RC Tank Warfare community hobby forum

Hi Guys Have found a problem does anyone else have it DBC and rx18 boards getting feedback from motors to the speaker ,the noise is realy bad so loud cant here any sound from rx18 or the sound card on the DBC.
Has anyone found a cure for it have sent e-mail to Darkith asking about it .


  Regards pete

I am wondering where your DBC board is mounted, is it close to the motors and do all of the wires stay well clear? The only other thing I can think of is suppressors on the motors?

Had it setup with Rx14 and no feedback ,swopped over to the rx18 and the feedback started.

regards pete

I have the same problem. The noise is a high pitched whine and I think the FET amplifiers are the cause, not the motors. You hear it after wiring in the small sound card to the RX1? amplifier that gives the extra firing and hit sounds on the Darkith DBCs. I've tried moving the sound card away from the RX1? boards but to no avail.

It would be interesting to hear if anyone else has this problem and if there is any cure.

Cheers
Chris   

971wright wrote: Hi Guys Have found a problem does anyone else have it DBC and rx18 boards getting feedback from motors to the speaker ,the noise is realy bad so loud cant here any sound from rx18 or the sound card on the DBC.
Has anyone found a cure for it have sent e-mail to Darkith asking about it .


   Regards pete

what terminal are you attaching the sound card to

that noise is PWM(pulse width modulation). we had the same problems with the thunder1. we tried large caps on the motors for filtering the pwm. that was a hit and miss success. we tried all sorts of filters and still no success. the only solution we had that would stand up to all the different scenerios was adding a seperate power supply. for some reason the fets and sound module would walk on each other and go into a ground loop. i dont know if this would be an ideal set up with a dbc, but hopefully its a good step in the right direction.

bubbajoexx wrote: what terminal are you attaching the sound card to

I've only used RX18 boards on my DBC setups and the sound card is attached to the "ToAmp (input)" pin of the "VR" port. Using Darkiths instructions I shaved the insulation off of the wire between the plug and the volume adjuster, and soldered to the side.

Thanks CD - the separate power supply is interesting. At least there is a solution albeit not a perfect one.

Pete, did you say the problem is not apparent on the RX14 boards?

Hi Have the same setup using Rx13 and rx14 boards and no feedback systems work and no whine noise from speaker,the whine starts with the Rx18 board as soon as you touch the right stick to move the tank,I am about to test another unit with Rx 18 board and Dbc have tested without Dbc no whine or feedback,will let you know how it goes.

regards pete

971wright wrote: Hi Have the same setup using Rx13 and rx14 boards and no feedback systems work and no whine noise from speaker,the whine starts with the Rx18 board as soon as you touch the right stick to move the tank,I am about to test another unit with Rx 18 board and Dbc have tested without Dbc no whine or feedback,will let you know how it goes.

regards pete

make sure you use the connection pointed out in the pic to attach the sound from the sound card to the rx18 any other point will cause noise

the blue wire is preamp out from rx18 green is ground yellow is main amp in

Thanks for the info Bubbajoexx. I've been following Darkith's RX18 diagram which reckons (using your colours) that blue is B- Green is   
Amp Input and Yellow is CpuFxOut. So I connected the sound card to the centre (green) wire. 

I'll give your solution a go.

Cheers
Chris