Some links
http://amp8.com/tr-amp/foreign/aura/va100-2.htm
http://www.geocities.jp/tsoka/AURA-VA100.htm
4700uF/63V ?!? 50WRMS ?
It's my inspiration, how about that ?
Regard
analog guy
http://amp8.com/tr-amp/foreign/aura/va100-2.htm
http://www.geocities.jp/tsoka/AURA-VA100.htm
4700uF/63V ?!? 50WRMS ?
It's my inspiration, how about that ?
Regard
analog guy
Attachments
Constant gain & protection !
2*TL084 for constant gain amplifier and 1*LM339 for input : output gain comparator.
TL084 used for special calculate voltage gain (AV) of amplifier when used with vary impadance load output (hard to drive speaker) on the circuit you can see only RF/RI for calculate AV but this IC are special more than typical amplifier !
LM339 used for comparator INPUT : OUTPUT voltage when there're some problem with output such as shorted output relay was disconnect from LM339 function, Vo/VI not equal in same dB
Example
MAXIMUM OUTPUT : INPUT = 30V : 1V = 29.54dB = NORMAL AV
SHORTED or LEAKAGE OUTPUT: INPUT = 0V : 1V = -INFINITE dB relay will be disconnect
Regard
Analog guy
2*TL084 for constant gain amplifier and 1*LM339 for input : output gain comparator.
TL084 used for special calculate voltage gain (AV) of amplifier when used with vary impadance load output (hard to drive speaker) on the circuit you can see only RF/RI for calculate AV but this IC are special more than typical amplifier !
LM339 used for comparator INPUT : OUTPUT voltage when there're some problem with output such as shorted output relay was disconnect from LM339 function, Vo/VI not equal in same dB
Example
MAXIMUM OUTPUT : INPUT = 30V : 1V = 29.54dB = NORMAL AV
SHORTED or LEAKAGE OUTPUT: INPUT = 0V : 1V = -INFINITE dB relay will be disconnect
Regard
Analog guy
Attachments
Hi,
I own one of these Aura amps. There is a problem: the servis guy who has repaired a problem with source selector (it is working now) didn't have a spare part for another problem. So he bypassed something that stabilize amplifire (when I turn it on) before the signal comes to speakers. The result is when I turn it on there is a loud crackel in speakers even if the volume is set to minimum. Which part did he bypassed and where can I get it? Is there a substitute for this part? I can take a picture of interior of Aura if necessary.
Thank You
I own one of these Aura amps. There is a problem: the servis guy who has repaired a problem with source selector (it is working now) didn't have a spare part for another problem. So he bypassed something that stabilize amplifire (when I turn it on) before the signal comes to speakers. The result is when I turn it on there is a loud crackel in speakers even if the volume is set to minimum. Which part did he bypassed and where can I get it? Is there a substitute for this part? I can take a picture of interior of Aura if necessary.
Thank You
Another VA100 fan
Hi everyone, just read through this fascinating thread. I have a VA100 which I bought new in 1993 and am still enjoying today. It is only recently that I have started to give it some attention. I have replaced the bias resistors and reset the bias currents according to the service manual that B&W very kindly forwarded to me. Perhaps you can point me in the right direction of what I need to replace to reduce the mains hum. From new this amp always had a very slight hum (zero volume & no inputs connected) but now after 16 years the hum is audible from a few feet away. The hum is from the speakers, whereas I have experienced the amp humming (vibration) over the years with certain other appliances switched on.
Any advice greatly appreciated, at the moment I just want to reduce the noise, maybe later I will get more adventurous like some of you guys.
Cheers
Hi everyone, just read through this fascinating thread. I have a VA100 which I bought new in 1993 and am still enjoying today. It is only recently that I have started to give it some attention. I have replaced the bias resistors and reset the bias currents according to the service manual that B&W very kindly forwarded to me. Perhaps you can point me in the right direction of what I need to replace to reduce the mains hum. From new this amp always had a very slight hum (zero volume & no inputs connected) but now after 16 years the hum is audible from a few feet away. The hum is from the speakers, whereas I have experienced the amp humming (vibration) over the years with certain other appliances switched on.
Any advice greatly appreciated, at the moment I just want to reduce the noise, maybe later I will get more adventurous like some of you guys.
Cheers
Wonderful to see that you guys are keeping your good 'ol VA-100 amps alive! I have one too and used to love it. However after a couple of years in storage it seems to have gone a little bit "funny" somehow - maybe I just don't remember it right - but for now it is doing service with a friend of mine who doesn't have a stereo... I guess I will check up on it when I get it back some time 
/cdl
/cdl
Aura VA100 modification
Hello everybody, sorry if this is not the right place to post, but this is my very first "contribution", hope I´ll soon be able to start my own threats
I own an AURA VA100 evolution, wich I bought new in 1998. After having listened to my ARCAM AVR300 for a while, I switched back to the old stereo and am loving it again! The only thing I regret is that I cannot feed my AR sw30 active subwoofer (my speakers are B&W dm 604, reaching quite low though...). I don't want to use the high-level connections, maybe I wont' be using the subwoofer everytime...
I wonder if it's possible to turn the REC-OUT of the AURA (fixed volume) into a PRE-OUT (post-volume) so I can connect the subwoofer via line-level connections (and use its own crossover).
Thank you for your expert advice, greetings,
Andres
Hello everybody, sorry if this is not the right place to post, but this is my very first "contribution", hope I´ll soon be able to start my own threats
I own an AURA VA100 evolution, wich I bought new in 1998. After having listened to my ARCAM AVR300 for a while, I switched back to the old stereo and am loving it again! The only thing I regret is that I cannot feed my AR sw30 active subwoofer (my speakers are B&W dm 604, reaching quite low though...). I don't want to use the high-level connections, maybe I wont' be using the subwoofer everytime...
I wonder if it's possible to turn the REC-OUT of the AURA (fixed volume) into a PRE-OUT (post-volume) so I can connect the subwoofer via line-level connections (and use its own crossover).
Thank you for your expert advice, greetings,
Andres
Should be easy to do but must be done in such a way that the "new" output doesn't load the volume control or detract from the sonics.
As it's a sub you wish to feed then I would look along the lines of a high impedance buffer connected to the power amp input (volume wiper) perhaps using a FET opamp fed of the wiper of the VC.
The easier possibilty (may be the best actually ?) is to take a feed from the speaker outputs and attenuate to suit. Four resistors and that's it No possibility of it affecting the sonics either.
As it's a sub you wish to feed then I would look along the lines of a high impedance buffer connected to the power amp input (volume wiper) perhaps using a FET opamp fed of the wiper of the VC.
The easier possibilty (may be the best actually ?) is to take a feed from the speaker outputs and attenuate to suit. Four resistors and that's it
No possibility of it affecting the sonics either.Thanks Mooly, sounds very simple in your words, sounds very "chinese" to my ears ;-) I will transcript your reply to the people who would do the modification. Hopefully they will find it helpful! So your advise is definitely to take the signal from the speaker outputs and attenuate it? Wouldn´t it be better then to let the Aura untouched (I know this goes against your principles.. and make some kind of "little box" with the resistors and connectors, independent of the Aura?
and make some kind of "little box" with the resistors and connectors, independent of the Aura?