Helder's PWM low Pass Filter

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Jag
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Helder's PWM low Pass Filter

Post by Jag » Thu May 17, 2018 4:12 pm

Hello Guys.

Having followed Wermy's guide for the GBZ, I have managed to get the majority of the main components assembled and installed.

Im currently stuck at how to assemble the correct components for Helders through hole low pass filter to eliminate any additional interference coming from the raspberry pi audio out. Please see the link below:

http://market.sudomod.com/pwm-audio-b/

Ive attached all of the wires to the potentiometer as per Wermys guide and to the audio out pins on the Pi zero. Im just wondering what do I have to connect to this low pass filter in terms of resistors and other vital components and which wires go where.

Any advise or direction would be greatly appreciated.

Thanks in advance.

GunZi
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Re: Helder's PWM low Pass Filter

Post by GunZi » Fri May 18, 2018 5:00 am

I don't think you need any external components, all the components you need for the filter are on the pcb. PWM0 is GPIO18 and PWM1 is GPIO13 on your raspberry pi. You connect those directly. And if I understand it correctly the output of the filter RIGHT and LEFT go to your potentiometer.

Jag
Posts: 6
Joined: Tue Jun 13, 2017 10:50 am

Re: Helder's PWM low Pass Filter

Post by Jag » Fri May 18, 2018 5:07 am

GunZi wrote:
Fri May 18, 2018 5:00 am
I don't think you need any external components, all the components you need for the filter are on the pcb. PWM0 is GPIO18 and PWM1 is GPIO13 on your raspberry pi. You connect those directly. And if I understand it correctly the output of the filter RIGHT and LEFT go to your potentiometer.
Thank you for your response.

Do I not have to solder any resistors on to this PCB or ground it at all.

Thank you for your help

GunZi
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Re: Helder's PWM low Pass Filter

Post by GunZi » Fri May 18, 2018 3:42 pm

Jag wrote:
Fri May 18, 2018 5:07 am
Thank you for your response.

Do I not have to solder any resistors on to this PCB or ground it at all.

Thank you for your help
Besides the 270 Ohm and 150 Ohm resistors, no. You just need to solder the through hole components marked on the pcb and thats it. I think the ground on the left (where PWM0 PWM1 are located) is connected to the pi? (I could be wrong here) and then the ground on the right side (where RIGHT and LEFT are located) is connected to ground of the potentiometer/amplifier.

Jag
Posts: 6
Joined: Tue Jun 13, 2017 10:50 am

Re: Helder's PWM low Pass Filter

Post by Jag » Mon May 21, 2018 6:16 am

GunZi wrote:
Fri May 18, 2018 3:42 pm
Jag wrote:
Fri May 18, 2018 5:07 am
Thank you for your response.

Do I not have to solder any resistors on to this PCB or ground it at all.

Thank you for your help
Besides the 270 Ohm and 150 Ohm resistors, no. You just need to solder the through hole components marked on the pcb and thats it. I think the ground on the left (where PWM0 PWM1 are located) is connected to the pi? (I could be wrong here) and then the ground on the right side (where RIGHT and LEFT are located) is connected to ground of the potentiometer/amplifier.
Thanks again for your reply.

Following wermys guide I'm going for mono sound aswell so will I only need to connect the right channel output from the low pass filter.

I've soldered the resitors to the board. Ill attach a picture as I'm not too sure if what I've done is correct.

Any help is much appreciated.
Attachments
20180521_005116.jpg
20180521_005116.jpg (3.9 MiB) Viewed 204 times

GunZi
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Re: Helder's PWM low Pass Filter

Post by GunZi » Mon May 21, 2018 7:08 am

Looks pretty good to me if you're going for the right channel. But since you're doing mono sound you don't need both PWM0 and PWM1 at the input. As far as I can tell just by looking at the pcb, leaving either PWM0 or PWM1 should be ok.

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