Discussion in 'Exclusively Sansui' started by skippy124, Jun 22, 2015.
+1 A little fanciful I would say.
I must say that Shavalievdd1 is perfectly right> due to the acquisition of a pair of new speakers the impedance switch on my AU-X701 (rather, the related wires as my amp is direct coupled there, as you may know) had to be re-set to 8 Ohms and, thus, the bias went up to 24mV in spite having been rightly aligned to ~19mV before (not so easy to maintain spot-on). after re-adjusting it to ~19mV again the mids/highs became much purer and more transparent, and the bass pretty well defined, though it's 'only' -5mV difference - which, as it sounds, is a lot, IME, in terms of sonics. go figure...
Impedance switch , switches to a lower voltage winding of power transformer , when set to 4 ohms. So if you had it correctly set to 19mv , it would of decrease just a bit , and then when reset the impedance switch to 8 ohms bias would come back to it's original value. Never the less bias small adjustments do not change the way sound comes out of the amp , and specially this drastically .
Not to mention that bias decrease does not sounds like this , but quite the opposite. Like cool -freezing the sound , making it more clinical.
clear ... jomark suggest: set on the same channel nominal value and the second 3 mV more - OK? Be after what you hear OK? ............... Theories are not worth anything ...
setting a higher value than the face value causes thickening of sound and loss of detail, reduce the value of shallowing sound and more delicate.
The Sansui is important even a small value! especially within the factory! In models mos fet this effect is even more significant!
Also I was surprised at first.
Since 3 mv is no big deal why Sansui instructions sets the decimal ????? for example, model 907 limited - 28.6 mV, models 907 .... 8,8 mV ....
Precise setting of BIAS current is important for temperature stability of power stage and complete functioning of power stage... so there are no any kind of magic there.
you're right ! It's not magic! However, has its consequences in the sound ... I hear that colleagues and I agree with that - and you stick with theories ...
No... I just working exactly what service documentation says. I would rather believe to Sansui engineers than to hearing impressions of some peoples who I dont know.
I also (we have, service materials as you know), but also hear and draw conclusions!
I don't think we are having a valuable discussion here, just a slight difference of opinion, shall we just agree to disagree? - leave it there, and get on with our lives?
I agree with you John!
You should read more carefully. I didn't suggest what you say. Try to listen or read what people are saying or typing before you draw your wrong conclusions .
Sansui AU alpha 907 limited and not only ....
Check for example Sony TA-F830ES, 4x 18.000uF Caps for Current amplifier and 2x 10.000uF for voltage amplifier. or Sony TA-N80ES, 4x 22.000uF for current amplifier and 6x 4.700uF for voltage amplifier
even some small ampl;ifiers were designed like that, its so called Spontaneous Twin Drive, almost every Accuphase also used similiar technology, input amplifiers in Accuphase were powered with higher voltage than final stage
Hi JoMark911, how did you go trying to get manuals you requested? It's quite a time ago so I guess you have done something already.
but the au alpha 907dr who 2x3900 mF + 2X5600 mf are not few?
You know the Tamura transformer alpha 907dr how many VA and '?
I have the same CD player. The CD-A917xr. Quiet a gem...eh.
It's festooned with Elna Silmic capacitors and loads of copper in the chassis.
One sweet player, that.
I have the amplifier AU ALPHA 907DR, my cd player and 'ALPHA CD 717DR.....
my question was for the amplifier
Congratulations for your CD player , I can not find the instructions of my own in English because 'I have it only in Japanese....
You keep asking this question:
You have been asked why you want to know this information, but you have never responded, you just keep asking over and over again.
So I'll ask you again, WHY do you want to know the VA rating of the transformer? - the answer to this question will help give some context for any reply.
You should also start your own thread titled appropriately for your question.
This thread is about 'AU alpha907 Limited' NOT 'AU alpha907 DR'.
the transformer and capacitors are the same for the two amplifiers, demand and 'curiosity' as a passionate technical ...
Well, I'm a 'passionate technical' as well, if anyone knows the answer I am sure they will post it here.
Separate names with a comma.