Mo-fi Ultradeck owners - popping noise from speaker upon power off


Guys, I got a mo-if ultradeck with mastertracker cartridge and I have a problem that I cannot figure out. When I turn the power switch off, I get a loud pop through my speakers. If turn the volume down or switch to another channel, then obviously I do not hear it.

I got the player replaced with another new unit and the same thing. I have tried everything - that I can physically do, replace power cord, hook up power cord to a different outlet, using different phono preamp, etc.

Does anyone else experience this? My other Project Classic SB TT does not have this at all in the same system.

I have searched the whole internet and found one post on Stevehoffman forum about experiencing the same and that person did all sorts of experimentation to no avail.

https://forums.stevehoffman.tv/threads/popping-on-power-down.1000508/

A $2500 player should NOT have issues like this. Period.
128x128dandaroy
Either a bad cap or sloppy engineering. My cheapo Sony 4k player does this, occasionally,  when resuming from pause. Hope it doesn't blow out my tweeters.
As others have noted, I had this issue with my VPI Classic 2.  VPI sent me a replacement capacitor for the motor (for free).  It was very easy to swap out and fixed the problem.
Unfortunately, I have to let go of this TT. I believe I have another defect in my turntable for which I will not be able to keep the TT. When the platter rotates, the center spindle sways or wobbles from side to side as it turns suggesting that there is some eccentricity. I took the platter off and reseated it several times with no luck. The platter seems to spin without any wobble. It is shocking to me that a $2500 table passed this quality inspection at Mo-Fi. I do not want to spend $2500 and have to worry about a warped table what it might be doing to sound quality.

https://www.youtube.com/watch?v=cve86r1Jkyk
Never noticed that with mine. Then again I always turn the volume down to a low level at the end of the record. Love the TT, my only complaint is the cheesy plastic bumpers that continually fall off the dustcover.
this unit is for sequentially timed turn on/off of amps/components, with 30 second intervals. 

adcom ace-515

https://www.usahifi.com/sites/default/files/product/494/manuals/Adcom%20ACE-515%20AC%20Enchancer%20Manual.pdf

it may solve your problem, avoid need to turn volume down.

I have one I am not using, I could put it up for sale here if you want, for what I paid, $60. or you can find them on eBay, ... they seem to be asking more these days

if it doesn't solve your problem, you can send it back, full refund, you pay return shipping.
The key is the little shock, when you touch the tonearm... the black wire mentioned was NEVER figured out... Where is it grounded.

TT pops can drive you nuts.. I thought it took a resistor to dump a cap to remove noise, when shutting down... Either the resistor is bad OR it doesn't have one hooked up, IN THE RIGHT path when shutting the switch OFF, It may be there in the on position, but gone when you flip the switch, to the OFF position. 

You follow my reasoning?It's there but need a jumper or maybe moved to a different common location, to dump the cap that's discharging.. when you flip the switch..

I don't turn switches off when I'm in concert, It just doesn't happen...
VERY bad practice. 30 min motor warmup, and the TT may not get turned off for a week at a time..

My units have platter breaks and litteral gear shifters, to engage and disengage, the platter or the motor.. 

Volume is always turned down...with an LP flip. ALWAYS.. Dual TT roll one down, and roll one up at the same time,  that is DJ 101. Blow the speaker up doing that.. Drop an arm with the volume up.. LOL BAMB... Folks will want their money back...

Regards
@dandaroy
I had the same problem with my VPI HW-19. The capacitor between the switch and the motor was the culprit. The Mo-Fi deck that you have uses the same Hurst motor as the VPI. That loud pop could damage your tweeters!
This is the motor!
http://hurst-motors.com/documents/PA_PB_Synch_DD.pdf
BTW, none of my other components make this noise. Only this TT. My other TT is quiet when switching on or off.
At least if I knew the fix, I could attempt to get it resolved. Looks like the other post of stevehoffman tried everything to no avail.
I have that exact TT and do not have this issue.  BTW, I love this table.  Just do.  
This is pretty common. I forget the electrical reason for it, but when you have a signal feeding from whatever source, be it digital or analog, into the amp, then when you turn off that gets looped back and get a little crack at the end. The lower the volume, the lower the signal, and the less of a crack.
I have two VPI tables in two different systems and have had two other VPIs prior to these that I own now, the three using 300 rpm motors have nor had any issues but the 600rpm motored Scout does the same thing your table is doing. VPI offers a fix by changing or adding a resister/capacitor to the motor. Sounds like this might be your issue as well. Enjoy the music
You found the fix. You always make sure the volume is down when powering off. I wouldn't obsess about it. Probably some weird electronic switch thingamajig phenomena.

If you like it otherwise, enjoy it. I demoed one just as it was introduced. Nice table. I think it would shine with a $5-1K MC cart and decent phonostage. I don't recall experiencing the pop however. 

The company will likely address it if enough users complain about it. Otherwise play some cool records LOUD.