• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Linlai 300B-N

Would you post a schematic of how these are implemented? If you don't want to share publicly, a PM would be appreciated!
Thanks.
Dave
The EML tubes have a five year warranty. The Linlai has a 90 day warranty:

[LINLAI™ Global] are not responsible for any subsequent losses or damages from the use of our vacuum tubes. These are solely to the buyers’ own responsibility and risks to take.

So you pay your money and take your chances.

This is the amp I was referencing:

2A3 SE EC8010 driver CCSamp.jpg
 
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Hum has many causes. One or another of these may, or may not apply:

sumotan,

B+ ripple
AC powered DHT filaments
Ripple on DC powered DHT filaments
Input connector ground loop, and input tube ground loop.
B+ ground loops
Steel Chassis
Magnetic coupling from power transformer and/or choke to the interstage transformer.
Magnetic coupling from power transformer and/or choke to the output transformer.
AC powered filament to cathode leakage (a concertina is a good example, and so is an input tube with a self bias resistor that has no bypass cap.
Hum from your signal source; hum of a signal source to amplifier ground loop.

Solving hum issues requires determining which one or more are the causes.
 
Hum has many causes. One or another of these may, or may not apply:

sumotan,

B+ ripple
AC powered DHT filaments
Ripple on DC powered DHT filaments
Input connector ground loop, and input tube ground loop.
B+ ground loops
Steel Chassis
Magnetic coupling from power transformer and/or choke to the interstage transformer.
Magnetic coupling from power transformer and/or choke to the output transformer.
AC powered filament to cathode leakage (a concertina is a good example, and so is an input tube with a self bias resistor that has no bypass cap.
Hum from your signal source; hum of a signal source to amplifier ground loop.

Solving hum issues requires determining which one or more are the causes.
Thanks for the advice. Will pay careful attention to these when I rebuilt the amps
 
Sumotan

I don't think Linlai is cheap, I think the price is right.
I think a Western Electric is very expensive and I don't believe that the difference in sound is worth the amount paid.
But it's just my opinion.
Depends on which version I guess. There's this version 300B-T2 seems interesting but it Usd 400 per pair but still 1/4 of Western's price. Lol
Seems like Linlai is not recognizing any online sellers in Aliexpress so is it safer to make purchase through Linlai Global ?

Thanks again
 
Sumotan

I think TJ 300B-N and Linlai 300B-N are the same design.
The TJ 300B-N is currently produced by Psvane, which bought the brand.
Linlai is a company that emerged from engineers who left Psavane.
So there is a great possibility that these three brands sell exactly the same tube.
 
" Tubes bearing [LINLAI™ Global] logo are engineered, produced and carefully screened to exclusively meet western music listeners’ preference:

1) Aim to high degree of faithful reproduction of western music instruments, such as piano, acoustic and electric guitar, acoustic and electric bass / double bass, kick drums etc, which are common in western recordings but not as common in Asian music;

2) Create live-like sound image width and depth, and offer realistic balance across high, mid and bass frequencies, without exaggerating the ultra high frequencies (much of Asian music does focus more ultra high’s and Asian audiophiles are accustomed to such a type of sound).

LINLAI™ Tubes sold to vendors in mainland China, Taiwan, Hong Kong and Macau are tuned, produced and screened to meet Asian audiophile’s listening habits and preferences. They bear a different domestic logo – which is written in Chinese language. Such tubes will NOT have warranty from [Linlai™ Global] to buyers from outside of above-mentioned Asian regions.

Linlai™ Factory recommends all overseas buyers to purchase with factory authorized vendors for your region, in order to validate your purchase warranty and avoid unnecessary financial losses."
 
This 'different grade' also reminds me of products that did not match the QC that are sold 'locally' to sellers active on Ali, for instance. I bought potentiometers with 20% off difference between the stereo channels for instance, then you can easily measure.
but . .
I bought a quad 300B graphite (the same anode as a 211) when I worked in China, so 'internal market quality', and they still work well after 20 (yes, twenty) years. So as longlevity goes . . Shuguang factory matched was very good. But on current (63mA quad), on harmonics was also possible, then the current was not the same. But twice the cost. Wow. What a service and insight. My solid carbon plate versions have an excellent 'slam' - fit for electronic music.
I'll now opt for mesh (perforated) anode plate or solid metal (black iron they say, I hope they don't rust 😉). Just to hear a difference if it is not the pentode driver I still hear the sonic signature of (I am sure I will 🙄).