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.
Two examples of good multimeters.
This is a good multimeter that will last... The extra cost feature of LoZ setting eliminates false phantom AC voltage readings. Klein Digital Multi-Meter, TRMS Auto-Ranging, Temp, Low Impedance . This is also a good multimeter. It doesn’t have LoZ though. Klein 600 Volt Digital Multimeter, TRMS Auto-Ranging, Temp
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@jea48 , when my old Radio Shack meter failed the drop test and I needed a new one (like immediately to bias my amp) I went to Lowes (because they are super close) and I bought a South Wire. How do those stack up? I saw that they had Fluke meters, but for what I thought at the time was an ungodly amount of money. I could always upgrade to a Klein; I am pretty sure that now Lowes sells them as well. |
Is this the meter you bought? Compact 3-In-1 CAT IV Digital Multi-Meter Is this the amp?
If you are only using the multi-meter to measure DC ma it's probably ok. https://www.caryaudio.com/wp-content/uploads/2013/06/CAD-280SA-V12.pdf Just curious what are you setting the DC ma bias at?
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No, @jea48 , it is actually the Southwire "10041N autoranging multimeter." I use it mostly for DC mA but occasionally I use it for checking continuity and less often for checking AC voltages. It is not like I am a tech person, but I would like to think that the readings I am taking are close to being accurate. As far as the bias on my amp, it is currently set at a few hairs (on both sides) under 260 mA. Without going back and checking, I am about sure the manual says 270 to 300; back at the end of '17 when Cary tech support would still take telephone calls, in some context the subject came up and the tech guy said to shoot for 40 to 50 mA a tube. (I think the context of that conversation was how to bias it if running less than six tubes per side.) @decooney told me that when he had his V-12 he liked it set way lower, but when I tried that I didn't think I liked it as well. Who knows, maybe it was psychological. on my end.
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