FAQ Hum ************************** Msg # I use to hang around here a while back and we made some real progress on here with the WMLS11B. The only ole timer I can remeber is Gary. There was an issue with noise that drove me crazy. I was 95% sure it was a ground loop and tried a couple things and I left off with using two power supplies (because we wanted something simple for the average joe) verse a board re-design and such. I followed up with the directions below and sure enough, the "Hum" is gone once you gut the ground and the cricket noise/chatter (from data transfer) goes away with the diode/resistor. Link to PDF in the Files section of this group http://f1.grp.yahoofs.com/v1/0PQQSIJGrY9hBV1BGFScWaDlaXeBKcLhMbuEN9sIczNRYLPwA6zqv6Yrn20OabkUcxcDOTubxOdAOgYlKk6PmGRRxnynv6AH/NoiseFix.pdf Anyway, I jsut wanted to close the loop and share what I had found. It's been about 16 months round trip... Regards, Matt ************************** Msg # 2745 Re: [wmls11b] Re: Sound from right speaker only A better alternative in my opinon is to purchase an component speaker system normally used with your computer. Most are three speakers which included a sub woofer and a left and right speaker. They are usually powered which is a requirement. You can get great sound, plus it also eliminates the "humming sound" from you unit. You might have to purchase an additional speaker cable to connect the unit to your WML11b,but believe me, you'll enjoy the enhanced sound. Peace! dj Earl Bullock ************************** Msg 2565 # RE: [wmls11b] Easy fix for buzzing noise - Radio Shack Ground Loop Isolator Just replaced my speaker cables with the Radio Shack Ground Loop Isolator. All hum is gone (now I don’t have to listen to the hum when the units turned off). Probably more expensive than the other fix offered on this website, but I’m not to adept at rewiring. ---------------- Most of the focus in the posts to this group have been on the power cables causing the ground loop - this does appear to be true. However, since the buzzing is transmitted through the speakers, I decided to try a Radio Shack Ground Loop Isolator (part 270-054), which replaces the speaker cables going from the "2 ch output" jack on the center unit to the "input" jack on the speakers. I have had no buzzing at all for over a month since I installed the fix! Thanks. crecord Chris Record ************************** Msg 1956 This is due to how Linksys implemented the mute function. When you hit mute, the WMLS11B simply cuts the line-level audio output from the BridgeCo chip – not to/from the audio amplifier (located in the right speaker). Since the amplifier remains powered on and active, any noise that pollutes the audio signal after it leaves the BridgeCo chip will still be magnified and audible as the clicks, chirps, and static that we see. That’s why I’ve been working on replacing the audio amplifier circuit (I’ve already completed one replacement for it and the Gerbers and BoM for that design are in the Files section of the group). I’m currently working on an even better mod. .tony ************************** Msg 847 Fix for Noise Problem After some experimentation, I found a fix for the noise problem (both the low-freq hum and the high-freq chirping) that involves only modifying the power cable that runs from the center unit to the right speaker. I have modified three units with this fix and it has eliminated or greatly reduced the noise for all the units. The fix involves modifying the speaker power cable (again, the one that runs from the center unit to the right speaker) as follows: 1) Cut the ground line (the black wire) on the cable. With this cut, the audio cable's ground will now carry the DC current. This breaks the ground loop between the speakers and the center unit. I first tried breaking the ground on the audio cables (like others have tried), but this did nothing to the noise. For my three units this ground-line cut reduces the low-freq hum. 2) Add some series resistance in-line on the positive power-cable line (the wire with the white stripe). This reduces the chirping to almost nothing. I have had success with a either a 5 ohm resistor or a common 1N914 diode (available at radio shack). To make sure the series components (either the resistor or diode) can handle the DC power, I measured the current draw thru this wire. It varies from 80mA at low volume to 200mA at max volume. For the resistor, this works out to be 0.2 watts dissipation. For the diode (with .6V drop at 200mA) this works out to be 0.12W. I ended up using the diode for my three units because of the lower voltage drop. It is rated at 450 mA peak current. I hope others can use this info to fix their noise problem without having to resort to using a second power supply for the speakers. johncerney