Anyone Know Where I should Look to Figure Out This Hum?
https://www.dropbox.com/s/faxmop972rok7i1/Noise.m4a?dl=0 Sorry, bad link copy and paste. I can't change it on the original but here it is. |
The first thing to do is to get a ground tester and use it to check the ground and polarity of all your outlets. If they all test fine, then disconnect the main cable line that feeds the home and observe if the him goes away. This should eliminate a ground loop created by your cable/ISP. Just because your outlets test fine for ground and polarity does not mean that you are gremlin free. Any house hold appliance could be causing the issue and back feed the hum into your system. I know this because my system did the same thing and I traced it back to my new cooktop. I did all of my suggestions above, installed a ground loop isolator, bought a $2500.00 surge/line conditioner: made sure the entire system is routed through it and the hum was still there. I even had my electrician rewire the cooktop which improved but did not eliminate the issue. His conclusion was that my 65 year old electrical mains is out of date and out of code and needs to have a new ground installed. Luckily, the hum only rears its ugly head when the cooktop is on so I power the the system off when cooking. I did purchase IFI AC Line Purifier for $100.00 and so far I have not heard the hum but it is only a band aid until the electrical mains can be addressed.So the lession here is that a common appliance that you do not think is a problem is the problem, finding is the hard part. |
First couple days, silent. Now this. It's coming from both sides equally, turning up the volume makes it louder.My suggestion is unplug everything from the unit, check inside the unit for any loose connection and make sure all tubes are firmly insert to their sockets then reconnect the unit to your system. From the picture I can see some (2?) cable with screw-in connectors inside the Lamm LP2. https://www.lammindustries.com/PICS/LP2/modified/LP2%20inside.jpg |
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Well to be fair to Ralph, there may very well be something wrong. The hum is happening everywhere I hooked it up, including my neighbor the electrical engineer's bench. The solution my simply be covering up the problem, possibly something going wrong with the transformer since my neighbor testing most of the component. I'm emailing all the info to Lamm. I can be patient waiting for a response. Hopefully they will help me figure this out for the long term. |
A *hum* is 60Hz *only*. A *buzz* is based usually on 120Hz but can be heard in the tweeter. So we might have a nomenclature issue. A ground loop would produce more of a buzz than a hum, at least in every case I've encountered! Lamm tech said they found the LP2 to be incompatible with older home wiring and the cheater plug is the fix.This is troubling; the cheater should only be used for testing. The chassis is grounded for safety reasons. If that is defeated and the equipment is damaged such that if the power gets shorted to the chassis, it can become a shock hazard. I wonder what is meant by 'older home wiring'? If old enough, the wiring is knob and tube so there's no ground, so its not that. Slightly newer wiring but still quite old employs conduit. The conduit is usually the ground. This type of wiring works the same way that ROMEX type wiring does- the conduit is tied to the earth ground and the neutral side of the fuse/breaker box. |
But why the ground loop hum not happened in first couple days?My initial thoughts were how would this be solved by a cheater plug but.... It is likely a very good indication that something has failed or is on the verge of failing internally in the Lamm and was just very unfortunate timing on the ops part. Did you buy it used? If it was myself and it had started acting up after just two days I would be talking to the seller...... |
I’m not worried. Seller is a friend. My wife is saying that our fridge problems started around the same time. Maybe it’s related to the fridge some how? Who knows. Maybe when the fridge is fixed on Friday the hum will come back and I"ll have to take the cheater plug off. That would be funny. All I know is this phono preamp sounds incredible! |
So sorry to revive an older thread, but am curious about two things.... 1. Were you able to solve the hum/buzz problem? Was it the fridge, the wiring from an older house, bad capacitor, etc. Are you still using the cheater plug as the fix? 2. I am considering getting a Lamm LP2.1 and am wondering if the LP2.1 is also incompatible with older home wiring as my house is over 76 years old now. Thank you, Don |
Still using the cheater plug and have since heard from two Lamm owners that have had to float a ground for some reason and a few that haven't in old homes. It's all a mystery and yet it really doesn't matter. I would be hard pressed to imagine a better sounding phono preamp than the 2.1 that doesn't cost $25k. I will be making that upgrade from the LP2 at some point this year if all goes well. |
