Technics cassette deck headamp section

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CHiroshi

CHiroshi

Member
Joined 2014
Hi!

Just got hold of a nice Technics RS-B555 cassette deck in really good shape, and looking at its service manual I found this rather interesting looking headphone amplifier section schematic, see attachement. Are those opamps in parallell somehow? The diamond-shaped resistor arrangement between the opamps looks rather intriguing to me...

It does drive my 250 ohms Beyer DT-770 to good listening levels without having to turn the volume all the way up. Sounds good too!

Could anyone explain to me what we are looking at? :)
 

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  • Headamp Technics RS-B555.png
    Headamp Technics RS-B555.png
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I

Iomis

Member
Joined 2015
Hello,

That configuration is Technics' 'gimmick', ClassAA. They used it everywhere, starting with SE-A100. In the service manual of this power amp is explained how it works. Also, there are references on different forums...
This config. is (was) found everywhere from input buffer to output stage.
I was surprised to read on Technics site that is still used in some modern model, but only as headphone amplifier.

Best regards,
Cosmin
 
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