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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
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johngp's avatar
johngp OP
226 posts
 
Jcspinks,
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.

John
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
 
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.
johngp's avatar
johngp OP
226 posts
 
Jcspinks,
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...

Best,
John
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