I've made this little page because I've been asked several times how to replace those strange tubes on those chinese amplifiers, that are so popular nowadays.

For Italian readers: this page has been the source for writing an article for VideoHiFi, a popular free web hifi magazine. You can found it here.
 

DISCLAIMER:

I don't encourage tube substitutions and rolling to inexperienced people. If you're unsure on what you're doing, please refer to a competent technician, or ask where you bought the amplifier. Remember that working in tube amplfiers can be VERY DANGEROUS due to high voltages involved, EVEN WITH THE AMP UNPLUGGED from the wall outlet. 

 

First, an equivalence table, please note that NOT all china-tube types are listed here, mainly because they don't have a direct euro-american substitution. I have to thank Jogi for those tables.

If you have questions, email me. 

 

And here another table, for some types that aren't listed above. This table contains equivalences: please note that China amps use more other tubes, but they're named the same as their euro-american counterpart.

It is usual for chinese tubes to drop the last letter, 6N6P becomes easily 6N6. Always remember that the "H" is cyrillic, so it is an "N" in our alphabeth, as in the tables above. 

This means that most of the times, on the glass of the tube you'll find 6H8 instead of 6N8!

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                    Czech Note:

6CCxx tubes were manifactured by Tesla in the former Czechoslovakia. They used latin alphabeth, so 6CC doesn't mean 6SS. The labeling used by Tesla in the '50s was a mixture of European and American systems: for example "6" stands for 6.3V heater, "CC" for a double triode (as in ECC88) and "4" for NOVAL base. The Czech tubes are easily recongizable because no real Russian tube used two middle letters. 

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As always, if you have doubts email me, or better, ask where you bought the amplifier ;)

Tubes in italic, like this text, are not "direct replacement" types. However they may work in some circuits, and some of them are known to work.

* Note: ECC40 is only electrically equivalent to 6N1P, its socket is different so a direct replacement is impossible.

Find some other references for your tubes here!

Some known problematic tubes to replace:

• 6N6 (chinese), 6N6P (russian). This tube has NO known direct replacement: the best replacement is another 6N6 - 6N6P. However if you are experienced, and with the proper tools, it could be replaced (given socket rewiring and maybe some circuit tweaks) with 5687, 12BH7, ECC99 or E182CC. This last tube seems to be the closest equivalent.

• 6N2 - 6N2P: the question here is, can I replace it with ECC83/12AX7? Yes you can, but you HAVE TO REWIRE THE SOCKET. Refer to the tube datasheets for this: as always I suggest to have this work done from experienced people, don't try poking inside dangerous tube amplifiers if you haven't done this before!

• 6N1: not much info. Best replacement is still another 6N1. ECC88 and its various cousins might work, but be careful of the much higher filament current for the 6N1, and much lower allowed plate voltage for the ECC88. If the amp runs the 6N1 at less than 130V you can safely replace 6N1 with ECC88 (don't know how it will sound...), but if the quiescent plate voltage is more, ECC88 might fail and ruin your amp. See also here for deeper information.

• 6N30 - 6N30P - 6N30PI - 6N30PI-DR. Absolutely no western equivalence: the only known source for these is Sovtek that still makes them. However, russian NOS ones are even better but they're becoming scarce and expensive. 

 

 About russian tube logos:
http://www.ominous-valve.com/russtube.html

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