Amp / Pre-amp Impedance Matching

dminches

Well-Known Member
Oct 22, 2011
1,959
929
455
Hopefully this question makes sense. I have an Ayre VX-R 20 amp and want to get a preamp to replace my Ayre K-5xe MP. The main reason why I am replacing the pre-amp is that I want one with a balance control since my seating position is off center and I don't have much flexibility to move the speakers.

Should I be paying close attention to the output impedance of the pre-amp? The K-5xe output impedance is 55 ohms per phase.

I have been looking at the BAT Vk-43SE which has an output impedance of 200 ohms per phase. I am also looking at the Bryston BP-26. I am not sure what the output impedance is for that unit.

The input impedance of the Ayre VX-R 20 is 1 Mohm per phase.
 

K3RMIT

Well-Known Member
Sep 4, 2020
372
116
48
aside of end sound yes absolutely may I ask what is the amps input imp and cable run type se or bal
the point is low preamp output imp to high input imp of amp. A general rule is 10 to 1 ratio with pre being 1 amp 10. this has a almost no effect of loading the preamp. some may say even more. i have a krell 700cx amp it’s input is 100 ohms
very low for an amp
it needs a preamp max 10 ohms output. i had to buy a krell preamp to match.
same goes for headphones to headphone amp. if the amp used is 10 ohms the headphone must be much higher or the tone is off badly.
i was going to try a imp iso transformer to make up the imp issue but I was advised it still would be bad.
I hope others here comment back I for one like real world experience beyond just theory.
ps the 2 preamps I had did not play well
 

dminches

Well-Known Member
Oct 22, 2011
1,959
929
455
aside of end sound yes absolutely may I ask what is the amps input imp and cable run type se or bal
the point is low preamp output imp to high input imp of amp. A general rule is 10 to 1 ratio with pre being 1 amp 10. this has a almost no effect of loading the preamp. some may say even more. i have a krell 700cx amp it’s input is 100 ohms
very low for an amp
it needs a preamp max 10 ohms output. i had to buy a krell preamp to match.
same goes for headphones to headphone amp. if the amp used is 10 ohms the headphone must be much higher or the tone is off badly.
i was going to try a imp iso transformer to make up the imp issue but I was advised it still would be bad.
I hope others here comment back I for one like real world experience beyond just theory.
ps the 2 preamps I had did not play well

The input impedance is 1 Mohm.
 

cpcat

Well-Known Member
Jun 20, 2016
85
99
125
South Carolina
One megaohm is extremely high and should match well with just about anything.
 

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