[jea48]

"* X2 needs to be connected to the equipment chassis ground point. This makes X2 winding lead the neutral conductor. (The grounded Conductor) This will also connect to the silver color screw on the output duplex receptacle."

Just want to triple check - I just grounded the shields to Chassis ground

Now - we ground X2 AND the White wire to the same Chassis ground?

see pic

Can I leave the white wired to X2 and I just run one wire from X2 to chassis ground
OR
do I need to run Wire X2 to Chassis ground
AND White wire to Chassis ground

Then I will probably need to install spades to get all those wires to fit on one chassis ground screw lug

see pic

Just run a jumper wire from the other X2 terminal screw to the chassis ground terminal like you show in your picture. Or from the same one as the white neutral wire.

Make sure you check the voltage and polarity at the transformer's output duplex receptacle outlet. Follow my instructions in my last post.

Yes after you check the voltage and everything thing is fine you need to re- terminate the stranded wires using Sta-Kon eyelets

Example of,
https://www.emisupply.com/catalog/thomas-betts-stakon-c1010-noninsulated-ring-terminals-1210-hole-p-16152.html?utm_source=googprod&utm_medium=product_search&utm_campaign=google-product-search-us-en&utm_term=TNB-C10-10&gclid=CLWS27aI_NACFZC2wAodVDMBGg#.WFWf51zm9-w

[jmdesignz2]

@jea. Thanks I will check

@jea48

Wiring done - -
on the iso trans output - hot to ground is 118V, neutral to ground is 0V

however, I checked the hot on the duplex outlet that the ISO trans plugs into
TO the hot connection coming OUT of the ISO Trans - this is 238V

So - the Iso trans output is Out of Phase with the input? I have a lamp plugged into the output of the iso trans now - seems ok

[jea48]

@jea48

Wiring done - -
on the iso trans output - hot to ground is 118V, neutral to ground is 0V

however, I checked the hot on the duplex outlet that the ISO trans plugs into
TO the hot connection coming OUT of the ISO Trans - this is 238V

So - the Iso trans output is Out of Phase with the input? I have a lamp plugged into the output of the iso trans now - seems ok

For now lets not address that. That's a simple change.

First I would like you to measure for voltage from the hot contact of the duplex receptacle connected to the output of the ISO transformer to the other branch circuit wall duplex receptacle hot contact the other audio equipment plugs into.  Does it measure zero volts, nominal, or does it measure around 238Vac?
 IF zero volts, nominal, the two power sources are in phase with one another. IF it measures 238Vac, the two are out of phase with one another.

Post back your results.

[jmdesignz2]

For now lets not address that. That's a simple change.

First I would like you to measure for voltage from the hot contact of the duplex receptacle connected to the output of the ISO transformer to the other branch circuit wall duplex receptacle hot contact the other audio equipment plugs into.  Does it measure zero volts, nominal, or does it measure around 238Vac?
 IF zero volts, nominal, the two power sources are in phase with one another. IF it measures 238Vac, the two are out of phase with one another.

Post back your results.

from the seconds dedicated 20A line to the ISO Trans duplex receptacle out

Hot to Hot = 0V
Hot to ground = 118V

so that means the iso trans output is in phase with the 2nd dedicated 20A output circuit

[jmdesignz2]

For now lets not address that. That's a simple change.

First I would like you to measure for voltage from the hot contact of the duplex receptacle connected to the output of the ISO transformer to the other branch circuit wall duplex receptacle hot contact the other audio equipment plugs into.  Does it measure zero volts, nominal, or does it measure around 238Vac?
 IF zero volts, nominal, the two power sources are in phase with one another. IF it measures 238Vac, the two are out of phase with one another.

Post back your results.

The hum is actually much worse now from the speakers

[jmdesignz2]

For now lets not address that. That's a simple change.

First I would like you to measure for voltage from the hot contact of the duplex receptacle connected to the output of the ISO transformer to the other branch circuit wall duplex receptacle hot contact the other audio equipment plugs into.  Does it measure zero volts, nominal, or does it measure around 238Vac?
 IF zero volts, nominal, the two power sources are in phase with one another. IF it measures 238Vac, the two are out of phase with one another.

Post back your results.

I bypassed the ISO transformer and the hum is less than half it was from the rewired iso trans...

I suppose I should rewire the ISO trans back to what it was or is there something else?

[jea48]

from the seconds dedicated 20A line to the ISO Trans duplex receptacle out

Hot to Hot = 0V
Hot to ground = 118V

so that means the iso trans output is in phase with the 2nd dedicated 20A output circuit

so that means the iso trans output is in phase with the 2nd dedicated 20A output circuit

That is correct.

IF you measure from the hot contact of the duplex receptacle the ISO transformer plugs into to the hot contact of the other 20 amp circuit good chance you will measure around 238Vac. IF that is the case that means one 20 amp branch circuit is fed from Line 1 and the Other is fed from Line 2 in the electrical panel.

IF you feel your connections are good, test the 2 mono amps. You should be good to go.

 You should still buy some crimp lugs to make better secure connections. I prefer eyelet, ring, type Sta-Kons.

  Those wires you see that are not under the terminals screws of the transformer screws basically just reduce the size of the stranded conductors/wires of the power cords to only those under the terminal screws. 

 

[jea48]

I bypassed the ISO transformer and the hum is less than half it was from the rewired iso trans...

I suppose I should rewire the ISO trans back to what it was or is there something else?

Before you put it back the way it was try reversing the Hot and neutral of the power cord feeding the primary winding of the ISO transformer, at the transformer screw terminals.
 Check the output voltage at the receptacle and check the AC polarity at the output receptacle again. It will be the same. The only difference will be the Hot contact of the output receptacle will now be in phase with the hot contact of the wall receptacle the transformer is plugs into. Not sure though that will help with the hum.

The problem with the way you had it wired originally it is not electrically safe. Both of the secondary leads that were connected to the output duplex receptacle were both hot conductors. The secondary winding was floating above ground.

[jmdesignz2]

Before you put it back the way it was try reversing the Hot and neutral of the power cord feeding the primary winding of the ISO transformer, at the transformer screw terminals.
 Check the output voltage at the receptacle and check the AC polarity at the output receptacle again. It will be the same. The only difference will be the Hot contact of the output receptacle will now be in phase with the hot contact of the wall receptacle the transformer is plugs into. Not sure though that will help with the hum.

The problem with the way you had it wired originally it is not electrically safe. Both of the secondary leads that were connected to the output duplex receptacle were both hot conductors. The secondary winding was floating above ground.

Thanks JEA48

I will try that - right now, I am enjoying the sound of these amps direct from the dedicated line.

[jea48]

I bypassed the ISO transformer and the hum is less than half it was from the rewired iso trans...

I suppose I should rewire the ISO trans back to what it was or is there something else?

I bypassed the ISO transformer and the hum is less than half it was from the rewired iso trans...

I went back and reread this post of yours again.....
 
See the thing is, the dedicated circuit that feeds the wall duplex receptacle outlet is fed from a grounded AC power system. The same as you have now with the secondary of the ISO transformer wired as a grounded system.

 But when you plugged both amps directly into the wall duplex receptacle the hum drops in half.

That is puzzling indeed.

Just curious, how far is the ISO transformer from the nearest power amp? Maybe now that you are using single ended ICs the magnetic field of the transformer is being picked up by the ICs. You might try to get the transformer as far away from the nearest amp as possible.

If you get a chance still try reversing the feed hot and neutral wires on the primary side of the transformer.
Jim
 

[jmdesignz2]

Jim - the transformer is at right angles to the amps which are on shelves about 12 inches above the ground. Right in the middle about 6 inches behind the amps on the floor is the iso trans.

You are probably right, the culprit is the combo of the iso trans+ single ended ICs + power cords picking up the magnetic field?

I will try reversing the hot and neutral on the primary side but the system is sounding pretty good right now.

[jmdesignz2]

I went back and reread this post of yours again.....
 
See the thing is, the dedicated circuit that feeds the wall duplex receptacle outlet is fed from a grounded AC power system. The same as you have now with the secondary of the ISO transformer wired as a grounded system.

 But when you plugged both amps directly into the wall duplex receptacle the hum drops in half.

PS - the hum drops by much more than half