Sjöström Audio DIY forum

Projects => Headphone amplifiers => Topic started by: chinook9 on April 27, 2017, 07:25:47 PM

Title: QRV-08 Place to connect PWR LED
Post by: chinook9 on April 27, 2017, 07:25:47 PM

Is there a best place to connect a power LED...,around 20 mA.

Thank you
Title: Re: QRV-08 Place to connect PWR LED
Post by: peranders on April 28, 2017, 06:40:18 AM
I recommend that you check how many mA you really need. I'll guess 2-5 mA is what you will need. Best point is to connect the LED after the rectifier bridge.
Title: Re: QRV-08 Place to connect PWR LED
Post by: chinook9 on May 01, 2017, 07:27:49 PM
Thank you P-A.  I'm not going to put a power LED in at this point. I have a cheap enclosure from China and the power switch does not work so I'll work on it after I get a replacement.

The amp still sounds great in the enclosure and no ground loop problems.  That's always good.
Title: Re: QRV-08 Place to connect PWR LED
Post by: chinook9 on February 27, 2019, 05:58:04 PM
heaveno P-A!

I have been enjoying my QRV-08 for a long time now but I still have not finished enclosure installation with power LED.  I have been afraid of damaging something if I mess up the LED wiring. I understand very little electronics and would not be able troubleshoot if I cause a problem.

I understand how to measure the LEDs I have and calculate the required resistor, however I have not found a specific location on the PCB that I like for the connection.

My friend Keith connected a 1000 ohm resistor to the + side of G31 but I am not comfortable with this location. it is 25V which requires a larger resistor (1500 ohm 2 Watts) and the way I have G31 soldered I have very little space.

Is there a spot you could suggest that would provide 15V and possible is a through the board hole that would be easier to make a good and safe connection.

Thank you P-A I appreciate your help.
Title: Re: QRV-08 Place to connect PWR LED
Post by: peranders on March 20, 2019, 11:03:23 AM
I'll recommend that you connect to the unregulated voltage in order to avoid unnecessary heat in the voltage regulator. Adjust the resistor value so the light is enough.