i'm not very experienced in preamp building so i want to ask i found this preamp here ,built it and realized that it is not very good quality thurthermore its output power is about 50% lower than my pc sound card(AC'97).Can somebody post link or circuit with preamp ,which quality and output power would be much higher than that preamp's.
suggestion
I have seen your link and circuit.
Since you have already bulit the pre-amp, why not up-grade it?
There are lots of room for improvment for this bad design.
The quickest way is to change the opamp. Try the pin for pin compatiable premium audio opamp such as the
Burr brown OPA604, OPA134 or the analog device AD797. I graruntee, it will be much better. Next, use batteries as power supply, like 2 SLA 12V 1.2Ah.
I am not sure if you have a good layout. It's very important as well.
If you are looking for a total change, ie build another one.
If you are interested in my suggestion, pop me a email and
I'll show you a very simple and nice sounding circuit. (Also
based on opamp)
I have seen your link and circuit.
Since you have already bulit the pre-amp, why not up-grade it?
There are lots of room for improvment for this bad design.
The quickest way is to change the opamp. Try the pin for pin compatiable premium audio opamp such as the
Burr brown OPA604, OPA134 or the analog device AD797. I graruntee, it will be much better. Next, use batteries as power supply, like 2 SLA 12V 1.2Ah.
I am not sure if you have a good layout. It's very important as well.
If you are looking for a total change, ie build another one.
If you are interested in my suggestion, pop me a email and
I'll show you a very simple and nice sounding circuit. (Also
based on opamp)
Hmm.. never seen that biasing method before... how does it compare to the method used in the PPA headphone amp:
http://tangentsoft.net/audio/ppa/amp/misc/schematic5.pdf
http://tangentsoft.net/audio/ppa/amp/misc/schematic5.pdf
1 more thought:
If you use that design to drive headphones, you will need
to increase the output stage bias current from 30mA(present)
to at least 50mA. To do this, add one more diode so that the bias
voltage increased to 2.4V. With the emitter resistors at present
of 10ohm, the bias current will be 60mA which is good enough
for most good quality hi-fi high impedance headphones. You will need to change the transistors to BC337 / BC327. You can increase the bias current to 100mA by changing the emitter resistors to 6ohm. However, don't push it too hard! Have fun
James Yung
Praise! Audio
If you use that design to drive headphones, you will need
to increase the output stage bias current from 30mA(present)
to at least 50mA. To do this, add one more diode so that the bias
voltage increased to 2.4V. With the emitter resistors at present
of 10ohm, the bias current will be 60mA which is good enough
for most good quality hi-fi high impedance headphones. You will need to change the transistors to BC337 / BC327. You can increase the bias current to 100mA by changing the emitter resistors to 6ohm. However, don't push it too hard! Have fun
James Yung
Praise! Audio
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