Driving 1 ohm


Hi,

I'm actually driving my recently refurbished Acoustat 2+2 electrostatic speakers with a Conrad Johnson MF 2500A. My Acoustats have been completely modernized with new more rigid frame, new electronics in the interface, Medallion transformers and other tweaks.They really get down low with a lot more dynamics than before.

A lot of electrostatics owners will often chose pure Class A amplifiers to drive the load these speakers command. The 2500A plays beautifully and doesn't get very hot at the task.

My question is : am I slowly damaging the amp without noticing it ?
andr
I have an amp you'd like I think that fits perfect for your speakers,Appogee's et al.1991 Krell KSA 300S.Only model Krell TRULY stable into 1 ohm they ever made (and you do the math that's doubling power for each load halving from 8 ohm nominal for a huge 2,400 watts!!).Class A of course and went for $9500 back in '91.Now you can get them for $3K to $3500.Others might prefer some subtleties of latter amps but signature Krell sound is same.Funny though they don't sound good at all with Maggies so being the ex Krell salesman that my friend turned to for his underpowered 3.6's I hooked him up with the classic Bryston/Maggie match.Ask Acoustat what Krell sound like with and if it's a go remember KSL was only true 1 ohm amp they made.I am using he Krell KRC2/KPE combo in one system but the amp I have has just sat in basement for 6 years.Maybe time to sell it all or separate.But there are others out there.
Cheers
chazz
A true high current amp will double it's output as speaker impedence halves. Some of the early Krells would double their load all the way to .5ohms. Some of the Apoggees were .5ohms.
Ha .5ohm you say?--bring back the oldies but goodies-- my Electro Research A75s would drive 0.25 Ohms load no problem all day!

The Primary of the Dayton Wright XG8 ELS transformers.

DesW
Rwwear, ESLs do not respond well if the amplifier can double its power as impedance is cut in half. It will result in no bass and too much highs. This is why tube amplifiers are often preferred for ESLs, despite the misguided attempts of several ESL manufacturers of making the speaker's impedance really low in an attempt to make them work better with transistors. The result is often a speaker that neither tubes nor transistors can actually make sound right.

For speakers like this tubes and a set of ZEROs are usually the best solution. See

http://www.zeroimpedance.com
and
http://www.atma-sphere.com/papers/paradigm_paper2.html
for more information.