The Reference 6SN7 Thread

[TLO]

Just wanted to let you guys know. They are all not the real Chrome Dome. The pair OP bought is just Sylvania 6SN7GTB, very common. The real Chrome Dome basically has the flash getter cover the whole glass envelope, you cant really see the interior. Link: https://www.head-fi.org/threads/the-6sn7-identification-guide.209782/ Adhoc has the description here and I have seen it myself. BTW, I have the followings for reference:

SYL VT-231/6SN7 GT
SYL 6SN7 GTA
SYL 6SN7 GTB
SYL 6SN7 W
SYL 6SN7 WGT

A note on Sylvania Chrome Domes:
The “Chrome Dome” moniker was first applied to particular early 1950s vintage Sylvania 6SN7GTs by tube enthusiasts. The name came about in response to the tube’s appearance – it had a beautifully shiny top getter flashing that nearly reached the bottom of the tube, obscuring almost all of the internal construction from view.

These particular 6SN7GTs are extremely rare, and as time passed, people began applying the “Chrome Dome” moniker to many other Sylvania tubes with top getter flashing.

The following Sylvania tubes are often (incorrectly) called ‘Chrome Domes’:
6SN7GTA
6SN7W
6SN7A
6SN7WGT
6SN7WGTA

Lastly, here is a good example of a real Chrome Dome but a pair of 6SL7GT (note: it is GT, not GTA or GTB)
https://www.ebay.com/itm/2653268335...brand=SYLVANIA&_trksid=p2334524.c100667.m2042

 

[Renexx]

Thank you for the enlightenment!

How about this pair ?
Opposing T-plates but the flashing is not covering the glass completely but looks a little different...maybe only due to the lighting in the picture.

https://www.ebay.de/itm/Sylvania-6s...2349624.m46890.l49286&mkrid=711-127632-2357-0
The seller said it's the real ones

 

[TLO]

Thank you for the enlightenment!

How about this pair ?
Opposing T-plates but the flashing is not covering the glass completely but looks a little different...maybe only due to the lighting in the picture.

https://www.ebay.de/itm/Sylvania-6s...2349624.m46890.l49286&mkrid=711-127632-2357-0

Ok, if my memory serves me right, these are the Sylvania GT series:

6SN7 GT - 4 versions
1. T- plate, lower flash getter, full base (VT-231)
2. Same as above but 3 holes on plate and spiked upp mica (6SN7 GT - Bad Boy)
3. Flat plate, lower flash getter, full base
4. T- plate, flash getter covered almost whole of short glass, full base (chrome dome)
6SN7 GTA - 3 versions
1. T- plate, chrome top, short glass, full base
2. Angled T- plate, chrome top, short glass, full base
3. Angled T- plate, chrome top, tall glass, low base (Tall Boy)
6SN7 GTB - ? version
1. T-plate, chrome top, short glass, low base
2. Angled T-plate, chrome top, short glass, low base

Generally, low base is GTB but I have seen GTA using low base, I guess they are trying to use up the balance of short glass marked with GTA on top when transiting from GTA to GTB. Chrome Dome is GT.

 

[Renexx]

I have found another pair which has clearly visible GT print on top of the tube and also a short base.

https://www.ebay.de/itm/6sn7-GT-Syl...2349624.m46890.l49286&mkrid=711-127632-2357-0

I think they are the same like the ones I mentioned in the forum before

https://www.ebay.de/itm/SYLVANIA-6S...2349624.m46890.l49286&mkrid=711-127632-2357-0

They can't be the real ones because of the short base ?

 

[TLO]

I have found another pair which has clearly visible GT print on top of the tube and also a short base.

https://www.ebay.de/itm/6sn7-GT-Syl...2349624.m46890.l49286&mkrid=711-127632-2357-0

I think they are the same like the ones I mentioned in the forum before

https://www.ebay.de/itm/SYLVANIA-6S...2349624.m46890.l49286&mkrid=711-127632-2357-0

They can't be the real ones because of the short base ?

Sylvania ECG is very much later, like in the 70s if I am not wrong, so yes, they are not Chrome Dome, which is early 50s. Short base on Sylvania GTB only started to appear in around 1954 or 1955.

Btw, why must you look for SYL Chrome Dome? If you really must, another option is SYL 6SN7W. They are made in the same period or earlier. There are 3 version.
1. T-plate, chrome top, supporting pole, short glass, full base
2. T-plate, chrome top, supporting pole, tall glass, full base
3. T-plate, chrome top, supporting pole, tall glass, metal base

Careful with the metal base, they are said to go microphonic easily.

 

[Renexx]

I have a nice pair of Sylvania 6sn7A metal base already. The chrome dome is not different sound wise compared to The metal base ?

 

[TLO]

I have found another pair which has clearly visible GT print on top of the tube and also a short base.

https://www.ebay.de/itm/6sn7-GT-Syl...2349624.m46890.l49286&mkrid=711-127632-2357-0

I think they are the same like the ones I mentioned in the forum before

https://www.ebay.de/itm/SYLVANIA-6S...2349624.m46890.l49286&mkrid=711-127632-2357-0

They can't be the real ones because of the short base ?

BTW, all of these Chrome Dome and 6SN7Ws are going for high price (~USD300-500 / pair), dont expect under USD100 / pair like the GTA or GTB. There are many other great 6SN7 tubes to go for that are priced more reasonable.

 

[TLO]

I have a nice pair of Sylvania 6sn7A metal base already. The chrome dome is nothing special sound wise compared to The metal base ?

Cant say, have not tried 6SN7W / 6SN7A metal base or chrome dome. At those prices they are going for, I wont bother. The only reason I bought a pair of 6SN7W is it is priced at a reasonable price and brand new in original military boxes.

 

[Renexx]

BTW, all of these Chrome Dome and 6SN7Ws are going for high price (~USD300-500 / pair), dont expect under USD100 / pair like the GTA or GTB. There are many other great 6SN7 tubes to go for that are priced more reasonable.

Well my bank account hates this hobby. I should have started it 10years ago since prices were super low.
The Sylvania metal base is really a nice tube. Neutral sounding holy grail for my Feliks Euphoria amp.

 

[Galapac]

For you chrome dome hunters…here is the real deal…if you got the $$$.

https://www.ebay.com/itm/334165856451?hash=item4dcdd650c3:g:4Y0AAOSwB0lhTLog

 

[Renexx]

For you chrome dome hunters…here is the real deal…if you got the $$$.

https://www.ebay.com/itm/334165856451?hash=item4dcdd650c3:g:4Y0AAOSwB0lhTLog

Mine

 

[bcowen]

Mine

7A4's are also worth a try. They are half of a 6SN7 (ie: single triode) with a loctal base so you'll need 2 tubes and an adapter. But prices are good and so is the sound. Notice any similarities with the chrome dome 6SN7?

Just an example:

https://www.ebay.com/itm/1541104072...zDQ4K3skcRTMcNaas4i0|ampid:PL_CLK|clp:2334524

 

[Ranger Ron]

Which of these two is considered the real ‘chrome dome’ ? I always thought the one on the right was. Both labeled 6sn7 GT. The one on right is 40’s the left is 52. 2 hole plate vs 3 hole plate. Obviously different micas. The GTA with opposing plates doesn’t sound as good as either one of these.

 

[attmci]

Who is advertising Syl chrom some here? Not impressed. LOL.
The metal base A/W is good.

 

[Ranger Ron]

Who is advertising Syl chrom some here? Not impressed. LOL.
The metal base A/W is good.

All of the 40’s ‘race track’ mica, top getter Sylvania’s are good, IMO.