To Aesthetix users

Do you have the Io plugged in to the same outlet as the EP 15A? If you use separate outlets, do you know if they are on the same circuit (breaker)? This may be hard to determine in an apartment building. Also, the ground may be flakey. You can always get a Rat Shack outlet tester.

In my system, I ran a dedicated 20 A circuit and have all the outlets "star" wired. No voltage drops or ground loops. With the Io, there may be some 60 Hz hum. This can be from inbalanced tube sections or bleed through on the heaters. With the gain that the Io has (70 dB or so) it is near impossible to get rid of all the noise.

You can achieve the "star" wiring with a outlet strip such as the PS Audio Power Directo, their Juice Barr, the Nordost "Thor", or one of the IsoTek products. You can also make one up yourself with some outlets and wire.

The "star" wiring will eliminate the ground loop. If you use the line level input on the Io for a CD player (or any other device), I have found that to be a source of ground loops and hum when listening to vinyl. So, when I play a record, I unplug the AC power to my CD player (which is plugged in to the Io).

I have also found that using the XLR outputs from the Io drops the noise floor and any residual hum.

Chasing hum is thankless, good luck.

oldvinyl

Hi oldvinyl,

Thanks for the detailed response. I use the XLR outputs too and love them. I don't have the version with the line level input (and volume controls) - I run the Io to a BAT linestage. No CD player in the system at all, as a matter of fact...

I have wondered whether the hum is intrinsic to the Io, but I didn't notice it much in my prior location. Of course, I might have a bum tube, especially because it is more noticeable in the right channel. But the right channel is also picking up a radio station distantly at certain times of day, so it could just be the physical placement of the gear (which I'm loath to experiment with for obvious reasons, even though it might be the simplest solution!)

Both the EP15A and the Io Sig are in the same outlet, and although there are separate circuits in the house, including an air conditioner outlet that must be clearly separated, I can sometimes hear a pop through my speakers when my wine chiller cycles on and off (not since I've installed the EP15A), and a definite nasty sound when I switch on a high-intensity lamp that's supposedly in a different circuit (even after the EP15A was in the system).

In any case, there's no way for the EP15A's power cord to stretch to an outlet on one of the other circuits.

So the electrical system is far from the best. I own my apartment but wonder if upgrading just the internal apartment wiring will solve the problem - seems like the whole building needs it (built in 1955).

I installed my 3-prong outlets myself - the apartment only had 2-prong when I got it! My Rat Shack AC checker says polarity is fine and grounding is fine on my outlets.

All your 20A outlets have grounding wire running right back to the box? (or a spike in your backyard - I've heard that's the best - unfortunately there is no backyard 110 feet in the air). Impressive.

The one thing I really don't want to do is send my Io Sig and PS (just one thank God) back to Aesthetix - they've gone twice and though I LOVE them to death, (1) I can't do without them even for a short term - I only listen to vinyl and once you've heard the Io anything else is a letdown and (2) the pain and peril of shipping these massive but fragile units 3000 miles and back just drives me insane!

Maybe I should just experiment with retubing, but that gets into hairshirt quality audio of which the Io already has so much of... I've done the NOS tubes (are they REALLY NOS? is your tube checker calibrated? is your dealer honest? is the hype on brand X tube from 1950 really justified? oh no, your tube doesn't have the -C code on it for military grade? and the rest of it) -- it's a road which I really don't want to travel down!

Plus the RFI in the right channel makes me think it's placement... makes me hope it's placement.......

I am running the Io flat out right now. I know I could go down to 72 dB instead of the 80 dB and probably conquer most of the problem right there. But (1) I'm eager to get rid of the problem whether it's very audible or nearly inaudible, and (2) I like the extra oomph of 80 dB with my 103R... it gives off slightly better output than other samples, not into overload range or distortion I don't think, but man I like the sound.

So there you go, complete audiophilia nervosa summed up in one post!

Best
Patrick

P.S. I've heard amazing things about the Nordost Thor, which the reviewer on whose recommendation I impulsively bought th EPA uses it in between his equipment and the EP15... 'course this would still bring Jim's objections into play...

Patrick

For my house wiring, the 20 A circuit is dedicated (only the audio outlets, 4 WattGate). They are "star" wired. Yes, the AC+, AC- and ground all run directly back to the circuit breaker panel. The house is grounded with 2 ten foot copper rods and is also tied to the cold water pipes. The breaker panel is 220V, so there are AC breaker on both sides of the 220V (different phases). I made sure that the heavy duty equipment in the house is on the other phase from the audio gear to further isolate it.

Sounds like you need AC isolation (such as the ultimate outlet, it will remove the nasty noise from other devices on the same circuit). The Thor would also allow all devices to operate from the same power and ground (but it is quite expensive and will not help if the ground is not good).

If you converted from 2 wire to 3 wire plugs .... do tell ... where did you get the ground wire??

If you are getting radio reception through the Io, try some shielding to get rid of the noise (such as cryotweaks http://www.cryotweaks.com/product.asp?pf_id=ERS).

For tubes, search around, there is plenty written up. From my experience the best bet is Telefunken ECC83 (12AX7) in the V1 & V2 positions. Get a good NOS matched pair, and there are still places to get good ones.

You can always try swapping the power supply cables to see (well hear) if the noise switches channels. Then at least you'll know whether it is in the power supply or the phono stage. The next thing to do is swap the tubes in right and left channel in the phono stage and/or power supply.

Oh heck, just go all out and get the second power supply. Swap out the EL-34's for some KT-66 and let 'er rip.

Enjoy!

Just a warning here: I understand that you MUST take great care when swapping the power umbilicals here. When you power the Io down and then disconnect the power cables between the Audio and PS chassis, you MUST wait at least 20 minutes before reconnecting these cables or the solid-state regulators in the PS will be destroyed. I tend to take a more conservative approach and wait an hour.