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Old 10th December 2004, 06:45 PM   #1
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Default Do you think this is a limiter?

What do you think?

I made some simulations, and i found some limiting, but very poor action of limiting.

Also some compression, but also, poor compression.

Can someone explain what a good japanese factory intended to do with that amplifier in the feedback line.

Can you see errors?

regards,

Carlos
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Old 10th December 2004, 07:00 PM   #2
moamps is offline moamps  Croatia
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Default Re: Do you think this is a limiter?

Quote:
Originally posted by destroyer X
Can someone explain what a good japanese factory intended to do with that amplifier in the feedback line.
DC servo amp, maybe.

Regards,
Milan
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Old 10th December 2004, 07:16 PM   #3
Konrad is offline Konrad  Norway
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This time Carlos you are studying a DC servo inserted so that you dont have to worry abt adjusting. Exept from that its a straight forward mirrored input single transistor vas.
Gain = 47/48 * (1+ 10k/470)

Werry mild winter this year dont you think ?
So what do you think abt the used vas loading tequnics involved here ? To late to put the new potatoes down in ground so il have to wait intill spring time. Do you see any rom for simplifying or other improvements here ?
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Old 10th December 2004, 10:12 PM   #4
uli is offline uli  Austria
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Default Re: Re: Do you think this is a limiter?

Quote:
Originally posted by moamps
DC servo amp, maybe.
defintely.

Uli

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Old 10th December 2004, 11:48 PM   #5
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Default Moamps, Konrad and Uli, i thank you all by the kindness to inform me

I was confused, now i am less confused.

I made simulations and i could see some help when amplifier was starting to distort...but a very small help... something we can cut out without loose something very important to sonics.

I put a switch, in the simulator to see the results fast, and i could see that i can misadjust to use as a hard limiter... compressing and blocking dinamics.

This way answering friends, i could not understand so many components used to a so small result.. with the standard adjustment do not make a good work.

I factory had decided:

Will compress audio, but will never distort, we will limit at half power!

If that decision was taken by factory enginneers i will face that more easier...but they do not did that.

I will answer you again..... do you think this circuit are intended to another use?... something we are forgeting?

Factory is Kenwood, year 1984, amplifier with 65 RMS with very small distortion, and reaching 80 with some distortion (not limited!!!!).. 80 watts reaching 0.1 percent, and 65 watts around 0.02 percent.

But power consumption is strange, 380 Watts!!!... normally you produce 260 watts total, and specifications, are telling 130 (65 plus 65) or 160 (80+80).

Nothing in the circuit to absorb the other watts, no lamps enougth or circuits that can make that difference in consumption....oh!!!...uops!!....yes, 4 ohms loads can go to 260 RMS.... so, clear the power doubts from you mind, please.

regards,

Carlos
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Old 11th December 2004, 09:42 PM   #6
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yes, this opamp is definitely a dc-servo
but i don't know what are these diodes doing

the effect of dynamics compression may be caused by very big R69, making considerable loss of voltage.
you may use smaller R69 combine with huge electrolitic C29 (say 470u)
sometimes using higher power transformer and bigger caps in supply is the best way of dynamics fidelity
cheers
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Old 11th December 2004, 09:58 PM   #7
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Default Darkferinz thank you, the diodes may be to limit

Maximum voltage to 0.7 volts, cutting negative and positive cicles over that limit...as a zener.

Thank you the ideas, to make changes in simulator and see results.

thank you.

regards,

Carlos
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Old 11th December 2004, 11:26 PM   #8
moamps is offline moamps  Croatia
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Quote:
Originally posted by darkfenriz
...but i don't know what are these diodes doing...
IC's input circuitry protection.....Uli?
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