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
4,788 posts
 

@obarrett 

I sent you a PM.

Click on the two Web Links. Especially  the Reverse Polarity Bootleg Ground Testing Video.

Just in case the electrician only uses a plug in circuit tester and says they look Ok to him.

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.         04-01-2025 at 01:11am

Here is a photo of a two wire old rubber cloth covered conductors Bootleg grounded outlet . The wiring is really old. pre-Thermoplastic, PVC, insulated wire. PVC Thermoplastic insulation is really old too. THHN/THWN replaced it, going from memory, in the early 1970s.

Here is good video on Bootleg ground wired outlets. (FYI, a bootleg ground is a NEC code violation. Always has been)

Reverse Polarity Bootleg Ground Testing

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obarrett OP
28 posts
 

I suggest you try another test. Plug an OEM power cord into outlet 1. Insert one of the test lead probes into the IEC female ground contact. 

Turn mm to V and touch the other test lead probe to a bared (unpainted) metal place on the heat radiator. You can also use the LoZ setting on the mm as well.

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.

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.

The building super claims to be an electrician and he’s supposed to work on it tomorrow. When he opens it up I’ll have a look.

here is a video documenting it: https://youtube.com/shorts/t1jazBAT3M4?si=uweJOKoK0xRxrYDH

jea48
4,788 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.

.

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?

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