2. amps-preamps
  3. 193768-203308

Did I just cook my preamp?

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.

obarrett
jea48
4,787 posts
 

I spoke to the landlord/my point of contact for the management company yesterday. He repeatedly told me he ‘never had any trouble with the electricity’ in my apartment until now. I don’t think I can make him understand just how serious this is.

Sure you can. You can easily show him, with your multi-meter.

The ground contact is Hot 120Vac to the heat radiator.

 

My goodness it’s 120Vac on both settings. It is a hot ground. That’s so disturbing. Someone could easily have died and I’m surprised someone hasn’t yet.

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If you have any problem with him just mention you could have been electrocuted if you had touched the radiator with one hand and the HOT 120Vac Amplifier metal case with the other hand. electrocuted, dead.

Don’t forget to remove all of those 2 to 6 power receptacle extenders.

obarrett OP
28 posts
 

Yes I’m going to replace them with power strips and I’ve obviously stopped plugging anything with three prongs in there. As for the landlord, he’s sent someone to fix it, but he seems unwilling to replace the preamp. He doesn’t really seem to understand what voltage is or even what a ground is. I will try to get the super to convince him of the significance but I have little hope. I can tell him this stuff about electrocution, but he will just say that he’s ‘never had a problem.’

immatthewj
3,300 posts
 

@obarrett , I don't suppose you have renter's insurance?

obarrett OP
28 posts
 

The deductible is too high, the v2 of the 110LP new is only $600 and renter’s insurance would give only the actual/market value of the used one I have, which is considerably less than $600.

it’s not really a problem, I’m just grateful to be alive. If I had touched the tone arm of my turntable at the same time as I was touching my CD player, I would’ve died, even if both were turned off

jea48
4,787 posts
 

@obarrett 

https://youtube.com/shorts/t1jazBAT3M4?si=uweJOKoK0xRxrYDH

In your video, when you measured for voltage from the receptacle ground contact to the heat radiator the test probe connection to the receptacle ground contact was poor. The 120Vac reading was not a solid contact connection.

You should have used the OEM power cord ground. Insert the mm probe into the center ground contact. That also frees up your hand and you can focus your eyes on the probe connection to the radiator valve and the meter.

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WARNING: I hope you saved the plastic outlet cover plate you removed from the receptacle. When you remove the 2 to 6 outlet extender everything metal you see is HOT 120Vac to anything grounded. Don’t put your body between them.

** EDIT: On second thought. Don’t remove this one. Just leave it be.

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Also in case you haven’t thought of it. You are going to have to move the speakers and audio equipment out of area the electrician will be working. Take some pictures first of the equipment where it normally is sitting. Just in case he asks.

The Electrician needs a minimum of 3ft working space in front of the wall outlets. The more the better. A happy Electrician is a productive Electrician.

 

Did you watch this video?   Reverse Polarity Bootleg Ground Testing 

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