Kind of Bride of Zen

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If you don't need balanced inputs, balanced outputs or are having trouble finding a 4-gang pot, and want a non-inverting output then you may consider trying something like the circuit below.

It is a variant of BoZ with some of the features of BoSoZ.
I gave it the name of KoBoZ - Kind of Bride of Zen.
Tell me what you think.

PS. The supply voltages and bias current reflect what I've got in my arsenal of spare (leftover) parts.



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I think your amp looks very nice.

You like to invite more attention...?
Okay, here is my silly question. What made you consider
the differential amp for the unbalanced operation?
How is the taste of the sound, red wine or white wine?

Hi JH,

Well, we all know about the advantages of diff amps - high CMRR, balanced to unbalanced conversion ability, etc. What follows is an extract from one of my old electronics books in regard to differential amps:

" When operating as a single ended amplifier, the Q2(or the fet which gate is grounded in my case) common gate stage provides the voltage gain and Q1 stage provides the current gain. Since the whole circuit is biased by a current suorce, the voltage gain remains fairly constant over a wide range of frequencies. This, coupled with the fact that the common drain - common gate circuit has inherently good frequency response, results in a circuit characterizes by excellent voltage gain with high input and moderate output impedance and with excellent frequency response."

Initially I wanted to build the BoSoZ, but have great difficulties finding a 4-gang pot here Down Under. Then I examined the BoZ project and thought it would be a good starting point, but did not like one aspect of it - its output is inverted, which means that somewhere else along the system the signal must be inverted again to be in phase with the input. I know, many people will say that the absolute phase is notso important, but I'm from a different school.

Also the fact that I have no balanced sources or loads (read amps) with balanced inputs made me think about a simpler solution which will still achieve good results.

I haven't built the circuit yet, building it at the moment, but considering its simplicity I'll probably have a prototype by the end of the week.

The aim of my first post was to initiate a discussion about this circuit, about its pros and cons so to have a better idea whether I should go this path.

That's about all for the time being, thanks for your response.

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