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charles mills
Reply with quote  #1 
I obtained one Sansui BA 303 (KT88's in triode mode) and two BA202 (6RA8 triode) stereo valve amplifiers. Very interesting amplifiers. The BA303 weighs 26kg and I managed to get it working. What a nice sounding amplifier this is.  I am looking for the service manual for these two amplifiers. I still have to restore the two BA202 amplifiers. Help will be appreciated.

Kind Regards


Charles Mills  
Keeper
Reply with quote  #2 

Quote:
Originally Posted by charles mills
I obtained one Sansui BA 303 (KT88's in triode mode) and two BA202 (6RA8 triode) stereo valve amplifiers. Very interesting amplifiers. The BA303 weighs 26kg and I managed to get it working. What a nice sounding amplifier this is.  I am looking for the service manual for these two amplifiers. I still have to restore the two BA202 amplifiers. Help will be appreciated.

Kind Regards


Charles Mills  

You are a lucky man who found a BA-303. One of the best Tube Amps from Sansui. A service manual is very difficult to find but it's available for BA-202 at http://www.obsinc.us/Dep_VOVS_Literatures.htm

charles mills
Reply with quote  #3 
Thank you for the information regarding the BA202 service manual.

Kind Regards


Charles
charles mills
Reply with quote  #4 
I also managed to get one of the BA202 amplifiers working - tested it with an audio signal generator. Changed the ECC82 and ECC85 tubes. One of the ECC85's Ia was only 35%. 

Kind Regards

Charles   
RICARDO
Reply with quote  #5 
hi
i'm a lucky one too i have the ba202 and the ba303,and i have the ba202 and ba303 manual.a copys,do you have the preamp?whats about the tubes 6ar8?
they are ok?
regards
ricardo
charles mills
Reply with quote  #6 

Dear Ricardo,

 

You are also a lucky person to have both of these fine Sansui amplifiers. I obtained a copy of the BA303's manual from a Sansui user in Canada and from a friend of mine the manual for the BA202. 

 

I do not have the Sansui preamplifier but are using a Luxman CL35 (obtained it with the BA202's and the BA303). It is a valve preamp with variable line inputs.

 

I manage to test the 6RA8 triodes (not 6AR8 as you mentioned in your response) with an AVO valve tester and they all are more or less 80% ok according to the AVO 163's test readings. I am investigating what modification can be done to use other output valves in place of the 6RA8's as these valves are now very hard to find.

 

Last night I adjusted the bias settings according to the manual specifications on one of the BA202's.

 

Kind Regards

 

Charles

alessandro ferrari
Reply with quote  #7 
Hi Charles,
unfortunately my reply to your message was refused by the system, so I'm back to the Sansui forum to try to communicate with you. I'll surely send you the manual as it arrives, but I would like to know what pre-amp are you using for the BA 303.
I hope this time everything'll work,
best regards,
Alessandro, Siena, Italy
Diego
Reply with quote  #8 
Hi, I´m putting myself in this chat maybe a little bit too late (2 years hohoho), but anyways, I have a BA303, BA202, and I have the preamp CA303. The sound of these gear is awsome!. But right now I´m having trouble adjusting the bias in the big one (BA303). I´m having ground noise in the left channel. Anyone knows how the Bias Test works? Any help will be appreciatte. Thanks 
Keeper
Reply with quote  #9 
There are two hum balancers, one for each channel for 12AU7 and 6AQ8 filament.  Adjusting these might eliminate the hum.
 
As for the bias adjustment, it looks like you need to calibrate the meter reading by setting the bias knob at the AC position first.  Then, adjust the bias for each tube by setting the meter reading at the right place.
Diego
Reply with quote  #10 
Hi, thanks for the help with the bias adjust. Is working!! Now I have the same trouble to find the 6RA8 replacement. Is there any chance to use a EL86 instead? If that´s the case what modification should be done? What about another tube? Thanks in advance 
Keeper
Reply with quote  #11 
Quote:
Originally Posted by Diego
Hi, thanks for the help with the bias adjust. Is working!! Now I have the same trouble to find the 6RA8 replacement. Is there any chance to use a EL86 instead? If that´s the case what modification should be done? What about another tube? Thanks in advance 

The BA-202 is optimized to use 6RA8, which is hard to find.  You could use
EL86, but you will need some wiring modifications to use EL86 in triode
connection.  It appears to be that EL86 is a little less tolerant than 6RA8
with the plate desperation of 13W vs that of 15W of 6RA8, so that I would
use it at lower plate voltage and shallower bias setting.  In any case,
because the BA-202 uses rare mixed bias system (using fixed and self bias at
the same time) for the optimum performance of 6RA8, I would avoid to convert
it to use a different power tube.  You might be able to find 6RA8 at the
Japanese auction sites  http://www.yahoo.co.jp/  or stores because 6RA8 was designed by the Japanese electronics industry. 

Let google translate the Japanese site to be understandable.    

Carlos
Reply with quote  #12 
Hi,

I know I'm writing it a lot of time after last, but maybe somebody ca help me.

I bought a near mint BA303 and don't have the user manual. I check capacitors and resistors and all is OK, but the BIAS meter apparently is not functioning. The amp is in perfect condition and operate very well, but off course I want to put the tubes on correct BIAS point.

Can you help me on it please?

Many thanks in advance.

Carlos
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