Wow,
that's REALLY BAD!

Sounds like something from a dimmer as it's very rich in harmonics or it could be from the head motor drive. The frequencies don't seem to line up with either 50 or 60Hz which makes me suspect something in the camera is where the noise is originating.

Certainly this needs attention. You can SEE the problem very clearly on the Vegas T/L. Those regular spikes are noise that shouldn't be there.

Bob.

Ahh yes, I see them now Bob - thanks.

I tried to record 2 min. without anything attached to it and it was ok - no sound at all. The sound is also there if I just put it in cameramode and speak into the mic attached.

Do you think Sony will be able to locate it and repair it - I don't have any experience with sony repair yet ?

/Ulf

I can only speak from local experience.
Down here Sony Broadcast products are handled by an entirely different set of places to their consummer products and those who work on the broadcast stuff are gnerally pretty good so I'd say you should be fine.

I suspect the noise is coming from the circuit that drives the Voltage Controlled Amplifier. When you turn the AGC off what happens as you turn the gain between 0 and 10?

In the PD150/170 turning AGC off and on doesn't change much, it just switches control of the VCA between the level detector and the manual gain control. I wouldn't be surprised if you find the noise gets worse with AGC off as you turn the gain down!

Bob.

Thanks again Bob, I really appreciate all your help and knowledge on this one.

I tried several thing, and found some thing very interesting.
If I have the audiolevet at 50% (where the markers are) the sound is quite noticeable, but if I turn the audio 100% up, it is less noticeable, not gone but less.

Another thing I found out that is very interesting is, if I turn on the camera and leave it for some minutes to go into the standby mode, but still on (I suspect the motor to stop completely or something like that) the sound is gone totally.

Thanks again, Bob.

/Ulf

Both things agree with what my thoughts are.

The noise is from the head motor, in Standby the heads stop spinning, no noise source.

As you turn the manual gain down you're affecting the voltage coming out of the VCA.

That's what I really don't like about the audio section in the 150/170. Most of the audio noise in the mic circuits doesn't come from the preamp as such, it comes from the VCA and even with AGC off that is not bypassed, so you get this silly situation where the noise doesn't follow the gain when you're in manual, yuck.

Sony improved the S/N in the 170 by 6dB by adding a 10 cent capacitor to filter the noise coming into the VCA from the control circuit. Also in both the 150 and the 170, the audio lines run from the audio bridge in unshielded flexible PCB. No wonder the BBC decided to rip their 150s apart and use external mic preamps.

But regardless get the camera looked at. It might not be the audio section at all, something could have gone wrong elsewhere that's generating way too much RFI.

Bob.

I had a similar problem with a PD250. We had blown a capacitor in the input
due to static electricity. We were an office with carpet and needed to change to a
different mic. When we walked across the carpet and attached the mic we noticed
the noise.

They were able to fix it. I don't remember the exact price but was around $150
including head cleaning/ tape path lube.

Thanks for your input RCourtney - I'll call Sony next week and talk to them.

/Ulf

And my thanks too. I'll run all this by our local Sony repair facility as well.

Jack

Thanks again all for your time on this - I'll report back when I talked to Sony. Now back to productivity :) I hate to fiddel with things like this.

/Ulf

Agree with Bob, a camera mounted mike will pickup the head motor noise as well as the zoom motor. That's why professional best practices dictate using an off-camera mike.

Also, leaving an unterminated cable plugged into a mic input will make it act as an RFI antenna. Don't do that.

Talked to Sony today. I will bring the camera to them, tomorrow and they will have a look at it - it's only 15 KM away from home - Denmark is a small country ;-)

/Ulf

Just to be clear, this is electrical pickup, like RFI. It's not the sound of the motors it's the electrical noise from them. Worse still the peaks of the interference are higher than the audio recording.

I think you are right Bob. I have made a very long failure description based on your knowledge as well - thanks again, Bob.

/Ulf

2 hrs. before I was going to Sony, I just looked at the camera once more. A freind of mine had said I should try to get ground connection on a pipe or something like that when I was trying the thing. It did not make any difference, but after that I just gone through the menus on the camera and found omthing called "mic noise reduction" that was on. I switched it to off, and BINGO - it seems to be gone. I hope it stays away!! :-) There still might be some kind of problem with this NR thing, but the sound is super now - no "extra" noise, so I will save mu $200 an hour for the Sony guys for now.

Thanks again Bob and all others who have been great help here. I simply love this forum, that you also can find very competent answers on OT things that others you in your whole production.

/Ulf

To me the hum sounds like a ground loop problem. Try running it on battery power alone with "mic noise reduction" back on to confirm.

If the noise is gone try a three prong to two prong adapter on the extension cord when you use the AC adapter and see if the hum disappears.

If not borrow another one to make sure you don't have a defective AC adapter.

If the problem exists on battery power as well it may be the result of the AGC circuitry which would be exascerbated by the noise reduction circuitry. Which is why it wasn't as noticeable with manual gain.

It may also be worth noting that the Sony PD170 had a hum problem affecting a notable number of units that were fixed under the warranty. Many people noticed the hum when the LCD screen was opened. The affected units fell under the 1213500 serial number being given via ABCDV.com from Global DVC by Jan Van Der Meer for the PAL version of the camera.

Theo Vessies Sony Communication & PR Coordinator Business Solutions of Sony Benelux B.V. stated that from start some (but not all) PD170 did have audio problems with an opened LCD screen.

"All new shipped PD170's starting Januari 20, 2004 with serie number 1213500 and up, will have a modification and according to this report have better signal/noise ratio than DSR-PD150. For buyers with this audioproblem in Holland with a Silversupport guarantee Sony will offer a free modification. For the rest of the world please contact your local Sony repaircenter."


For Dutch Buyers:
"Gebruikers welke op dit moment het genoemde audioprobleem bij de DSR-PD170P constateren kunnen de unit via de Sony Silversupport garantievoorwaarden laten checken en modificeren. Productiemodellen vanaf serienummer 1213500 zijn reeds aangepast en vallen derhalve buiten de modificatie regeling. Praktisch komt het erop neer dat elke unit welke vanaf 20 januari 2004 vanuit de Sony voorraad geleverd is op dit punt is aangepast."


More here.

John