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Author Topic: Popping Noise Need Advice  (Read 11321 times)

Offline jcmusic

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Popping Noise Need Advice
« on: February 19, 2009, 09:16:37 PM »
After getting my seduction finished my tech started to mod my Otari 5050 BII, wiring directly from the heads to RCA's we are hearing a noise that sounds like the end of an LP. Anyone have any expirence with this?

jay
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
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Offline ironbut

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Re: Popping Noise Need Advice
« Reply #1 on: February 19, 2009, 11:14:33 PM »
Hi Jay, please give us some more details. Is the Seduction hooked up to Otari and a preamp? If so, try it without the Otari hooked up (no input to the Seduction). Also, see if the noise is there with the Otari hooked up but not powered up. Routing the wiring correctly around the motors and transformer is critical to prevent their noise from entering through the wiring (the signal from the heads is tiny).
If it seems to be coming from the Seduction, try hooking up a turntable/cartridge to it. If you don't have one, any source will do just to establish that the noise is not from the Otari.
steve koto
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Offline jcmusic

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Re: Popping Noise Need Advice
« Reply #2 on: February 20, 2009, 06:48:22 AM »
Hi Steve,
Thanks for replying, we have gone through almost every situation you could think of. The noise is coming from the Otari deck for sure. I was hoping that someone else had a similar problem when they modded their deck. I forgot to mention the noise is from both channels at the same time and on 2-3 second intervals.

Jay
« Last Edit: February 20, 2009, 07:46:22 AM by jcmusic »
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
 Ah Njoe Tjoeb 4000, Rogue Magnum 99, Korneff 45 SET Amp, Klipsch K-Horns Bass Bins/2" Tractrix Horns 2" BMS Drivers, Vintage Tubes.

Offline docb

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Re: Popping Noise Need Advice
« Reply #3 on: February 20, 2009, 11:00:48 AM »
Unfortunately the Otari uses coax cable instead of shielded twisted pair from the heads to the audio board. That limits the possibilities of shielding configurations. It might be worth trying to connect the ground post of the Seduction to the ground post of the Otari.
Dan "Doc B." Schmalle
President for Life, Bottlehead Corp.
Managing Director - retired, The Tape Project

Offline steveidosound

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Re: Popping Noise Need Advice
« Reply #4 on: February 20, 2009, 11:35:38 AM »
That kind of noise can indicate a discharge of DC potential to ground. Are you very sure you don't have an issue with the B+ voltage inside the Seduction?
Another very off the wall thing I experienced that caused a similar problem was - believe it or not - static discharge to ground from  metal 10.5" tape reels that were isolated from ground. It would happen more often in fast wind, but if the static charge built up to a certain point you could see a tiny static electricity arc jump from the edge of the reel to the nearest grounded point about 1/8" away, making a loud pop in the audio as it did so.  If it is more like static than isolated pops every few seconds I would suspect another cause such as a poor connection in a low level stage.
Steve Williams

you don't want to know what equipment I listen to...

Offline jcmusic

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Re: Popping Noise Need Advice
« Reply #5 on: February 20, 2009, 12:32:43 PM »
That is a possibility, but even with the seduction turned off the noise is there. We are thinking more along the lines of the cable is picking up an electronic signal from some where in the deck.

Jay
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
 Ah Njoe Tjoeb 4000, Rogue Magnum 99, Korneff 45 SET Amp, Klipsch K-Horns Bass Bins/2" Tractrix Horns 2" BMS Drivers, Vintage Tubes.

Offline jcmusic

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Re: Popping Noise Need Advice
« Reply #6 on: February 20, 2009, 04:01:56 PM »
We may have figured out the problem, seems that the wire we tried the first time around did not provide enough shielding. A change of wires and a big improvment, no more noise!!!

Jay
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
 Ah Njoe Tjoeb 4000, Rogue Magnum 99, Korneff 45 SET Amp, Klipsch K-Horns Bass Bins/2" Tractrix Horns 2" BMS Drivers, Vintage Tubes.

Offline ecir40

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Re: Popping Noise Need Advice
« Reply #7 on: February 23, 2009, 11:18:55 AM »
Popping noise was as Jay decribed. Envision the needle skipping at the end of a record. There must be a pulsating signal with some of the electonics in this deck that was being picked up by the cable since there was nothing mechanical moving while the noise was observed.

The first cable I used was just a standard shielded mic cable, it was replaced with some bulk audioquest diamondback wire which solved the noise problem. Cabling was routed the same as the stock wires with the rca's mounted at the rear of the deck.

Doc, what kind of wire have yall been using for this?

Brad
Brad

Offline docb

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Re: Popping Noise Need Advice
« Reply #8 on: February 23, 2009, 02:04:32 PM »
We reroute the stock wire. As I mentioned above, I think that shielded twisted pair would probably be a better choice than the stock coax cable if you want to replace it. I'll ask Shawn to post any specifics about how he routes the wire inside the machine.
Dan "Doc B." Schmalle
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Offline ecir40

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Re: Popping Noise Need Advice
« Reply #9 on: March 04, 2009, 10:45:46 PM »
Did another rewire and will probably settle on this in the future of doing this.

I went through my stash of Belden wire that I stock up on during demos of construction at work and found a piece that worked great.

Belden 8728
https://edeskv2.belden.com/Products/#s=8728&r=0

Allows both channels (easier to route) in one cable and was very quite.

Terminated from the heads to small switchcraft rca's staight to the seduction.

Brad
Brad

Offline steveidosound

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Re: Popping Noise Need Advice
« Reply #10 on: March 05, 2009, 10:27:13 AM »
Since that  wire is 2 pairs of 2 conductor shielded cable, are the L/R  +/- head connections on each  inner pair? If so, then what did you do with the shield ground? Is it terminated to chassis ground at the amp end and floating at the tape heads or some other configuration?
Steve Williams

you don't want to know what equipment I listen to...

Offline jcmusic

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Re: Popping Noise Need Advice
« Reply #11 on: March 05, 2009, 03:21:50 PM »
Hi Steve,
If I am not mistaken the way Brad did it was to ground one to the chassis and the other to the Seduction.

Jay
Redpoint Model D TT/Soundsmith Sotto Voce Cartridge Otari MX 5050 BII/BH Tube Repro deHavilland Model 222
 Ah Njoe Tjoeb 4000, Rogue Magnum 99, Korneff 45 SET Amp, Klipsch K-Horns Bass Bins/2" Tractrix Horns 2" BMS Drivers, Vintage Tubes.

Offline ecir40

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Re: Popping Noise Need Advice
« Reply #12 on: March 05, 2009, 03:47:57 PM »
Hey guys,

I have the drain floating at the head and grounded at the chassis bananna ground.

Brad 
Brad