The REX has a 200 Ohm output impedance and the Lamm M1.2 1 41,000 Ohm input impedance. This ratio (>20x) should be fine.
12 responses Add your response
Thanks Classic Jazz and Sarcher30 for the reply. The only reason I was concerned because with my BAT32SE I had background hiss sound at moderate listning seating position (8ft)which used to appear and dissappear randomly at certain volume levels and I suspected mismatch in gain as one of the causes. Anyway once I hookup my Rex i will post on my Virtual system forum thread regarding its performance and synergy with my Lamm 1.2
Unless BAT has made some modifications since this review: http://stereophile.com/tubepreamps/208bat/index4.html, its output impedance is:
However, its output impedance was a little higher than specified, at 1000 ohms at 20kHz, 415 ohms at 1kHz, and 4.8k ohms at 20Hz. The last is due to the necessarily finite size of the output coupling capacitors. As MF noted, it should not be a significant issue in listening to music as long as the power amplifier has an input impedance greater than about 50k ohms. (BAT's own power amplifiers have input impedances well above 100k ohms.)
It looks like you'll lose bass with this combination. It'll also be more sensitive to interconnect cables. Looks like a poor choice to me.
I think this shows the value of JA's work at Stereophile. He's compiled a great resource.
Impedance being a function of frequency, manufacturers can easily quote an optimistic value. Even if the frequency at which the impedance is measured is specified, there's no way of knowing if the value is worst case or best case or who knows.
Why not just ask Victor Khomenko of BAT(he's the VK in their product names), he posts regularly on Audio Asylum in the Tubes and Amp/Preampss forums. He'll give a straight answer on this. Here is latest post two days ago
I am also using a BAT Rex, but with solid state amplifiers. People say you cannot get tube-like sound with solid state amps, but I beg to differ. Perhaps it is because of the overbuilt power supply on the Rex. The Rex adds the texture, depth, and note decay without overdoing it. The build quality is also a benchmark for tube equipment. I have not added aftermarket powercords yet, but I bet there will be much more clarity, transparency, and bass impact.
Avsource1, congrats! If you like what you hear now wait 2-3 months. Someday you will be sitting and listening thinking to yourself, "wow, my system sounds absolutely awesome."
I am using the REX with a Spectron MKII amp and totally satisfied but always looking for small improvements. I have ordered some Elrod Gold Statement power cords for my REX and BAT CD player. I will be posting my impressions in the future.