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Russian 6H9C / 6N9S vs US 6SL7
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Author:  gofar99 [ 31 Jan 2014, 16:35 ]
Post subject:  Russian 6H9C / 6N9S vs US 6SL7

Hi Everyone, I just got a number of Russian tubes that were supposed to be 6SL7s. The ones before were new production and have different bottles and no additional markings. These are clearly NOS. They are marked as 6H9C which Franks tells me is a 6N9S. Specs are the same as 6SL7s. The other markings are date code 8808. A symbol that sort of looks like a verticle oval with a donut around it and a wide diamond with a rectangle inside it. Anyone familiar with these tubes and markings?

Good listening

Author:  Geek [ 31 Jan 2014, 18:49 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7


You get the D-getter ones on the left hand side and they'll smoke the fanciest NOS 6SL7.

I'mk assuming you have a Reflektor logo?

The white diamond probably has "OTK" in it or near it. This is the russian equivalent of a "SQ" tube. I've traded these up to $100/pr.


Author:  gofar99 [ 31 Jan 2014, 20:22 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7

Hi, Thanks, yes they are NOS Reflectors. I got 20 of them. I have not compared them to the 4 I already had (different date code) but the first ones are awesome.

Good listening

Author:  wolfdog428 [ 01 Feb 2014, 10:31 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7

I have 30 of the same tubes I use them in place of 6SL7's. They have a little more gain than the 6sl7. They soung great with more refined sound and a great low end.

Author:  Soundbrigade [ 02 Feb 2014, 04:07 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7

The "OTK" marking is a sort of quality control mark. It says "Otdyel Tekhnicheskovo Kontrolya" or "Department of Technical Control".
Most products in the Soviet Union carried this stamp.

Author:  mwhouston [ 02 Feb 2014, 19:29 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7

Geek: thanks for the info and particularly the link. I have been looking around for a 6N1P preamp cct. for some time. That was fine though I was distracted by 800 other builds completed over the last few years (lol). I made a remote driver stage for a KT120 bread board amp some years back. I used a 6N1P and have ten more tubes I got for $2 each new. I never pulled the stage down. Now I can rewire it as a preamp and use my standard PS with wall warts and backward step down trannies. Happy days!

Author:  Chrisuk [ 02 Jan 2020, 12:39 ]
Post subject:  Re: Russian 6H9C / 6N9S vs US 6SL7

Hi, I'm a bit late to the party but I have got an amp (gemtune Bl-02) but it did not have any paperwork and I have been able to fine precious little info on the Internet.
I have compared the valves in the manual (1 page basically just valve location) to what I have, slight differences.
I have 2 x EL34-B which is correct
I have 2 x 6h9c which according to the manual should be 6n9p
And rather than a 5z3p I have a 5u4g.
Would I be right in thinking that these could be acceptable alternatives and would just deliver a different type of sound or would they blow or just not work if they were used?

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