Sansui B-209 "The Tube"

craggd

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Just picked up a very nice limited addition (200 run) 1997 Sansui B-209 tube power amp. Very unique collaboration with George Kaye Chief Engineer of Moscode. Designed by Sansui but built in the US exclusively for the Japanese market. All 200 units were pre-ordered. It was Sansui's last original designed tube amp (the AU-111vintage and AU-111G came later but were remakes of the original AU-111). 6L6GC PP tube power amplifier. 30W + 30W into 4 to 8 ohms. Tubes include 5U4G, 6SL7, 6SN7, and 6L6GC. Very beautifully built and sounding amp.

I have a posting on the Sansui forum with more pics and a YouTube video:

http://www.audiokarma.org/forums/index.php?threads/b-209-the-temptations-struck-again.762308/

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That definitely looks like it has the goods. Thanks for sharing pics on that rare beasty
 
Just picked up a very nice limited addition (200 run) 1997 Sansui B-209 tube power amp. Very unique collaboration with George Kaye Chief Engineer of Moscode. Designed by Sansui but built in the US exclusively for the Japanese market. All 200 units were pre-ordered. It was Sansui's last original designed tube amp (the AU-111vintage and AU-111G came later but were remakes of the original AU-111). 6L6GC PP tube power amplifier. 30W + 30W into 4 to 8 ohms. Tubes include 5U4G, 6SL7, 6AN8, and 6L6GC. Very beautifully built and sounding amp.

I have a posting on the Sansui forum with more pics and a YouTube video:

http://www.audiokarma.org/forums/index.php?threads/b-209-the-temptations-struck-again.762308/

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I know what the 6AN8 is used for in the tube lineup, voltage amp and phase splitter if it follows the previous Sansui circuits. But, what is the 6SL7 used for?
 
Excuse me but did you not say there was 6an8 tubes in your amp. Looking closer at the pics it is obvious that the 2 small tubes are octals. So, 1 6sl7 and 1 6sn7 per channel ? I am guessing the sl7 for voltage gain and sn7 for phase splitting. Is it a long tail pair like in EICO?
 
Primo, you are correct I had originally incorrectly indicated the amp had 6an8 tubes. I had copied that from a Sansui site and had not verified it. I corrected the original post when I found the error. I believe your assumptions on the functions for the sl7 and sn7 are correct but cannot confirm if it is a long tail pair. I will try to post a copy of the wiring document when I get home.
 
Hi thanks for the info. The diagram is not really a schematic but more like a tube chart/flow diagram, since there are no values give to the components. It appears from the photo that you are using chinese or russian tubes. Most of their generic tubes are not as good sounding as vintage usa type . IME, Sylvania 6sn7gta vt231 if you can find some and tung sol 6sl7 or Westinghouse 6sl7 are excellent sounding type which are not too expensive. GE 6sn7gta is also exc. But the top of the line are the RCA red bank 5692 and 5691 tubes. If you find the need for tube rolling the 6l6gc the 6p3se Russian tube is excellent. in usa brands ge 7581 and rca 6l6gc are excellent if you can get strong used ones. You don't need a matched quad since your amp has fixed bias.
 
It would be relatively easy to fill in the missing resistor and capacitor values from the amp itself.
 
Hi thanks for the info. The diagram is not really a schematic but more like a tube chart/flow diagram, since there are no values give to the components. It appears from the photo that you are using chinese or russian tubes. Most of their generic tubes are not as good sounding as vintage usa type . IME, Sylvania 6sn7gta vt231 if you can find some and tung sol 6sl7 or Westinghouse 6sl7 are excellent sounding type which are not too expensive. GE 6sn7gta is also exc. But the top of the line are the RCA red bank 5692 and 5691 tubes. If you find the need for tube rolling the 6l6gc the 6p3se Russian tube is excellent. in usa brands ge 7581 and rca 6l6gc are excellent if you can get strong used ones. You don't need a matched quad since your amp has fixed bias.

Appreciate the suggestions, the actual tubes are 6L6's United Electron Made in England, 6SL7's (red bank 5691) and 6SN7's are RCA and the 5U4's are Sylvania, so no Chinese or Russian tubes. They sound very nice but also open to upgrades..
 
All right you got some 5691, one of the best made tubes. RCA 6sn7 are ok, but the ones to get are the dark glass especially the ones with the 2 small rectangular mica spacers on the top that help to keep the plate off the glass. I hope you did not pay a lot for the United Electron tubes. UE did not make any tubes and they were just a tube seller back in the day. So, the 6l6 you have are actually Russian made 6l6, nothing wrong with that. If you don't want to get vintage the 6p3se are pretty much the best buy. I have read that some users really like the Svetlana "winged c" 6l6gc but i have no experience with that tube. .
If you wanted to go "all out" the tubes to get would be el37 or kt66 originals. You would need to know if the amp can support the extra filament current these tubes need which is about 2 amps more. It looks like your power trans is hefty enough but knowing for sure would be the safe thing to do.
 
Thanks Primo. I am going to enjoy the amp as is for a while. I have RCA black plates 6L6's in my AU-111 and they are very nice. From what I have researched the United Electron tubes were likely made by GE, RCA, Sylvania, or Mullard so they should be acceptable. They came with the amp so I didn't pay extra :). I do like the look and feedback seen on the Svetlana "winged c", Some nice options.
 
Right , i have some rca 6l6gc that have the 2 side getters at the top. I did not think that tube style was us made so i always thought it was a russian tube. Back in the 80s anything was possible when it came to where a tube was from and where it said it was made.
 
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