Tape Project Forum

Tape Machines => Reel to Reel Tape Machines => Topic started by: jukka on January 13, 2010, 06:43:55 AM

Title: Otari MX5050 output hum
Post by: jukka on January 13, 2010, 06:43:55 AM

Hi,

I'm new here so I'm sorry if I ask something stupid. I have used Otari MX5050 and I'm wondering if it is usual for these machines to produce some hum to output (both XLR outs and headphones) or do I have some problems with grounding or what? That sound is something like -55db and seems to be the same sound the motor makes but not that loud. I'd be very grateful for any help in how to get rid of that hum.

Title: Re: Otari MX5050 output hum
Post by: ironbut on January 13, 2010, 12:54:21 PM

Hi Jukka, (btw we use our real names here)

Welcome to the forum.
If your Otari is stock, it's probably a ground loop.  Go through your preamp (or what ever you have the outputs of the Otari plugged into) and disconnect the other sources one at a time. If you find the component that is forming the loop with your machine, you probably need to plug it into an entirely different house circuit.
If none of this works, try grounding your Otari (I can't remember if it has a grounding post but if it doesn't, just use a screw that's in contact with the chassis) to the preamp.

Hope that helps.

Title: Re: Otari MX5050 output hum
Post by: docb on January 13, 2010, 01:56:01 PM

Is it buzzy hum (usually at 120Hz) or a deep, more rounded sounding hum (usually at 60Hz)? 120Hz is usually some electrostatic issue and is tackled as Steve says, by trying various grounding schemes. If it is 60Hz it is usually magnetic coupling with the heads or playback electronics and might require some fiddling with the location of the tape deck relative to other gear that has a power transformer.

Another possibility is that one or more electrolytic caps in the power supply are getting a little long in the tooth and should be replaced.

Title: Re: Otari MX5050 output hum
Post by: jukka on January 14, 2010, 04:05:53 PM

Thanks for your kind replys and help.

It is the same sound no matter where I place the machine in the house. Have to try that cheater plug maybe. Just haven't found such things to fit in Euro socket (I'm from Finland). Hopefully it's not anything to do with the components because I really don't know how to replace them and don't have the money to get it fixed by some professional.

--
btw, my name really is Jukka :)

Title: Re: Otari MX5050 output hum
Post by: joeljoel1947 on January 16, 2010, 08:24:32 PM

Try the cheater, it will fix it.  Have seen this in many systems/houses with the MX-5050 series.