I have a Simaudio Moon 110LP phone preamp amplifying a Dynavector 20X2L cartridge on a VPI Classic. It feeds in to an Outlaw Audio RR2160 amp which drives Magnepan LRS speakers.
I recently moved and two months in I realized my speaker placement wasn’t quite right, so today I reorganized my listening room. This involved unplugging some power cables but I kept most of the interconnects in place. I did have to disconnect the phone stage from the amplifier.
After getting things back into place, I listened to some music using coaxial input before reconnecting the interconnects of the phono stage. When I tried to, I actually got some electric current that burned my hand slightly. This came from the back of the amplifier. I made sure everything was unplugged and tried again - this time a spark and smoke from the interconnect making contact to the back of the amplifier.
I’m so confused why this would happen, but eventually I did get everything connected. Now the output from the phono stage is just a bump every 1 second. It doesn’t amplify the signal from the TT.
My amplifier has a built in phono stage and using this I was able to verify that the turntable is still producing a signal. The built in phono stage sounds terrible, however, as thin and flat as paper. It is music, however.
When I connect the phono stage to the power, the blue light on the front illuminates for a moment and then goes dark.
Incredibly, when I was unplugging the phono preamp, I actually got some current from simply touching the exterior of the box. Something is seriously wrong and dangerous with my setup, and this box was grounded to the turntable with a ground cable, which was connected to the outlet with a three prong cable with ground.
Has anyone experienced anything like this before? I will email Simaudio and see if they’ll repair it. I’m also taking recommendations for replacements. I liked the 110LP and maybe will just replace with the 110LPV2.
Yes I verified your question about subwoofer in earlier comment today. The subwoofer pins are only two even though the power cord has three prongs. So I assume it’s ungrounded. But note the CDP is grounded and the amp is sitting on top of it and connected via coaxial cable.
Yes the sup amp is ungrounded. AC power wiring in the sub amplifier is double insulated.
So where was the spark fault current path? What is the source.
No doubt there is a difference of potential, voltage, between the output of the phono preamp and the RR2160 amp signal ground, (outer shell) of the analog input jacks.
Saturday, check for voltage from the outer shell of the output RCA jack of the phono preamp to the outer shell of the analog input RCA jack on the RR2160 amp.
Should of done that to begin with...
Both units powered on.
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I think we are back to square one.
When you get a chance check the wall outlets the equipment plugs into for proper Hot / Neutral polarity and for equipment ground. At least you will be able to check them off your list.
I don’t remember reading a post where you responded to this.
If you did not read, measure, high voltage, or any voltage... Question... Is the SMPS 120Vac plug in blades the same width or is one wider than the other? Therein polarized. If both blades are the same reverse the SMPS 180 degrees in the receptacle and perform the test for high voltage again.
That is from the long winding thread I posted yesterday.
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One other thing I didn’t think about yesterday. The tests for the SMPS I had you do for checking for AC mains high voltage on the output side of SMPS were unloaded.
I don’t know what I was thinking yesterday... I should of had you do the tests with the phono preamp connected to the SMPS. Therein the connected load. Likely a defective connected load that might be overloading the SMPS. A real world test...
Probably also should have had you use the wall outlet that the SMPS is normally plugged into. IF, one of the blades is not polarized, therein it could be plugged in either way, it would be plugged in the direction that caused the electrical spark fault event.
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IF you want to try the test again.
Test procedure is a little different than yesterday.
You will still use the OEM 3 wire power cord to connect one of the mm test lead probes to the wall EGC. ( an extension of the probe lead)
1) Set up for the test.
Before the SMPS output power cord connector is plugged into the phono preamp.
Connect an IC (interconnect cable) into one of the RCA output jacks on the preamp. Extend the other end of the IC so it will be easy for you to touch the other test lead probe of the mm to the outer ground shell of the IC RCA plug.
2) insert the mm black test lead probe into the female EGC ground contact of the plugged in OEM power cord.
3) Set mm to "V". (mm will default to V AC.)
4) Plug SMPS output power cord connector into phono preamp. (Blue light starts doing its’ thing. Preamp has DC power. SMPS has a load on its’ output)
5) Touch mm test lead probe to the outer ground shell of the IC RCA plug.
What voltage is measured, displayed, on the mm? No need to check for LoZ voltage. The connected load of the preamp is more than enough load. LoZ would only add a small additional load.
6) Check again for a voltage reading after the blue light on the front of the preamp is no longer lit for any difference of voltage measured.
7) Just to cover all the bases... Repeat the test measuring for DC voltage. You probably should let the phono preamp do a reset by disconnecting the SMPS power cord plug from the preamp. Just trying to cover all the bases.
At some point i was going to buy an outlaw amp but I read a thread that a few people said it caught on fire I would not plug that back in .I don't rember it being an audiogon thread.this could be destructive to all your equipment.be careful.
In looking at the forums alot of the outlaw amps had a ground loop hum and people were going from 3 to 2 prong bypassing the ground.as stated above this is frowned on.hope you get this fixed.there are alot of smart people on here some are electric engineers. Good luck and make sure you have an observer that can throw the breaker off or some surge protector that can trip.when we built our hospital the young apprentice electrician got fried on the roof .we could not save him be careful.
I could be wrong, ( the amp hasn’t been checked out yet) but I think the phono preamp is the problem.
I base that on this resent post from the OP.
But since all this I’ve listened to about 3 hours of music using the amp with no issues whatsoever (phono disconnected of course).
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He also posted the same thing earlier in the thread.
@jea48 RR2160 amp has built in DAC and has two coax inputs. One to CD player one to bluesound node. Since this episode I’ve been listening to music off the node without problems.
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