Impedance match

Matching concerns for all passive preamps is even more critical, if one doesn’t get at least a 1:6 ratio or higher from source to input and from output to amp then the wrong conclusions will be drawn about passives and the way they sound.

If done right they will give more transparency and better dynamics than preamps can hope to give. And save you a great deal of money as well by not buying $$$$K active preamps.

Better still is going direct if your source has a volume control, but there are things to look out for here too. As well as hearing your source without preamp colourations, you may not like it's sound, as it's ruthlessly revealing and dynamic.

Cheers George

Yes when the output impedance to input impedance (O/I)  ratio got down to 1:5 then a couple listeners said they could hear the dynamics may have been getting a little effected, but they said it was very small and don't think they could of blind A/B'd it.
But most of the 40 odd listeners said they could just detect 1:3 ratio. So a safe bet would be say 1:6 or higher.

Cheers George 

 

noble100

    I always read and was taught by members here that the guideline was at least 10x but will work well together with anything greater, too. Identical match is definitely not correct.

With source to pre, pre to amp.
Once you have a "Output to Input" impedance ratio of say 1:10 or more, your fine.
 
We had a large participant demo at our audio society meeting, about 35-40 "golden ear'ed" audiophiles were present.
I designed a switchable on the fly input impedance changer on an excellent amp that was in a very good system.
 
This impedance changer change the "O/I" impedance ratio in 20 increments from 1:100 down to 1:5. It was at 1:5 that only two "super golden ear'ed" audiophiles "thought" they could hear a difference for the worse, but they also both said they probably couldn't pick it in a blind A/B.
All said they heard a difference at 1:3.
AC levels were checked to the mV for all ratios to be the same.

Cheers George