How good is PCM54?

mudihan · 17th September 2007, 06:53 PM

How good is it soundwise? Especially it's Voltage Out? I am considering buying an old cd player with this chip and use its voltage out directly for sound (feed it to a 10k stepped attenuator).

Thank you!

Bernhard · 17th September 2007, 07:10 PM

PCM54 is like most other multibit DACs, 10% of them are good.
I think it has Iout so passive I/V or external I/V with modern opamp is possible. The player should have a pair and not only one...

mudihan · 17th September 2007, 09:25 PM

So using the Vout directly is not as good as using the Iout with modern op amps -- It makes sense since op amp inside the chip is not comparable to the modern ones.

As for a passive I/V, with regard to PCM54, what value of resistor should I use? Thank you!

mudihan · 17th September 2007, 10:02 PM

Also, would I need a buffer inbetween this passive i/v stage and my 10k stepped attenuator (is the voltage after the i/v stage strong enough, with regard to PCM54)? Thanks again!

Bernhard · 18th September 2007, 09:08 AM

Quote:

Originally posted by mudihan

As for a passive I/V, with regard to PCM54, what value of resistor should I use? Thank you!

500 ohm is a good starting point.
You could use a pot and check for distortion.

Bernhard · 18th September 2007, 09:09 AM

Quote:

Originally posted by mudihan
Also, would I need a buffer inbetween this passive i/v stage and my 10k stepped attenuator (is the voltage after the i/v stage strong enough, with regard to PCM54)? Thanks again!

A buffer with some gain after the filter.

17th September 2007, 06:53 PM	#1
mudihan diyAudio Member Join Date: Jan 2004 Location: Texas	How good is PCM54? How good is it soundwise? Especially it's Voltage Out? I am considering buying an old cd player with this chip and use its voltage out directly for sound (feed it to a 10k stepped attenuator). Thank you!

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17th September 2007, 07:10 PM	#2
Bernhard diyAudio Member Join Date: Apr 2002 Location: Munich	PCM54 is like most other multibit DACs, 10% of them are good. I think it has Iout so passive I/V or external I/V with modern opamp is possible. The player should have a pair and not only one...

17th September 2007, 09:25 PM	#3
mudihan diyAudio Member Join Date: Jan 2004 Location: Texas	So using the Vout directly is not as good as using the Iout with modern op amps -- It makes sense since op amp inside the chip is not comparable to the modern ones. As for a passive I/V, with regard to PCM54, what value of resistor should I use? Thank you!

17th September 2007, 10:02 PM	#4
mudihan diyAudio Member Join Date: Jan 2004 Location: Texas	Also, would I need a buffer inbetween this passive i/v stage and my 10k stepped attenuator (is the voltage after the i/v stage strong enough, with regard to PCM54)? Thanks again!

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