2. amps-preamps
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anyone have any experience with Krell Amps humming

I just got a new Krell Theater Amplifier Standard, and when connected to my system it hums at about 52db, it's not ground loop related as it does not vary with volume at all. (at least I think that's correct) I've done everything everyone will suggest from line conditioning all the way down to reverse engineering my sytem and there is no way to eliminate the hum, I can add to it and have identified a couple of other issues I'll have to resolve, but it's always there. Just curious if that level hum is normal, or if anyone else has any experience with Krell like this, and if so, what they did. I'm about to take the amp back for exchange.
arthursmuck
rsbeck
887 posts
 
Your Krell is a theatre standard, I assume that's a mutli-channel amplifier. Does your Krell draw more juice than the other amplifiers you tried? And, do you have a powered sub-woofer?
Did you have a powered sub-woof plugged into the same circuit
when you tried the other amplifiers? Amplifiers and powered sub-
woofers draw a lot more juice than anything else in your system.
If your Amplifier draws more juice than the other amps you tried
and/or if you have a powered sub-woofer plugged in with the Krell, but you didn't with the other amplifiers, you don't have an apples to
apples comparison. It is curious that adding the Sub-woofer makes the hum worse.

arthursmuck OP
451 posts
 
didn't change anything from one amp to the next. Krell is sending pins for xlr connects and hopefully that solves this. meantime, havig a dedicated circuit put in for amp with Hubbell HG outlets, if that doesn't kill any noise, I give...
rsbeck
887 posts
 
You'll want to add a couple of dedicated circuits if your budget allows. I had humming problems and nothing worked until I installed dedicated circuits -- now it is stone silent -- no more humming of any kind. One other thing -- I did specify 10 gauge wire for the 20 amp circuits. Please write in and report after you get the pins and dedicated circuits -- I want to hear a success story!
sogood51
2,157 posts
 
Rob, I think the RCA center conductor is wired in parallel with pin 2, the shorting pins short pin 1 and 3. I think the small silver piece he is talking about is the cable release. Krell amps come from the factory with the pins in I think? If the amp was new then Krell screwed up or if it was used, the former owner was running it balanced and may have lost the pins. You can bend a small nail to use as a pin if you had to I would think.

Dave
edwards
43 posts
 
Rather than bending a small nail go to the hardware store and purchase about a foot of #12 solid copper wire. Remove the plastic shield and using a pair of long nose pliers just bend yourself some shorting pins...be sure to run some 200grit sand paper over the ends to round them out and keep the inside of your xlr's scratch free. Wipe the sand grit off before inserting in the amp. If this does not work ship the amp back to Krell for a repair...in the last 12 years I have owned 7 Krell amps and have never had a single issue with noise or anything else.......Good luck
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