Shuguang Treasure tubes....

I'm not sure if this is in the right place but this is about the tubes in my amp so here goes....Has anyone else given these Shuguan Treasure tubes a try?

I recently bought a used tube amp(VAC Phi 110) and the tubes that came with it were shot so I started poking around for some new tubes. I was looking for some Shuguang tubes, which are what I believe VAC supplies as standard/stock, and ran across Shuguangs limited production Treasure tubes. I poked around and did some reading, found a review or two and decided to give the only distributer for N. America(Grant Fidelity) a call. I spoke to a very kind and helpful lady who was patient with me(quite the task I might add!), was very nice and helpful and was darn knowledgeable on the tubes. Before I knew it my wallet had leapt out of my back pocket and I had splurged and ordered a matched quad of the Treasure Tubes, KT-88s. Within a couple of hours I had a tracking number and about a week later a box labeled "FRAGILE: GLASS!" was waiting for me when I got home from work.(A quick side note; during the short wait for the Treasure tubes to arrive I was using a borrowed quad of stock VAC KT-88 tubes and they were wonderful, great sounding tubes that I could live with forever....or that is until I found the Treasure tubes anyway.)

When the Treasure tubes showed up I ripped into the box and was shocked to see that each pair comes in a really nice presentation box with each tube very well protected in a foam insert, very classy. I removed the tubes, admired their beauty(they really are sweet looking tubes!) and popped them in the VAC and let them warm up for about 15-20 minutes. I then set bias on them and hit the play button expecting the usual tube break in time-wrong!...right out of the box these tubes sound fantastic! Seriously, I am shocked how at just good they sound fresh out of the box. Smooth clean highs, strong deep bass and all the other audiophile words we so endear. If they're this good right out of the box I can't wait until I get 100 hours or so on them. I'm no reviewer but I can say that these tubes offered a noticable improvement in my system and are worth every penny of their asking price, no doubt about it! So far they are chugging along and sounding beautiful and hold a rock solid bias, ZERO fluctuation.

Please understand that I have no affiliation with Grant Fidelity but when I run across a company that treats their customers so well and offers a product that performs at this level I feel I should share my experience with others, I'm one VERY hapy audionut!

Yes I actually do have a question and here it is; They(Grant Fidelity/Shuguang) also offer a 6SN7 substitute called the "CV-181", this is supposed to be a direct replacement for standard 6SN7's and I'm very interested in those as well. Has anyone else had the opportunity to give these tubes a try? Thanks for your replies.

John, thanks for the review and congrats on the great new amp. I have been using the Genelex Reissue tubes in my VAC monoblocs and have found them to be quite a bit better than every other new production tube I have tried (and I've pretty much tried them all), including the VAC branded tubes. I have been waiting to read some first hand comparisons between the Genelex and the Treasures, but I haven't been able to find much so far. Keep us informed as they break in.
I just tried mixing Sylvania 6SN7GTB Chrome Top Yellow Label with RCA 6SN7GTB Black Plate Red Base Bottom D Getter Orange Label tubes in the VAC amp and the sound blew me away. You get the best of both worlds. You get the warmth of the RCA's and the detail and open quality of the Sylvania's. You can buy these new old stock tubes from Andy at Vintage Tube Services in Grand Rapids. These tubes are from the 50's and no new Chinese or Russian tube comes close.
Jwm, here is one reviewer (Mark Wheeler - TNT UK) who has a different opinion. You are of course entitled to yours :)

JWM - I am enjoying a mix of Sylvania and RCA 6SN7s in my Atma Sphere amps, and agree with your assessment. I have not heard the Treasure tubes, though, and won't say they can't sound better then NOS w/o having heard them first. Have you actually heard them? I would have given them a try, but the price was scary, and I was afraid of getting plain old Shuguangs in a fancy bottle.
Yeah, the KT77's are the cat's pajamas too. I've been using a set for a few months and am very impressed.

I'm going to pick up a set of the CV-181's soon to try as well.


Did they make a 6SN7 for a while? I thought I remember seeing them advertised here. Or were those the CV-181s? Does anyone know if they would work well in Atma Sphere MA1s?
We are talking about the VAC amp here not Assemblage. I tried the Chinese and the ones I mentioned are way better.
I am placing the tubes in this order from left to right. Sylvania RCA Sylvania RCA. All this is relative. If I say I like a certain Digital Cable or analog cable and compared them to lots of other cables; remember this is my system. What works here may not work for you. Its like fine tuning a sports car.
Hi Everyone,
Thanks for the responses. So far I'm loving these darn things, great tubes! My original post was a copy & paste from last week that I didn't get around to posting so it's a few days behind my current posts.

I gave the system a good listen last night and it seems the bass has gone a tad mushy on me and the midrange has lost a little punch but I have a strong suspicion this is the TT's going through a break in period. I will keep y'all posted.

I went and printed out the specs on the GF Treasure tube CV-181 and the 6SN7 GTA and they have obviously designed the 181 to be a direct replacement for the 6sn7 as the specs are identical though the 181 is quite a bit larger in size. I REALLY want to try these tubes in my VAC, have a gut feeling they'll take it over the top-if they'll fit in there!

I do have a few NOS 6sn7's and I tried them in my Vac(RCA & Sylvanias) and though they were good I ended up prefering the sound with the stock Vac tubes back in there. Of course that is just my taste and may not be yours, that's the cool thing about this hobby.

Now I would like to give those Genelex reissues a try some day, a good friend of mine actually brought a quad over this past weekend and neither of us even bothered to remove the TT's and give the Genelex a try. We were just enjoying the music so much at the time we never got around to it, but someday I will give em a go. I'll be sure to post here when I do compare them.

I really do not think these are plain old Shuguangs in a fancy bottle. I'm no tube pro but due to their performance so far, compaing them side by side with a standard Shuguang etc. they seem to be a different animal altogether. I feel they are a very high quality tube and hopefully an option for getting NOS sound in new production tubes. Don't quote me on this but I think that Grant Fidelity offers a money back guarantee, if so give them a try and let us know what you think.

Hi Ian,
I spoke to you on the phone about the tubes a few weeks ago, thank you for all your help. I really would love to give the TT CV-181's a try but I just read that review you posted and I have a question; in his review the gentleman states;

"This is why the CV181Z might not be a drop in replacement for the 6SN7. Typical 6SN7 heaters draw about 0.6A and the CV181z draws about 0.9A (900mA), the old Mullard CV181 drew 950mA. This 50% increase in heater current amounts to 0.6A for a pair of CV181 in a circuit, which as you can see represents the load of a whole extra double triode."

I printed out the specs for a standard RCA 6SN7 GTA and for the TT CV-181 and the specs on the TT CV-181 specify a draw of .6 MA not the .9 MA draw the reviewer states. Is he mistaken? I would worry if the 181 did draw .9 MA as my Vac needs a quad of them and that would add up to possibly to much current draw then wouldn't it?

Thank you for your time!

Hi John, this is Rachel here from Grant Fidelity.

I spoke with both Shuguang and the reviewer about the CV181-Z specs and compatability with other CV181 tubes.'s comments were based on reviewer's assumption that the Treasure CV181-Z was of the same spec as other CV181's. The reviewer is in the process to put a note to the original review to clarify the issue. (It's summer vacation time now so the website isn't updated weekly until later next month). The reviewer's comments about CV181 tubes vs. 6SN7 tube are valid to all conventional CV181's, but not to the Shuguang Treasure CV181-Z.

If you still have doubts or concerns before using the Treasure CV181-Z in your amps, do forward a copy of the specs (published on our website) to your amp manufacturer to get a final confirmation.

Thank you.
Rachel @ Grant Fidelity
John, can you ask about compatability for the CV-181Z and the Phi 300.1 when you ask about your 110? Thanks!
Welcome to the VAC family. You're going to really enjoy this Beta 110. I'm glad you are trying out these new Shuguang Treasure Series KT88-Z tubes. Supposedly they take 300 hours to fully break in. Ouch! Keep us posted on their progress. If you end up keeping these with a "thumb's up" then I'm going to buy a quad for my VAC monoblocs.

They will go through stages of sounding odd from time to time. IIRC--I found them great out of the box up until 50 hours, to be bright and spitty, with sloppy bass for maybe 100 hours after that, then they will really start to come around. After 300-400 hours, everything really snaps into focus and the bass really tightens up and becomes quick, tuneful and really quite good.


Not much for an update on tube break in as I've torn down my system to rearrange my rack but will have it back together and up & running today.

Thank you for your response, much appreciated. I figured something was amiss as I was comparing the specs of the two tubes side by side and it appears they are identical spec wise.

I spoke with Kevin Hayes and he said that we should be fine as long as the specs match. He asked me to let him know of my thoughts on the TT 181's so I think I'm going to be the guinea pig and give them a try.

Thanks again for all your help Rachel, it was a true pleasure dealing with you and Ian and I hope to call you here soon to place an order!


As I mentioned above I spoke to Kevin Hayes and I did ask him about your 300.1, he said the CV-181 should be good to go in either amp as long as it's the Treasure Tube CV-181Z, the older/or true 181's will not work as they do have a higher plate voltage. I hope this helps you!

Hi Sherod,
Thanks for the warm welcome! Man I love this amp, what an improvement it made. Shoot even my wife loves it, now that's an added bonus!! I'll post here as I get some more time on the TT KT-88's.

Hi Lee,
Thanks for the heads up, I think I'm currently in the "odd" stage at the moment, they were great out of the box and then took a little step or two backwards but, I had a feeling it was just break in. I haven't kept an accurate count on my hours but I think I'm probably around 65-75 hours or so. We'll see come this weekend as I plan on putting some serious hours on them....

Quick update; I've had the amp on for two days straight now and was finally able to spend a few mintues giving them a listen late last night. The Treasure tubes are starting to sound better, bottom end is getting tighter, the midrange seems to have a little more punch to it but I'm not sure yet, and no doubt the top end is beginning to smooth out some. I've got to be close to or even a little over 100 hours now. I'll get to spend plenty of time with them this weekend, I'll keep ya posted....

Ok now we're talking! I've kept the amp on since the 29th and last night I sat down for a serious listen. The Treasure tubes are definately going through a change for the better; the bass has tightened up allot compared to what we heard Sat/Sun and is now very nice and tight as well as they seem to be digging even deeper than before. The midrange punch is back with a vengeance and the highs have gotten much smoother and don't sound grainy at all. The highs are really nice and smooth now with no SSSibilance what so ever.

I must have somewhere in the range of 250 hours or so on them now so these babies do take a little time to break in but the wait is well worth it. I've heard they can take up to 300 hours but I'm very happy with their performance right now and if they get better than what I heard last night I'll be jumping for joy!

I'm no reviewer so I'm not too gifted word wise but, if any of you were having reservations about these tubes I highly recommend you give them a try, they aren't cheap-I'll admit that(what is in this crazy game we play), but they have proven to me to be worth every dime spent and I intend to retube whatever I can with them as funds allow, I'm that happy with them. I cannot wait to save up the coin and give the 181(6sn7) a go. I love these tubes!


Side note: One thing that was odd was for a day or two I seemed to have lost some of my imaging. We noticed that this weekend and it was noticable enough that we tried adjusting my speakers/seating position and never could get it right but as of last night everything has popped back into place and is rock solid. I haven't had that happen before with new tubes so keep that in mind if you decide to try these tubes.
Sounds good as I have a quad of EL34 Treasures coming for my Shanling SP-80s. They are due to arrive today from their trip from Calgary. I will certainly want to hear them a but, but it sounds like I'll need to pop in some relatively worn-out driver tubes and let 'em cook for at least a week. I too will post results. I will periodically pop in the real drivers, check bias on the Shuggies, and listen.
I am very curious to see how they perform relative to my stockpiled quads of 70's era RFT "Siemens". I am also curious to hear how they respond sonically to different biases. The Siemens' sound is quite alterable by varying the idle current by a small amount.

Johngp, have you played with the bias?
Thanks for your response. Once you get those babies you'll note they're pretty darn good right out of the box and then after 30-50 hours they take a dive, hang in there-they'll be back.

I have yet to play with the bias though I would like to but, I have to admit I'm a big chicken as I don't really know what I'm doing and it's a VAC amp, in other words if I break it I probably couldn't afford to fix it for a while! Let me know how the bias thing goes for you and what you hear and hopefully by then I've grown a set...

Please keep us posted on your thoughts as the tubes go through their break in period. I have a friend who uses EL34's and I've been trying to convince him to give the TT's a try, your thoughts will be very valuable to him, and the rest of us as well.

I too was concerned but it was very straightforward using the SRS dual bias tool (available on EBay for about $55) and a good multimeter. The reason I was concerned is that I was told that I would first have to open the bottom and then remove a circuit board etc. to get to a cathode resistor... The tool is just a couple of octal sockets with pins and a lead (each) that you insert into the power tube sockets. You then insert the tubes and take a reading, adjusting the pots from the top of the amp. The values for the acceptable range of mA are easily calculated from the max power for the tube type and the design voltage for the tube. One then adjusts to the lowest value within the range that sounds good. What you are actually measuring is the idle current into the cathode, which should be about 60 - 70 percent of max. For the EL34s this turns out to be 30 -40 mA. The amazing thing is that changing the value smallamounts tailors the sound quite audibly. It really is easy and now I consider it absolutely necessary. It really "perfected" the sound.
The 6CA7s are in the amp and biased at a VERY different setting from the Siemens to acheive the same idle current of 33mA. The current was heading for 50mA!

With the WWII RCA driver tubes the sound was very fat, so the Siemens are therefore relatively leaner sounding. I changed to Italian Fivre 6sl7s and the sound tightened up considerably. These drivers are in the ballpark of more typically accepted standards for balanced sound, so I believe the warmer RCAs were complimenting the thinner Siemens.

That aside, with the more complimentary driver, the Shuggies sound very good out of the box, initially with very extended but natural vocals, balanced and full midrange. The bass straight away was comparatively softish, not in amplitude, but in definition. I believe someone else callled it initially flabby. True that. After two hours of run in, the bass is already improved. The treble region actually sounds less good now, perhaps a bit spitty as some else put it. Despite these comments I am impressed so far. I will burn 'em in. Anyone know if idle current is sufficient - I don't want to play music all day. By the way, did I say that they are visually gorgeous?
24 hours in, they are sounding pretty undignified. Vocals somewhat distant and indistinct, no imaging, as predicted. A bit off-putting but I will remain patient.
Thank you for keeping us updated. Hang in there, I was thinking the same thing as well. They obviously take quite a few hours before they really start to sing, I'm pretty sure that mine are still improving and I know I'm approaching 300 hours now. Keep us posted...

50 hours of mixed playing and simply leaving them on. Much better today. Highs are not yet pristine (as they were for a few brief minutes after installation) but much better. A bit diffuse but now quite musical. Bass is better defined but not yet on par with the Siemens. What is very interesting, and now contrary to what I said earlier, they now sound best with the RCAs! That means that they have skinnied down in the mids and bass, making them closer to the Siemens' signature. Yikes! What a lot of change!
I think you bring up a very cogent point in tube rolling!

It's not the type of exercise where one can replace one tube in an amp, be it output, driver, phase splitter, etc., and be done with it. Rather, the combination of tubes must work synergistically.

I personally find in most of my amps, the combination of driver and output tubes should should be looked at as a marriage. If I do change output tubes, I'll normally need to then return to maximize the results by finding the right driver tube to mate with them.

But, it's an awful lot of fun. Getting the most out of one's amp ala the tube combination offers a lot more to the end result than many people would realize.

Continued best of luck with your Shuguangs!
I have a pair of the 300b-z that I am running in in a Manley neo preamp. These are "grey market" i.e. they are not the premium tubes from Grant Fidelity. They have matched plate current of 37mA, which is below the Grant acceptable select values of 48mA to 70mA.
Already, without significant break in, they are better than EH gold grid, Svetlana, TJ mesh gold pin, or JJ's.
I would say initially that the difference is "weight" and "balance". Density but with delicacy, and excellent soundstaging. I will make more observations as they run in, I guess it is expected that they will be a little goose-ey at times until they reach their recommended break in of 300 hours.
Shuggies are sounding better in the bass region; much tighter now. What I am not yet hearing is upper end refinement. It is a bit gritty and cymbals do not yet sufficiently like metal. Soundstage depth is somehow quite 3D at the moment with vocals In front nicely. So still not there but this is a paltry 80 hrs (!?!) so far. More later...
I am curious if anyone has tried these tubes
in a Cary 300b SEI. I would also like to
hear from those that have full burn in.
I have tried several 300b's and have found
that some of them sound really good for
about 50 hours and then they lose there
soundstage and midrange magic even after
full break in.

The best tube so far has been the EH gold grid
and I have tried Sophia's and WE's.
Hang in there, I have got to be in excess of 300 hours and my top end really snapped into place. If you're only at 80 hours or so you've got a little while to go. I said screw it and just left my darn amp on, got tired of waiting. I'm a little impatient at times...

Glad to see that others are interested in these tubes, they're worth the price of admission. Now, someone chime in on the CV-181's!! I want those babies something fierce but funds just aren't there at the moment.

JohnP, there is a very positive (as in replaces his NOS favourites)review over on TNT-Audio for the CV-181's.

Cjfrbw, the very unfortunate thing about factory matching is that they think +/- 20% is fine for matching, which is the industry norm and as cool as their test gear is, the Amplitrex AT-1000 tester gives much more accurate and detailed results. We do have to rematch everything we recieve. Btw, NOS and other new production tubes also don't fair well in the Amplitrex for close 'Hi-end' matching. It can take many pairs to create a good pair and gets harder for quads etc. We hope our gear has at least 5% tolerance between parts in each channel, 2% being our specs and I've seen some guys go even lower to 1%, kind of doesn't make sense to throw in 20% tolerance tubes or worse eh !

OK. 150 hours for the 6CA7s on the books and some very nice improvement in the vocals and treble. Now far smoother and outstanding imaging, very precise and fast, yet never in your face. Great resolution of detail now that was previously the opposite, somewhat slurred. I would say in each of these regards it (for now) surpasses the Siemens. Where the Siemens still excel is in the upper bass, where they do a better job of keeping the pace moving forward. Some of this is of course bias-dependent, but I'm pretty sure that the Siemens would win there now regardless of bias. Cymbals are still more real with the Siemens, but it is getting much closer.

These Shuggies are starting to impress me. Let's see if they can go all the way. I'll keep cooking them.
200 hours in on the 6CA7s. Upon first listening after resetting bias to 34.8, the sound seemed very similar to the 150 hour mark with great vocals and detail, but with a minor lack of upper bass drive. Cymbals still a small tad less believable than with the Siemens. So, I decided to once again play with bias. I lowered it by one mA to 33.8 and got a shift to a tad more upper bass and cymbal realism with no destruction of image or vocals. Still looking for a bit more drive, I went ahead and lowered it by one more mA to 32.8, and by God I got it. It is responsive after all. However at this setting vocals started a bit of recession backward and imaging went softer. I reset to 33.5 and promptly got the best of both worlds, sounding very, very good indeed. The sound is now in competition with the Siemens.

I am still stunned by how these, like the Siemens, are SO responsive to smallish deltas in bias.

Perhaps this weekend I will reinstall the Siemens for a reality check. We all know how our audio memory is sometimes. However, I am pretty sure these are close and may even exceed the NOS tubes.
This is your second great post in this thread!

We in the high-end audio crowd overlook the importance of bias in our tube amplifiers. Generally, the guitar amplifier crowd has a far deeper understanding of this parameter, and there are tuners build their business simply from the proper application of bias.

In actuality, bias is more important than the tube itself, as it is where the tube operates which determines the tone of the amplifier. Optimizing bias in one's amplifier is the key to getting the best sound.

This is not as simple or obvious as we hope as the characteristics of both tube and amplifier must be thorougly balanced. By this I mean that tubes of the same type from different manufacturers are more different than we may think. Likewise, it seems obvious the differences between amplifier A and amplifier B are often such that simply biasing an output tube to the same value (say -40 mV or whatever) would go against the grain of the manic tweaking and tinkering (cabling, isolation devices, room treatments, cryogenics, rolling tubes, etc.) of the high-end audio today, yet that is exactly what happens.

Hopefully, the new tubes work out for you in the end.
Good points. I now wonder how much of changing sound due to selection of driver tubes (for me 6SN7s & 6SL7s) is that they also affect the power tube idle current (hence operating range) by tenths of of mAs. Previously I had not reset bias on the power tubes when rolling drivers. For these driver tubes with twin triodes, each power tube is tied to only one of the triodes in each tube for my amps' push-pull design. Any inequities in the triodes and any delta gain relative to the reference drivers seems to affect the measured current.

After the Shuggies reach equilibrium I will reexplore interactions with drivers and power tubes, checking both sonically and for associated changes in idle current.

Now at about 225 hours...
I have more than reached 300 hours and have only listened briefly due to other issues, but what I have heard is very, very good. Properly biased, very fine level detail without being too forward and very deep and pitch-defined bass. The RCAs thus far are a very good match, giving luscious midrange that the Shuggies execute faithfully, again provided bias is perfect. More detailed reportage and comparison to NOS soon.
The Shuguang 6CA7s win The contest by a nice margin. I compared the NOS Siemens with the same bias that I had optimized to two weeks ago to my latest settings for the Treasures. The Treasures are much more well articulated with excellent detail, great midrange and bass hitting hard with no fluff at all. They are simply exquisite! I am currently still using wartime RCAs as drivers with great results. I have tried many others and got some good sound, but since break-in I always came back to the RCAs and 33.3 mA of bias for the sweet spot. Absolutely the best sound I have yet heard out of two speakers.

The break-in was long and tedious but more than worth it. Give Ian your money NOW and you'll be glad you did. Case closed. Now I'm going to need reserve quads and I'll go broke.
Hi Jcs,
I've followed along as you posted your progress, thank you for keeping us updated-fine job sir!

I've been enjoying the Treasure tubes immensely and they've only gotten better but now I seem to have developed some sort of biasing problem with the VAC so I guess it's off to Kevin for repair. Oh well, hopefully it's not gone long.

Anyway, thanks for your VERY informative posts, I've enjoyed reading them. Hopefully more people find this thread and discover for themselves what great tubes these darn TT's are!!

Yup. I was really surprised at how far they have taken the sound. I thought the system was resolving before, but this an altogether new level. Even from the other room I am hearing things in familiar recordings that I had not heard before. Somehow they manage detail without sacrificing liquidity and warmth AND bass drive. It's really quite stunning. Also Nels in his article at enjoythemusic was less thrilled with the 6ca7s mostly due to relatively less bass solidity compared to the 88s. There is NO lack of bass power, pitch definition, or clarity here. It is producing some the most hard-hitting yet somehow elegant bass that I have yet heard.

Considering that they are a fraction of the cost of a good amp but are responsible for an enormous amount of sound quality and refinement, I'd say that they are a bargain given a reasonable useful life. I am getting a Hickok 580 that I will have gone over by Roger Kennedy here in SoCal and willonitor their measurements over time.

By the way everybody, absolutely play with bias because it REALLY is responsible for the final sonic signature. A half milliamperes significantly alters the sound. My other strong advice is to get your power right. The psAudio PPP made an enormous difference in refinement. And yes, fuses can matter too. They are clearly audible changes akin to power cord changes.

All that aside, the Shuggies rule.
I bought a matched quad of KT-88s and a pair of 300B-Zs from Grant Fidelity to put in a Quad II-forty pair of monoblocks (for the KT-88s) and a Manley 300B Neoclassic preamp respectively.

There was an extended break in time for the 300B-Zs in the Manley, but within hours they were far better than the EH 300Bs supplied as stock tubes with the preamp. The experience that I've had with the tubes has been extremely positive. They are very fine devices and the sound is gorgeous. There is an extended thread here on Audiogon re the Shuguang Black Treasure 300B-Zs in similar Manley gear to mine, so I won't be repetitive.

The experience I had with the KT-88s was quite similar to the previous posts in this thread, but the break in period was considerably briefer. I found the differences after 50 hours to be quite minute and I had to listen to CDs and repeat tracks or sections to discern a difference.

For the KT-88s, I replaced Genalex Gold Lion KT-88 reissues. There was no contest. The Shuguangs represented a significant and discernable upgrade and, even taking into account the premium price, they were cheap. A friend of mine replaced Mullard EL-34 reissues with the 6CA7 and his experience paralleled mine: an initial break in period of 50-60 hours and the difference was pronounced and quite wonderful.

These are marvellous valves and worth the cash.
I'm currently running 4 of the Treasure 6CA7's in my Cary SLI-80 and my experience is similar to above. I'm liking the Treasures so much I'm considering selling my carefully hoarded NOS Amp/Mullard xf2 and Tesla brown base el34's. I'm not ready to say I like the Treasures better than my quad of Tung Sol smooth blackplate 6550's in my amp, but they are darn close, and the best part is hopefully they will keep producing them!

I've also fairly recently put a pair of the Treasure cv-181's in the 6sn7 driver location of my amp---again, to my ears these are comparing very favorably with my NOS 6sn7's (such as TS roundplates, Brimars and Ken Rad VT-231's). I was skeptical at the 'premium' price of the Treasure series tubes, but in my experience their performance has been first rate, as has been my dealing with Ian and Rachel at Grant Fidelity.
Rrsclyde, did your 6ca7s need lots of break-in such as mine or more like Bannister's KT-88s much lower time? My tubes' bass improved markedly relatively quickly, but the mids were not full or treble refined til much later, only getting close after 225 hours. Even then the bass was not exacting as it is now. The last 75 or so hours is what moved them into magnificence.
It's kind of sad that this new Treasure KT88 tube needs 300 hours to fully break in when the overall life of the tube is @5000 hours. I guess it's worth it if they sound that remarkable.
I guess you just have to think of it as a 6% tax! That leaves 94% of its life, for blissful listening which does make the story sound better. Also, although it takes a lot of patience, listening to the changes IS entertaining! I don't regret it for a second with my 6ca7s.
What i don't understand is why Grant Fidelity doesn't break the tubes in. How can they choose the top % of tubes if they change so much after they run for 300 hours. It wouldn't take much for a manufacturer / distributor to set up a rig where they could plug 50 tubes in and let them cook for a couple weeks. It wouldn't be too labor intensive. This comment really applies across the whole industry - if you have to run your system for 300 - 800 hours every time you buy a new piece of gear, your system won't lasst very long. I have heard some say that itis really our ears that are really breaking in; I dont know if this is true.
Honest1, you make an interesting point. As far as I know, Kevin Deal of Upscale Audio is one of the few, if any, people providing such service. Though, if I recall correctly, the position he takes is one of reliability. I think the way he has historically put it in his advertising is, "We do not use your amplifier as a tube tester."

Given that Grant Fidelity seems to be a customer oriented outfit, I would not bet against them taking your suggestion to heart. I believe it would make good business sense, as it would serve as extra incentive for those in Canada and the USA considering a purchase of these more expensive tubes. Since the Shuguang Treasure tubes are also available from HK/China and Europe (though likely without any price advantage in Europe) via outlets like ebay, any edge a North American importer can find in these instances is always welcome.

I really liked a lot of things about my Treasure 6ca7's right out of the box; I'm in the 275 hour range now and honestly can't say I hear a marked difference in the last 50 hours or so, but unfortunately that's possibly because I've not been able to 'critically listen' in the last couuple of weeks. My quad did go thru a period in the 50-80 hour range where I heard the slightly spitty/ragged edge of detail a bit, but seemed to smooth out fairly quickly. Maybe my mid/treble will continue to improve, but I'm really liking the sound right now!
I agree that a vendor break in is a good idea when they are so rough to begin with and require so much time. Believe me though this is not a customers-ears break in. The tubes change significantly.
I agree that a vendor break in is a good idea when they are so rough to begin with and require so much time. Believe me though this is not a customers-ears break in. The tubes change significantly.
I agree with you; this is not a "customers ears break in thing going on here".

How are your TT's doing now? Any new updates or thoughts on them since your last post? I'm going nuts here waiting for my VAC to get back from the factory. I'm currently using a Classe CA-300 and though it's a fantastic amp I am seriously missing the tube sound!