High Current Amps

[macallan]

I have always read that high current is more important than total wattage for driving speakers, especially ESLs. I am currently using a B&K ref 200.2 to drive Klipsch speakers and would like to move to Vantages or Spires. I was wondering if the B&K would be sufficient for driving Logans so I called B&K. They mentioned that the B&K amp has 75 amps of current and would drive the Logans very well. So i looked up some other brands to compare and to my surprise the B&K is one of the highest current amps on the market, it is higher than Parasound, Bryston, McIntosh, and even the Krell Evolution series. Is this correct? How much current do you need? It seems odd that such a modest brand as B&K would be the leader in this regard.

 

[eknuds01]

It's hard to put a number on the exact amount of current.

One handy rule of thumb is that we like amps (SS amps) that double the wattage as the impedance gets cut in half. One thing to look at is how stable the amp gets when the impedance drops below 1 or 2 Ohms.

I am sure the B&K will do fine.

Erik

 

[marlin]

High current amps

I have noticed that many in this group use McIntosh amps. They rate their wattage the same no matter the impedance. I myself have a 7270.
Does this mean they are not a higher current amp? I don't remember seeing a spec on current output on their products.
I have no problem driving my AeonI's with it.

 

[macallan]

That is not what i am saying, Macs are awesome amps, i actually could not find specific measurments for current on the Mac but the B&K at 75 amps is pretty high, Krell is around 35, Parasound 60 etc. I was just surprised how high the current is on B&K.

 

[twich54]

Keep in mind the high current rating you refer to is a "peak-to-peak" rating, not continuous. Regardless your amp will be fine as far as power to drive Vantages.

Also remember this...with our Logans we are basically driving a large capacitance load with the ability to 'kickback' to the amplifier, thus the stability factor of ones amp is paramount. As Erik stated the ability of an amp to 'double down' its power with respect to 8 vs. 4ohm ratings is a welcome sign of stability.

Also the Voltage vs. Current (tube vs SS topology) is to be considered when looking at our hybrid with their powered bass modules thus allowing the tubes to "do their magic" on the panels.

 

[David Matz]

I have always read that high current is more important than total wattage for driving speakers, especially ESLs. I am currently using a B&K ref 200.2 to drive Klipsch speakers and would like to move to Vantages or Spires. I was wondering if the B&K would be sufficient for driving Logans so I called B&K. They mentioned that the B&K amp has 75 amps of current and would drive the Logans very well. So i looked up some other brands to compare and to my surprise the B&K is one of the highest current amps on the market, it is higher than Parasound, Bryston, McIntosh, and even the Krell Evolution series. Is this correct? How much current do you need? It seems odd that such a modest brand as B&K would be the leader in this regard.

Personally, I would not focus on the measurements. There is a lot more to music than measurements. Since no one understands all of the factors that affect reproduced music, there is no complete set of measurements that currently exists.

A few years back, the Japanese (Yamaha, Sony, etc.) released equipment that measured great but sounded awful.

It is best to pick a price point and to listen to as much stuff as possible at that price point. If you like what you hear, check the measurements.

Good Luck!

 

[C.A.P]

As Dave stated. Peak to peak is not the whole picture. Tubes can do wonders on the panels. B&K makes decent gear that goes a long way for the dollar. It will power your speakers fine. B&K has always made a good high current design. I have demoed them on several occasions. The older ones really had a good sound. Especially with Ribbons.

 

[nsgarch]

'reserve' current?

The "high current" amp thing vis-a-vis electrostats with big impedance dips (and not always at hi-freq. either as with ML's) really applies to conventional design SS amps. It does not apply to tube amps (OTL tube amps may be an exception, I'm not sure) and it does not apply to SS amps with autoformers (like many of the McIntosh SS amps have.)

The problem with 'normal' SS amps and stats is that as the impedance goes toward zero (even over a very limited frequency range) it starts to look to the output transistor(s) like a short circuit, which in a 'normal' SS amp are directly connected to the loudspeaker! Next, the amp goes into oscillation at the freq. in question and, poof! Blown output transistor.

If a SS amp has enough reserve current capability along with sophisticated protection circuits, it's usually safe to drive most stats, and it usually costs more than msrp $3000 these days ;-)

 

[gmartan]

Summits with McIntosh

I have noticed that many in this group use McIntosh amps. They rate their wattage the same no matter the impedance. I myself have a 7270.
Does this mean they are not a higher current amp? I don't remember seeing a spec on current output on their products.
I have no problem driving my AeonI's with it.

I had an all McIntosh system. I had to replace my MC402 with a Classe 3200 to get great sound. The transformers pretty much acted like a low pass filter when presented with the Summit's low impedence at high frequencies.