Zen pre-amplifier help

Vivek · 18th March 2005, 05:13 PM

Hi all,
I have just bought parts to build the Balanced Zen Line Stage to go with a power amp I built at home. I read the article from Mr Pass but I do not understand one thing. I do not want to use the balanced inputs/outputs. I want to use just unbalanced RCA inputs/outputs. There is a plus and minus for the input and output. Which one do I use for balanced operation.
Suppose I decide to use the balanced input/output, how do I connect my CD player's RCA plugs. I am totally confused. Please help and thanks in advance.

Cheers,
Vivek

Alain Dupont · 18th March 2005, 06:16 PM

Vivek
Balanced Zen Line Stage

I want to use just unbalanced RCA inputs/outputs.

Just look at the attached Schematic.
Use the + input to plug the CD player...

Alain.

Alain Dupont · 18th March 2005, 06:19 PM

And only Unbalanced Input and Output...

Alain.

stefanobilliani · 18th March 2005, 06:23 PM

Quote:

Originally posted by Vivek
Hi all,
I want to use just unbalanced RCA inputs/outputs.
Cheers,
Vivek

Hallo Vivek ,

look at attacched schematic in previous post :
if you like to use also RCA ( unbalanced ) at the output of the preamp , use the + signal and leave unused the other ( - signal) .

stefanobilliani · 18th March 2005, 06:28 PM

Quote:

Originally posted by Alain Dupont
And only Unbalanced Input and Output...

Alain.

... many thanks ! I was just slow in posting.

Alain Dupont · 18th March 2005, 06:35 PM

And more, for a very long time Master Nelson has said:

"The better converter for Unbalanced to Balanced and reverse is a Bosoz"

if you look at the release schematic of the X2 ....

It uses balanced to Unbalanced Bosoz then the attenuator {unbalanced}

and the outouts are Unbalanced to Balanced... Bosoz "encore"

Wouahh... thats a marvelous thing !!!! ingenuity, and simplicity.

Add a 1 or 2 CCS to this preparation, and you get a "master class" preamp.

Alain.

Vivek · 19th March 2005, 04:49 AM

Hi guys,
So I just use the + input and + output for unbalanced operation, leaving the - input and - output free. Is that correct?
Few more questions.
Will pots just at the output be good enough to use as a volume control?
In India it is difficult to get fancy pots like the Blue Alps. And I think ordinary carbon pots will introduce distortion. Will a stepped attenuator with 1% metal film resistors work well?
Thanks again.

Vivek

Raoul · 19th March 2005, 06:16 AM

I am using one of the Taiwanese stepped attentuator (eBay special) at the output my BZLS. It is built with 1% Dale resistors. Works fine.

Note: Some have reported clicks when adjusting these attenuators. Mine is silent during adjustment. Luck of the draw, I guess.

edit: I think there are a few threads which discuss the best type of attenuator for the BZLS, as well as the Aleph P. Nelson even chimed a few times, if I remember correctly. A search might turn up something.

JEKYLL · 19th March 2005, 08:15 AM

It is recommended to put the -Input to ground for unbalanced operation.

Alain Dupont · 19th March 2005, 11:13 AM

Vivek,

>> So I just use the + input and + output for unbalanced operation,
>> leaving the - input and - output free. Is that correct?

No, in this case you have to ground the - input with a 220 Ohms...

Regards.

Alain.

18th March 2005, 05:13 PM	#1
Vivek diyAudio Member Join Date: Nov 2000 Location: Bangalore, India	Zen pre-amplifier help Hi all, I have just bought parts to build the Balanced Zen Line Stage to go with a power amp I built at home. I read the article from Mr Pass but I do not understand one thing. I do not want to use the balanced inputs/outputs. I want to use just unbalanced RCA inputs/outputs. There is a plus and minus for the input and output. Which one do I use for balanced operation. Suppose I decide to use the balanced input/output, how do I connect my CD player's RCA plugs. I am totally confused. Please help and thanks in advance. Cheers, Vivek __________________ Thank God for DIY audio.

19th March 2005, 04:49 AM	#7
Vivek diyAudio Member Join Date: Nov 2000 Location: Bangalore, India	Hi guys, So I just use the + input and + output for unbalanced operation, leaving the - input and - output free. Is that correct? Few more questions. Will pots just at the output be good enough to use as a volume control? In India it is difficult to get fancy pots like the Blue Alps. And I think ordinary carbon pots will introduce distortion. Will a stepped attenuator with 1% metal film resistors work well? Thanks again. Vivek __________________ Thank God for DIY audio.

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18th March 2005, 06:35 PM	#6
Alain Dupont diyAudio Member Join Date: Sep 2003 Location: Paris - France	And more, for a very long time Master Nelson has said: "The better converter for Unbalanced to Balanced and reverse is a Bosoz" if you look at the release schematic of the X2 .... It uses balanced to Unbalanced Bosoz then the attenuator {unbalanced} and the outouts are Unbalanced to Balanced... Bosoz "encore" Wouahh... thats a marvelous thing !!!! ingenuity, and simplicity. Add a 1 or 2 CCS to this preparation, and you get a "master class" preamp. Alain.

19th March 2005, 06:16 AM	#8
Raoul diyAudio Member Join Date: Feb 2003 Location: OR	I am using one of the Taiwanese stepped attentuator (eBay special) at the output my BZLS. It is built with 1% Dale resistors. Works fine. Note: Some have reported clicks when adjusting these attenuators. Mine is silent during adjustment. Luck of the draw, I guess. edit: I think there are a few threads which discuss the best type of attenuator for the BZLS, as well as the Aleph P. Nelson even chimed a few times, if I remember correctly. A search might turn up something.

19th March 2005, 08:15 AM	#9
JEKYLL diyAudio Member Join Date: Jan 2004 Location: FRANCE	It is recommended to put the -Input to ground for unbalanced operation.

19th March 2005, 11:13 AM	#10
Alain Dupont diyAudio Member Join Date: Sep 2003 Location: Paris - France	Vivek, >> So I just use the + input and + output for unbalanced operation, >> leaving the - input and - output free. Is that correct? No, in this case you have to ground the - input with a 220 Ohms... Regards. Alain.

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