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Topic: Question for Paul Franklin |
Steve Schmidt
From:
Ramsey, MN, USA
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Posted 5 Jan 2004 11:50 am |
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About 5 years ago I purchased a Mesa Boogie Studio Preamp and a Mosvalve 500 power
amp. I had mounted them in a 6 space SKB rack. I found that I had to seperate
them with the Mesa Boogie on the top and the Mosvalve on the bottom, otherwise I
experienced hum. I even went as far as cutting all my signal and power cords no
longer than I needed. I did not use low impedence cords though. I still experienced some hum. I remember liking the tone, but was so frustrated with the hum and hauling around a 6 space rack, that I sold the Mesa Boogie. I still have the Mosvalve.
I have in the last year bought back my old 68 twin reverb that I sold many years ago and am really liking the tube sound of the twin. I would like to get another Mesa Boogie and mate it with the Mosvalve 500
in a 4 space rack. Im just curious if you split your gear to more than one rack,
or if you have all your gear in one rack, do you experience hum, or what did you do to fix it. I guess I'd just like some feedback regarding rack connections, and hum, possibly low impedence connections between the units, etc.
I appreciate your help
Steve Schmidt
Ramsey, MN |
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Steve Stallings
From:
Houston/Cypress, Texas
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Posted 5 Jan 2004 1:54 pm
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I'm not Paul but if you look at the thread entitled "Tips for Rack Users" you will find the answer to your problem. 
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God Bless,
Steve Stallings
www.pedalsteeler.com
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Steve Schmidt
From:
Ramsey, MN, USA
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Posted 5 Jan 2004 3:14 pm
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Thanks Steve, but I did utilize the humfries isolators. It may be possible that low impedance cables may help to aleviate the problem. I guess Im curious if you can have the 2 units next to each other in a 4 space rack and still have a quiet system.
Steve |
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John Macy
From:
Rockport TX/Denver CO
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Posted 5 Jan 2004 3:28 pm
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Hey Steve,
I bought that 6 space rack from you, and have a Mesa mounted right next to a MosValve with no problems at all. Could have had some improper chassis ground in one of the units... |
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Larry Bell
From:
Englewood, Florida
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Posted 6 Jan 2004 6:51 am
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I suspect what you have is a ground loop that the humfrees won't resolve. You may want to try a HUM ELIMINATOR from EBTECH. They're the best solution I've found. You can avoid the potentially dangerous practice of lifting the ground on whichever devices are causing the loop. Same goes for using two combo amps with grounded plugs.
It's basically just a high quality transformer that is totally passive (no power required). It has 'smart jacks' that convert TRS balanced to unbalanced automatically, so you can use it with either two or three conductor patch cables or equipment that use either bal/unbal signal path.
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Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps
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