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Impedance matching between 2k ohm phono pre and 100k ohm amps via passive pre

Howdy - 

I have a noob question about passive preamps.  

I am running my Wright Sound wp200c tubed phono stage (2k ohms output) through a passive preamp into two Dayens Ampino mono blocks (100k ohms input).  

It sounds good to my ears, but just wondering if this raises red flags to anyone?  Tortuga Audio says the ratio of amp to source should be more like 100:1, and I'm at 200:1 right now.  Cables are less than three feet. 

Thanks!
subterranean6
georgehifi's avatar
georgehifi
4,966 posts
 

George -

If I’m putting 2k ohm into a passive pre with an input impedance rated at 10k ohm, it means I’m not going to get 100% of the bandwidth? Signal?
Yes you will.
Just that you may loose a "little" total level (no dynamic loss) from the output of the phono stage.
 As it’s "starting" to become a voltage divider with 2kohm into 10kohm, if you have plenty of voltage (>2v) to start with, it doesn’t matter.
But from my experience a phono stages generally has less voltage output than cdp’s or dac’s.
So better to go a 20kohm passive volume control.

Cheers George
subterranean6's avatar
subterranean6 OP
13 posts
 
George - 

Thanks so much for your response!

It seems this phono pre is a little weird in having 2k ohms out.  Manual does say it can "drive loads down to 600 ohms".  And it has gain knobs I can play around with.  

I'll keep playing with it. 
georgehifi's avatar
georgehifi
4,966 posts
 
"drive loads down to 600 ohms"  
!!!!! yikes. This is c**p if it's 2kohm output impedance, (say I said before about being a voltage divider) you'll end up with very little output.

Are you sure the phono is 2kohms output impedance, or does it say 2kohm minimum load impedance?

Cheers George 
subterranean6's avatar
subterranean6 OP
13 posts
 
"

Output impedance:
2 kilohms nominal; will drive loads down to 600 ohms with slight loss of output level.

"

Yeah, it's pretty 'hot'.  Gain is only at 9 pm and I have plenty of volume.


subterranean6's avatar
subterranean6 OP
13 posts
 
"

This is a low-impedance output (nominally 2 kilohms) that can easily drive any standard vacuum-tube or solid-state amplifier.

"
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