Penultimate Zen SNR?

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#4
amo said:
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
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#5
Re: Re: Penultimate Zen SNR?

Panelhead said:
amo said:
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
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Thanks. Where can I find information on a C-L-C filter?
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#6
Re: Re: Re: Penultimate Zen SNR?

amo said:


Thanks. Where can I find information on a C-L-C filter?
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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
 
#7
amo said:
my calcultion puts it around -80dB... Does this sound right???
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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.

😎
 
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