Help with noise


I have an LP-12 with a low output (.23mV) Dynavector 17DII. I have this connected to a KAB electronic stepup device and this is connected to my Fisher 400 receiver, which needs about 4.5mV input. I am getting tons of noise thru the phono section. I have tried the following:

1) With nothing connected to the phono inputs of the Fisher, the noise level is very low, perfectly acceptable to me.

2) With just the turntable connected to the phono inputs, the noise level is about the same.

3) With just the step up device connected to the phono inputs, the noise level rises quite a bit, more than acceptable.

4) By moving the TT ground wire from the stepup to the receiver, the noise is reduced, but still unacceptable. Also adding a ground to the stepup does not do anything.

5) With the TT connected to the stepup and the stepup connected to the phono inputs, the noise level rises even more.

By moving the stepup device around, I can make the noise become greater or lesser. By shielding the unit with my hands, the noise is *greatly* reduced. Do you think that if I enclosed the stepup within another metal case (a pseudo Faraday cage), this would reduce the noise? Due to number 5 above, are there any phono cables that are quieter than others? Could I also shield the phono cables with aluminum foil? They seem to be acting as antennas for noise. Having just bought the Fisher, which is a restored and modified unit from Bizzy Bee (and sooo sweet), I just do not have the funds for a better stepup device. Any advice on what to do (cheaply) would be greatly appreciated!

Mike
mike_cole
You're talking about the KAB, right? I'd let Kevin know, so he can address the issue in his product.
Well, I found some sheets of very thin aluminum that can be molded by hand and cut with scissors. I built a cage and the hum went away. There is still some hiss left but it was the hum that was most irritating.

Mike
Although you don't say what the problematic noise is like qualitatively (RFI? Gain device 'rush'? Induced hum? Grounding-related hum? Static-y? Same in both channels?), I'll assume with you that it's mostly some kind of induced noise because you can vary it with placement and physical shielding. Independently of one another, both your cartridge and your receiver sound like they're probably fine, although they may not be a great match for each other in terms of gain structure. But it does seem as if your step-up preamplifier may be picking up something from the immediate environment, whether or not it's also a questionable match (I'm assuming that the cables you're using fromt the step-up to the receiver are shielded). Have you tried unplugging everything else from the wall, and just listening to the step-up through the receiver, with or without the cart attached? (As far as the extra noise you hear at step #5, have you tried cupping the cart within your hands? - it could be the cart and not the TT cables.) I'd call up Kevin at KAB and tell him everything you've got and what you're hearing, I'm sure he'll be of help.
a good step-up device as far more costly than offered by kab.
noise-free step-up trans is at least $200 for each channel.
if you're ok to wait just get the HO cartridge and wait to get more serious level.
I don't know, but try this guy:
http://www.2baudio.com
He is very familiar with Fisher equipment and turntables and may have some good suggestions. Been very helpful with my 2nd (antique) system...