If you have been playing with vacuum tubes long enough, you might have run into a situation that a new tube, shipped from a vendor, arrived with a piece of floating glass inside (see reference picture below). What is it? Where does it come from? Is the tube damaged beyond useful?
Here is the answer:
This piece of floating glass is a broken-off piece from the tube filament glass stem. See picture below showing where it is exactly broken off from.
2. This broken piece is often resulted from the heavy filament structure in vibrating motion during shipping and handling. However, since the tube glass stem is a wide structure supporting the full filament structure – a small piece
broken off from the tip won’t hurt the tube structure’s integrity at all.
3. We see this ‘floating glass’ from TJ Full Music 300B tubes, but not much from other Chinese brand such as Shuguang 300B tubes produced in southern China. Our guess is that the glass supplier for Full Music (located in Northern China) is likely different and glass production technique isn’t exactly the same.
4. This piece of floating glass won’t affect tube function at all and won’t interfere with the vacuum capacity inside the tube. Glass is non-conductive. User only needs to stand the tube up, let the floating piece to fall to the bottom of the tube enclosure, plug the tube into socket vertically, then it is all done!
Here is an email feedback we received from customer Thomas L about his personal experience of buying from Chinese vendors vs. Grant Fidelity:
“Hi Rachel,
Just thought I’d give you a little feedback with my recent purchase.
Your tubes are expensive (adding in all the fees and shipping). I think you would agree as well, although you may argue nothing is cheap with this Audiophile hobby, which I would agree as well. With my recent purchases, I think it was pushing around $2000 CAD. This was for 5 845s, and two pairs of 300Bs. Honestly, I had been looking at the GF tubes for a while now, never had the $$ or the guts to pull the trigger as the number of tubes that I need for my amps in total would put a dent in my bank account. With the boxing day / black friday sales, I figured it would be a good time or timing to replace my existing OEM tubes. So …. Here’s what I have learned.
Prior to this purchase, I had been buying tubes online from China or locally from a friend. But what did I get exactly? * Noisy tubes.
* Tubes that broke after a listening session.
* Tubes that looked like they were shorting out (they were supposed to be new!!!!).
Then I had to contact my friend or vendor in China to have the tube(s) replaced. And on one occasion I had to pay duty for the replacement tube.
So, after I plugged the GF tubes in my amp(s), I had a moment where I was thinking, “this is what I get for paying a premium price.”
The tubes are quiet, like very quiet. The difference between OEM vs the GF tube is obvious. I used to think that my amps were noisy, but only after I plugged in the GF tubes, I realized a good amount of noise was actually from the tubes itself.
Balanced sound stage. I am referring to the left and right channels. With that comes a solid image. You have vocals that comes directly to you. I’m particularly picky when it comes to this as I hate to hear vocal lop-sided.
Last but not least, sound quality. Smooth, very Smooth but not losing both top and bottom end.
Overall was it worth it? The decision is leaning to a Yes. With the tube and sound quality accounted for. And most importantly, this is a case where I plugin, dial in and enjoy the music without having to worry too much about reliability (knock on wood, so far so good).
Lastly, great service. Thanks again for the quality products and super fast shipping.
(Now, I will have to save up again for the next tube upgrades).
“The tubes are magnificent. The change in musical quality is astonishing. This is the best investment I have made after spending thousands to improve the signal path. I cannot believe how much music I have missed until now. Kirk”
We have just received the feedback below from Greg K from Germany! Greg owns a ‘Feliks Euforia headphone amplifier’ which came with Psvane CV181-TII as driver tubes.
Read about his first impression after swapping to [Linlai™ Global] E-6SN7 for 26hrs – it might help those who wish to know how the E-6SN7 compared to Psvane tubes: (note: Linlai tubes full burn-in will take approximately 100hrs)
“I have now burned in the tubes for a good 26 hours so far.And on the Feliks Euforia, where the Psvane CV181-TII were before, a lot has happened. I listened with the Audeze Lcd 2 C headphones which are quite neutral. And relabelled 6080 Sylvania power tubes which also arrived on Saturday.
Compared to the Linlai Global E-6SN7, the Psvane are quite neutral in sound. I noticed this immediately after the exchange. This is no longer the case with the Lin Lai, they play much warmer.
The bass has increased considerably where before they were bloodless in direct comparison to the Psvane CV181-TII. The good thing about the Linlai is that the mids and highs are relatively unchanged compared to the Psvane CV181-TII. I didn’t notice any loss there, they seem to have gained a bit of sparkle.
They are also more accurate, closer to the music and go a bit deeper in the highs and a bit longer in the low end. Detail resolution is also very good, I like it better than the Psvane tubes.
Vocals are a bit more distant and more central than with the Psvane, or less voice accentuated, which I personally find better.
All in all, they are definitely worth the money and improve the sound of the Feliks Euforia dramatically. Before I was always getting disturbed by something, but that has gone since the first hour since the Linlai have been in. I don’t regret buying them. Much more the Psvane that you can book at Feliks.
It makes the Feliks neutral but cold, with the Linlai it’s just the opposite.
That was my first impression and I know they still need a little time to burn in. But they are getting better by the hour. Linlai has done a really good job. It also shows that after such a short time they are already so open and show the direction they are going in.
I am enthusiastic about the tubes. And I wanted to tell you that much about how good they are in the first hour.
You may have noticed that our tube offerings are priced to different gradings – the best, also the most expensive, grade is ‘Top 10% Best of Best Grade’ at a price premium over typical ‘factory QC pass grade’.
Is the ‘Top 10% Best of Best Grade’ worth the money? What are you paying for the best grade?
Tubes, like most bulk commodities, are graded according to their tested parameters from lab equipment. Although vacuum tubes are industrial products, they are not cookie-cutting universal exactly the same when rolling off the production line. Consider tubes like premium coffee beans: They are all coffee beans, but not all the same coffee beans, and are not sold at all the same price.
Tubes are hand-made products. Many human factors play into the final quality and lifespan of tubes. Tubes are also live creatures – they are not in static fixed state through their lifespan – they change with the environment they work in, and change itself unexpectedly like a ‘living creature’.
An example on 300B tubes:
A factory QC pass grade 300B tube can have 60-70% of full emission but still considered ‘QC pass’ by a tube factory. Our selected ‘top 10% Best of Best grade’ will have minimum 85% up to 110% of full emission. The top grade will have approximately extra 30%-50% emission (in comparison terms between the two grades) to allow your tubes last much much longer.
Additional screening of our ‘Top 10% Best of Best Grade’ also have matched transconductance to the best possible range and no other imperfections in tested specs.
Why called top 10%? Because these tubes only take about 10% of the entire tube production batch. They are rare and hard to come by, when ALL parameters considered.
This comparison on 300B grading also applies on other tube models.
If budget isn’t an issue, we as buyers would personally go with top 10% best of best grade on these high end tubes, to make sure to get the best possible commodity for longest time enjoyment.
Hope this helps with your tube purchase selection!
We sometimes receive amp owners question about tube substitute related to 6SN7. Here is a short summary:
GT stands for ‘Glass Tube’.
GTA is an enhanced version of original GT version – to allow higher plate dissipation than the GT version.
GTB is variant of GTA, with a heater warmer control to further enhance reliability when this tube was used in TVs.
Very early 6SN7 tubes can handle max 300V. Today’s new production 6SN7 tubes can handle max 450V.
In short, new production 6SN7 can replace your old 6SN7 without frying the tubes. But you should not use a NOS 6SN7 designed to handle 300V, into a modern circuit of 450V.
All our listed 6SN7 tubes (no matter what suffix it has) can electronically replace 6SN7GT, 6SN7GTA, and 6SN7GTB.
Do check dimension clearance to make sure the different glass bulb shape can fit into your amp space!
Some amps have preamp 6SN7 tubes placed in a very tight real estate – i.e. two tubes are placed very closely to each other so the new high end 6SN7 with curved larger / wider glass enclosure cannot fit in side by side.
A customer from Europe recently told me his solution and I think it is worthwhile to share! That is – use a socket saver to raise one of the tubes up!
Just google ‘8 pin socket saver’ (not ‘socket adapter’ which may change pin layout connections) and make sure to purchase from a reputable audio parts vendor. Some lower quality socket saver can introduce current leakage to your circuit and cause unexpected noise issues.
We have received so many inquires lately from customers asking us to help them to make a choice between the two tube brands out of China. So here is a summary of our take – OBJECTIVELY:
Power of design:
High end product design need vision and dedication. Psvane had a track record of pumping out a few series of high end tubes for the worldwide audiophile upgrade market, since they initially launched ‘Treasure black bottle’ tube series back in 2008 till the recent ACME series.
That original Psvane design team includes the same people who left later on from Psvane to form Linlai brand. So, Psvane had proven track record. Linlai™ split out with a good number of the design / production team so they started off with good design strength too.
Conclusion: We have absolute confidence in the late new comer Linlai™’s design ability to pump out GREAT hifi tubes. Two brands provide varieties to the market – users can choose based on their preference.
2. Business focus:
When a business grows, they do tend to increase their offering to cover more market segments to increase revenue. Psvane indeed have taken the golden opportunity to expand and fill in the void left by Shuguang tube factory’s shutdown in 2019 due to sale of land and relocation, and Psvane has set the stage for expanding into the mass production guitar amp market, which mostly use small signal tubes and EL34/KT88/KT66 etc. Large triode tubes such as 300B/845 tubes are mostly used by HiFi market and are not the focus of the guitar amp musician market.
Shuguang now has resumed production in 2023. Psvane’s market share is being squeezed so they appear take more aggressive moves to maintain market share. However, we think the whole problem of Chinese tubes is about consistent quality. When Psvane grows to cover as wide scale as Shuguang used to be, the quality consistency might suffer.
On the contrary, Linlai™ set itself to be a niche player focusing on HiFi market only. They do not appear to take overly aggressive moves for market share. Instead, Linlai appears to be genuinely concerns about quality. Sub-par quality or un-confirmed quality tubes are not offered for sale on their official export website [www.linlaiglobal.com] to maintain brand reputation.
Conclusion: current Psvane tubes such as ACME series are confirmed by worldwide customers as ‘great tubes’ but quality consistency must be observed by diligent buyers . We are confident that Linlai™ will and may have caught up in the competition with their strong focus in the HiFi market.
3. Statistics says about Quality Control:
We have randomly taken 28 tubes from each brand that we have received and plotted their plate current. Blue line is Psvane, Orange line is Linlai™. We see a less deviation from Linlai™ measurements than from Psvane.
What does this chart tell us? It says: We are indeed getting great quality Linlai™ tubes with a very consistent measurements! The Linlai™ people are really serious about their products and take our quality control parameters to action and test numbers tell it! In our opinion, those Psvane tubes with plate current less than 48 should NEVER has been released to outside of China market if they were to maintain their brand reputation in the international market.
4. What if? – The Warranty question:
Both Psvane and Linlai offer a better warranty term than the state owned Shuguang brand used to offer. They are changing the reputation of ‘Made-in-China’ tubes.
Linlai factory backs up their [Linlai™ Global] tubes sold through their own website and their authorized overseas resellers. Buyers tempted by cheaper price and bought the Chinese version of Linlai tubes (it doesn’t have the [Linlai™ Global]) is only covered by their sellers (mostly located in Greater China).
Conclusion: Buying [Linlai™ Global] tubes does not leave the buyer to hold the bags, when problems arise. Consistent quality means less warranty cases – it will be a better user experience.
5. How do they compare, sonically?
We know this is the holy-grail question for audiophiles. But since this comparison is all about being ‘objectively’. We as vendor must leave this question to be answered by the audiophile community.
Objectively, we can shine some lights on Linlai™ design which will add to definite positives to the sonic performance. E-series with molybdenum material produce a much stronger electron emission than other type of plate material such as graphite or hybrid plate, and sustain higher voltage. This translates to more dynamic to the sound, better reliability and longer tube life. DG overhang filament series achieves better vibration control than other filament structures. With all these features, we trust that they are evident to well trained audiophile ears to hear the sonic improvements.
Conclusion: we have been selecting high quality tubes from China for over a decade. Our past combined experience does tell us that Linlai™ is a brand with great potential for both sonic quality and reliability – so far we have not seen a single defective tube from our 4 Linlai™ shipments, except one tube broken in handling from China to us.
We hope by sharing the above information and data, worldwide music lovers and audiophiles can be confident in making a well informed choice between the two brands.
Keep in mind: enjoying music is a journey. It’s not a quest for the absolute best. If there were ‘absolute best’ in the audiophile world, we wouldn’t have had today’s numerous HiFi brands and mind boggling choices from worldwide brilliant HiFi creators. We simply cannot answer your questions about ‘what is the best tube to buy’.
It has come to attention that some shoppers are confused by the different ‘6SN7SE’ tubes available on the market now.
We here clarify as below:
What we offer is called ‘Treasure Globe 6SN7-SE’ (GF-Select Special Edition).
GF stands for ‘Grant Fidelity’.
Globe is the shape of the glass enclosure as most 6SN7 tubes are either straight bottle, or mini 300B shaped with a shoulder.
SE stands for Special Edition, as this model was custom made for us based on the best possible design feature and electronic specs for single ended triode (SET) tube amplification.
We contracted tube factory made the special batch for us. We screen all tubes by our QC standards, not factory’s QC, and then further graded them to ‘low noise Grade A’ and ‘driver grade B’. For those not passing these two grades by our QC standard (about 53%), we instructed factory to destroy them (this we cannot verify if done or not, or these sub-grade tubes flew out of back door to some other vendors).
All our ‘Treasure Globe 6SN7-SE’ (GF-Select Special Edition) tubes are only sold from THIS website, not any other vendors directly or indirectly. Whoever claim they sourced the tubes from us and of same quality, it’s NOT true.
Psvane itself has launched 6SN7SE (clear glass globe shape, with white ceramic base), and 6SN7BE (blue glass globe shape, with white ceramic base). Both are offered under ‘HIFI series’ as varieties to entry to mid level 6SN7. These are NOT the same tube as our ‘Treasure Globe 6SN7-SE’ (GF Limited special Edition). Other tube factories in China may also offer globe shaped 6SN7 and call it ‘6SN7SE’ – they are NOT the same as our offering and have no relations to us either.
Hope the above clarifies the confusion around this SE model, and allow all shoppers to shop wisely with adequate information.
