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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.

Sincerely,
John
johngp

Showing 17 responses by jcspinks

jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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?
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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?
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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!
jcspinks
17 posts
 
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...
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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...
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
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.
jcspinks
17 posts
 
The Treasures are still stunning. My fellow audiophile friend was over Monday for a four-hour listening session and was blown away. He thought that the soundstage and musicality was like never before, ranking the sound among the best he had ever heard (we go to many audiophile demonstrations and shows here in SoCal). Of course it is not just the tubes, but they made a substantial positive difference. I couldn't be more proud and pleased.
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