Switch on thump

[ciderglider]

I have a Systemdek IIX, and when I switch the motor on (using the switch on the front of the plinth), there's a switch-on thump noise that gets into the phono stage, and out to the speakers, louder than I'd like.

Do all IIX units have this issue, or is mine deective in some way? I imagine the switch could be faulty, or maybe not wired up correctly.

The switch on the front of the plinth doesn't have a neon indicator. (The Instruction Manual on this site states that the switch has a neon.)

The noise isn't a show stopper, I just switch the motor on before powering up the phono stage, and switch it off after I've powered the phono stage down.

[nascar03]

No thump with my IIX.
graham

[sb11]

From memory mine used to do it before I ditched the stock motor in favour of a Origin Live DC motor kit. Going that way is somewhat expensive and overkill to cure the thump, but the sound improvement is immense.

One way that should cure it is to wire an X2 rated contact suppressor across the switch contacts, RS part number 206-7825 should do the job.

[ciderglider]

Thanks for the advice. I have thought about the Origin Live DC motor - was it easy to fit to the IIX?

[sb11]

The motor was easy to fit. The only challenge was cutting a hole in the metal base as the OL motor is more cylindrical than the "pancake" style stock motor. It's only a couple of mm too deep, but enough to stop the base fitting properly. So it Hopefully that makes sense. Even that wasn't much work with a drill and file or dremel style tool. Another option I guess would have been to pad out the base mountings with a few washers. As well as the incredible difference in sound, you also get 33/45 at the turn of a switch. This my wife appreciated for the ability to play singles.

[Trackside]

In what ways did the sound improve with the OL DC motor upgrade? - I'm particularly interested in any improvements in pitch stability.

[sb11]

Difficult to describe mainly because I did the upgrade about 5 years ago. Simply everything was better , which doesn't really help you. Pitch stability was much improved, bass was tightened up and a clearly mid range. From memory it was a big step change, not as dramatic as this years change from stock Linn Basik Plus to Audiomods arm, which was a real OMG moment.

[willb]

Re: O.P's thump:

It's probably either a dirty switch which needs a clean with servisol or the 2 caps across the switch need replacing. My IIX900 has a couple of 22 or 33nf (0.033uf) polyesters (MKT, orange drop type), but X2's would be better. Need to be 400v dc as it's for mains AC.

Re: SB11's OL motor:
The best thing to do with that heavy baseboard is to remove it altogether!
That's what Systemdek did with the 900's and 2X2's anyway. It was cheaper to make and sounded better (most people took 'em off anyway). The bit of hardboard under the later models was just to cover the mains wiring for safety.

Generally the order of play was:
1) remove base
2) fit better armboard (on IIX's as 900's were alloy anyway)
3) Fit acrylic platter.

Damping does help, but only if it's LIGHT, like cork or thin sorbethane/deflex fitted under the alloy sub-chassis. Heavy damping defeats the object of the design and won't improve things.

One thing I did was to replace the original motor with a low vibration Premotec one from a rega which is much smoother and quieter. Used with a decent thrust-bearing (available from at least 2 E&*y sellers), will be not far shy for a lot less outlay!

I just wish I could get a new set of springs as mine have seen better days and trying to get a response from Audio Note is like waking the dead

[abril]

As said the thump is almost certainly down to the switch or the capacitors across the switch contacts.

The OL DC kits do not have the best of reputation for speed stability so probably your best bet if you want to replace the motor is one of the new updated Premotec motors which produce much less vibration than the old type if used with with the right supporting components.

[sb11]

I hadn't realised what a controversial subject the OL DC motor kits are. There is a lot on the web in various forums, criticizing the kits for value for money, lack of motor feedback, speed stability, etc. All I know is that based on sound quality it works for me, which is what matters. I can't remember how I discovered them, it may well have been a review on TNT audio.

[KeepSpinning2]

It's true about Audio note not answering back, I emailed them about there
feet for there turntables and once they found out I had a Systemdek I heard
nothing back,and about your switch maybe you need a new one and if it's not
add a cap across it.


KS2

[MadPom]

Sucess thanks to advice on this forum!

Hi Gents just to say i was getting a switch off thump seroiusly loud and cringe making. I put a post on the forum and was told it was likely to be the capacitors.

I took the bottom of the turntable no obvious sign of damage but i decided to replace the capacitors anyway there's four in total a couple of large ones one end and 0.33uf 400V and 0.47uf 400v at the other two smaller ones 0.01uf 400v each

I found the correct values available from parts express (dayton audio caps) but had to bump the order up to reach minimum so I got some cable crimps a crimping tool and a 6 inch digital vernier as well.

I swapped them all out - result no noise at all except the click from the switch itself. The record player is playing at the correct speed and if anything sounds better - probably a bit more speed stability with the new caps. Very worthwhile. I cut a quarter inch of my tone arm earth and stripped it back - bit less crackle now too. Tools required soldering iron, solder sucker, side cutters, solder and a couple of philips screwdrivers. A spot of glue to fix the nylon circuit board spacers to the underside of the table too.

Many thanks.