F5 & ESL 57

Status
Not open for further replies.
Jump to Latest
#6
ESL 57 Impedance

The impedance ranges from 60 ohms in the bass region to 1.8 ohms in the treble region. They can be driven well from 15-25 watts of amplifier power, but the amplifier must be stable into a low impedance at high frequency. Does that describe the F5?

Brian
 
#10
Why F5?

Why F5? Because higher powered amps can cause arcing and the 25 watt rating of the F5 seemed just right. Two amps from long ago that have the reputation of a good fit with the ESL 57s are the Bedini 25/25 and the Mark Levlinson ML-20 - both in the same power range. So if the F5 does the job with the difficult load, it would be ideal (and I already have Peter Daniel's F5 boards).

Brian
 
#11
Yes- that was me that wrote that review - and I had both the Naksa and the F5 together at the same time. The Naksa is really very very good. Its a pre-built kit so the initial cost is a bit more, but all you need do is add Tx and connectors.

Hugh is also involved in this amp: http://www.diyaudio.com/forums/aksa/191053-swordfishy-aspen-fetzilla-power-amp.html

I'd bet it would sound good too......

F5 though is a nice build and will suit a lot of speakers.

Fran
 
#13
Oooh would be very hard to choose. Both sound different but very good. The higher power rating of the naksa might make it more compatible with more speakers but I've used the F5 with a good few speakers and it always sounds excellent. First time it suffered was with the stacked 57s. Treble went harsh and I also took out a few source resistors. Probably due to some kind of oscillation with the load?

Anyway both sound great. Note that the F5 throws out a fair bit of heat, but the naksa runs barely warm.
 
#16
How about the Quad 303? Cheap and good and plentiful.

I would suggest you look for amps designed to go with the ESL 57, some can be had for very reasonable prices.

The Quad 303 and the ESL 57 are a special combination not to be over looked on price and practicality grounds. Leak 30 series amplifiers are a good cheap option, and Sugden also design their amplifiers for the Quad speakers, I think Sugden stuff is higher quality sound than Quad Amplifiers which are more ergonomic than the fiddly Sugden. JLH Class A amplifier I had as a student sounded wonderful with them best option in my opinion, though I never finished the project amplifier project due to money. Higher powered amps are often a very bad combination with the ESL 57, apart from fear of damage they often sound distorted. As an atypical example I would recommend against the Quad 405, which fails in a similar but different way from other amplifiers of higher or similar power range with the ESL 57's. Remember that amplifiers specifically designed for the ESL 57 such as the Sugden A21 will need their capacitors completely replaced, even 1980's kit will. This will likely cost 70-80 Euro at a web retail supplier to replace an amp with similar sized power supply and speaker decoupling capacitors. You may well up the values of some components in older designs, extra capacitors in the 303 is nice to have for Bass performance.

You could alternatively go the output transformer approach of valve amplifiers. Valve amplifiers, and Macintosh solid state amplifiers use transformers to decouple the output impedances. Sugdens are Capacitor coupled , like the Quad 303, which provides some impedance decoupling but unfortunately like the transformer capacitors negatively effect low frequency response, when you have ESL 57's a pair of lovely full range Electrostatics this lower power delivery at low frequencies will in my opinion even play as an advantage.

If your amplifier is not well suited to the Quad ESL 57's which I assume is usually caused by current clipping, you might find putting a very small high power resistor in series with the amplifier, it will reduce sensitivity but avoid the amplifier current clipping, with that sharp impedance drop.

Regards

Owen
 
Status
Not open for further replies.
Top Bottom