Carlos! This is my amp

My amp still has a problem which need to be solve . If volume is set at high level and then I turn on the pre-amp , DC protection circuit will operate .
Perhaps overload-protection-circuit operated after I had turned on pre-amp .Then offset voltage got high and enough to activate DC-protection-circuit .
I had to buy new power transistors for many times before .
 

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Thanh, this new picture...hummmm, the avatar....oh!..oh!...oh!... what a pretty lady!

Well thanh...old friends we are, can you send me some pictures of that lady..the one in the avatar.... a hell pretty lady!.....if not your wife, of course!

nanabrother@yahoo.com

Thank you very much Thanh, very king to show me your schematic, and those problems with switch on or even switch of, can be solved with big caps to delay the voltage rise into the differential emitters.... resistor and electrolitic may delay enougth.

Maybe if you create some loss in Vas voltage, installing some rail resistors followed by condensers may help.

Did you not apreciate the charge suckout condenser in parallel with your 100 to 330 ohms (tone adjustment and output bias adjustment float resistor)... sometimes it help a lot... try 100N or 220N there...just as a research.

Very good schematic, fully simetrical, remember Leach amplifier, but better in my idea.

As you are using a simulator Thanh, inform us some technical specifications, despite this is not the guarantee of good sonics, have some interesting informs to many data guys.

To me, please, tell me how is the sound.

regards,

Carlos
 

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can be solved with big caps to delay the voltage rise into the differential emitters.... resistor and electrolitic may delay enougth.
Oh ! i can't understand .! I don't uses differential emitter resistor .
Did you not apreciate the charge suckout condenser in parallel with your 100 to 330 ohms (tone adjustment and output bias adjustment float resistor)... sometimes it help a lot... try 100N or 220N there...just as a research.
I actually don't understand because my dictionary can't work .
Adding a capacitor in parallel with 100//330ohms can't solve the problem .
To me, please, tell me how is the sound
I told you about its sound in Mikeb's thread "explendid .... "
Its sound soft . I think that all stage can be improved more so i improved current source . The output impedence of current source will determine CMRR
i think
clean = low noise
low noise = low noise transistors , caps , resistors and CMRR


Are C3 & C7 NP cap ? If not, Maybe C3 & C7 can connect like attached picture
Hi Sky Chu !No , they are polarity cap . If C3&C7 are connected in series with each other , " component L " will increase .So i connect like that to decrease "component L" and to increase "component C "
If you have good cap , you dont need do like me



oh ! guys ! my amp has a incomportable to use but i still work and never has any failure
 
My suggestion thanh, is to hold one 220N capacitor between your fingers, and play

Music very loud, having metal instruments playing.

Now discharge the 220N capacitor, producing a short circuit with its leads over some metal.

Now, playing music, with your fingers holding the capacitor, touch the 100 to 330 ohms resistor extremes...tell me if you could perceive some difference.

Try to observe the effects in voices and bass too.

Good luck!

regards,

Carlos
 

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Hi amplifierguru ! If my pre-amp is always on but my CD-drive haven't "fade-on and fade-off " function , DC-protection will still get me in trouble
Generally ! if pulse signal or big signal feed my amp suddenlly , overload protection will operate
If amp is playing music at high level volume and I turn-off amp or pre-amp , the trouble will appear
 
Hi Thanh,

You should turn down volume control or press tape loop button (for mute) on preamp so CD player can be switched off. Then leave preamp on always and switch off power amp only.

Otherwise, if you need to switch everything off, switch off and discharge power amplifier first as then nothing can come from the speakers when you switch off CD or preamp.

Cheers,
Greg