ADA Depot - A Forum To Support Users of ADA Amplification Gear

Let's Get Technical => Troubleshooting Problems => Topic started by: dave_daut on April 07, 2014, 07:01:29 AM

Title: Ground hum noise
Post by: dave_daut on April 07, 2014, 07:01:29 AM

Hi,

I have a MP-1 110V US version and use a 230V converter, because I live in Europe. Everything is fine, but the hum is too loud. Is there a problem with converters ? Will the noise mod also effect the ground hum ? Where to start to eliminate the hum ? I looked through the forum already: will the MDRT also effect the ground hum ?

Title: Re: Ground hum noise
Post by: rnolan on April 07, 2014, 07:39:47 AM

Hey Dude, do the MDRT, it will (IMHO) fix your issue.  e.g. I tried a US ADA MT100 poweramp with (I'm in OZ) 240 to 110 convertor, lots of hum, not good etc.  The other MP1 noise mods are also worth doing, but makes more difference (from what I can glean) if you run really high gain; to sort out really high gain on a MP1 ( >:D ), go with all the 3TM/noise mod options  :thumb-up: , it will cook....

Title: Re: Ground hum noise
Post by: dave_daut on April 07, 2014, 09:17:32 AM

Hi,

I do high gain settings but the noise is fine with me - only the hum is annoying. So I will give it a try with MDRT within the next weeks...thanx

Title: Re: Ground hum noise
Post by: rnolan on April 08, 2014, 04:37:20 AM

No worries, MJMP may have some other ideas re the hum but I'd start with a MDRT and get away from the step down tranny.

Title: Re: Ground hum noise
Post by: dave_daut on April 08, 2014, 05:36:41 AM

Hi,

what about putting a 230V transformer in the MP-1 ?! Is that possible ?! So I won´t need the transfomer anymore...

Title: Re: Ground hum noise
Post by: rnolan on April 08, 2014, 08:45:59 AM

Absolutely, and you can just buy a 230v replacement (http://www.marshalljmpmodshop.net/miscellaneous_parts_and_replacement_tubes.htm) which is less expensive than the MDRT.  BTW if you go this way, get one from MJMP, some other replacement trannys can have issues and break down over time.  In MJMP I trust.... :thumb-up:
However, the MDRT not only works on either 110/240v it improves the sound of your MP1. (from MJMPs site; The MDRT is a 24VA transformer which can deliver 12.6V to the heaters. The high voltage has gone up to 240Vdc / 8mA. The original is only a 12VA transformer, and will only deliver between 8 and 9 V to the heaters and the high voltage is 190Vdc / 4mA. So the MDRT will enhance the sound, producing better low end, less noise and the sound will sound less compressed.) which is why I would go MDRT (but it does cost more)