The Reference 6SN7 Thread

[leftside]

Interested - I have a CV423/13D1 (25SN7) of this tube, and the markings on it are RF | KB/FB and 3c3 under the '13D1' etching that is barely visible .. are any of these date codes? If so, what date?

3c3 could be a date code. Or a Brimar tube type code. The last 3 could be the year. I’m sure there are folks out there who know Brimar tubes very well - but not me. Doesn’t seem to be as much info out there as there is with GEC, Philips or Mullard. Nice tubes tho. I have quite a few of their 6SN7, 6J5, 6SN7GTY, 6060 and 12AX7.

Regarding the 12AX7. There are very few European with black plates. The ones I know of are the insanely expensive first version by Mullard in 1953, Marconi Italy 1950’s and also Brimar 1951 - 1955. Often these tubes do have the date codes. I believe Brimar was the earliest at 1951. Strangely enough all these black plates from Mullard, Marconi Italy and Brimar look identical….

 

[Isaacc7]

Here’s a controversial one for you.

Got a pair of them for my birthday. Will be interesting to hear the difference. I don’t think it is the same as having a solid state preamp/input section on an amp because the circuit is still based around the 6sn7. Tube circuits and solid state circuits are very different. I do hope these give me some of what solid state is known for, namely bass and detail. Will report back next week when I get home.

 

[g0ldl10n]

Here’s a controversial one for you.



Got a pair of them for my birthday. Will be interesting to hear the difference. I don’t think it is the same as having a solid state preamp/input section on an amp because the circuit is still based around the 6sn7. Tube circuits and solid state circuits are very different. I do hope these give me some of what solid state is known for, namely bass and detail. Will report back next week when I get home.

Are these supposed to work in place of any amp using 6SN7?

 

[LobalWarming]

Are these supposed to work in place of any amp using 6SN7?

Not really. Designed for use in a schiit amp.

Also... that hollow bulb only contains solid state gubbins... not so much controversial as thermionic betrayal

 

[bcowen]

Here’s a controversial one for you.



Got a pair of them for my birthday. Will be interesting to hear the difference. I don’t think it is the same as having a solid state preamp/input section on an amp because the circuit is still based around the 6sn7. Tube circuits and solid state circuits are very different. I do hope these give me some of what solid state is known for, namely bass and detail. Will report back next week when I get home.

What's the date code on those? Early 2020's?

 

[Isaacc7]

Are these supposed to work in place of any amp using 6SN7?

Well, that’s what I assumed when I asked for them as a gift. Looking around now Schitt is being pretty clear that they designed it for their gear only. I had read that before and assumed it was just the usual cover their butts disclaimer. Thinking about it more I realize that they have specific operating points that they designed to. A 6sn7 can be used across many different operating points but solid state devices do not have nearly as much latitude. Now I wonder if the LISST will work in my equipment at all. Hmm… Gotta figure out what operating points my equipment uses and what Schitt uses.

 

[leftside]

I use a Dremel with brass brushes, followed by a wipedown with Isopropyl Alcohol on the tube pins. As for the sockets, I've never cleaned mine short of blowing a little compressed air in every now and again.

Would brass brushes be a little harsh for tube pins?

I also use a dremel, but use felt polishing drill bits. Also considering these rubber polishing drill bits:
https://www.amazon.ca/TEMO-Bullet-Rubber-Polishing-Compatible/dp/B07G4L262S/

 

[ColSaulTigh]

Would brass brushes be a little harsh for tube pins?

I also use a dremel, but use felt polishing drill bits. Also considering these rubber polishing drill bits:
https://www.amazon.ca/TEMO-Bullet-Rubber-Polishing-Compatible/dp/B07G4L262S/

No, the brass bristles are very soft and work fine on both the pins and the plastic.

Found this video a while ago, for reference:

 

[JTbbb]

I use what I know of as fine Carborundum paper, or wet n dry. Cut into thin strips then wrapped around the pin and rubbed up and down, works a treat.

 

[leftside]

No, the brass bristles are very soft and work fine on both the pins and the plastic.

Found this video a while ago, for reference:

Yeah look at that even uses that brush on his fingers.

 

[triod750]

I use what I know of as fine Carborundum paper, or wet n dry. Cut into thin strips then wrapped around the pin and rubbed up and down, works a treat.

My method too. I have 600, 800 and 1500 grit. Then I use electronic/contact spray on a cotton bud to remove any debris left (which is plenty).

 

[LobalWarming]

My method too. I have 600, 800 and 1500 grit. Then I use electronic/contact spray on a cotton bud to remove any debris left (which is plenty).

Oh... you're lapping the pins to mate with the CPU heatspreader.... oh wait... wrong forum.

 

[triod750]

Wrong indeed . I'm lapping them to make the sliding for electrons easier. I'm speaking tubish.

 

[JTbbb]

My method too. I have 600, 800 and 1500 grit. Then I use electronic/contact spray on a cotton bud to remove any debris left (which is plenty).

Ditto with the electronic switch spray but with a pipe cleaner.

 

[Mr Trev]

Oh... you're lapping the pins to mate with the CPU heatspreader.... oh wait... wrong forum.

Makes me wonder if anybody has tried using liquid metal as a contact enhancer