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!
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IMO if it sounds good, then you're good to go. Any serious impedance mismatch would sound like there is something very wrong.

No matter what, you won't hurt anything with that setup as you have it.
tubed phono stage (2k ohms output) through a passive preamp into two Dayens Ampino mono blocks (100k ohms input).  
With the phono stage output impedance being high at 2kohms, I would search for a passive that uses a 20kohm volume control (potentiometer) not 10kohms one.
As it will still be a better match, and also still be a good match for the 100kohm of the poweramps.

Cheers George  
The low impedance is on the drive side so that is not a concern.
The output impedance of the source is 2kohm, so the load it should be at least a 20kohm passive. The the output of the passive will be fine with the 100kohm input of the poweramp. 

Cheers George
The output impedance of the source is 2kohm, so the load it should be at least a 20kohm passive. The the output of the passive will be fine with the 100kohm input of the poweramp.

George -

Ah ok - that makes sense.  Noob that I am, it did not occur to me that passive pre's have in and out impedance.  

Seems I'll either have to change pre-amps or the phono pre.  Maybe.  I have a Schiit Valhalla 2 that I can try too, but there's no spec on input impedance.  


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?  
Anyways, I really appreciate the help, all!  

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
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. 
"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 
"

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.


"

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

"
I mean, I'm running this through this Sys passive pre, and the there is plenty of volume.  I'm just wondering if I'm going to damage something...
But yeah - I see a bunch of phono pre-amps that are less than 100 ohms out, so 2 kilohms does seem like a big difference.  
subterranean6 OP9 posts02-17-2017 11:50amI mean, I’m running this through this Sys passive pre, and the there is plenty of volume. I’m just wondering if I’m going to damage something...
No, if you can do this then you have plenty of output from the phono stage. You would have a touch more output again if the the Schiit Sys was 20kohm instead of 10kohm, would’nt worry at all about then.

Just make sure the interconnects to and from the Schiit are low capacitance ones less than <100pf per ft which the specs should show, if not ring the maker he should know. An keep them less than <1.5mt.

Cheers George
Ah ok - that makes sense. Noob that I am, it did not occur to me that passive pre’s have in and out impedance.
Yes the input impedance (if wired in normal fashion) is the the value of the pot, in your case 10kohm. The output impedance (at worst) is around 2.5kohm.
That’s why in your case with a source of 2kohm out ,and amps of 100kohms in, a 20kohm passive pot would be the ideal. But you have enough volume so all is fine.

Cheers George
George - 

You're a Godsend.  Thank you so much!!

Sam