Radio Mesa

[kungfujews]

I'm picking up radio signals on my MKIV - and even got the local taxi firm during a gig last week! Has anyone any tips on reducing this irritating side-effect of valve amps? My leads are all top-drawer and guitars are humbuckers and earthed etc. Obviously I know that this comes with the territory but any help or advice will be greatly appreciated. :x

 

[crane]

Your V1 tube may be microphonics. Try to change it.
You can also have a tech add a 68k resistor before the grid of V1A. It must be placed right after the input cable going to V1A, the closest possible to the grid pin of the socket. This will help picking up unwanted signals.

 

[domct203]

RFI can also enter the amp through the AC voltage supply.
Have you tried a different outlet? Try a good power conditioner,
one with RFI/EMI filtering. Did the trick for me and my Roadster.

Dom

 

[kungfujews]

Thanks for the advice guys - I've just replaced my V1 with a SPAX7 and still received the signals, albeit reduced. However I think I'll try a power conditioner. I've seen them advertised but they vary greatly in price. There are some on ebay for about £30 although there are others nearer £150...will the £30 one do? It's advertised as having an RFI filter on it.

 

[domct203]

Just remember, you get what you pay for. IMO don't skimp on your amp's protection. A good power conditioner not only filters EMI/RFI (some 'less expensive' models can actually add noise due to cheap components) but can also protect the amp during a power surge or spike. Think about how many refridgerators/coolers and air conditioners may be cycling on and off at a medium sized bar!

I use this Furman unit with good results. It squashed a local radio station that was coming through my Roadster loud and clear.
http://musical-instruments.pricegrabber.com/power-conditioners/Furman-PL8II-BLACK/m3846906.html The new models are now the 'Series II'.

I just purchased this ART unit when I ordered my MKV:
http://www.artproaudio.com/products.asp?type=84&cat=7&id=147

I know that $400 seems like a lot of money but it's only 10% of the replacement cost of the Roadster and MKV, not to mention my G-Major, Axess CFX4, X2 Wireless, FCB1010, and handfull of frontend pedals.

My $0.02 - Spend Wisely

Dom

 

[kungfujews]

Cheers Dom - totally accept your point on not wanting to spend a fortune in the long run on repairs. Think I'll save up and get a better one instead. Like the look of the firman unit - if it works with your Roadster it'll surely do the job with mine!

 

[pokerrules47]

I wonder if you talk to your guitar, maybe you can order a cab without picking up the telephone? :lol:

 

[SonicProvocateur]

Don't overlook small stuff like using crappy unshielded cables, and even unshielded cables in between your effects and combo, etc. Also, if you are using a wireless system (especially VHF) you are going to be more prone to these things.

Start with the simplest thing and work your way to the largest. Odds are is your Mesa is probably not on the fritz...especially if it doesn't do it all the time...