High Current SS amps with input impedance = 200K

In the particular case of the Bel canto Ref 1000 Mk.2s, the 'moderate' peak current of 45 amps is deceptively low. . . As the 1000 Mk.2s have a balanced output with active positive and negative leads on the speaker terminals, the current is roughly equivalent to a 90 Amp peak for a more common non balance output design, where the active signal would be relegated to the positive terminal, while the negative is left to float. I have used the Bel canto babies on my big Vienna mahlers v1.5s, and the authority that they yield is something to be beheld.

Enjoy them, Mapman! G.

Thanks Guido,

For some reason, whenever I read "high current" I always picture the pure Class A massive heatsink monsters from the late 80's/early 90's like the Class DR-3VHC, Levinson ML-2, Krell KSA-100, etc.

I guess that caused me to associate high current with high heat and huge size.

Guido -- While I certainly don't question your subjective comments, I don't think that the statement that 45 amps from a balanced amp output is roughly equivalent to 90 amps from unbalanced amp outputs is correct. If the spec is 45 amps (and btw I don't see that spec at the Bel Canto site), a maximum of 45 amps (plus whatever margin is built into the specification) would flow between the amp's red speaker terminal and black speaker terminal, regardless of whether both of those terminals are actively driven, or only one of them is actively driven.

The specs I do see are 500W into 8 ohms, 1000W into 4 ohms, and a rated minimum load of 2 ohms. If we assume that 2000W can be delivered into 2 ohms, that corresponds to a current of 31.6 amps.

Mapman -- Congratulations on the new amps! Enjoy!

Darkmobius -- As you realize, Class D technology is at the opposite end of the spectrum, relative to Class A, in terms of the amount of power that can be delivered relative to the amp's size, weight, and heat generation. Your characterization of them as "voltage amplifiers," though, is correct in the sense that they typically have extremely low output impedances (or, equivalently, very high damping factors). That allows them to deliver an output voltage which is directly proportional to input voltage regardless of load impedance, within the limits of their current capability (which in this case is very substantial).

Regards,
-- Al

Thank you Al, the figures of 40 to 45 Amps on peak current are inline with published specs for ICEpower 1000 ASP offerings from several other manufacturers. It is worth while pointing out that the 1000 ASP module is capable of yielding a more/less continuous output of 500W, hence the 30.1 Amps max continuous current you have calculated, while the peak current of 45A is sustained only in short bursts, hence the seemingly discrepant figures of peak current vs max power rating. Regards, G.

al,

the 45 amp spec is published in the amp's user guide on the bel canto website.