Keneda linestage

Kaneda Linestage

What do you think about this?
http://extra.newsguy.com/~stigerik/kaneda.html
I think it looks very good, no capacior in the signal path. And it's very simple, with good specs.
I will probably build this to replace my BoZ.
And as volume controll I will use a rotary optical encoder with gray code output, and a bunch of resistors and transistors to create a nice shunt volume controll. And a battery PSU.

BTW: Do you know where I can find a cheap Gray code rotary optical encoder.



[Edited by Freddie on 08-09-2001 at 08:51 AM]
 
The Kaneda Linestage could easyly be made without the global feedback, if you add 2 emitter resistors to the 2. stage, as a lokal feedback. Further more you can add an extra output buffer, to make it a balanced output.

BTW Freddie, You say there's no capacitors in the signalpath!
The feedback-loop is indeed a part of the signalpath, so the 10p capacitor IS in it :-(

But all that said, it is a nice little circuit.
 
Hi Freddie ;-)

Global feedback or not is more or less a religious question, but since this circuit is so simple, why not prepare the PCB-layout for both options. It'll make it very easy to compare the different religions, oups, I mean theories.
Global feedback has it's pro's and con's, lively discussed in this forum, and I'm not to say wich is the best. All I know is that I'm still working on a fully ballanced linestage without global feedback, since I'd like to live without it right there, where it's easy to avoid it.

Yes, the 10pF is making the circuit stable, since high frequencies are bypassed the resistor through this capacitor, and thereby reduces the gain at these high frequencies. No gain, no Jazz.
 
Hello Freddie,

I think that the overall open loop gain is very high, and its not a good thing, because possibility of transient intermodulation distortion, and high frequency instability.

It's a good idea to insert resistors in the emitters of the transistors (1st and 2nd pair only !) typically 1/10 value of the collector resistors. It may be possible that you must modify others resistors in order to keep correct bias, specially common emitters resistors, typically 1/10 less.

Overall feedback will correct residuals distortions, and will stabilize overall gain.

Power supplies should be perfectly filtered... as usual.

Best Regards,
Pierre Lacombe.

[Edited by P.Lacombe on 08-09-2001 at 06:06 PM]