Has anyone substituted KT-90 tubes in place of the stock 6550 in the ST-120? What do the owners of the ST-120 find to be the best tubes they have installed?
+4
eickmewg
bluemeanies
deepee99
nmchiefsfan
8 posters
Tubes and the ST-120?
nmchiefsfan- Posts : 77
Join date : 2012-03-21
I have been using the same set of KT-120s in mine for about 5 1/2 years. It is probably time for a new quad as they have around 3000 hours on them but they still sound great to me. I purchased mine from Jim McShane. I still have the original Sovtek KT-88's which also sounded good; but not as good as the KT-120s
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
I would try the Gold Lion KT-88s, which Jim McShane also stocks. Spendy, but a very nice sound. Also, consider putting your hard-earned $$ into the driver section. That has more influence than the output toobs, IMHO.nmchiefsfan wrote:I have been using the same set of KT-120s in mine for about 5 1/2 years. It is probably time for a new quad as they have around 3000 hours on them but they still sound great to me. I purchased mine from Jim McShane. I still have the original Sovtek KT-88's which also sounded good; but not as good as the KT-120s
bluemeanies- Posts : 274
Join date : 2015-02-09
Age : 73
Location : Folsom Pa.
deepee99 wrote:I would try the Gold Lion KT-88s, which Jim McShane also stocks. Spendy, but a very nice sound. Also, consider putting your hard-earned $$ into the driver section. That has more influence than the output toobs, IMHO.nmchiefsfan wrote:I have been using the same set of KT-120s in mine for about 5 1/2 years. It is probably time for a new quad as they have around 3000 hours on them but they still sound great to me. I purchased mine from Jim McShane. I still have the original Sovtek KT-88's which also sounded good; but not as good as the KT-120s
Driver tubes IMO are more important than the Output tubes
Genalex reissued B749/12AU7 driver tubes are a good recommendation from Jim himself.
eickmewg- Posts : 103
Join date : 2014-08-29
I tried the KT-120's as replacements for the Sovtek KT-88's that Bob sent with the kit. As opposed to many other opinions, I didn't think they were the best thing since sliced bread. I sold them and got some reissue Gold Lion KT-88's which I liked. I sold a quad of Black Treasure 6CA7's from another amp and with the proceeds, I got some Black Treasure KT-88's for the ST-120. I really like these tubes and I think they are just a little nicer than the Gold Lions. For drivers I now use octals: the center is a Black Treasure CV181-Z flanked by very nice Sylvania 6SN7's. No more tube rolling for me now.
deepee99- Posts : 2244
Join date : 2012-05-23
Location : Wallace, Idaho
I would concur with eickmewg that theSG Black Treasures (or PsVanes) both in KT-88-z and CV-181-z configurations are great tubes, probably the best-sounding even over NOS if you get a good batch. The Chinese have come a long way in quality control, but it's still a crap-shoot and returns, while do-able, are not worth the money spent on China Post, so if you get stuck with a lemon you're just SOL. If you buy Russians from Jim McShane he'll back the product and the Gold Lion KT-88s are very fine and durable tubes.eickmewg wrote:I tried the KT-120's as replacements for the Sovtek KT-88's that Bob sent with the kit. As opposed to many other opinions, I didn't think they were the best thing since sliced bread. I sold them and got some reissue Gold Lion KT-88's which I liked. I sold a quad of Black Treasure 6CA7's from another amp and with the proceeds, I got some Black Treasure KT-88's for the ST-120. I really like these tubes and I think they are just a little nicer than the Gold Lions. For drivers I now use octals: the center is a Black Treasure CV181-Z flanked by very nice Sylvania 6SN7's. No more tube rolling for me now.
Again, I'd focus more on your drivers. GIGO, as the output tubes are only thru-putting what the drivers send them. There's a lot of hash out there about "burning-in" cables and such which is nonsense, but when it comes to the tubes themselves, put 100s of hours on them before making a judgment. Tube-rolling every 20 hours is a fool's errand, as I learned the hard way, and it's tough on the sockets. It produces no meaningful results.
Guest- Guest
What 12AU7 drivers would you recommend for the ST-120?deepee99 wrote:I would concur with eickmewg that theSG Black Treasures (or PsVanes) both in KT-88-z and CV-181-z configurations are great tubes, probably the best-sounding even over NOS if you get a good batch. The Chinese have come a long way in quality control, but it's still a crap-shoot and returns, while do-able, are not worth the money spent on China Post, so if you get stuck with a lemon you're just SOL. If you buy Russians from Jim McShane he'll back the product and the Gold Lion KT-88s are very fine and durable tubes.eickmewg wrote:I tried the KT-120's as replacements for the Sovtek KT-88's that Bob sent with the kit. As opposed to many other opinions, I didn't think they were the best thing since sliced bread. I sold them and got some reissue Gold Lion KT-88's which I liked. I sold a quad of Black Treasure 6CA7's from another amp and with the proceeds, I got some Black Treasure KT-88's for the ST-120. I really like these tubes and I think they are just a little nicer than the Gold Lions. For drivers I now use octals: the center is a Black Treasure CV181-Z flanked by very nice Sylvania 6SN7's. No more tube rolling for me now.
Again, I'd focus more on your drivers. GIGO, as the output tubes are only thru-putting what the drivers send them. There's a lot of hash out there about "burning-in" cables and such which is nonsense, but when it comes to the tubes themselves, put 100s of hours on them before making a judgment. Tube-rolling every 20 hours is a fool's errand, as I learned the hard way, and it's tough on the sockets. It produces no meaningful results.
ArlanB- Posts : 73
Join date : 2011-01-23
Age : 76
Location : Santa Cruz, California
As far as KT88's go I can positivly say that if you find that the Black Treasures are a little steep in cost, you might try what was originallly Penta Labs KT88SC solid plate version from Shuguang now being marketed by The Tube Store in their Preferred Series and Ruby Tubes also marketing their version. I have had my present set of Penta's in use now for over 5 years and they sound just as good now as they did new. I have purchased a new backup quad from the Tube Store twice now, once in November of 2016 and again in November 2017 because they knocked $20.00 off the price of each tube in an unadvertised sale. So now I have enough backups to last a while. This sould attest to how much I like them and the fact that their warrantee is longer than most is a plus. As to 12AU7's, am unable to make any reccomendation due to the fact that my VTA ST120 will be 10 years old in 3-4 months and has the higher gain board using 12AT7's. When I built the amp I was able to obtain 9 Mullard CV 4024's for $22.00 each. I am still on the first set of three. At this rate they will last longer than me.
Dave_in_Va- Posts : 443
Join date : 2013-04-02
Location : Mid. VA
The best sounding driver tube I've found for my VTA ST 70 is a Dutch Amperex 7316 (ECC 186).
Bob Latino- Admin
- Posts : 3263
Join date : 2008-11-26
Location : Massachusetts
ArlanB wrote:As far as KT88's go I can positivly say that if you find that the Black Treasures are a little steep in cost, you might try what was originallly Penta Labs KT88SC solid plate version from Shuguang now being marketed by The Tube Store in their Preferred Series and Ruby Tubes also marketing their version. I have had my present set of Penta's in use now for over 5 years and they sound just as good now as they did new. I have purchased a new backup quad from the Tube Store twice now, once in November of 2016 and again in November 2017 because they knocked $20.00 off the price of each tube in an unadvertised sale. So now I have enough backups to last a while. This sould attest to how much I like them and the fact that their warrantee is longer than most is a plus. As to 12AU7's, am unable to make any reccomendation due to the fact that my VTA ST120 will be 10 years old in 3-4 months and has the higher gain board using 12AT7's. When I built the amp I was able to obtain 9 Mullard CV 4024's for $22.00 each. I am still on the first set of three. At this rate they will last longer than me.
Just to be clear > Arlan's ST-120 dates back to June of 2008 and is almost 10 years old. At that time, the VTA ST-120 used the higher gain 12AT7 driver board. In April of 2012, we transitioned the VTA ST-70 and VTA ST-120 to the newer CCS driver board. The newer CCS version of the VTA driver board is a lower gain version of the original board and uses 12AU7 type driver tubes. This also includes 5963, 5814, 6189, CV4003 and 7316 tubes. You may also use the slightly taller 12BH7 driver tubes in the VTA ST-70 and ST-120. As a side note > All The VTA M-125 amps have always used a lower gain 12AU7 type driver board.
Bob
Guest- Guest
Thanks for all of the responses.
kevinmi- Posts : 88
Join date : 2009-11-17
I've had my ST-120 for several years now. It originally came with the hi gain driver board that used 12-at7 tubes. I had the best sound with a France made Amperex tube in the center position. In my low gain board, I'm using RCA clear top 12-au7 tubes with good results. No matter what board you use, I have always had better luck with good quality vintage tubes as opposed to the new tubes.
As far as power tubes, I'v tried The reissue Gold Loins, the reissued KT6550, Sovtek KT-88, and KT-120. I like the KT-120 tubes the best, but It's been a few years since I've done any tube swapping. I'm sure I'd like some vintage power tubes, but I can't afford them!
As far as power tubes, I'v tried The reissue Gold Loins, the reissued KT6550, Sovtek KT-88, and KT-120. I like the KT-120 tubes the best, but It's been a few years since I've done any tube swapping. I'm sure I'd like some vintage power tubes, but I can't afford them!
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