I did not recognize big changes in sounding...
For 60volt supply it needs more changes than multiple MJLs,
The inputstage would blow, means need cascodes or other bjts,
and biasing needs to be reduced to avoid heating up of the small bjts,
but should not be difficult.
Do you really need 200watts into 8ohm ?
Mike
For 60volt supply it needs more changes than multiple MJLs,
The inputstage would blow, means need cascodes or other bjts,
and biasing needs to be reduced to avoid heating up of the small bjts,
but should not be difficult.
Do you really need 200watts into 8ohm ?
Mike
Hi Cortez !
No, not really, i've been evaluating and checking and comparing...
I added one more cap to "further" improve quality.
So far, i think for standard topology (no EC or SE and so on) this
is a very good sounding amp, having a warm/natural/detailed sound.
You could try it, i think it's worth !
Michael
No, not really, i've been evaluating and checking and comparing...
I added one more cap to "further" improve quality.
So far, i think for standard topology (no EC or SE and so on) this
is a very good sounding amp, having a warm/natural/detailed sound.
You could try it, i think it's worth !
Michael
Early Electrocompaniet amps
Hi,
I'm a slow starter I remember a small Electrocompaniet power amp and that it was really bad mechanic construction and also that they often don't work, I just thinking about all esoteric designs from 70's and all odd products.
I will place the Electrocompaniet on first place on my odd and peculiar designs list.
Can anybody remember if Philips used the LOW TIM Ottala designs in their mainstream products, if not why.
I also remember some really odd designs from Rappaport how do they sound and how was the construction.
I still have the JC-2 on my real list as No. Uno
Ok I'm not a audio guru or a audio judge but too much b......t has entered the audio scene.
I do like strange designs but they must be reliable and again like the JC-2 a landmark in audio design a new way of thinking, Ok maybe the Electrocompaniet and their mates was a kind of new age in audio but they have put out a lot of pollution.
Hi,
I'm a slow starter I remember a small Electrocompaniet power amp and that it was really bad mechanic construction and also that they often don't work, I just thinking about all esoteric designs from 70's and all odd products.
I will place the Electrocompaniet on first place on my odd and peculiar designs list.
Can anybody remember if Philips used the LOW TIM Ottala designs in their mainstream products, if not why.
I also remember some really odd designs from Rappaport how do they sound and how was the construction.
I still have the JC-2 on my real list as No. Uno
Ok I'm not a audio guru or a audio judge but too much b......t has entered the audio scene.
I do like strange designs but they must be reliable and again like the JC-2 a landmark in audio design a new way of thinking, Ok maybe the Electrocompaniet and their mates was a kind of new age in audio but they have put out a lot of pollution.
It seems not only me 
I calculate roughly, the diferential has gain of 3k9/2k15=1.8x.
I calculate the current gain of current mirror (could be wrong) = 4k7/2/2/750=1.56x?
(the first "2" is due to parrarel, the second "2" is due halfing for upside and downside transistor)
The final stage has inverting gain of -12k/0=infinite?
I cannot calculate the gain of this amp.
I dont understand the definition of "impedance". Some said emitors has low impedance, collectors have high impedance. How to determine value of each impedance. For example, what is the impedance of point A, before J1?
I calculate roughly, the diferential has gain of 3k9/2k15=1.8x.
I calculate the current gain of current mirror (could be wrong) = 4k7/2/2/750=1.56x?
(the first "2" is due to parrarel, the second "2" is due halfing for upside and downside transistor)
The final stage has inverting gain of -12k/0=infinite?
I cannot calculate the gain of this amp.
I dont understand the definition of "impedance". Some said emitors has low impedance, collectors have high impedance. How to determine value of each impedance. For example, what is the impedance of point A, before J1?
Hi lumanauw !
The impedance before J1 is "infinite", but after j1 pulled down
to 12k via the resistor. So the gain at this point is ~12000*2/750.
(Only a guess, in reality always lower)
But the load from the following stage decreases impedance even more.
This schematic seems to waste a lot of power, as the outputstage
uses ccs fed by 10v zeners, it will clip 10volts below supplyvoltage...
Mike
The impedance before J1 is "infinite", but after j1 pulled down
to 12k via the resistor. So the gain at this point is ~12000*2/750.
(Only a guess, in reality always lower)
But the load from the following stage decreases impedance even more.
This schematic seems to waste a lot of power, as the outputstage
uses ccs fed by 10v zeners, it will clip 10volts below supplyvoltage...
Mike
Hi, Mike,
Nice to see you again
Inverting amp's gain factor is -RF/Rin, here RF is 12k and what is the value of Rin?
Your calculation G=12kx2/750=32x. The front end (the open loop part) has gain about 2.8x, so total=89x? I think this is too high.
Yes, the front end is not too efficient, but it is supplied from higher supply than the output stage, so it should be no problem to the output stage.
Nice to see you again
Inverting amp's gain factor is -RF/Rin, here RF is 12k and what is the value of Rin?
Your calculation G=12kx2/750=32x. The front end (the open loop part) has gain about 2.8x, so total=89x? I think this is too high.
Yes, the front end is not too efficient, but it is supplied from higher supply than the output stage, so it should be no problem to the output stage.
Well I can recall one EC amplifier - a 3" high black box , I was told cost a shi*load of $$$, that radiated heat to the room - seriously, you could fry eggs on it! And with no vents, component ageing must've been a shocker.
Wonder if they do a roaring trade in replacement electro's or whether owners just didn't hear the (not so) slow decline? A typical electro's 2000 hrs at 85C. Perhaps the (purposely?) elevated temp reduced the Zc impedance for better sound?
Wonder if they do a roaring trade in replacement electro's or whether owners just didn't hear the (not so) slow decline? A typical electro's 2000 hrs at 85C. Perhaps the (purposely?) elevated temp reduced the Zc impedance for better sound?
Hi, Amplifierguru,
Is that the gain factor can be calculated by C (not R)? If we follow the ordinary equation, the gain should be -220/1000, but what you calculate is 1000/220, is that if we use C for determining gain, the position of nominator/denominator is upsidedown than ordinary inverting amp formula (calculating with R)?
Maybe what you see is the original 25W classA /earlier Electrocompaniet?
It is the schematic of EC120, the "modern" Electrocompaniet. I think it should run cold, cause the bias is under 100mA/device.
Is that the gain factor can be calculated by C (not R)? If we follow the ordinary equation, the gain should be -220/1000, but what you calculate is 1000/220, is that if we use C for determining gain, the position of nominator/denominator is upsidedown than ordinary inverting amp formula (calculating with R)?
I have an EC 4.7 preamp and AW120 power amp.
The preamp has recently been to the doctors and had the volume pot and heap of caps replaced, plus an upgrade from Electrocompaniet.
The sound improved considerably but the problem I had observed remained. While the preamp was away (it took weeks to get the parts from Norway as there is currently no agent in the UK) the power amp remained in use as my CD players (Marantz CD63KI and Shanling CD-T 100) both have volume controls.
A short while after switch-on, one or both channels will lose all sound. It crackles and pops for a while and after a couple of hours settles down and performs well.
Boosting the volume considerably shortcuts the process but is uncomfortably loud.
Before these problems manifested themselves it was a very nice sounding setup other than the mid bass is a bit prominent.
It is way beyond my skill level to go rooting around in these things with any likelihood of a successful conclusion so I will leave it to those who are more able. Got to dig deep into those tired old pockets though.
The AW120 does run quite warm, which saves on the central heating, I suppose. You can fry eggs on the Shanling though.
The preamp has recently been to the doctors and had the volume pot and heap of caps replaced, plus an upgrade from Electrocompaniet.
The sound improved considerably but the problem I had observed remained. While the preamp was away (it took weeks to get the parts from Norway as there is currently no agent in the UK) the power amp remained in use as my CD players (Marantz CD63KI and Shanling CD-T 100) both have volume controls.
A short while after switch-on, one or both channels will lose all sound. It crackles and pops for a while and after a couple of hours settles down and performs well.
Boosting the volume considerably shortcuts the process but is uncomfortably loud.
Before these problems manifested themselves it was a very nice sounding setup other than the mid bass is a bit prominent.
It is way beyond my skill level to go rooting around in these things with any likelihood of a successful conclusion so I will leave it to those who are more able. Got to dig deep into those tired old pockets though.
The AW120 does run quite warm, which saves on the central heating, I suppose. You can fry eggs on the Shanling though.
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