Job 225
- Thread starter soundArgument
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Cheater plug didn't work for me, either. I attempted to use the "star system," knowing that it could lead to liability for Goldmund were I to be electrocuted after lifting the ground on the amp. No success.
I put the cheater plug on the amp and left the preamp grounded. Also tested everything with only the amp connected to the mains (with and without cheater plug). Still got the noise. For these tests, sources were disconnected from the preamp. I tested with different preamps and in different buildings. No luck.
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These units are defective. The noise is coming from the unit itself. I connected the interconnects to a device without the power cord connected on the device. Hence to, there was no ground connection on the device and of course, no power and yet there is still hum coming from the amplifier. So with only one ground point the unit still hums and not in a good way 
So, I believe the ground loop is between channels in the amp and I'm now thinking the transformers are out of spec.
Of course, take this with a grain of salt as I'm an unlicensed, non-professional, not even weekend, electrical engineer!
So, I believe the ground loop is between channels in the amp and I'm now thinking the transformers are out of spec. Of course, take this with a grain of salt as I'm an unlicensed, non-professional, not even weekend, electrical engineer!
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These units are defective. The noise is coming from the unit itself. I connected the interconnects to a device without the power cord connected on the device. Hence to, there was no ground connection on the device and of course, no power and yet there is still hum coming from the amplifier. So with only one ground point the unit still hums and not in a good way
I did the same test with several different preamps (and sources) and had the same result.
It seems that this grounding stuff is not going to work. The amplifier clearly is creating a ground loop with itself when both RCAs are connected to the same component.
Good point! The original and apparently defective JOB 225 I received will arrive at Goldmund tomorrow. If they ship a replacement on Wednesday, I might have it by the weekend. I'll report on what I hear from the new unit.
SoundArgument: Yes, please do. In the mean time, I will borrow a friend's cheater plug (I know you tried this), and will try it on both the amp and my dac. I am not using a preamp.
By the way, remember that receiver I am using to burn in the Job? Well I just hooked up a cd player to the receiver and BARELY got a buzz from the speakers. I'm beginning to think this is a my dac vs. the Job problem.
By the way, remember that receiver I am using to burn in the Job? Well I just hooked up a cd player to the receiver and BARELY got a buzz from the speakers. I'm beginning to think this is a my dac vs. the Job problem.
In my case, it's clear the the buzz is coming from the amp itself. There's clearly some kind of interference when both ICs, which share a common ground, are connected. I tried the amp with a total of six different devices before I sent it back.
This is the letter I received this morning.
Dear Tom,
We are currently putting in place a procedure for returning the device for repair in the United States, a modification is requested to decrease the hum of the amplifier.
Please send your device to our american distributor by Fedex priority
Rhapsody
Mr Bob Visitainer
27 W24th St # 506
10010 New York
USA
Tel : +212 229 1842
Mr. Visintainer will take care of your unit and send it back to you as soon as the modification will be done, all freight cost are free, please use our Fedex acount number
I copied Mr. Visintainer to this email, he will contact you if needed.
Best regards
Dear Tom,
We are currently putting in place a procedure for returning the device for repair in the United States, a modification is requested to decrease the hum of the amplifier.
Please send your device to our american distributor by Fedex priority
Rhapsody
Mr Bob Visitainer
27 W24th St # 506
10010 New York
USA
Tel : +212 229 1842
Mr. Visintainer will take care of your unit and send it back to you as soon as the modification will be done, all freight cost are free, please use our Fedex acount number
I copied Mr. Visintainer to this email, he will contact you if needed.
Best regards
Will have my amp back from Switzerland tomorrow evening. I'll provide an update on what I hear.
I received my modified amp from Goldmund today.
The hum is gone.
I'm in concurrence with Joeinid on this thing. It sounds very, very impressive.
And congratulations to Goldmund for (i) acknowledging and fixing the problem and (ii) returning my amp to me (in Massachusetts) from Switzerland two business days after I sent it.
Most impressive . . .
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