Audio reserch reference 3....driving Nagra VPA amp

Hello Nick , just be sure the input impedance of the Nagra is 100kOhm or more to get full profit of the lower frequencies .Unfort.the side of Nagra did not tell the info about the input.ARC will tell you why the input imp.of the poweramp should be more than 100 kOhm.
Greetings Hans

The Nagra has input impedence an sensivity below:

Input sensitivity: 400mV for maximum power. Input impedance: 100k ohms

the reference 3' output below:
OUTPUT IMPEDANCE: 600 ohms Balanced, 300 ohms SE main (2), 20K ohms minimum load and 2000pF maximum capacitance

The Nagra has only Balanced in's and thats the way i want to drive them trough the reference 3, so basicaly 600 Ohms in balanced mode for the output.
I want to drive a pair of TAD horn speakers, 2 15" woofers with a compression loaded 2" horn.
Their Nominal impedence is 4 Ohm's and the sensivity rated at 98Db.

be careful, especially since you can't listen before buying

One of my friend used to own a pair of Nagra VPA 845 monoblocks driving a pair of Tannoy Westminster Royal SE's at 99db sensitivity driving 1 x 15 inch driver.

He found while the Nagra's were very nice, they could not really drive the Tannoy's properly and sold them a couple of years back.

YOur speakers with 2 x 25inch drivers may be a harder task to drive successfully.

The Nagra has unblanced inputs also. The earlier series only had balanced ins. I have a later set, and it has both balanced and unbalanced.

Wonderful amps.