Accuphase M1000 vs CAS2 Emitter Cascode only in the first Stage of Output Buffer Darl - diyAudio
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Old 8th June 2011, 11:51 AM   #1
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Default Accuphase M1000 vs CAS2 Emitter Cascode only in the first Stage of Output Buffer Darl

This I haven't observe in other commercial design's, even not by most designs from Accuphase. Only by the M-1000.
http://wegavision.pytalhost.com/accu...e-M-1000-3.jpg
Accuphase clone

Is there really a particulary advantage ??

By reading of the schematics from Threshold CAS-2 you will note, that the complete darlington is implemented in the cascode unit. That's better to understand for me.
Threshold CAS 1 (post #10)
THRESHOLD CAS-2 poweramp.
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File Type: jpg Accuphase-M-1000-3.jpg (249.8 KB, 207 views)
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File Type: pdf Threshold CAS1 schema redraw.pdf (21.6 KB, 103 views)

Last edited by tiefbassuebertr; 8th June 2011 at 11:54 AM.
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Old 8th June 2011, 06:21 PM   #2
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There are a couple of reasons to try this, and not a lot of downside.

Obviously cascoding is slightly helpful for drivers by virtue of locking the
Vce of the devices, but also allows better (but more wimpy) devices to be
operated at higher bias without dissipation issues.

The downside is the voltage loss of such a stage with regards to swinging
as close to rails as possible, but then these losses are covered by the
separate supply for the front end.

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