pre-amp hum

[cwymanj]

I am getting ready to get a pair of SDA2s and I have a Hafler DH500 amp.
The amp is currently being run from the pre-amp output of an older Denon
receiver through some Bose bookshelf speakers and works superb.
So here is my problem:I was planning on using a Harmon Kardon 2.0 signature series pre-amp. When I hook it up to the Hafler I get a LOUD hum/buzz.
The pre-amp is designed for a surround system but I was planning on
using it to just power my SDA2s. Should I be able to use the "Front" output from my HK pre-amp to my DH500 and get full sound out of my SDA2s or does such a pre-amp have to have all outputs(sub,center,surround)connected to a surround amp or several amps? Any thoughts on the hum. It happens with or
without any source input. It happens no matter which output I use.
Thanks for any thoughts,CJ.

[george daniel]

Does the HK have "pre outs":confused:

[cwymanj]

It is pre-amp out only;not an integrated amp.
It has Front;Center;Sub;&Rear pre-outs. Made to go to
a multi-channel amp. My question is can it be used to just power
2 speakers through a plain 2 channel amp using the "front" channel
output or should I just get a different pre-amp and use the HK for my living room for a small home theater. I saw an Acurus R-11 pre-amp for sale;It got
great reviews and would meet my needs for a remote pre-amp.
I would prefer to use my HK for now if I can. This Hafler DH500 really
sings! Thanks CJ

[Zen Dragon]

You should be fine for 2 channel listening just using the front pre-amp outs to the Hafler. The Hafler DH-500 is a nice amp that has some good power out. If you have hum it could be a couple different things, but most likely it is a grounding issue.
You can try putting a ground buster on any of your components that have 3 prong electrical connectors, or you can run a common ground wire to the chassis of all your components.

[Tour2ma]

Yup, ground loop is the likely problem, but the possible causes are numerous.

Assuming the HK has a headphone jack, give it a listen through that (using headphones obviously) and see if the hum is present. Do it where it is and if it is there, take it to another room, on a completely separate house circuit, and give it a listen there.