To Aesthetix users

Hi, I have the Io Sig w/VC and 2 supplies. I live in a very RF rich environment near a hospital. On one occassion when trying different ICs I did discover some RF bleed through.No hum with the IO or subsequent RF problems.

Your IC's must be very well shielded and you must exhaustively experiment with dressing the leads and positioning with equipment and try different brands.While not the best, Musical fidelity make a type with RF ferrite clamps on the cable...it may be worth a try to see the result. In the past when I had a Counterpoint head amp this problem would drive me crazy.

Fourtunately the Counterpoint weighed in at about 5lbs so you could wave it in the air and find a good position. Hard to do with the Io.

Also make sure your connectors are scrupuously clean. Any oxidation and the connectors will act as diodes in a cyrstal radio singing through your system.I like the Caig products here not comfortable using any of the silver based contact enhancers as they can be difficult to clean out of the connectors if it does not work out.

I doubt that your electrical system is properly grounded if you had to add new grounded receptcles to replace 2 prong ones. If you have armoured cable or conduit(maybe in NYC) then the outer sheild/conduit may be acting as a poor ground back to the main panel. Get a electrician to seen if you have a "separate" ground wire back to the panel and properly bonded to the neutral at the box. Old vinyl gave good advice on disconnecting and swapping Ic's to discover if the problem is the Io or the amp for hum... working from the source forward to determine the possible cause...don't ignore the dressing of your tonearm cable.

This is exhausting and thankless work but it can be done..goodluck!

Interesting thanks Nkj.

Yes, I suspect there is something off with the receptacle grounding. There is no ground wire, but there may be an armored cable or conduit - the instructions said that the receptacle could be grounded if it made mechanical connection with the box as you screwed it in.

This sounded screwy to me, but then the fact that my AC polarity checker said that the grounding was fine made me think that in fact this had grounded the receptacle.

Perhaps having an electrician in is the next step? Always pricey and frequently unreliable in Manhattan...

Patrick

Hello,

A couple of other thoughts:

* You obviously do not have a continuous ground through to the receptcle. If you unscrew the receptcle from the box and leave it in free space then your ratshack tester will show a missing ground. I don't know your electrical code (I'm in Canada) but I understand that in major centres like Chicago and probably NYC conduit is required in commercial/multiunit applications for fire code and protection from pests. If you are comfortable you can mechanically bond a ground wire from the recepticle to the recepticle box with a screw.You'll still have a problem on the other end though with perhaps poor bonding of the conduit to the box... the whole system circa 1955 may not be grounded anyway? An electrician's advice is good here if you are not savy in opening up your main panel for a peek.

* You could try running an extension from your AC outlet to the Io just for fun and see the results.

* If the AC line works (or even if it does not) and you can make the investment in one dedicated circuit back to the panel then this may be worth it to eliminate clicks and pops from other appliances. Decorative panel mold conduit is available to make the run as unobtrusive as possible.

* You are running the Io full out with possibly an improper ground in NYC (RF hell I imagine) so you may have to back off a bit. This is a function of the overall sensitivity of your system from cartridge to speakers and the room interface. I'm thinking this is your real problem!!!

* Try eliminating your power conditioner on the other equipment and see what happens to the hum... make sure you have no other inputs tape,tuner etc connected to your pre. They may be causing a groudloop via the common buss on the pre back to the Io.

* Start swapping cables L-->R and tubes L--R... If you have known good tubes for the PS supply swap them in. If it bothers you enough and you don't want to ship the unit for testing then perhaps buy a complete tube set and try swapping them in (for god's sake mark them first so you don't confuse yourself...ask me how I know)...man I'm getting tired just thinking about it!

The good news is the Io is very silent on my system so I know you can get there with this equipment with proper wire dressing, grounds, and good tubes.

All the best

Thank Nkj. I just opened the receptacle and checked ground with the ratshack tester - and it is just as you describe - grounded when the receptacle is screwed into the conduit box, not when unplugged.

I was going to run a wire from the ground screw to the box as you also suggest, but my multimeter shows continiuty from the ground screw to the receptacle ends, which are firmly screwed to the conduit box anyway, so I don't see the point of a separate wire. Effectively, screwing the receptacle to the box grounds the box, as the ratshack tester shows.

Unfortunately I don't have the skills to check to see whether the conduit is firmly grounded to the circuit breaker box at the other end. It sound like I need to bring an electrician here, and in fact I have been considering a dedicated line for some time.

For now I'm going to replace the receptacle as it was (unless you really tell me a wire from the ground screw on the receptacle to a screw on the conduit box is somehow different from the (ground-continuous) receptacle-ends being firmly screwed onto the box).

Next I'm going to try swapping the Io's power umbilicals, and then the EL-34s, to see if that makes any difference.

I take your point about running the Io all-out in NYC. I probably could use the 72 db setting as well. But the 80 db setting sounds so good in my current system that I'm reluctant to switch.

I haven't been able to get in touch with Jim White yet - he's a hard man to get hold of!

Patrick

Just realized there's no point in swapping the EL-34s if swapping the power umbilicals makes no difference. And swapping the umbilicals makes no difference - the RF is more in the right channel.

I've just realized two things:

- moving the Io PS power cord around reduces the hum, but not the RF

- the RF problem and the hum may be in the Io tubes. I guess V1/V2 are the candidates for replacement. Perhaps I should try swapping the channel pairs first?

Patrick