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jhewes

Buzz on phono input

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Hi all,

 

I am getting a buzz on the phono input on my Scott 299C. It's low enough that I don't notice it until I turn the volume knob to the 12 o'clock position.

 

The turntable is grounded to the amplifier chassis. When I disconnect the cables from the turntable the buzz goes away. The buzz does not appear on any other inputs.

 

Any thoughts on how to make this go away? 

 

Many thanks, 

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Clean your phono cables & check for cracks .  Clean your phono inputs

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On the RCA ends coming from the turn table if possible squeeze them in the way to make them grab the RCA jack firmly, another possible cause of a loud buzz can be a poor connection at the inner conductor but I doubt that is your problem. If you want to confirm its a connection problem turn the amp up to where you hear the buzz then gently rock the RCA in the sockets. If it is a connection problem you should be able to get the noise to come and go. This noise can also be caused by a problem with your turntable cables/cartridge/grounding or the location of your turntable. You want to turntable as far away from your amp as possible (especially the power transformer on the right side of the amp).

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Thanks Craig. The cables are rock solid Luminous Audio cables that actually tighten onto the connector. I've gone between the two MAG LO inputs and get the same thing. Once the turntable is disconnected it's dead quiet, as it is on all the other inputs.

 

I lifted the ground on the turntable but no joy. 

 

As far as location I have little choice in that matter. The turntable is indeed right next to the amp but there's nowhere else to go. 

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Ok totally from left field but.... have you turned the AC cord for the turntable upside down.  i.e. so the prong that was neutral is now hot and vice versa?

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Does your turntable have a plastic arm or metal arm?  If you touch one of the screws that holds your cartridge on, does the buzz go away?  How loud is the music at "12 O'Clock", if you play music at that volume level and smoke comes out of your speaker, then you need to back the volume down and not worry about this.

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Hi all,

 

1. Craig - by swapping the position of the amp and TT on the table, I was able to move that power transformer further away. But that didn't help (but I'm leaving it in that configuration anyway).

2. I swapped out cables between the TT and the amp, but that didn't help - until I connected the ground wire that is built into the second set of cables. Two ground points helped a lot. the buzz isn't entirely gone but it is low enough so that I can go to what i consider full volume (12-1 o'clock on the volume knob) without hearing the buzz. 

3. I did wiggle the cartridge connections a little but that made no difference either way. The tonearm is aluminum on a VPI Classic 1. 

4. I had tried reversing the plug on the amp, no change. I cannot do the same with the TT since it is 3-prong. I did move that plug to a different outlet - no change. 

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57 minutes ago, jhewes said:

4. I had tried reversing the plug on the amp, no change. I cannot do the same with the TT since it is 3-prong. I did move that plug to a different outlet - no change. 

did you try a cheater (ground lift) on the TT?

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Followup:

 

This evening I did some more fiddling, and found that one ground wire was enough, so that wasn't the solution. I was wondering if the ground point on the amp chassis made a difference - it did not.

 

It could have been moving that power supply further away from the turntable, as Craig suggested. It could have been moving the floor lamp from behind the console (with an AC wire in close proximity to everything). Who knows. But now the buzz is gone. There is still hum, but it's well below and not much of a bother (although all other inputs are dead quiet).

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7 hours ago, audiowize said:

  How loud is the music at "12 O'Clock", if you play music at that volume level and smoke comes out of your speaker, then you need to back the volume down and not worry about this.

 I consider the 12:30 to 1 o'clock position to be the maximum safe volume level. When i was a teen I would blow tweeters on a weekly basis, so I gained some experience with clipping and overload. It is the point at which the sound level is satisfying yet does not crowd the room or cause my ears to bleed or speaker components to smoke. 

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Like I always ask in troubleshooting: When did this begin?  Yes I see you moved some things as a cure and the buzz turned to a hum.

 

E.g. is this a new for you turntable? new for you amp?  Have there been other changes to your system?

 

WMcD

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3 hours ago, WMcD said:

Like I always ask in troubleshooting: When did this begin?  Yes I see you moved some things as a cure and the buzz turned to a hum.

 

E.g. is this a new for you turntable? new for you amp?  Have there been other changes to your system?

 

WMcD

The amp is new. I had been running an HK solid sate amp until last Friday. 

 

The hum was always there, very low, but the buzz was much more apparent. 

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On ‎10‎/‎7‎/‎2016 at 4:15 PM, jhewes said:

Thanks Craig. The cables are rock solid Luminous Audio cables that actually tighten onto the connector. I've gone between the two MAG LO inputs and get the same thing. Once the turntable is disconnected it's dead quiet, as it is on all the other inputs.

 

I lifted the ground on the turntable but no joy. 

 

As far as location I have little choice in that matter. The turntable is indeed right next to the amp but there's nowhere else to go. 

  What side of the amp?

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What phono cartridge are you using ..check the leads to the arm from the cartridge.. Or if your

M m cartridge stylus is mounted correctly .. Check riaa phono tubes in your amp..

Possible lose tubes or bad tube

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On 10/8/2016 at 4:32 PM, NOSValves said:

  What side of the amp?

The turntable WAS on the right, amp on the left. I switched them, bring that transformer on the right side of the amp away from the turntable.

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Okay, well since the noise subsides when the turntable is unhooked. Their had to be something going on with the turn table or its possible a grounding issue is present with the phono section shielded signal cables inside the Scott. 

 

I have a few more questions

 

  Have you tried both MAG 1 and 2 inputs?

 

  What input are you using?

 

 What cartridge are you using?

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Sorta related; when I was setting up my last turntable I found a distinct noise that is hard to describe. I discovered that the wireless router nearby was causing a disturbance in the field when data flowed.

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