Electrocompaniet, how does it sound?

[lumanauw]

Hi, analog_sa,

Offcourse...How silly of me. I just never heard of Electrocompaniet name, I never know what series they are making, I tought they only make that 25W amp.

So, they make alot of models. Is the basic topology the same as the 25W or different?

The company itself still exist (can look at the website), but it seems they do not make audio power amps anymore.

At least now I know there is series AW180 and AW250. What watt rating are they?

 

[jacco vermeulen]

Mmmm, let me think.

180 watts and 250 watts ?

 

[analog_sa]

At least now I know there is series AW180 and AW250. What watt rating are they?

You have no idea how much you can learn from Google 🙂 While you're at it have a look at the monstrous Nemo.

The AW180 is rated 180W 8ohms and 350W 4ohms. It didn't impress me with sounding that powerful though.

Circuits are very different to the 25W amp. No global NFB.

 

[lumanauw]

Hi, Analog sa,

For me now, it is like seeking the edge of the sea. Found something, but found that it is only the beginning.
Is that all types of Electrocompaniet are good sounding, due to different topologies? Or some type only?

 

[MikeB]

I've just built an amp quite similar, at least similar for the vas.
It uses normal ccs-fed singlediffamp, this kind of currentmirrored
vas and my standard tripledarlingtonout. I can post schematic later...

The results from this were surprising, the quality overwhelmed me,
it's definitely the best amp i've ever heard. It has some warm and
natural sound, but is extremely detailed with superb separation,
and a real asskicking bass !

Seems, that this kind of topology has very much potential !
Sims showed that the amp is very fast, polefreq is at ~27Mhz.

Mike

 

[destroyer X]

No!....i cant believe *** kicking!...really, this is a very strong bass!..can you ...

Show that wonderfull amplifier, with schematics, many pictures and details, and part lists, and all tricks to us?

regards,

Carlos

 

[destroyer X]

Hey Mike, please, buy a good camera and send pictures to us

I will be happy to see the prototype....do not mind appearance... good focus is enougth....hehe...to see secrets on it!

Carlos

 

[markp]

They were known for using very low capacitance power supplies for the output size of the amp. Kind of minimalist in approach overall. They did sound good though when not over pushed.

 

[runebivrin]

"Snubbers", T:s and Z:s

I thought I'd just point out that the schematic shown is snubberized with 0.68µF in series with 1ohm, all in parallel with 0.1µF.

Also, it uses an inverting configuration with a T network feedback. and a classic Zobel on the output.

Interestingly, there's no Miller cap, all the compensation is emitter-emitter on the diff pairs, plus an input roll-off.

What do we make of al that?

Judging from the schematics, there might have been issues with idle current run-away when the bias trim pot gets old.


Rune

 

[demogorgon]

I remember hearing a EC amp with the SEAS Thor at a DIY speaker shop here in norwy some time ago. i had my favourite cd with me for the occation. that's how i got the bug.
I almost cried like a litle baby, the music sounded so damn beautiful, natural and rich.
I wont be satesfied untill i'v managed to build something that sound so damn beautiful, or better.

 

[lumanauw]

I've just built an amp quite similar, at least similar for the vas. It uses normal ccs-fed singlediffamp, this kind of currentmirrored
vas and my standard tripledarlingtonout. I can post schematic later...

Interestingly, there's no Miller cap, all the compensation is emitter-emitter on the diff pairs, plus an input roll-off.

I also have made this kind of VAS (current mirrored downside), It has to use Miller cap (C dom). I wonder why this cct can use no-miller cap.

 

[MikeB]

Hi lumanauw !

Mine is also without cdoms, and uses rc to gnd instead.
My prototype seems perfect stable. The sound is very pleasant,
beautyful...

Mike

 

[Cortez]

MikeB:
Thx for sharing ! This is your latest cct, and looks like the best till now ?
I guess, you are on the right way, to have a very good quality amp ! 😉
Dont U like DC-servo instead a cap in the FB ? Maybe with an LF411 opamp... 😎

 

[MikeB]

Hmm, i like it simple ! After having bypassed the electrolytic with
a 100nF filmcap the sound was ... perfect !
I think this is the one for me, still need to test with higher supply
of 36volts, but i have no suitable torid yet. Hopefully sound doesn't
get much changed with higher voltage.
DC is ~2mv, so i see no need for DC-servo.

Mike

 

[Cortez]

> Hmm, i like it simple !
> After having bypassed the electrolytic with
> a 100nF filmcap the sound was ... perfect !
> DC is ~2mv, so i see no need for DC-servo.
A cap is also a solution, i know this, but maybe you should try a DC servo later with LF411.
(Just as a test, to give a chance for alternative solutions ! 😉)

> I think this is the one for me, still need to test with higher supply
> of 36volts, but i have no suitable torid yet. Hopefully sound doesn't
> get much changed with higher voltage.
Waiting for the results !

And why do U used MPSA-s in the input instead of BCs ?

 

[MikeB]

Have you ever looked into the specs of mspa18 ? Ouch !!!!!!
Measured hfe at vce=5v was ~980, it's very low noise, high speed,
and has much voltagegain. Just one hell of device !

 

[Cortez]

> Have you ever looked into the specs of mspa18 ?
Yes, just asking... 🙂

Emitter degeneration in the first stage, tried ?
Why do U need so much gain here, and
whats the gain of the 2nd stage ?

 

[MikeB]

Openloopgain is ~1:5000, makes ~1:20 for 1st stage, 1:250 for 2nd.

 

[adason]

anybody actualy built this?
http://users.otenet.gr/~athsam/electrocompaniet.htm
i am realy tempted now

 

[UniQ]

MikeB,

I wonder wether using output signal from both side of the diff amp cancels 3rd overtone and could be the contribution to the good sounding of this topology with current mirror VAS?


Michael