2. amps-preamps
  3. 1323999458

Have I mismatched my preamp/amp?

Hey all; I recently purchased a Cary SLP-50B which I will be mating to a Rawson clone of the Pass Aleph 2. When I started doing the math, I know I'm slow, I looked up the output impedance of the Cary and its Aleph 2 from the Pass site and it's 2.2 K Ohms I checked the Pass site for the Aleph 2, being I don't have the exact spec on the Rawson, and the input impedance is 10 K Ohms unbalanced and 25 K Ohms balanced differential. The Cary only has unbalanced outputs. So, how mismatched is this? I understand the 20:1 rule and I'm way off. My point was to use the Cary to warm up the sound a bit of the Rawson, its brutally sharp and I thought warming it up was a good idea. Advice/Comments are welcome. Jack
fz1jmp
atmasphere's avatar
atmasphere
11,944 posts
 
Those are pretty amazing output impedances for any preamp, let alone a tube one, how does he do it?

Lots of feedback. But if you check the 20Hz output impedance you will find it to be higher.
marakanetz's avatar
marakanetz
5,473 posts
 
Atmasphere,
Isn't it more important to have minimized feedback on power amp vs. preamp?
As far as I know, the differential preamp stages have 100% feedback... Why do engineers need to avoid it technically?
unsound
7,333 posts
 
http://www.diyaudio.com/forums/pass-labs/133067-someones-diy-aleph-j-sale.html
fz1jmp OP
33 posts
 
OK, received the Cary and took a long long listen. As the ears are the true test, hear goes (pun intended); did what I wanted it to do. Before the sound was what I considered sharp and I did not hear the space between sound. When I qued up Cowboy Junkies "Trinity Revisited" well honestly I've listened to it since it came out 4 or so years ago and never heard it before! The space between Margo's voice is palpable, the harmony, and Natalie's voice is breath taking. The sharpness has been replaced with rich thick sound, clear, but smoother. I have telsa tubes in and have ordered some more, just to play. I'm very happy with the outcome, so thanks for the opinions, comments and slight moral dilemma.
pubul57
3,712 posts
 
Now that is a nice way to settle into the holidays. Cheers!
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