Tír Na HiFi

Anyone apart from Tony using one of these or had them in their system at any point?

I might have a mains issue as when I was disassembling the TT for the DAC session recently I noticed that the seperate housing for the motor was actually vibrating! When I put my hand on it you could feel the gentle hum. When I plugged it out, the hum stopped. Not talking about an audible hum in this case but rather you can easily feel it when you touch the housing. Leads me to suspect that there might some DC on the mains. I remember the Airtight transformers hummed much louder when I moved in although the Jadis is completely quiet.
Anyway, given that I live in an apartment I'm sure I have mains fluctuations throughout the day.

It possibly might be a worthwhile addition to the system for relatively little outlay.

Yeah, I have a 1500 in use at home. I often wonder if it's doing anything, and then I remember that my system used to sound differently on a regular basis but I don't really notice that happening any more. The day I decided I was definitely getting one was the day where sound quality suddenly and audibly plummeted, I opened the door to ask Hazel if she'd done anything, and it turned out that she'd just put on the kettle.

Only caveat is fan noise. It's not all that intrusive, but my room is dead silent otherwise so I can slightly hear it if I put my mind to it. I see they've gone up a bit in price since I bought mine.

Have you all of your gear connected it to though? 1500Watts continuous is a fair bit. My PC at full load doesnt even draw that much. Did you ever connect the Quads to it?
My old Leben amp would give an audible click whenever the fridge kicked in so I think the mains could do with a bit of cleaning up. My place has some background noise so maybe the fans wouldnt be noticable.

Wow it must be osmosis Seb suggested this to me in a discussion yesterday pondering if regenerator was needed.

I had a mains issue in the house also publicized here. Lights were flickering on occasion and I took it that it related to the fact it was low energy bulbs in a large chandelier. Long story short Pearse couldn't get his superduper PC to work at a meet(Sure isn't that a regular occurrence!)
but mine was working fine. Mains issue in my house fixed by the ESB now affected Pearse's zuma. Mine was fine as it ran through the regenerator.

For an amp that costs circa €12k new protection of the transformers is I think a must and if it did nothing but that it is still required.
I can't comment except subjectively but I do remember recently Seb pointing out a dac not sounding great and it was noted it was off the regenerator. It is small change in the scheme of your hifi Dave and sure since you aint upgrading to dacland soon!

Hard to know what the cause is exactly.

Not sure what the configuration of the motor actually is i.e. AC or DC. I suspect it is a AC motor... running on reduced voltage via a transformer inside.

Transformers by their nature will hum, even when working correctly. However some transformers due to their design will hum less, whilst others can really really hum to very noisy levels. I remember in one place of work we had two main transformers, one hummed really really noisily, the other was humming but much much quieter, I mean like 80% less. Numerous reasons where given i.e. bolts holding the lamination's require tightening, transformer could be slightly distorted due to poor mounting / foundation, cables on one side of the transformer being too tight etc etc...it was quiet a long and comprehensive list as to what makes a transformer excessively noisy.

I take it the motor was switched on when you put your hand on it? Or was it switched off? Was your mega computer switched on at the same time also?

Electricity quality is an issue with more SMP supplies present, higher power computers, and in apartment blocks small amounts of pollution can build up to bigger levels and these can all cause problems for sensitive equipment.

Adrian wrote: I take it the motor was switched on when you put your hand on it? Or was it switched off? Was your mega computer switched on at the same time also?

It was switched off and everything else was plugged out including the PC. So this really surprised me when I could physically feel the hum when I touched it. Its an AC motor.

DaveF wrote:Have you all of your gear connected it to though? 1500Watts continuous is a fair bit. My PC at full load doesnt even draw that much. Did you ever connect the Quads to it?

At the moment I only have the CD player connected and I've never connected the Quads. For whatever reason, I have a problem that if the power requirement goes over a certain level, the regenerator itself starts to emanate a fizzing sound. My amps each draw about 450 watts (most of it dissipated as heat!) so total load is a sizeable 1000w when amps are plugged in. Still, well within the 1500 limit. I sent the first one back to Power Inspired and they simply couldn't reproduce the problem, but they sent me a new one anyway (definitely a new one!) That has the exact same issue in my place. I send Power Inspired a video, they agreed that it clearly fizzes above a certain level, the could clearly hear it on the video, but they couldn't get any of their units to do it even after extensive testing with over-voltage, under-voltage, etc. For a while I thought it was my amps perhaps offering a funny load, but testing with my toaster confirms that it's not specific to hifi.

In short, I've no reason to disbelieve Power Inspired, they were very helpful about the whole thing, and I've never seen this problem mentioned anywhere else. I'm afraid to wonder what's going on with our mains at home, but in the meantime I just use it for the CD player.

Hmmmmmm..... now that is a surprise.

I would suggest.... having a look at the AC motor.... I think the base has 3 or 4 set screws which can be removed.

If the switch is on the primary side of the transformer winding... then it should not be the transformer making the hum / vibration.

If the switch is on the secondary side of the transformer winding... then it could be the transformer making the hum / vibration.

It could be possible that with age... the transformer inside has very slightly moved to touch the mounting or some other point, and is very slightly vibrating up against the casing / housing etc.

There are two other tests...

1) Remove the fuse in the plug... this will disconnect the Line / phase side... and plug it back in... if the motor is still humming / vibrating that way you will see if stray currents are flowing in the neutral phase, which should not be the case as the neutral phase should be well earthed at the fuse board.

2) As the motor is portable... take it into work with you... and see if it hums / vibrates there. In fact you could take it over to somebody else's place who has a AC
re generator and plug it in there. Maybe it is a quality issue.

3) Check to see if everything else is off, including immersions, electric showers, ovens etc etc.

I remember years ago I would also get a audible click / pop on the speaker in an apartment, eventually traced to the ignition circuit on the central heating / gas boiler.

What some on the Naim forum went for was a 2000VA (and some even larger for bigger setups) toroidal balancing transformer like from www.toroidy.pl, the Audio Supreme model which is fully submerged in reisin and enclosed in a stainless steel can like this:


Diameter: 21cm, height: 9cm, weight: 11.8kg. The price is about GBP200. 

Here is a bit of information... however I suspect it is for more industrial motors etc...

http://www.vibrationschool.com/mans/Spe ... nter32.htm

It could very well be that the motor is designed to vibrate, which is why it is mounted on those little rubber strips. Does the vibration stop when the motor is running?

I almost forgot to say... I think Aleg's idea of running a Isolation Transformer is a good idea.... 240V / 240V, as the TT motor should be drawing very small ampere's then you should be able to pick one up cheaply... may even have one at work?