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Discussion Starter #1 (Edited)
...coming from my phono pre-amp. It is volume dependent. I have a 12ft run of rca's from phono amp to pre-amp...too long for an unbalanced run?

actually the noise is coming from my speakers...but only occurs when the phono amp is on...:eek:
 

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Discussion Starter #2
it's not a hum...more a buzzing sound. At lower levels its inaudible, but when the volume is cranked it can be heard, especially between songs and gets louder the more I crank it. My phono pre has tubes in output stage. Bad tubes maybe?
 

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I read it wrong the first time, if it is volume dependent, then it's more in the front end. Disconnect the turn table first and see whether the buzzing goes away. If it doesn't, try disconnect the phono amp from the preamp and see whether the buzzing goes away.


Do you have the phono preamp plug into the same outlet as the preamp and power amp? If not, you might have ground loop problem. You put the turn table and phono amp so far away from the rest, is there any way to put them closer together?


If disconnecting like I suggested above stop the buzzing, first try to use an extension to power the phono preamp from the same outlet of the preamp and power amp and see whether that reduce the buzzing.
 
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Sounds like a ground issue.
 

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...coming from my phono pre-amp. It is volume dependent. I have a 12ft run of rca's from phono amp to pre-amp...too long for an unbalanced run?

actually the noise is coming from my speakers...but only occurs when the phono amp is on...:eek:

Keep the cable from the turntable to the phono preamp very short; 2 feet maximum.

The cable from the phono preamp to the amp is less critical, but 12 feet is undesirable for any unbalanced cable.

Try changing cables in each case and see if the problem is changed, or not.

Also, run a ground wire from phono preamp to everything else.
 

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Discussion Starter #6
ok...today I decided to take all of your advice and swap out cables. I also decided this would be a good time to clean up system cables that had been used and later disconnected and were just contributing to a general untidy mess behind my rack.
having done that, before swapping cables I turned my system on and listened without music playing. I had to put volume at 12 o'clock and put my ear to my speaker to hear this noise I've been worrying about...and even then it was very faint to the point I would consider it a non issue. Well, I surmised those unused cables were causing some kind of interference because the grunge was gone.
so...I put an album on and it sounded great. cranked it up a bit...no noise...great. By the time side one was finished the grunge was back.
I am pretty sure cables are not the issue.
Now my guess is that when the tubes in the phono pre get warm, they somehow cause this noise. So...if that's the case, would the tubes themselves be the culprit...or is my phono stage on the blink?

Anyone had this issue?

this is the first piece of tube gear I've owned so I am in new territory.
 

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It’s probably not tube related. Try this but be careful. Warm up the hifi including the phono pre. Turn up the volume with the turntable on. Don’t play an album. Does the hum get louder as the volume increases? If yes, try to move the cables and see if the hum gets louder or softer. If so, it’s a grounding issue. The solution can be hard to fix other than finding the bad ground.
 

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Tubes don't inherently have buzzing, I designed very high gain tube guitars amps, much higher gain than phono stage. Buzzing is not a problem at all. You might hear a slight hissing sound when you crank it up.


You might have a dirty connection, the outer shell is the grounding, if it is loose, or have dirt, you might not have a good connection. Make sure everything is nice and tight.


The suggestion I gave using an extension 3 prong power cord to power the phono preamp by the same outlet of the power amp and preamp should help reducing the ground loop noise, but if you are happy, don't worry about it.
 

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Discussion Starter #9
It’s probably not tube related. Try this but be careful. Warm up the hifi including the phono pre. Turn up the volume with the turntable on. Don’t play an album. Does the hum get louder as the volume increases? If yes, try to move the cables and see if the hum gets louder or softer. If so, it’s a grounding issue. The solution can be hard to fix other than finding the bad ground.
yes it gets louder with volume increase. I moved the cables but no diff in the sound. I've had ground loop issues in the past with my cable box...this is more a gritty buzz than a hum.

Tubes don't inherently have buzzing, I designed very high gain tube guitars amps, much higher gain than phono stage. Buzzing is not a problem at all. You might hear a slight hissing sound when you crank it up.


You might have a dirty connection, the outer shell is the grounding, if it is loose, or have dirt, you might not have a good connection. Make sure everything is nice and tight.


The suggestion I gave using an extension 3 prong power cord to power the phono preamp by the same outlet of the power amp and preamp should help reducing the ground loop noise, but if you are happy, don't worry about it.
not clear on what you mean by using a 3 prong cord. The phono pre uses a wall wart (possible cause?) which IS plugged into a Triplite power unit, which has a 3 prong cord.
just to be clear...I don't get the noise until the phono pre warms up for 10 minutes or so which is why I guessed a tube issue.
 

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Get the wall wart as far as possible from the interconnects.
 

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I assume you have 3 prong outlet like this:
https://electronics.howstuffworks.com/everyday-tech/question110.htm


Use this kind of 3 prong extension so you have the neutral from the same 3 prong plug that power the power amp and the preamp:
https://www.amazon.com/s?k=3+prong+extension+cord&ref=nb_sb_noss


Point is powering up the phono preamp with the 3 prong extension from the outlet that power the power amp, you are grounding the phono preamp with the same ground as the power amp. You avoid ground loop ( grounding problem) that causes hum and buzz.


If your phono preamp has only TWO prong with plug like this, then don't worry about it.
https://www.amazon.com/s?k=2+prong+extension+cord&ref=nb_sb_noss_1


Managing the grounding is VERY important to avoid hum and buzz.
 

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Discussion Starter #12
ok I did a little experiment.

this morning I fired my system up, except for the phono pre-amp...let it warm up for an hour or so. My Parasound P5 pre was switched to input 1, which is my TT input. Turned volume to 12 o'clock. Dead quiet.

I then turned on the phono pre...dead quiet.
5 min later...dead quiet
10 min later...dead quiet
15 min later...left speaker has some faint noise, right speaker dead quiet
20 min later...left speaker noise is louder, right speaker has faint noise
30 min later...both speakers have noise at same level

I should note that neither turntable was turned on during this little test.

I would think that a ground issue would be audible as soon as I turned the phono pre on...no?

when tubes go south what are the characteristics...is the sound degraded or does the unit stop working?
 

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ok I did a little experiment.

this morning I fired my system up, except for the phono pre-amp...let it warm up for an hour or so. My Parasound P5 pre was switched to input 1, which is my TT input. Turned volume to 12 o'clock. Dead quiet.

I then turned on the phono pre...dead quiet.
5 min later...dead quiet
10 min later...dead quiet
15 min later...left speaker has some faint noise, right speaker dead quiet
20 min later...left speaker noise is louder, right speaker has faint noise
30 min later...both speakers have noise at same level

I should note that neither turntable was turned on during this little test.

I would think that a ground issue would be audible as soon as I turned the phono pre on...no?

when tubes go south what are the characteristics...is the sound degraded or does the unit stop working?
That's a good test, yes, you are correct, ground issue is independent to warm up time. it either have it or not.


Do the same experiment again after warm up with noise, disconnect the turn table, the phono preamp until you can pin point which one cause the noise.


I won't pin it on the tube just yet, I never have experience tube making buzzing noise, I worked enough with tubes to tell you this. How old is you preamps and power amps? Another possible thing is one of the filter caps inside might be old.


BUT don't speculate at this point, just pin point which one is the problem by disconnect one at a time first. Then post back.
 

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I forgot to answer, when tubes get old, usually it just lose gain and more distortion. In guitar amp, it's not necessary a bad thing until the power drop to the point that it's not loud enough. BTW, those preamp tubes can last a long long time. The power tubes ( which you DON'T have in the phono preamp) wear out much faster.


How old is your phono preamp with tubes?


The tubes in the signal path will not give buzzing even if it is old. The only tube if you have that is the rectify tube that can possible give buzzing. I don't have the schematic, you never give the brand and model, so there is no way I can tell whether your preamp has a rectify tube.


I am more suspect the buzzing is from power supply some where, so it's important for you to pin point which device cause the buzz.
 

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My Parasound P5 pre was switched to input 1, which is my TT input. Turned volume to 12 o'clock. Dead quiet.
The Parasound P5's Input 1 is, of course, a standard line input. But you have not said what happens if you utilize instead the P5's built-in phono preamp (connections shown on bottom left corner).
 
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Discussion Starter #16
That's a good test, yes, you are correct, ground issue is independent to warm up time. it either have it or not.


Do the same experiment again after warm up with noise, disconnect the turn table, the phono preamp until you can pin point which one cause the noise.


I won't pin it on the tube just yet, I never have experience tube making buzzing noise, I worked enough with tubes to tell you this. How old is you preamps and power amps? Another possible thing is one of the filter caps inside might be old.


BUT don't speculate at this point, just pin point which one is the problem by disconnect one at a time first. Then post back.
I disconnected each turntable one at a time...same buzz remains. The P5 is about 3-4 years old...amp is just over a year old.

I forgot to answer, when tubes get old, usually it just lose gain and more distortion.


How old is your phono preamp with tubes?


The tubes in the signal path will not give buzzing even if it is old. The only tube if you have that is the rectify tube that can possible give buzzing. I don't have the schematic, you never give the brand and model
it's a Pro-ject Tube Box DS2 about 2 yrs old. I don't lose gain...but I DO have distortion
 

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Discussion Starter #17
The Parasound P5's Input 1 is, of course, a standard line input. But you have not said what happens if you utilize instead the P5's built-in phono preamp (connections shown on bottom left corner).
I can't utilize the P5 phono section. As I stated in my original post my turntables require a 10-12ft run to the pre-amp...which is,of course, too long of a run.
 

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I can't utilize the P5 phono section. As I stated in my original post my turntables require a 10-12ft run to the pre-amp...which is,of course, too long of a run.
Temporarily place a turntable(s) on a table, chair, the floor, etc., close to the Parasound to check noise.
 
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I disconnected each turntable one at a time...same buzz remains. The P5 is about 3-4 years old...amp is just over a year old.



it's a Pro-ject Tube Box DS2 about 2 yrs old. I don't lose gain...but I DO have distortion

I looked at the picture of Pro-ject Tube Box DS2, it has only two tubes for a two channel preamp, so you don't have a rectify tube. I highly doubt the tubes are old after only 2 years even if you use it often.


1) How about disconnect the Pro-ject Tube Box DS2 from the preamp ( the 12ft cable)?


2) jiggle the cable between the Pro-ject Tube Box DS2 to the preamp, when you have the buzz, see whether moving the cable change the buzz.You did say when you clean up the cables, the buzz got lower, I still want to rule out bad connection.
 

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Temporarily place a turntable(s) on a table, chair, the floor, etc., close to the Parasound to check noise.
Good idea, follow this.
 
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