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Matching tube preamp to ss amp

First time of venturing into tubes and i'm a little confused on impedance matching, the pre amp is a Prima Luna Evo 100 with an output of 2800 ohms and the amp is a Nad 220 that I just had recapped with an input of 25Kohm It seems like it might not be the best match, which is why I'm putting this out to you folks that have far more knowledge, and I would like to know better before purchasing the preamp.
oldgzzrr
georgehifi's avatar
georgehifi
10,312 posts
 
Are you saying as is, these two would not be a good match?
Yes as they are they’re already borderline 1 : 10 (output to input) ratio. And with the coupling caps raising that 2800ohm output impedance even higher at low frequencies the bass quality "could" and probably will suffer. It would be far better if those Prima Luna output coupling caps were 2uf instead of .47uf.

Do get me wrong, it's safe to use it though.

Cheers George


lowrider57's avatar
lowrider57
5,418 posts
 
I agree with George, it’s borderline. Under normal conditions it shouldn’t be a problem, but during peaks and transients, there might be noticeably weak bass.

Don't play the 1812 Overture.


pmm
241 posts
 
There are plenty of tube preamps that have less than  2800 ohms output impedance.
jjss49's avatar
jjss49
6,612 posts
 
pmm is correct

conrad johnson tube pre's for instance, have for years made their low output impedance an important selling point

cj premier 16ls2 is <700 ohms
cj et5 is 100 ohms
mesch
3,530 posts
 
It is not be the best match, as others have said,  it is borderline. How low in the bass region do your speakers go? How do the pair sound to you? While saving for another amp. look into ones having input impedance of 50ohms or greater. 
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