Monolithic SuperSymmetry with Current Feedback

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#662
A food in a can could be convenient and, yeah, speedy. Maximum need is putting it into microwave oven for seconds and eating. The taste might be acceptable.

By the way, who would like to put his well cooked yummy food on the shelf in the instant food corner?

Just a joke (if it has a value as a joke).

JH
 
#666
Looks like it works with some new changes still with the LM.

Here is another mad :idea: :

newidea.jpg


The circuit is not complete yet, there should be another seperate gain stage on each side, this is only for theory of operation.



It should work like this:

The output of the amp goes to a differential ampB where the original input signal of the amp is subtracted from it.

So on the output of the differential ampB should be the distortion of the amp.

This distortion goes to a differential ampA where it is substracted from the original input signal of the amp.

So the amp should be free of distortion.

Comments ? 😕


Also instead of substacting the distortion on the same side, it could be added on the other side.

Hypersymmetry ? :devily:
 
#669
jh6you said:
The pre, BOSOZ, is set with about 10dB gain while this power amp has approximately 24dB.
Click to expand...

I informed that the power amp had 24dB gain. It was a wrong info. The actual gain is 4, i.e. 12dB (with R1 and R3 of 22k).

The latest R1 and R3 are of 22k, and R15 and R16 of 7.5k.
With the lowered R15 and R16 to 7.5k, the measured square waves remains clean until the output voltage swing reaches 34 Vpp. The 7.5k is for an assured boost of AC current necessary for 4 ohm load.

The output power of the amp is 18W for 8 ohm load, based on the clean square wave results. I did not measure the power for 4 ohm load, but I presume as greater than 25W.

JH
 
#670
Until now, I have put my effort on the matter of loop gain and stability. As a result, the amp works well to my full satisfaction, without giving any trouble.

By the way, I newly introduces R23, R24, C3 and C4. These are not for the amp's stability, but for the cure of the sound of too much apparent treble. The amp has given somewhat overemphasized cymbals and "s" and "ch" sounds in vocals. The new components works for the attenuated bright treble.

I think I have enjoyed the technical experiments and development enough. I will put these aside. It seems to be the time for me to return to the music and movies. (Today, I enjoyed Welcome to Collinwood. I liked it very much. Whhahaha...) O, this however does not mean that I have given up expectation of your helpful tips about sound improvement if you see anything better...

JH
 

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#671
🙂 Fixed my PSU, so now the rails are 25V.

Applied 20Hz sine and increased the volume while watching the wave form on the scope.

All clear.

At 60Vpp the coil of the poor little 8" test speaker started to smell like burned rubber :dead: and I aborted the test. 🙄

Today evening I will do this with a bigger speaker...
 
#672
jh6you said:
By the way, I newly introduces R23, R24, C3 and C4. These are not for the amp's stability, but for the cure of the sound of too much apparent treble. The amp has given somewhat overemphasized cymbals and "s" and "ch" sounds in vocals. The new components works for the attenuated bright treble.JH
Click to expand...

JH,

is the output the right place to make a frequenxy compensation ?😕

I never experienced any frequency response problems like too many highs :scratch: not with the standard circuit and not with the high power circuit.
 
#673
Bernhard said:
🙂 Fixed my PSU, so now the rails are 25V.

Applied 20Hz sine and increased the volume while watching the wave form on the scope.

All clear.

At 60Vpp the coil of the poor little 8" test speaker started to smell like burned rubber :dead: and I aborted the test. 🙄

Today evening I will do this with a bigger speaker...
Click to expand...

You could use a dummy load instead of a speaker...
 
#675
Bernhard said:

is the output the right place to make a frequenxy compensation ?😕
Click to expand...

Bernhard

As you know well, the use of Zobel network, connected from the amplifier output to earth, is well known in power amplifiers. I use 10 ohms and 0.22uF, which provide the 3dB frequency of 72.4kHz. I could change the capacitor value or entirely remove the network—case by case with respect to speakers and cables.

There is no technical problem. I just do not like "s" and "ch" sound in vocals and so want to cut them off.

JH
 
#676
jh6you said:


Bernhard

As you know well, the use of Zobel network, connected from the amplifier output to earth, is well known in power amplifiers. I use 10 ohms and 0.22uF, which provide the 3dB frequency of 72.4kHz. I could change the capacitor value or entirely remove the network—case by case with respect to speakers and cables.

There is no technical problem. I just do not like "s" and "ch" sound in vocals and so want to cut them off.

JH
Click to expand...


JH,

but you could do the same on the amp's input ? :cannotbe:

What has "s" or "ch" got to do with frequencies at 70 kHz ? :scratch:
 
#677
Bernhard said:



JH,

but you could do the same on the amp's input ? :cannotbe:

What has "s" or "ch" got to do with frequencies at 70 kHz ? :scratch:
Click to expand...


I think JH is searchin' a more " euphonic " effect listenin his preaferred music , since I am convinced that "s" and "ch" are not eliminable. This effect is caracteristic in the Audio region of the spectre. Do the same at the input.....: 70 Khz is beyond this effect... and do not depend from this kind of filtering .
 
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