Electrocompaniet ECI - 2

[Mandryka]

Does anyone know if this runs in Class A up to a certain point? If so, at what point does it switch to Class B?

There’s a booklet online here

https://www.manualslib.com/manual/599497/Electrocompaniet-Eci2.html?page=3#manual

but it’s not specially helpful IMO. It says it consumes 70W for 2x50W output into 8 ohms.

I have one of these amps, it’s not especially big and heavy, it runs hot but not very hot.

[struth]

By looks of its construction, no, or not much.

[Mandryka]

Yes boot the booklet says


All stages work in Class A

These stages are explained as follows


The amplifier is divided into two separate sections or gain blocks. The input block is a transconductance amplifier without overall feedback. This avoids large output current being fed back to the input, and mixed with the minute input signal. The output block is a transresistance amplifier with parallel feedback. This is done to prevent higher frequencies than the feedback loop can handle, from entering the loop.

and


The amplifier will be warm.Due to the high class A operating point used in the Electrocompaniet design, it is normal that the amplifier feels warm

It's an extremely nice amp, by the way. I have one.

[struth]

sorry i was looking at a 3... yup that heatsink suggests some class A. I doubt it will be all class A tho.

[Mandryka]

If it isn't all class A, pure class A, then I think that ELectrocompaniet have been downright misleading.

[struth]

No many amps run in constant class A. Most do first 10 watts. some 20w. Very occasionally 40 or 50 but the heat sinks are huge. and they get very hot. TBH if it runs even 10 in class A then you may never come out of it unless your in a very big room.Surprising how loud 10 watts is.

[struth]

For instance this is the inside of a MF A1000 50 w classA.

http://www.hifishock.org/galleries/electronics/musical-fidelity/integrated-amplifier/a1000-1-musical-fidelity.jpg

I had one of these once and those huge heat sinks get so hot they remove skin. PS, that is a full size amp and the psu is seperate

[Mandryka]

I own a Krell KSA 50, it's being restored right now, I haven't heard it. I wonder how it will sound compared with the Electrocompaniet.

Why did Krell (and others) make such powerful Class A amps if 10W is so loud? Was it just for driving inefficient speakers in big rooms? I mean there's a KSA 200!

And no-one ever says that 10W Class B is loud, that you'll never clip a 10W amp unless you're in a large room! I don't understand what's going on actually.

[struth]

some krells didnt use all class a either. think the older ones did.. Macca and Oli will know more about them; both have them. My speakers are efficient and probably only use a few watts of power, but then there is reserves for heavy work needed. Sure Macca said his krell only lights up one or 2 lights and he plays quite loud. his amp stays quite cool comparatively . the MF I had got pretty hot after a couple of hrs. certainly kept the house warm:D

[Yomanze]

No way is it a pure class A amp... heatsinks are just too small. The clue is in the description. “Due to the high class A operating point”.

Thus, it’ll be a few watts class A, biasing into A/B past that.

[walpurgis]

Is there a problem? If the amp sounds good, surely all is well?

[Yomanze]

Is there a problem? If the amp sounds good, surely all is well?

Definitely no ‘problems’. It looks like it’ll drive anything apart from 1 Ohm Scintillas. :)

[Mandryka]

Is there a problem? If the amp sounds good, surely all is well?

The reason is frivolous really. I've set myself a project of exploring Class A amps in one of my systems. Yes, this Electrocompaniet sounds good with the speakers, but I want to know what I've got, especially when the Krell arrives, which I'm more confident will be pure Class A.

[Mandryka]

By the way, another question. Can someone suggest someone to service it? Electrocompaniet aren't interested in the UK, they're a very small operation, one salesman operating from his kitchen table as far as I can see, and he's focused on selling their streaming equipment. The amp sounds fine, but if I think it may not be a bad idea to get someone to look at the insides. I'd give it to a local company, but in fact when I asked them they felt nervous because it was class A, they said.

[Mandryka]

Oh and her's a picture of the front of the amp, not mine as it happens, but that's what it looks like

https://i.ebayimg.com/images/g/CpsAAOSw29JcLge7/s-l1600.jpg

It just says in gold and black "Class A" -- if it's not, then I really think it's misleading, very bad form.

[walpurgis]

By the way Howard. Could you please put a more specific location in your profile? "United Kingdom" is too general, a town or region will be fine. Thanks.

[Mandryka]

By the way Howard. Could you please put a more specific location in your profile? "United Kingdom" is too general, a town or region will be fine. Thanks.

London, I'll change the profile.

[Iceman16]

A sample of pure Class-A

https://beta-static.photobucket.com/images/w486/jayson0328/0/c1b08350-0262-42e3-835a-e1f71bc351ce-original.jpg?width=1920&height=1080&fit=bounds

[Barry]

In an amplifier operating in pure class A the output power will double each time the load impedance is halved, as long as the power supply can provide sufficient current. The Electrocompaniet amplifier shows an increase in power as the load impedance is halved, getting on for nearly double but not quite.

Also, the standing (or idling) power dissipation will be at least double the maximum output power. Pure class A amplifiers draw constant power from the supply, and can never be more than 50% efficient. As the audio output increases, some of the power is dissipated in the speaker load, but even at maximum output at least half will be dissipated in the amplifier.

Thus the need for large heat sinks, and even then they get hot.


I built the amplifier circuit designed by Otala and Lostroh, as reported in the Journal of the Audio Engineering Society (on which the first Electrocompaniet amplifier was based) and it was excellent. About 25W, it sounded lovely into Quad ESLs.


The Mark Levinson ML2 is the only pure class A amplifier that I know of. A single channel amplifier providing 25W into 8 Ohm, it has an idling dissipation of 400W. As can be seen from the link below, the heatsinks are massive and (from experience) run hot.

https://stereonomono.blogspot.com/2017/12/mark-levinson-ml-2.html

[Johnny nocash]

Clear as mud Barry, cos electronics wise, I'm as thick as pig shit.
Glad you posted it though because I've always wondered how it worked technically.
Someone should make it a sticky!
Cheers

[Mandryka]

I received this email from Electrocompaniet today, regarding the crossover point from A to AB in the ECI-2


The exact point will vary depending on different factors, but the ECI-2 will work in Class A up to a couple of Watts, an then move to Class AB.

[struth]

as i suspected. still, at least you now know for sure

[Spectral Morn]

They used to have a dealer network in the UK and a service agent. I am a bit surprised to hear that's not the case anymore, though maybe I shouldn't be. I suspect the dealer model used in the UK caused them issues, as dealers renting the demo stock, rather than buying it outright would be a poor way to create a network of committed dealers, and if none created sales, or few sales, and then returned that rented stock, now much devalued that would be hard to take, with not enough sales (maybe I don't have figures) of product to offset the rental scheme losses. The retail side of the trade left me during that rental scheme period, so I don't know what happened afterwards.

Some of their product is nice, some a bit bland and perhaps over priced. A mixed bag in my view.

[Mandryka]

At least they replied to my query, if a bit vaguely and without much detail.

If you search the amp I have, ECI-2, for comments and reviews on the web, you'll see that everyone loves it, it has a cult following, and and at the same time many people agree with Spectral Morn that they're other stuff is a bit bland. I'm no expert, but I do think that the ECI-2 is a bit special, I am very glad to have it even if it is misleadingly branded as Class A.

[Ali Tait]

I own a Krell KSA 50, it's being restored right now, I haven't heard it. I wonder how it will sound compared with the Electrocompaniet.

Why did Krell (and others) make such powerful Class A amps if 10W is so loud? Was it just for driving inefficient speakers in big rooms? I mean there's a KSA 200!

And no-one ever says that 10W Class B is loud, that you'll never clip a 10W amp unless you're in a large room! I don't understand what's going on actually.

Jez posted this on another site, basically Krell fib about the power output of their amps, but in the opposite way to most manufacturers. The KSA 50 is actually a 75W amp, but will do 50w Class A as has been proven by independent measurement.

It’s a bit misleading all this Class A malarkey these days TBH, in the strict sense a true or “pure” Class A amp only has one pair of output transistors per channel, which limits output power available. Most “Class A” amps these days have more than one pair of output transistors- these are paralleled up to give more power, so in the strict sense of the definition are not Class A, but highly biased Class AB. In other words they will give a few watts in A before crossing into AB.

It’s pretty easy to tell how much an amp will do in A, just take a look at the heat sinks and how hot they get. Once you’ve experience of a few Class A amps, it’s pretty easy to estimate the power in A that will be available, just think of the size of the heat sinks on your Krell- 50w in A dissipates A LOT of heat.

[Ali Tait]

BTW, don’t be fooled by manufacturer’s comments that their preamp or preamp section in an integrated runs in Class A, as if it’s a special thing that makes the amp better- pretty much all run in Class A anyway- it’s the nature of the beast.

[Barry]

Clear as mud Barry, cos electronics wise, I'm as thick as pig shit.
Glad you posted it though because I've always wondered how it worked technically.
Someone should make it a sticky!
Cheers

Point taken - I did belabour it somewhat.

A simple "no" would have sufficed, but I thought some explanation would be preferred.