[oldmp3]

I'd like to drive a Rotel RB-1080 directly from an EE MiniMax DAC with volume control, but am concerned about impedance matching.

Although some members do not recommend driving any amp directly from the MiniMax (http://www.audiocircle.com/index.php?topic=72820.msg874742#msg874742
), at least one reviewer has had success (http://www.6moons.com/audioreviews/easternelectric/dac.html).

The RB-1080 has measured input impedance of 34k to 38k  ohms, while the MiniMax DAC has a rated output impedance of 22K ohms. The DAC tube output impedance has been measured at 7.5 to 12k ohms. Don't know about the solid state output.

Best case ratio appears to be 1:5. 

What are your thoughts or recommendations?

Thanks.

[wilsynet]

1 to 5 is not nearly good enough.  You want 1:20.

[cheap-Jack]

Hi.

I'd like to drive a Rotel RB-1080 directly from an EE MiniMax DAC with volume control, but am concerned about impedance matching.

Although some members do not recommend driving any amp directly from the MiniMax (http://www.audiocircle.com/index.php?topic=72820.msg874742#msg874742
), at least one reviewer has had success (http://www.6moons.com/audioreviews/easternelectric/dac.html).

The RB-1080 has measured input impedance of 34k to 38k  ohms, while the MiniMax DAC has a rated output impedance of 22K ohms. The DAC tube output impedance has been measured at 7.5 to 12k ohms. Don't know about the solid state output.

Best case ratio appears to be 1:5. 

What are your thoughts or recommendations?

Thanks.

Normally O/P Z: I/P Z not less than 1:10 should be OK.

The problem is many SS amps I/P Z is way too low vs high I/P Z of a tube amp.
So direct driving the low I/P Z SS amp will cause the driving voltage drop bigtime.

That said, I still suggest you to try it out with tube O/P direct driving yr SS amp & see how it sounds. If no good, you may need to add a low O/P Z buffer.

c-J

[oldmp3]

Thank you folks, I know this may be on (or over) the edge.  1 meter cables between DAC and amp.

[oldmp3]

I've since found the DAC's SS output impedance rated at 10k ohms, the Rotel's input impedance to be 34k ohms.  So this is just a little better than 3:1.

It sounds fine in this configuration, but I'm wondering what if anything is missing due to the very low impedance ratio...

[setamp]

I am running the tube output stage of my Minimax into a Beta22 headphone amp with 50k ohm Z for a 1:2.5 ratio.  What differences would I hear if I inserted a preamp or buffer to move this to 1:10 ?