To Aesthetix users

I use a PS Audio Ultimate Outlet (20A) which is simply a 1:1 isolation transformer. There is no restriction of dynamics. It cleaned up some grunge coming in on my AC power lines.

Also, I use PS Audio power cords, they really helped lower the noise floor and increase dynamics.

I don't know how many power supplies you use with your Io, remember that each one draws about 150W. A device such as the EP-15A should be sized accordingly.

Any way to try before you buy or get a money back guarantee?

Enjoy the music.

Oldvinyl

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

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!

Good point Jafox. I don't wait an hour though. Also remember to first disconnect the AC power cable before disconnecting the power supply umbilical.

One other thought about the hum. My SME arm had a DIN-RCA Music Metre silver interconnect that was fine in the first setup. When I moved, this cable picked up hum in the new setup. I tried several well regarded cables and settled on the Nordost Quattro Fil. By far, it had the best shielding (lowest hum). Turns out that it matched ny listening preferences best too.

One way to test this theory would be to simply disconnect the phono leads in to the Io and note if the hum is still there. The next step is to disconnect the hum in to the amo and note if the hum is still there.

I have found that Telefunken ECC83 (12AX7) in the V1 and V2 position significantly reduces noise level and provides incredible transparency.

Another ideal choice would be RCA black plate 12AX7/7025. A matched quad selected for low noise would suit the bill.

Tungsram 12AX7s are way less expensive and also dead quiet.

Have you tried swapping tubes out in the power supply?

If you have a tube tester, it may be time to check out all the tubes.