2. amps-preamps
  3. 135945-9672

Current, Amperage


I’m trying to make sense of the argument about various types of speakers [ sensitivity, brand, etc ] and their relationship with power/ current/ amperage.

Can someone please provide some basic perspective.

I have a 91.5db tall floor speaker [ Focal Chorus 826V ] and what should I look for in an amp to drive these? How much power do I really need with all things being equal? I use a VTL tube 2.5 amp if that matters to the discussion.

Thank you.
adman227
Post removed 
g_nakamoto's avatar
g_nakamoto
348 posts
 
i have a mcintosh mc602 power amp. it has 150 amperes per chanell. where does this stand in power amps?
kalali's avatar
kalali
1,977 posts
 
The amperes/channel spec is basically meaningless along with most other ampere ratings. Current is a function of (ohm) load and will swing as the load varies across the frequency range. My rule of thumb is picking a reputable (voltage source) amp that doubles its power as the load is halved is usually a good starting point. Adding a class A design is icing on the top if the extra heat is not a concern. Current source amp tend to pair much better with (very) high efficiency single driver speakers, based on my albeit limited experience.
almarg's avatar
Ag insider logo xs@2x
almarg
9,670 posts
 
Kalali 5-12-2018
The amperes/channel spec is basically meaningless along with most other ampere ratings.
+1.

Amplifier current ratings are meaningless and should almost always be ignored. For example, as stated above the MC602 is described as being capable of providing 150 amperes. 150 amps into 2 ohms corresponds to 45,000 watts. 150 amps into 4 ohms corresponds to 90,000 watts. 150 amps into 8 ohms corresponds to 180,000 watts! Meanwhile the amplifier’s rated continuous power capability is 600 watts into any of those impedances, and it is described as being capable of providing 1000 watts on tone bursts.

What the 150 ampere number most likely represents is how much current can be supplied into a short circuit (zero ohms) for an unspecified number of milliseconds (thousandths of a second), at which point the amplifier’s self-protection mechanisms would shut it down. And according to comments Ralph (Atmasphere) has made in the past about amplifier current ratings in general, it may not even represent that capability at the output of the amplifier, but rather at the output of its internal power supply.

Regards,
-- Al
adman227 OP
22 posts
 
@Kosst_Amojan

Thanks for the feedback; What about a Class D amp in terms of WPC. 
I realize all of this has a high number of variables built in.

Anyone else care to opine on this topic? 

Does anyone know what the 'Class' rating is for the Mcintosh MC252 ?

Thank you. 
More to discover