AudioLab 6000a humming

[Leif]

The question is at the end!

I ordered an AudioLab 6000a after having a loaner for a week. I was very impressed, a nice neutral sound. Anyway, the new one arrived, and had a hum from the box. Sometimes it was fine, for an hour, then the hum started. Sometimes it hummed straight away, then after a hour the hum went. The hum could be loud enough to be heard five meters away ruining some pieces of music.

From what I have read, this is due to a faulty toroidal transformer reacting to DC offset on the mains. The coil is either poorly wound, or not bolted down properly. AudioLab initially suggested I buy a DC blocker from them. The shop is now dealing with it, I said I wanted a replaced/fixed unit, or a refund otherwise. As I said, the demo unit had no hum, my six year old Arcam Solo Movie has no hum, my Akai separates owned for years had no hum. The problem is that the hum cannot be repeated at the shop, they have no DC offset.

So, is a hum from the 6000a a frequent occurrence? Any happy or unhappy 6000a owners here?

 

[hifinutt]

thats a pitb. many amps are susceptible to DC like hegel and many others . I would send it back and try something else

 

[Linear]

Its not faulty, its just some amps are more susceptible than others. I use a DC blocker with my 6000a. If you like the amp, I would think about getting it, and adding a blocker. Does add £100 to the price, which is a bit annoying, to say the least.

 

[Linear]

I had a Roksan Kandy k3, did the same.

 

[metlor]

Ask the shop to switch over the torroids from the two units.
From the internal pics it doesn't look too tricky.

I run a fairly large DC blocker here, but my mains are generally about 248v. It's unusual for equipment to run silently here.

I think most transformers are wound for 230, the higher the voltage then problems can show up, though obviously not in every case.

 

[TIU]

Open the case, a bee might fly out.

 

[Rayymondo]

Open the case, a bee might fly out.

A class A/Bee

 

[Leif]

Thanks all. AudioLab agreed to a replacement which makes me very happy as I really do like the sound from this lovely unit. Plus it looks nicer than the plastic NAD and Bluesound boxes which were the alternatives.

It replaces an Arcam Solo Movie, which is starting to fail. The AudioLab sounds so much better than the Arcam. The latter lacks clarity and is slightly boomy, which is odd because it should have been possible to make a neutral amp with a full frequency rsponse at that price.

The AudioLab also sounded much better than the Bluesound Powernode Edge, which is odd. I do wonder if the previous user had configured the EQ or some other sound settings. It should be possible to make a decent amp and streamer in a plastic case for £600.

Open the case, a bee might fly out.

There was definitely a bug somewhere.