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-   -   Penultimate Zen SNR? (http://www.diyaudio.com/forums/pass-labs/17718-penultimate-zen-snr.html)

amo 15th July 2003 12:37 AM

Penultimate Zen SNR?
 
Has anyone measured the SNR for Penultimate Zen? The documentation states 35mv... I do not know much about this, but my calcultion puts it around -80dB... Does this sound right???

Thanks!

Nelson Pass 15th July 2003 12:41 AM

The text says 35 micro Volts.

amo 15th July 2003 12:51 AM

Sorry, thats what I meant.

Panelhead 15th July 2003 12:56 AM

Re: Penultimate Zen SNR?
 
[QUOTE]Originally posted by amo
[B]Has anyone measured the SNR for Penultimate Zen? The documentation states 35mv... I do not know much about this, but my calcultion puts it around -80dB... Does this sound right???

I do not have the equipment to measure it. But I have a Croft OTL amp that HI-FI World measured the S/N at 107 db. My Zen V4 with a C-L-C filter is just as quiet.
My speakers are 100 db efficicent and the Zen V4 is silent paired with them. No hum or any transients on power up or down. I was surprised that charging the output cap did not produce noise on power up.

George

amo 15th July 2003 01:30 AM

Re: Re: Penultimate Zen SNR?
 
[QUOTE]Originally posted by Panelhead
[B]
Quote:

Originally posted by amo
Has anyone measured the SNR for Penultimate Zen? The documentation states 35mv... I do not know much about this, but my calcultion puts it around -80dB... Does this sound right???

I do not have the equipment to measure it. But I have a Croft OTL amp that HI-FI World measured the S/N at 107 db. My Zen V4 with a C-L-C filter is just as quiet.
My speakers are 100 db efficicent and the Zen V4 is silent paired with them. No hum or any transients on power up or down. I was surprised that charging the output cap did not produce noise on power up.

George

Thanks. Where can I find information on a C-L-C filter?

Panelhead 15th July 2003 02:34 AM

Re: Re: Re: Penultimate Zen SNR?
 
Quote:

Originally posted by amo


Thanks. Where can I find information on a C-L-C filter?

A C-L-C filter is a cap input, choke (L), cap filter. The circuit shows a single 22,000 ufd cap after the rectifier bridge and then the Zen V4.
Suitable chokes are not real common anymore. I used a 10,000 ufd cap, 2.6 mH 6 amp choke, and a 10,000 ufd cap.
This may be overkill. The series regulaor in the V4 does not really need more filtering.

George

Nelson Pass 15th July 2003 08:21 PM

Re: Penultimate Zen SNR?
 
Quote:

Originally posted by amo
my calcultion puts it around -80dB... Does this sound right???

Assuming a 25 watt ZV4, its output would be about 14 volts,
and comparing this to 35 microvolts, the SNR would be

SNR = 20 * log ( 35 uV/14V)

SNR = 20 * log ( .0000025)

SNR = 20 * -5.6

SNR = -112 dB

I think that's about right.

:cool:


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