Audio Research Ref 3 Opinions

I ordered a new REF 2 just before the new year, matter of fact, I didn´t know (neither my local shop) that the REF 3 was available, so originally I ordered a REF 2 and only early this week, when the shipment was suppoused to leave the States, we found out of the new REF 3. It´s on its way now, expected arrival by saturday next week toghether with a Krell 700 cx...I cannot wait!
Now, I have a question: I received the specs by fax yesterday from AR (incredible service, one call and 2 minutes later, 3 pages on my machine) and can see that there are several differences on the specs when compared to the REF 2. Specifically, the ones that rings me a bell are gain (lower than ref 2), higher impedance output than the ref 2. Can anyone enlighten me with what does these differences mean? I can post the specs here if needed, yesterday were not listed on the ARC Data Base.
thanks!
Brgds, Marcelo
Spain

The lower gain is probably no big deal, but the higher output impedance might make a difference if you decided to pair the preamp with a solid state power amp. The Ref 2 has an output impedance of 400 ohms and ARC suggests a minimum of 20k ohms input impedance for a power amp. ( 50/1 ratio) In balanced mode Pass Labs amps are 22k and some manufacturers offer amps below this figure. Most tube amps , including ARC come in at about 100k . In any event enjoy your new treasure.
Jeff

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