Nakamichi 620 - how does it work?

[Bigun]

As far as I know this circuit is in the public domain and no Copyright is being infringed here.


I am not familiar with this output stage - how does it work ?

 

[sregor]

It's what I would call a quadruple. Four emitter followers. Two going up (or down) into a current source, then 2 going the other direction. If thermally coupled, the temp balances should balance out. Similar to the Diamond output stage of some headphone amps, or the triple from this thread: http://www.diyaudio.com/forums/solid-state/188143-groner-triple.html

 

[Bigun]

I heard that it requires no idle current adjustment ?

 

[Zero D]

Yeah, looks like the bias is fixed. Also, note the 4.7R resistors across the emitter ones. Are they some sort of protection in case the R0.22 fail, or ?

Did you ever get that FM transmitter, if so what ?

 

[Bigun]

I'm not understanding how this OPS avoids the need for idle current adjustment ?

FM transmitter - not yet, but still on the list !

 

[Bigun]

I'm not understanding how this OPS avoids the need for idle current adjustment ?

FM transmitter - not yet, but still on the list !

 

[ostripper]

I'm not understanding how this OPS avoids the need for idle current adjustment ?

FM transmitter - not yet, but still on the list !

OPS CCS's adjust current , diamond is the thermally coupled to the OPS.

The Cordell diamond triple OPS is the more advanced version of this.

"trouble with triples" is the thread. Built it , works great.

OS