Radio Shack Accurian Receiver, quality of amp? (pics inside)

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Now i finally understood... a very standard and common schematic

nothing unusual or extraordinary...just normal.

Those double differential into the input is the hell thing...not a problem to a factory..but for us, to find matched parts is very difficult.... also we have double distortions...from the upper differential added to the lower differential... also double VAS is doubling the problem.

It uses a VI limiter... senses over current into the output and reduces current to the drivers..another audio killer that allow them not to use huge (and more expensive) power transistors... a very bad idea to audio quality.

I am glad i could see this schematic, i was deeply curious and interested because the TIP output..but i see this cannot sound special assembled at home.... we have to buy an Acurian from Radio Shack to obtain good sound (matching is needed)

bye folks...not needed any schematic anymore..thanks a lot.

regards,

Carlos
 
Thanks to all for input. . . this looks like the end of this. . . just one more schematic with some idle voltages. The VI limiter is interesting. . .someday maybe it would
be interesting to take it out.

PS - today is tax day. . . will continue to earn an income until July to pay for all
the taxes. . . Tea Party here I come!
 

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Try reading the thread and look at #98 for example:
http://www.diyaudio.com/forums/soli...r-quality-amp-pics-inside-10.html#post1338619
Bear in my they were 25W/8 ohm amplifiers using a single pair of TIP41/42 - not a lot of woofing or 4 ohm capability there.

So it already reaches 20Hz which is good, and if the sub-woofer is powered, everything should work fine. Obviously this is not going to be an audiophile quality setup. But the combination of the $15 Accurian (I was given for free,) $20 Insignia NS-SP213 80W 5-1/4" woofer and 3/4" tweeter, and to top it off a $88 Monoprice MSUB-122BL 150W.
 
I purchased about 3 of these amps, and 2 of the power speaker sets for about $10 each.
One amps failed when it was driven hard.
One of the speaker amps was dead when I bought it, probably a return or demo unit.
I don't think that they handle shorted outputs or low impedance loads when
driven hard.
Both had blown outputs and drivers in one channel.
One had the driver fail in such a way as it back fed supply voltage to earlier stages
with the transistors failing shorted so that close to the full supply voltage was applied
to the low voltage feedback electrolytic. It blew up with streamers of foil inside the amp.

I've been wanting to fix these for a while, soon I hope, or I might put an LM3886
chip amp into one.
 
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