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Old 12th March 2008, 08:54 AM   #1
miligor is offline miligor  Serbia
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Default Dual OpAmp in input of amp?

What is the catch here? Why not single opamp?
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Old 12th March 2008, 09:41 AM   #2
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Sometimes you prefer the sound from a certain opamp, which is only available as a dual opamp......
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Old 12th March 2008, 10:04 AM   #3
Electrons are yellow and more is better!
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It's possible also that the company uses lot's of this type and therefore gets a good price.
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Old 12th March 2008, 10:37 AM   #4
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Not because the Mitsubishi opamp has a high Max output current ?
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Old 12th March 2008, 11:44 AM   #5
Electrons are yellow and more is better!
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Lot's of reasons. This maybe one of them.
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Old 12th March 2008, 12:00 PM   #6
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All active parts on the schematic are Mitsubishi made, smells like a Mitsubishi integrated.

(reminds me i still need one of those fancy open style Mitsu DA-A/M JFET-input power amps)
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Old 13th March 2008, 06:43 AM   #7
miligor is offline miligor  Serbia
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It's Technics SU-V85A amlifier
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Old 13th March 2008, 08:21 AM   #8
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My bad, i should look at a datasheet instead of talking from the less dense part of my head.
The (zener) diodes are Panasonic made, aka MAtsushita as in MA29/MA4082, Technics = Matsushita .

The SU-V85 is a specimen of the late 80s/early 90s AA series, cost around $500, the TH502 thermistor in the schematic is likely the Class AA thingy.
The opamp however is Mitsubishi manufacture, which is amusing because Matsuhita corp. and Mitsubishi corp. are competitors.
So the choice for that opamp was cost related, must have been the most affordable option, the main motive for the high volume market.
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Old 13th March 2008, 12:23 PM   #9
miligor is offline miligor  Serbia
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Thank's jacco, but I have problem with Technics SU-V90D. Maybe You have schematic or SM for this amplifier? Before I buy this amp, somebody was changed these opamps with LM1458, and I'm was asking can I change 1458 with NE5532? (or must originally M5219)
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Old 13th March 2008, 12:53 PM   #10
AndrewT is offline AndrewT  Scotland
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Hi,
is the opamp operating as DC servo?
If so then input offset and offset variation with temperature become important.
5532 is not FET input.
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