Here we go.
The result is quite alright. Distortion is only 0.002%. This is a very clean sound.
LM7815 is good enough and easier to use than LM317.
Transformer should be a small 15VAC. Because the circuit does not draw much current.
Adjustment is to set the output of BD139 at 9.00 Volt. As seen in the schematic.
All resistors are 0.6Watt. This is because of the fairy low current in output.
I will be waiting for some pictures of your amplifier when is done.
The result is quite alright. Distortion is only 0.002%. This is a very clean sound.
LM7815 is good enough and easier to use than LM317.
Transformer should be a small 15VAC. Because the circuit does not draw much current.
Adjustment is to set the output of BD139 at 9.00 Volt. As seen in the schematic.
All resistors are 0.6Watt. This is because of the fairy low current in output.
I will be waiting for some pictures of your amplifier when is done.
Attachments
The 7815 source will over impose it's mediocre sonic signature and noise over the class A amp and all will be for nothing with dynamic signal.
That 1 uF capacitor on it's output will not help a lot with dynamic program like music. But sure, will measure perfectly with a static amplitude sin wave.
A plain rectification stage, plus heavy filtration, would be cleaner IMHO.
That 1 uF capacitor on it's output will not help a lot with dynamic program like music. But sure, will measure perfectly with a static amplitude sin wave.
A plain rectification stage, plus heavy filtration, would be cleaner IMHO.
A plain rectification option for the supply will probably do well.
In that case use a 12VAC transformer.
In that case use a 12VAC transformer.
Soooo mine is up and running too.... But havin a hum, coming from the Salas L-Adapter..... Think it´s my fault, since the L adapter is controlled via a ardiuno, whose PSU is a Meanwell IRM-10-5, sitting next to the toroid.....
The sound is fantastic 😀
The sound is fantastic 😀
Lineup I see you adjusted R2 200K trimmer 62,8%, 126K600 or measuring some voltage or current to get the values writen in the schematic?
Very nice amp, @lineup! Congratulations!
Two easy ways of bringing the distortion further down:
Red - bootstrap the load of the 2nd BJT.
Green - replace the Miller capacitor around the 2nd BJT with a different compensation (trim the resistors in the two RC networks for best square wave response).
Two easy ways of bringing the distortion further down:
Red - bootstrap the load of the 2nd BJT.
Green - replace the Miller capacitor around the 2nd BJT with a different compensation (trim the resistors in the two RC networks for best square wave response).
Ok was not the PSU.... Was the onboard sound card... Since I use the Sharkoon Gaming Dac Pro it is dead silent....
I doubt a computer sound card from the last 20 years could have hum....I think it's a ground loop problem, generated by the computer's power supply. That dongle may have a better PSRR...
If it is a ground loop, then you should be working with the ground connections.
Hard to say without knowwing how your gear is. 🙂
The rule is that you should not have several GND connections to any point.
Star ground is a way to acheive this.
Hard to say without knowwing how your gear is. 🙂
The rule is that you should not have several GND connections to any point.
Star ground is a way to acheive this.
Is there anyone who has PCB files for this amplifier?
I like very much to have such.
There must be someone who has got PCB files.
🙂 Stefan
I like very much to have such.
There must be someone who has got PCB files.
🙂 Stefan
About those 1W/2W/3W resistors on output stage.. which one is better - carbone or metal oxide ? In terms of linearity, long lasting, etc.
