Systemdek IIX Noise Floor

[neddyboy]

My TT has a pretty high noise floor.

I've had a IIX with the standard Profile arm (Jelco SA250ST I think) and a Signet MK110E MC cartridge for five years or so. I've done a lot of work restoring and/or modding it. The mods have been mild and reversible –– sound deadening mat on suspension and motor mount, acrylic platter, record weight, RCA terminals instead of the DIN cord. I use a home-brew MC step-up transformer box with Beyer Dynamic transformers, but I get the same low level noise with the MC inputs on my Apt Holman preamp and other MC phono stages. The TT sits on a wall mounted shelf with a pair of Vibropods under each foot. I've tried a Musical Fidelity phono stage too with no difference in the noise level.

I've lowered the noise level a bit with each change, but I still get a rumble/noise (not hum) under the music. I love the sound of this table compared to the Rega 2 I had before, in fact all of the unsprung decks I've had, but the noise level is bad. Does anyone have any further ideas that cost less than the cost of the table itself? Is the noise just a fact of life?

[Trackside]

Difficult to tell what is wrong without some measurements - do you have a test record and some digital recording software? Typical rumble will come from the main bearing or from the motor and or belt.

[neddyboy]

Oh my, I do have recording software. Will GarageBand do? I don't have a test record. Any suggestions? I've been learning as I go with this TT as I have not been playing vinyl for 30 years. Back then I didn't care about all these details.

My Systemdek has the spiral bearing and it SEEMS fine, looks good, spins well etc. The old motor's shaft was bent in the UPS incident, and the pulley has a very very small wobble. It was apparently distorted in the crash. I'm in the process of having a new one made. The motor is a low-hours Premotek. I bought the pulley a while ago and I do not remember where or what type. Probably eBay.

[Trackside]

A bent pulley will not be ideal for optimal sound quality - can't you just pull the old one off and put it on the new premotec motor? Also check the optimal capacitor value for the premotec as it will differ from the old Airpax motor and the wrong alue will give a lot of motor vibration. The oil pump bearing requires exactly the right quantity and type of oil to work properly - plenty of info about that on this forum.

[alternativeroute]

Which oil did you use? I had the same deck and did not follow the oil recommendation

The table still rumbled... Reread the manual, and re-cleaned the bearing and used the proper oil. Hey presto. Worked a treat.

Your next step would to be to try a power supply. Sounds a bit loony but those Premotech motors can run a whole lot smoother than they do with just a cap and a resister... For a budget PS look at a DIY geddon power supply (google it)...

[neddyboy]

Trackside: If only it were that easy! I only have the original pulley, the one that's deformed. I'm finally going to have a new one machined -- I've been looking for a replacement for years. The pulley wasn't that big a deal compared to all the other issues I've had to solve, but now I'm down to the smaller things. Good info on the Premotek though. I'll check on that,

Alternativeroute: It's been years since I dealt with the bearing. Knowing me I probably used the wrong oil. I'll read up. The PS looks cool. I've been eyeing Valhalla boards, but they're a bit pricey. Thanks guys.

[Trackside]

The actual pulley is deformed? - that must have been a bad accident Good luck with getting a new one made up but that and the correct grade of oil ( Gear oil AFAIK) should have your rumble problems fixed.

[neddyboy]

Just following up -- I put the new bearing oil and a new ceramic bearing in, and the rumble has diminished. The old bearing was in sorry shape! FYI new bearing from Boca Bearing in FL. I also acquired an isolation transformer and have been running the TT through it, but I've heard no difference. Still looking into the 'Geddon.

[Alec124c41]

Is the pulley deformed, or is the motor shaft bent?

Cheers,
Alec

[Simon Moon]

Also check the optimal capacitor value for the premotec as it will differ from the old Airpax motor and the wrong alue will give a lot of motor vibration. The oil pump bearing requires exactly the right quantity and type of oil to work properly - plenty of info about that on this forum.

I believe I am having this problem!

Do you know what the correct value is for the Premotec?

[abril]

What is the motor part number?
Should be on a label stuck to the underside of the motor.
What is the present capacitor value?

If it is wrong the motor will be very noisy.