Audio Research Ref 3 Opinions

Hi Jeff, thanks for the clarification. Currently, I have my LS25MK2 mated to a Krell FPB300c. The new Ref 3 will be mated with the 700cx, so I guess it will be no trouble matching those 2? The specs for the REF3 are:

freq. response: 0.2 Hz to 200 Khz
Gain: 11.6 balanced (18db on ref2), 5.6 db SE (12bd on ref2)
impedance: 600 ohm balanced (400 ohm on ref 2)
max input: 20 v rms max (balanced) (14v on ref 2)
output: 2v rms into 200k ohm (2 v into 100k ohm on ref2)
noise: 2.7 uV (20 uV on ref 2)
tubes: 4x 6H30P (plus -1 each- 6L6GC and 6H30P in power supply)

Does anybody sees what these changes suggests?

Thanks, brgds, Marcelo

Marcello, if I understand things correctly, and the Ref 3 has an output impedance of 600 Ohms on the balanced outputs, this change makes the device meet the standard for balanced output impedance. I spoke to a friend of mine who is a pass lab dealer. He told me that the ratio between pre output impedance and amp input impedance need be only 1 to 10 for good results. So for example, as the Ref 3 has 600 Ohm output impedance, and the new Pass Labs X600.5 amps I am interested in have an input impedance of 22K Ohms, the two should, at least in theory, work well together, as the ratio is 1/30. Needless to say, my knowledge of the subject is rudimentary at best.

Hi Guido, mi knowledge is also very very limited, here I am, talking about impedances and gains while I have not really a clue how this 2 work toghether...

Anyway, I will be using the REF3 with a FPB700cx that I ordered to arrive toghether, and I can tell you that the Krell has an impedance input of 100 Kohms and the input sensitivity is almost 4v. If we consider that the AR pulls out 4v when having a 2 v input (this considering the 6 db gain on SE of the REF3 and considering, IF I´M NOT MISTAKEN that the 6 db gain means doubling the voltage), there should not be any problems...I guess...what a mess...

Using your formula of minimum 1:10 ratio, do I understand correctly that with a 600ohm output (REF3) and a 100kohm input (Krell) we have something like 1/160?
brgds,marcelo

Marcelo, you are likely correct, but our hypothesis need be verified by someone more knowledgeable than us. When do you expect to receive the two units?

Expected delivery at my place is late this week (maybe as late as friday or even saturday) but this will be confirmed to me tomorrow or tuesday.
Word is that both units should be in Spain by now....

I can't wait, I´ve been going around in circles thinking of the Ref 2 for a long time (well, not that long, I´ve only had the LS25MK2 for 1 year...), as well as upgrading the Krell 300c.
brgd, marcelo