VinylRecorder Groove speed motor noise through record

[David34]

Hi ALL .. I am after some advice as I have tried everything to resolve this issue, and call upon your wisdom please!

I'm getting a "whine" through my record cuts (obviously more prominent during quiet stages of the tracks)

The whine noise is 100% from the Groove speed motor, so I have isolated it away from the cutter amp (it was on top of) and still the whine. I know it is the groove speed motor because as I adjust the groove speed, the whine changes in frequency and pitch. (Please listen to the audio sample - it paints a thousand pictures)

OK.. My ideas:

As the machine had European plugs on the ends, and I am in Australia, is there any chance that it is not earthed/insulated/the correct unit? (The Blue wave device)

Can it be what Souri describes as an "Earth loop" ?? I purchased a Furman M-10x E (Which is a Power conditioner - you run all your plugs into it - see attached link) to avoid this.
http://www.proaudio.com.au/shoppingcart/products/Furman-M%252d10x-E-10Amp-Power-Conditioner.html

I am warming my disc to 45c, using diamond heating at #10 (after running no audio through and adjusting noise levels) 45rpm. 20g weight

https://soundcloud.com/trixee/motor-noise1


Thank you all for your wisdom and assistance in advance..

[2bitcomputer]

I had a similar problem with motor noise in my cuts - The pitch of the noise varied with the pitch of the pitch motor(!) - At first I thought it was a vibrational noise but I managed to rule that out by using a spare motor and a belt drive - eventually fixed it by getting a better 12v power supply. Actually I got 2 and split the various loads between them.
Cable routing could also be involved...

[David34]

Thanks for the reply!

So when you say the 12v power supply - you mean the "Blue wave" box that Souri supplies as standard?

I'm presuming as the leads come out of that, it controls the voltage to the groove speed motor?

May I ask what you purchased to replace it please?

[David34]

ps: Cable routing? I have it standard as per Souri setup, i just replaced his ordinary RCA cords with gold plated ones. Wish the rig wasn't RCA's.

[David34]

OK.. So I had a very cluey mate come over and he plugged his oscilloscope into one of the leads that comes out of the groove speed control unit. The signal was smooth and not a PWM as we had originally thought.

We tried several different things, like bypassing the Main units EQ, but still the groove speed "pitch" noise is there,.. .

We tried isolating the Main unit out of the rack, as suggested by Souri (Earth Loop) still the pitch noice that increases with groove speed dial.

Now I am seriously thinking it is the "BLUE WAVE" box that Souri has supplied. What else could it be? Vibration from the motor down the shaft and into the cutting diamond??

Surely not??

Any help will be greatly appreciated !! Surely someone has had this.

PS: I am using a resharpened diamond with less than 4 hours cutting time. Everything is calibrated well - 15g weight.

[tragwag]

I don't know exactly what you mean by 'blue wave', are you talking about the power supply for the main unit?
with my system, it's what I call a power inverter. a radioshack made box that turns (here in the US) 120V wall power into 12V DC by way of a plug usually found in car systems.
I haven't had any issue with that myself, though I can see it being a problem.

I've personally bypassed the majority of the souri audio path, and just go:
audio interface out->main unit->meter in->power amp in->cutting head

[sat159p1]

that noise comes from the motor which is in the aluminium tube (where the cutterhead is mounted on). you cannot eliminate it. i have also tried everything inlcuding even silent cut without main unit audio connection and without sucking machine. it's till there. by the way. check your turntable connections/grounding. it may be the player. but a little motor hum will be still there. it's a ground noise, 50Hz and comb frequencies above.

[sameal]

A side note about furman: BEWARE what they call "power conditioning". They used to sell (and maybe still do) fancy rack boxes which had no power conditioning circuit in them - just daisy chained outlets, but still called it a power conditioner.

From my understanding, it has to have a transformer to do it right.

I bought a few used a long time ago that were fancy rack boxes and got rid of them. I won't buy furman again.


(I'll leave the merits of power conditioning argument out of this.)

[David34]

Thanks for your replies folks. Surely I don't have to live with this sound??

It's more prominent when cutting, for example Acoustic music, at 45rpm where I change the groove speed during quiet moments to save on vinyl disc space.

I just can't accept this as a thing to live with..

Any other VR users help me please???

[markrob]

Hi,

Have you isolated the noise to be electrical or mechanical? If you cut a silent groove with no connections to the cutterhead from the power amp and still have the noise, that would indicate it to be mechanical.

Mark

[David34]

Thanks Mark - No I have not tried this yet and I thank you for this advice.

So I will remove the two leads that go into the cutter head - that isolates the audio input.

Brilliant! I'll try this in a minute and get back to you. .

[David34]

OK.. Silent groove, cut a test cut.. Moved the groove speed controller dial, technics pick up - NO PITCH MOTOR SOUND..

So it is an audio signal, not mechanical from the motor.. .

What's next? Process of elimination..

Really appreciate everyones help here..

[markrob]

Hi,

Here are some suggestions to help you track down the solution:

1. Try using a speaker(s) in place of the cutterhead to monitor the noise pickup. That way you won't have to keep making test cuts to narrow down the issue.
2. Start by using only the power amp with no input connections. If the amp has input level controls, see if the noise follows the setting of the controls. Also try shorting the inputs as many amps are high impedance.
3. Work your way back to the start of the audio chain to see where the noise is entering the system.
4. Check the motor and add a .1uf 50V or higher ceramic capacitor across the terminals right at the motor. This will help kill any motor brush commutation noise. Making sure the case of the motor is ties to a good earth ground can be helpful. Twisted and possibly shielded wiring to the motor might also be helpful. If you go shielded, try terminating the shield at one or both ends of the line.
5. If you can, try to power the motor from batteries or another DC power supply to eliminate the possibility of the motor controller being the source of the problem.
6. Check your grounding of all the devices in the setup. It might help to float the audio device(s) with a ground lift adapter to see if that helps. In that case, you'll need to establish a single point earth ground for the audio components and motor controller. You don't want to run without a safety ground long term if that fixes the problem, but you may need to may need to play with earthing schemes to get rid of the noise. Note that there are audio isolation transformers available that can aid in fixing ground loop problems. I assume you are running a consumer style unbalanced system. They are more prone to this type of problem.

Hope that helps.

Mark

[David34]

Mark that is fantastic and I will try each and every step you have mentioned!

You will hear back from me in a week!

[tragwag]

as a VR specific step: remove the mixer entirely

that would be my first move

[David34]

What is the purpose of that terrible little mixer other than to switch from pickup to cutting diamond?

The volume i adjust on the audio source anyway so I don't require the volume slider...

When you guys have done away with it., have you replaced it with anything or just bypassed altogether?

[tragwag]

it's just to switch between monitoring the playback arm, and the cutting audio path.

I don't monitor when I cut, so I just did away with it.

[David34]

Thanks all.. I am told by Souri that it is an earth/ground loop..

I will pull everything apart as suggested and start from scratch until I get to the source of the noise!

Appreciate everyones suggestions on here!

[sat159p1]

Guys, have you all heard the OP's soundlocud file? It's the motor noise that can't be eliminated. As simple as that, but sorry, no way to get rid of it.

[markrob]

Guys, have you all heard the OP's soundlocud file? It's the motor noise that can't be eliminated. As simple as that, but sorry, no way to get rid of it.

Hi,

He indicated that noise disappeared when he cut a silent groove with no electronics connected to the head. If that was correct, then its not mechanical noise due to the motor. Its electrical noise generated by the the motor. That should be able to be reduced or eliminated by careful attention to grounding, filtering, and/or shielding.

Mark