Zen Linestages, X and unbalanced operation

[Kilentra]

I admit a relative lack of understanding about balanced operation and X-feedback, so I'll ask a quick question: What is the usefulness of a "balanced" preamplifier when using single-ended connections for both input and output... and what would I have to do to a balanced circuit to get it to work that way (for the time being)?

See, I'm looking to build a good preamp, but at the moment I have unbalanced sources (CD player/DAC) and unbalanced-input amplifiers (Zen V4 and/or Holton's sym amp). Keeping my choices to Pass circuits at the moment, the BOSOZ seems to have a better reputation than the unbalanced-only BOZ... and now some of us have added "X" to that circuit. Will the BLS or X-BOSOZ work if I ground the unused input and leave the unused output disconnected? I could also load the unused output with something similar to the amp's input network, if that would help with the feedback. Even if it does work, does this waste the advantage of balanced operation? What about X, is is pointless trying to use that?

Thanks for the help.

[Henrik]

My advise to you is to build the BOSOZ, as long as you are driving it single ended at both input and output. But if you gets an balanced power amp, the you can X the BOSOZ, it´s an easy task to do this modification.
If you use a XBOSOZ with singleended output, then you woun´t benefit from the X, and all you gets is the usual Negative Feed Back, I have not tried this but my gess is that it woun´t sound the best.

[moe29]

Kilentra - go ahead and build the BZLS i'm using it as
single ended IN to single ended OUT and it sounds fine.
It also sound great single ended IN to balanced OUT when
i'm running my SOZ amps.

Henrik, is the X effective if you are using the BZLS as an
unbalanced to balanced converter? I never really thought of
that... there just seems to be so few truly balanced sources
to run the preamp fully balanced.

(is there a truly balanced CD player for under $1,000 US?)


moe29

[Henrik]

moe29

Read this post: http://www.diyaudio.com/forums/showt...5141#post75141

Regards Henrik

[moe29]

thanks Henrik! - i'd read that before, but reading it again in this
new light helps.

...now if someone could just post a step by step way to wire
my BOSOZ and SOZ to X i'd be happy

even so, i'm really enjoying them as they are.

BZLS = Most Valuable Player of the PASS DIY circuits


moe29

[protos]

Originally posted by moe29
(is there a truly balanced CD player for under $1,000 US?)


moe29

You might be able to find the Teac VRDS-25 used for less than that and it sounds really twice as good than single -ended driving the Bosoz in balanced mode.

[Taco]

Originally posted by protos


You might be able to find the Teac VRDS-25 used for less than that and it sounds really twice as good than single -ended driving the Bosoz in balanced mode.

But driving the Bosoz in balanced mode will get you a unbalanced output. Or am I missing something?

[Variac]

The ADCOM GCD-750 CD Player has balanced circuitry and outputs But it is about $1300 new.

[moe29]

Variac, i've seen that Adcom player and thought that might be
a nice pickup. I was really almost ready to buy a Sony SCD-1,
because it can play SACD's too. But then i saw where Mr. Pass
said that it sounded better through it's single ended outputs,
because it had to process the signal through extra circuitry to
get a balanced output. So i guess just because a player has
balanced outputs doesn't necessarily mean they are truly bal.

maybe it's not that big a deal. It seems like you get a lot of the
advantage of a balanced output using the BZLS as a converter.
I'll save the money spent on a source for experimenting with more
DIY projects! (like learning to X a BZLS)

---------------------
moe29

[Variac]

Yup, I'm going to use the XBOSOZ as a converter for the near future, Maybe if a great, universal format balanced player around $1000 comes out I'll be tempted

I'm pretty sure that the Adcom is truly a balanced circuit, and from a series that includes the preamp using a Nelson Pass circuit, so it seems it would play well with our DIY Pass projects.