people say the Z performs on the cool side but i like their direct sound. the pentas perhaps show a bit more emotion but also sound a bit of muddier therefor.
Nunki
The times, they are changing...
Nunki,
Thanks for your direct comparison.
I have been living with the GLs for 10 days now and have a good overall impression of their sound signature in my amp. The GLs and Shuguang SC have their strong suits but it's obvious that the GLs are better in musicality, sound-staging, imaging, separation, height, depth and super black backgrounds.
The midrange of this tube is beautiful and they're a couple of things I wished were better, transparency is a little on the warm side but it doesn't affect extension and they reach much farther than the SC without any brightness...
@ Ivan: Did you get the opportunity to compare the GLs against the Psvane TII?
I love what the GLs do in my system but I prefer a little more transparency and the Psvane may be the ticket if they are more transparent and don't have a warm sound signature.
Wig
My GLs has registered 115 hours by the time I listen tonight and I'll takes some notes and listen to my daily selections and will switch to may stock Shuguang KT88 SC and give them a couple of days to settle in before determining which tube I prefer.
Acquired a pair of Psvane 12AX7 TII (Integrated amp requires 3)and WOW what a difference right out of the box compared to my stock Chinese 12AX7s. Way more transparent, better imaging, blacker background and no bloom, just better localization of instruments within the soundstage...
I'll give them time to burn-in and I'm sure another pair will be needed to take care of the final 12AX7 position. I did try some Tele Smooth plate a few months ago and they sounded terrible, flat and one dimensional but the ones I have in the 12AU7(4x Tele SP) position are amazing.
the GLs performed too charming to MY ears in MY gear with discoloured midrange. i purchased them twice and sold them twice again. since then i stick with black treasure Z and penta labs KT88.
N.
The times, they are changing...
Each KT88 tube is biased manually.
If the Psvane KT88 TII are that good, this is something I must try. Sent Grant several e-mails a few days ago but have not heard from them. Someone from A'Gon mentioned that the tubes his buddy received were matched but when they tested them on one of the best testers, the matching was terrible.
I'd hate to spend this type of money for factory matched verses a professional trained and skilled technician. Any other reputable sources that sells these tubes?
Thanks,
Wig
Then go for the Genalex reissues. Buy them from Jim McShane. They will amaze you and they will hold up very well. I've bought two quads from him and they were so closely matched in all ways that it was no problem at all to set the bias and play music. I've had thousands of hours on mine and they still sound just great! I bought two quads as I believe in backups but, alas, I've not had a failure...
As much as I admire the Psvane brand, it is very hard for me to justify them. I've a bunch as well, including power tubes like the 300B T-MarkII and their EL84-T's. Some will drop in to certain circuits and just sound great or not.
One can court bankruptcy in trying to attain 'perfection' with glass bottles. It is made of unobtainium. The circuit design, all of the capacitors and resistors in the signal chain, the preamp tubes, the power tubes and then that most mysterious of all things, the output transformers! Oh yeah, did I forget to mention speakers?! What is your signal source? Was it blessed by a Shinto priest? Is your tone arm tracking true? Was your cartridge made from an endangered species bones? You see where this goes...
If it sounds good to your ears then enjoy it and then play it into the ground with gusto! Your system only has to please you!
Since I have some GLs being matched by Jim and I'm wanting to try some new 12AX7, this is the perfect opportunity to order some Psvane TII and see how they sound to my stock Chinese 12AX7.
Thanks again for your expertise and advice.
Wig
Guys,
Thanks for your prompt and very informative post! I've contacted Jim and will be trying a matched quad set of GL and may try the Psvane TII at some point.
Ivan303)Are these Psvane tubes overly warm or are they somewhat neutral.
Thanks,
Ron
In fact, I'd say my NOS TS 6550 were much 'warmer'. The PSVANE KT-88 were far more fast and clean. Also very clear.
We were listening to a high end vinyl rig and on rebuilt QUAD 57 speakers, so clarity was a virtue everyone was listening for in order to decide what tube was best for this particular amplifier.
This was a room full of folks who were building this amp as part of the class so it was a pretty critical listening session.
Ivan303,
I'll see how the GLs sound after giving them plenty of time to burn-in and will contact Grant Fidelity about Psvane TII; open, clear and some warmth is what I'm looking for.
I'll have to keep my eyes open just in case a used pair of quads show up...
Stick with the KT88SC that you are already using as others have suggested. They are one of the best sounding currently produced KT88s on the market and are reliable. VAC picked those tubes for good reason.
Don't forget about the small signal tubes, changing those will make a bigger difference than changing output tubes. There I would go with top quality NOS to give the amp the flavour that you want.
The Penta Labs tubes mentioned above are I believe the same tubes that wiggy924 is already running.
The KT88SC tubes are made by Shuguang and sound very good. As the other poster mentioned,the PSvane are great tubes but the Shuguang Treasures are also very good.
As always don't ever discard the Genelex Reissues because those are very good as well and if you get them from a seller like Jim Mcshane that knows how to match them even better than the factory,they are tough to beat in most amps.
Honest amplification is better than excessive 2nd order distortion anytime.
Penta Labs KT88, great tubes made in China from Doug, great guy btw, http://www.dougstubes.com
PSVANE KT88, about the same as above, made in China but a great tube for the buck, http://psvanetube.com/wordpress
Penta would be my recommendation.....
.
“If you don't like what you're doing, you can always pick up your needle and move to another groove.” Timothy Leary
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