2. analog
  3. 1230422263

Help with problematic MC Step-Up

Hello A'goners
I have a dilema, I recently purchased a Step-up for my Denon 103.Consisting of a pair of vintage Altec Peerless 4722 mic transformers.Let me start by saying nice work (it came in some type of dark metal case with copper foil inside, WBT connectors for input,I had it wired on the output side with Canre' Inter-connects.But what I must say is the case has no ground attached (screw nor lead coupled with the IC's.

This leads me too my dilema,once I connected it to my Pre (Audible Illusions M3) I got a LOUD humm,I removed the transformers and put them in again when I noticed that when I touch the trannies the humming gets softer but never goes away. I've tried a few things- I've moved it far from my Pre-Amp ,switched the Altecs from L to R and then back.One last thing,I was wondering if this could be the problem, the output IC's are exiting the case right in the middle of the input connectors.As I've stated earlier it is shielded and looks to be assembled well.
I have contacted the person who assembled it and am waiting to hear from him.
Any suggestions would help.
thanks
braab
braab8
braab8 OP
56 posts
 
Mingles
I don't have a TT ground wire if you mean tonearm ground ...yes it is still no Luck.I had a question is anyone familiar with the Altec's? can they be bad?

thanks Bobas I've stated the case only has screws that keep it closed, should I rig a make-shift ground by screwing it to the chasis, then to the Pre?
hevac1
812 posts
 
The unit or your outlet could have been wired wrong. Get an outlet tester at Home depot to check. Are the plug blades the same size like some Meridian equipment cords are? If yes, reverse the plug and see if it still happens.
rccc
216 posts
 
I built an sut using the 4722 for my 103d and had the same problem. I ended up grounding everything to the case (hammond die cast) and then tt/arm to sut to preamp and had to move it around but it finally got quiet and boy what a sound!
bob_bundus
1,834 posts
 
thanks Bob as I've stated the case only has screws that keep it closed, should I rig a make-shift ground by screwing it to the chasis, then to the Pre

yes that's a good approach; try it.
More to discover