T network and supply snubber(?) revisited.

[ashok]

I was looking at M.Otala's amplifier circuit diagram and found that he has used the T network in the feedback loop and also used the RC (snubber?) on the supply rails , both being discussed on this forum. So I guess if it's on the Electrocompaniet amp it must be useful .
Suggest that others look at the circuit at
http://home.online.no/~tsandstr/Otala amp 1973, original.htm

Cheers.

 

[Franz G]

... very interesting!

And with the hand drawing, it looks like we have a double-t! It is not exactly clear, what the horizontal resistor is, what value? Connected to the feedback path?

And the snubbers, indeed! 0.68uF and 1R

Franz

 

[Upupa Epops]

Franz, quality of this amp make something different : dual rails, good linearisation of diferential amps and high open loop gain - not snuber.

 

[analog_sa]

So I guess if it's on the Electrocompaniet amp it must be useful .

The more current EC amps use neither so i guess it's not so useful

 

[ThorstenL]

Konnichiwa,

I was looking at M.Otala's amplifier circuit diagram and found that he has used the T network in the feedback loop and also used the RC (snubber?) on the supply rails

Yup. He also uses inverting mode!

Very interesting historical headsup.

Sayonara

 

[ashok]

The more current EC amps use neither so i guess it's not so useful

The new designer (?) can probably achieve the same acoustic performance without them . That doesn't mean that it never was good ! Just that he is using some other methods to achieve it - probably with less component count (?).
Would you have any idea ? Can you share the circuit diagram of the newer circuits so that we can make an informed guess ?
Thanks.
Ashok.

 

[Terry Demol]

Franz, quality of this amp make something different : dual rails, good linearisation of diferential amps and high open loop gain - not snuber.

This amp has low open loop gain. Each stage is degenerated.
The FB value is listed as 20dB... not large by any standards.


Cheers,

Terry

 

[Upupa Epops]

To Terry : I wasn't count it , yes higher values of degeneration resistors, I see, good linearisation .

 

[analog_sa]

The new designer (?) can probably achieve the same acoustic performance without them . That doesn't mean that it never was good ! Just that he is using some other methods to achieve it - probably with less component count (?).

Sorry, Ashok, i was just joking. The snubbers, t-network and inverting mode are all good features in my book. The circuits (or links) of AW70,100,120 were posted on this forum. If you can't find them send me a pvt mail and i'll be pleased to email them.

 

[Upupa Epops]

To Terry : Look at answer of John Curl on " Electrocompaniert page " .

 

[aHobbit]

... very interesting!

And with the hand drawing, it looks like we have a double-t! It is not exactly clear, what the horizontal resistor is, what value? Connected to the feedback path?

And the snubbers, indeed! 0.68uF and 1R

Franz

plus the 100nF (0.1uF) across each rail. Ala carlosfm

Nice!!!

 

[Franz G]

plus the 100nF (0.1uF) across each rail. Ala carlosfm

This is really common practice in many psu's! Carlos speciality is the "snubber" in the psu.

Franz

 

[sivan_and]

analog_sa []
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