Discrete line amplifier question

markoramius

Member
2008-03-28 6:58 am
Hello,

I was reading "The Audiophiles's project sourcebook" from Mr. G. Randy Slone, and came across a dicrete preamp that has 2 inverting gains stages and in between a tone control network (figure 3.6).

The thing is that there is feedback applied between the output of the 2nd gain stage (thru a voltage divider) and the input volume potentiometer (right where you normally put it to ground). Also, this feedback line passes thru the tone control network.

I was wondering if I can just make without the tone control network and still use both gain stages with this kind of feedback without changing any other parts.

The tone control network is coupled thru capacitors to both gain stages.

Thank you in advance for your kind comments regarding this issue.

Best Regards,
Marko.

PS: I don't know if I'm allowed to scan and upload the schematic from this book and because of that I did not do it.
 

markoramius

Member
2008-03-28 6:58 am
... Draw your modified circuit, capture it using 'Print Screen SysRq', paste it into Paint (Ctrl V), cut out the relevant bit, save it as a .jpg and post it.

w

HI W,

Ok. Thank for your kind reply.

This could be the modified preamp, without the tone control network and what I had in mind...

Thanks again.

Best Regards,
Marko.
 

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Gordy

Disabled Account
2006-11-02 6:15 pm
The volume control in the feedback loop varies the amount of feedback around the circuit to change the gain, hence change the volume. It changes the ratio of the input resistor to the feedback resistor; analagous to Rin and Rf in the attached diagram.
 

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