balance zen line stage input and output

[hc167]

hi:

I am new here. so if I ask something stupid, please forgive me. I want to build a PASS balance zen line stage preamp. and wondering how do I do it with unbalance input and unbalance output? let's say that my amp will have one input and one output, so how do I construct it in a way that the input and output can support both balance and unbalance? thanks a lot for any kind of help.

additional question, what do you think will be the match pass lab diy power amp for this preamp?

 

[Zen Mod]

ancient approach from Pro world:
make it balanced input and balanced output
make balanced volumes and balanced selectors
use XLRs for both input and output case connectors

then-if you use balanced source (or load) connect it balanced
accordingly -if you use unbal source (or load ) just tie minus and ground on CABLE xlr plug.....

 

[hc167]

this will work too, but my objective is to have both unbalanced and balanced input/output for the preamp that I am going to DIY. for example, I want my pre-out to have both XLR and RCA connectors. Is there any possible ways to do that?

 

[hifimaker]

Read Neson's BOSOZ construction guide on www.passdiy.com. THe BOSOZ manual is here: http://www.passdiy.com/pdf/balzenpre.pdf

I've built this BOSOZ as stated in the manual with both balanced and unbalanced in and out. My source selector has balanced in for 1 input and 3 unbalanced inputs.

Good luck,

-David

 

[thomasfw]

Dear HC167,
The attached may be what you want ?

Thomas

 

[hc167]

dw8083:

sorry but I was not able to find anything about balanced and unbalanced input/output physical connection information. This is what I can found so far from the file.

So is this the anticipated Bride of the Son of Zen? I suppose it is. It has
an identical topology and is perfectly suited for driving the Son of Zen,
but there is much utility to this circuit. It also serves as a nice balancedin
to unbalanced-out or unbalanced-in to balanced-out converter.

and also the following.

The circuit amplifies a differential input to a differential output. Given a
single input, it will amplify it into a balanced differential output, and is
useful to convert unbalanced signal to balanced, either because you
wish balanced operation or because you wish to convert a conventional
stereo amplifier into mono bridged operation.
Of course the circuit is happy accepting a balanced input, and besides
using it as simply a balanced gain stage, you can choose to view either
output polarity as a single-ended output of each phase. Thus the circuit
also functions as a general balanced and unbalanced converter.



But I do not understand how do I construct it in a way to support both balanced and unbalanced. sorry that I was being stupid

 

[hc167]

thomasfw:

your diagram made sense. and is definitly something that I can consider. but, what if I want both balanced and unbalanced preamp output? With this design, is that mean I have to have a switch (or selector) to control the output signal go to my RCA jack or the XLR plug? I just want to have a design that made sense. sorry if I ask stupid question again.

 

[Zen Mod]

you really didn't understand what I wrote or what?
if you use strictly balanced topology with connectors on case,volumes and selectors,then for bal-unbal switching you just use xlrs (cannons) on cable ends.........
what ever you (or anybody else) do-can't be simpler and tidier;

in any case-you can have both style of connectors in parallel ;switching to unbal is easy-just put shorts in appropriate XLR or put switches for that purpose (instead shorts)

 

[hc167]

Zen Mod :

from the wiring connection point of view. I understand what you said. however, in the document (http://www.passdiy.com/pdf/balzenpre.pdf) of balance zen line stage, it mentioned that "It also serves as a nice balanced in to unbalanced-out or unbalanced-in to balanced-out converter." I am just wondering if I want to take advantage of this part of circuit, how am I suppose to do that, the document did not mentioned anything like that. I just want to take the advantage of the original design.

 

[Zen Mod]

Zen Mod :

from the wiring connection point of view. I understand what you said. however, in the document (http://www.passdiy.com/pdf/balzenpre.pdf) of balance zen line stage, it mentioned that "It also serves as a nice balanced in to unbalanced-out or unbalanced-in to balanced-out converter." I am just wondering if I want to take advantage of this part of circuit, how am I suppose to do that, the document did not mentioned anything like that. I just want to take the advantage of the original design.

OK

regarding wondering----- easy-just ground minus leg of input (or output -depending what you need)

 

[hifimaker]

dw8083:

sorry but I was not able to find anything about balanced and unbalanced input/output physical connection information. This is what I can found so far from the file.

So is this the anticipated Bride of the Son of Zen? I suppose it is. It has
an identical topology and is perfectly suited for driving the Son of Zen,
but there is much utility to this circuit. It also serves as a nice balancedin
to unbalanced-out or unbalanced-in to balanced-out converter.

and also the following.

The circuit amplifies a differential input to a differential output. Given a
single input, it will amplify it into a balanced differential output, and is
useful to convert unbalanced signal to balanced, either because you
wish balanced operation or because you wish to convert a conventional
stereo amplifier into mono bridged operation.
Of course the circuit is happy accepting a balanced input, and besides
using it as simply a balanced gain stage, you can choose to view either
output polarity as a single-ended output of each phase. Thus the circuit
also functions as a general balanced and unbalanced converter.



But I do not understand how do I construct it in a way to support both balanced and unbalanced. sorry that I was being stupid

Hi hc167,

Please read the whole document, all of your questions are answered in the text. Nelson's construction article is very detailed and comprehensive.

From page 6:

"Speaking of input and output connections, I have not specified connector types for this project. Usually for this sort of project I use both XLR and RCA connectors on both the inputs and outputs. The inputs are female XLR with pin 2 = plus, 3 = minus, and 1 = ground. At the output it is a male XLR connector. In parallel with the XLR connectors are 2 RCA connectors, one for each polarity, with XLR pin 2 connected to the "live" of the sitive RCA and pin and XLR pin 3 connected to the "live" of the negative RCA. XLR pin 1 is attached to the grounds of both RCA connectors. These grounds are isolated from chassis ground. The case of the XLR connector, if metal, and shield are attached to chassis ground."

Good luck!

-David