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KT-88Z Treasures in VRDs


BE36

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You want to play with output tubes then first I have to confirm if I have updated your amps to the latest version....what are you biasing the output tubes at?

Now if they are updated to the latest version and you want to really hear the difference in output tubes... start playing with 6L6GC and variants, EL34's and Variants, KT66 and so on... KT88's/6550's are all going to sound similar to some degree. Start changing output tube types and you get a much more pronounced change to the Sonics. Please don't ask me to describe what they all sound like.... I'm just not the type to put that into words.

I ran KT-66 for about 8 months. I just switched to a really inexpensive Russian military surplus 6L6GC variant the other day. Fun fun and cheap to do.

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Quick! Hide that picture! It's revealing secrets too arcane and dangerous for mere mortals. If the Chinese get ahold of that circuit our national security is surely compromised.

Oh, cute Craig, hiding a choke where you think no one will notice. Aha, I'd suspected as much. If I didn't own a $50 Marantz8B, I'd be tempted to purchase one of these, \uh, to keep it safe from prying eyes out to do this nation harm.

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Oh, cute Craig, hiding a choke where you think no one will notice. Aha, I'd suspected as much.

Ummm I learned that trick from .........Marantz but it wasn't a darn $50 example you heartless scoundrel. How the heck do you sleep at night.... Oh wait you have the twins[Y] those hairy little pair of Sex goddesses.

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.55V Based on a professional inspection. . .

What do you mean by professional inspection? I hope you know that every time the output tubes are changed the amp has to be re-biased. You should also check and adjust the bias every 3 to 6 months without a tube change.You're kind of worrying me here. If you have not been biasing it with every tube change your Sonic results could be wildly skewed. There also a possibility that your endangering the amps, tubes or both by not setting the bias with an output tube change. Not trying to get on your case here but your responses seem kind of vague.

Craig

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Great thread with loads of good info. My VRDs came with GE 6550s . I plan on changing the front tubes but I am sacred to mess with changing the 6550s. I bought a spare quad off the garage. A couple of local experts with extensive knowledge listened to my VRDS. One said to change the front tubes at some point. One said dont change anything. Both said under no circumstances to touch the GE 6550s in this amplifier.The tung Sols would be the only feasable upgade in the power tubes but not worth the 600-700 dollar cost. Just another set of opinions.If I see a set of Tung sols at a deal I may buy them just to play with them at some future date. A friend of mine has a set of VRDs with some Pentas not yet installed- just sitting there as spares. I would think that they would be an improvement over the standard issue Valve arts that he is currently running.

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I have a really hard time spending $500 on current production KT88, and quite frankly have a hard time paying market prices for Tung-Sol 6550. I have found great success with the Penta Labs KT88. The Penta isn't your normal Chinese made KT88....it bests the standard Shuguang KT88s pretty easily. Clear, warm, nice detail, and act VERY stable in circuit. I have about 7 quads of these, as well as a similar stock of VA KT100, another "beefed up" Shuguang they had out a couple/three years ago that's another very stable tube in circuit - albeit not as smooth and detailed as the Pentas are.

I also prefer the Pentas over the Genelex reissues, although I'll vouch that the Genelexes are a good current effort.....but I definitely like the Pentas better in my rig (JM>VRDs>Heritage).

I have read others say that they like the Treasures over the Pentas, but I'm having doubts as to whether they are worth almost triple the $$$. I figure it's the typical "10% improvement for 300% of the cost". And given what I know of the VRD's, more bang for the buck comes from the front end tubes, and since I have two of the top four recent production offerings well in stock, I'm not grippin' over my output tubes much.....and I can run the hello out of them and not worry about running out of tubes.

That said, I'm glad Shuguang is trying to push the envelope. That's good for us tubers.

I bet the Treasures are some nice tubes.. But I'm with you the price is just way too high for what has to be a very small improvement. Heck I'm currently running a quad of tubes that costs me less then $30 NOS Russians LOL!! hey they sound okay nothin to write home about. I've heard these tubes are really tough so I'm running the dog out of a quad to see. I guess I'm bored...

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I would bet that a set of cheap Valve Art KT-88s would give most all those NOS tubes a run for their money depending on the driver tubes used.

The Valve Arts are on this list. All tubes in the survey were tested with the same driver tubes as well as accessory equipment to include speakers. I don't totally agree with the results as the GE's definitely got screwed. I agree with Mike about the VA KT88's, EH 6550's, but with that being said we all have our opinions. Furthermore, what some may think is too much too spend on tubes forget that everyone chooses to spend their money differently. While one person likes to frequent fine restaurants, always have a new car, buy a new house twice the size of what they really need, own expensive clothes...another saves his money and buys tubes that without argument sound the best. If someone's happy with the tubes they have, good for them but far be it for me to point fingers at anyone if they choose to buy tubes that have empirical evidence to prove their sonic superiority or if they buy tubes based on affordability. I just want to hear people say they like tubes because of what they hear, not because of what someone else says. I have 2 offers to buy quads so please do not ask if I will sell anymore Tung Sols. I still am not convinced I am going to sell as I probably will just put them in the vault and let them appreciate in value. I respect others right to choose...

And in here lies the problem with tube rolling... THERE IS NO ABSOLUE PROOF that one tube is superior to another. One guy loves this tube and the next guy loves another. THERE IS NO BEST. The best tube is the tube the owner of the system enjoys. Price really has little to do with the outcome. There is no tube without arguement that sounds the best since each of us has his own preference to sound. Then factor in the each brand tube will sound slightly different in each amp or preamp you plug it into... THERE IS NO BEST.

Just like there is no amp that is the best, There is no preamp that is the best, There is no speaker that is the best, There is no turn table, CD player that is the best, there is no speaker wire or Inter-connect that is the best... There is no power cord that is the best. The joys of audio. All us folks can do is state our opinions and the readers of the forum can maybe get some idea what we like in our system with our gear. Beyond that each user just has to dive in and see what he/she likes.

Craig

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I paid $440 (pricey, I know) for a brand new (NIB) NOS quad of GE 6550A's, and they are the best sounding amps I have ever heard in my system. I agree with others though as well... the driver tubes probably carry a little more weight in regards to overall sonics. As for biasing, I probably bias my amps more than most (about every 6 weeks) just because I'm anal, and I like to fiddle with them. [:D]

Mike

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I have found great success with the Penta Labs KT88. The Penta isn't your normal Chinese made KT88....it bests the standard Shuguang KT88s pretty easily.

I am confused by this statement above but perhaps I am reading it incorrectly.

Penta / Shuguang is our brand of Vacuum Tubes Manufactured at our plant in Shuguang, China. The Shuguang KT88SC is of the same construction as Penta's Gold Aero and Penta type tubes.

I know some tube dealers make claims that the Penta is exclusive or is somehow different but given the company says they are the same tubes and in fact advertises "Penta/Shuguang" as the name brand... I don't see how a PENTA branded KT88SC can be any better than the Shuguang marked one. Now if you are comparing a KT88SC to a KT88-98, ok, but that is architecture not name, correct?

Lots of reviews claiming the KT88-98 is at the top of the heap while others heap praise on the KT88SC. I have had the KT88-98's for a while (and have no real gripes about them but they don't make me leap for joy either) but I guess I will get a quad of the KT88SC's to listen to as well based on your assessment. Maybe even try the Tung-Sol reissues or the Genelex reissues. May as well have a few spares. Everything else is NIB NOS on these amps but I will not spend huge bucks on output tubes.

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Oh, yes, there is some innovation going on with tubes. Tung-Sol has come out with the KT120 - a pair of which can deliver up to 150 watts. I wonder when we will see VRD's modified to run that tube at its performance level. I know there are folks already working on modifying Dynaco amps to take advantage of that tube. Nothing built yet, just prototypes being evaluated.

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The Penta KT88-98 is not the same tube as the Shugaung KT88-98. The Penta KT88-98 actually is what Shugaung calls the KT-100.....(and no it is not the same as the Valve Art KT-100)

I believe we went over all this in a thread a couple years ago and you did not understand then and it looks like you still don't. But hey I'm not surprised [;)]

The Shugaung version of the KT-88SC is named KT88-GEC.... its pretty hard to find just like the Penta Labs version. I believe its because dealers are not willing to pay the premuim price for the tube. Heck as far as I know there is only one source for the Penta www.dougstubes.com

Both the Valve Art and Ruby KT88 is identical to the Shugaung KT88-98.... the penta KT-88-98 is a different tube.

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