Folks:
I'd appreciate your advice in debugging an issue with my Pearl / Ono phono stage. The source for the boards and most of the parts was a group buy hosted by Promitheus (http://www.diyaudio.com/forums/group-buys/52278-pearl-phono-pcbs-group-buy.html). It has been in service for about 10 years, performing brilliantly. Over the past six months or so, I've noticed a fast, "fluttery" sound in the background that is volume dependent. The sound is louder when the unit is grounded. At normal listening volumes the sound is not glaring but certainly noticeable, and I'd like to kill it.
It was suggested to me that the sound may be the result of a bad solder joint, so I resoldered every conection on both the Pearl and Ono boards (but, admittedly, not the power supply). The problem persists.
I have DVMs but no other test equipment.
Your suggestions are appreciated.
Regards,
Scott
I'd appreciate your advice in debugging an issue with my Pearl / Ono phono stage. The source for the boards and most of the parts was a group buy hosted by Promitheus (http://www.diyaudio.com/forums/group-buys/52278-pearl-phono-pcbs-group-buy.html). It has been in service for about 10 years, performing brilliantly. Over the past six months or so, I've noticed a fast, "fluttery" sound in the background that is volume dependent. The sound is louder when the unit is grounded. At normal listening volumes the sound is not glaring but certainly noticeable, and I'd like to kill it.
It was suggested to me that the sound may be the result of a bad solder joint, so I resoldered every conection on both the Pearl and Ono boards (but, admittedly, not the power supply). The problem persists.
I have DVMs but no other test equipment.
Your suggestions are appreciated.
Regards,
Scott
Attachments
Since you did not say if it was in both channels, I will assume it is. Start with the PS section, in which the big elkos are suspect because it is 10 years old. However, it will only take a few minutes to set you DMM on AC and start with the fuse between ground, check voltages working your way forward, including both sides of the terminal block. Which begs the question, even though the pics are not very detailed, why does there appear to be a large resistor between the two white wires, which many people call neutral? There should only be a wire connecting them, with no chance of opening up. Also, why is there a resistor between the hot wires? It is not a zero ohm resistor.
wayne (it's an honor!) and propitious:
Mea culpa -- yes, the sound is in both channels.
propitious:
Thanks, I'll start with the power supply and measure forwards, but since the sound is in both channels I expect to get comparable results when testing both power supplies. FYI: the schematic for the Pearl included 4.7R 0.5 watt resistors and a 0.1 uF film cap as an AC filter; Wayne's white paper said they were optional, but I included them in my build (see https://www.passdiy.com/pdf/pearlphono.pdf).
Swapping out the two big power supply caps is easy; I'll see if that helps and will report back in either event.
Thank you for the responses!
Regards,
Scott
Mea culpa -- yes, the sound is in both channels.
propitious:
Thanks, I'll start with the power supply and measure forwards, but since the sound is in both channels I expect to get comparable results when testing both power supplies. FYI: the schematic for the Pearl included 4.7R 0.5 watt resistors and a 0.1 uF film cap as an AC filter; Wayne's white paper said they were optional, but I included them in my build (see https://www.passdiy.com/pdf/pearlphono.pdf).
Swapping out the two big power supply caps is easy; I'll see if that helps and will report back in either event.
Thank you for the responses!
Regards,
Scott
propitious:
Thank you! As expected, the voltages in my power supply measured fine and were consistent between the two channels. I replaced the Panasonic caps in the power supply with Nichicon KGs, the only 10,000 uF caps on hand. The Nichicons are considerably wider than the Panasonics and had to be crammed in, but they fit.
The fluttering sound is still there but is considerably quieter; at normal listening levels it is now inaudible. At some point I may go on a hunt to completely eradicate the fluttering, but for the time being I am more than content.
Much appreciated!
Regards,
Scott
Thank you! As expected, the voltages in my power supply measured fine and were consistent between the two channels. I replaced the Panasonic caps in the power supply with Nichicon KGs, the only 10,000 uF caps on hand. The Nichicons are considerably wider than the Panasonics and had to be crammed in, but they fit.
The fluttering sound is still there but is considerably quieter; at normal listening levels it is now inaudible. At some point I may go on a hunt to completely eradicate the fluttering, but for the time being I am more than content.
Much appreciated!
Regards,
Scott
Folks:
Just a quick follow-up. Promitheus' Pearl / Ono kit group buy in 2007 included a 1 uF Mundorf capacitor in parallel with the 10,000 uF cap in the power supply. I've replaced the Mundorf as well, this time with a Mundorf EVO Oil unit. The fluttering sound that had been so prominent has been diminished by about 24 db and I am thrilled.
Thanks again to propitious for the gentle push and my gratitude to Wayne and Nelson for their generosity!
Regards,
Scott
Just a quick follow-up. Promitheus' Pearl / Ono kit group buy in 2007 included a 1 uF Mundorf capacitor in parallel with the 10,000 uF cap in the power supply. I've replaced the Mundorf as well, this time with a Mundorf EVO Oil unit. The fluttering sound that had been so prominent has been diminished by about 24 db and I am thrilled.
Thanks again to propitious for the gentle push and my gratitude to Wayne and Nelson for their generosity!
Regards,
Scott
Attachments
Last edited:
Folks:
It's been about 7 months since I replaced the power supply caps in my Pearl / Ono phono preamp. The "fluttery" sound is diminished as previously noted, but still evident in both channels. I'd like to resolve this issue for good or figure out an alternate phono preamp path.
Would it make sense for me to replace all of the electrolytic and film caps on the Pearl and Ono boards themselves? This presumes the problem lies in those capacitors and not somewhere else. If there might be another cause, what might it be? And if this is unresolvable, what should the successor be?
Regards,
Scott
It's been about 7 months since I replaced the power supply caps in my Pearl / Ono phono preamp. The "fluttery" sound is diminished as previously noted, but still evident in both channels. I'd like to resolve this issue for good or figure out an alternate phono preamp path.
Would it make sense for me to replace all of the electrolytic and film caps on the Pearl and Ono boards themselves? This presumes the problem lies in those capacitors and not somewhere else. If there might be another cause, what might it be? And if this is unresolvable, what should the successor be?
Regards,
Scott
Jim:
My cartridge is a Lyra Lydian Beta. It is old and has seen a decent amount of use but it continues to track well. I don't hear any degradation in its performance -- it isn't raspy and the tonal balance sounds fine to me. Are you suggesting it might be the cause of the "fluttery" sound (the sound could also be described as a soft puttering)? Do phono cartridges start making new odd sounds in their declining years (not unlike their owners)?
And yes, it was fun chatting with you at BAF2017. That festival is always a blast.
Regards,
Scott
My cartridge is a Lyra Lydian Beta. It is old and has seen a decent amount of use but it continues to track well. I don't hear any degradation in its performance -- it isn't raspy and the tonal balance sounds fine to me. Are you suggesting it might be the cause of the "fluttery" sound (the sound could also be described as a soft puttering)? Do phono cartridges start making new odd sounds in their declining years (not unlike their owners)?
And yes, it was fun chatting with you at BAF2017. That festival is always a blast.
Regards,
Scott
Also, I'd check for bearing noise and loose ground connections, like the ground posts.
There should be a ground from the bearing to the post, I believe, on the table. Guess it depends on the table.
Check for corrosion or loose connectivity. Would also clean all connections. Use 100% alcohol or Caig Pro Gold.
There should be a ground from the bearing to the post, I believe, on the table. Guess it depends on the table.
Check for corrosion or loose connectivity. Would also clean all connections. Use 100% alcohol or Caig Pro Gold.
Folks:
The plot thickens. A little background may be helpful: my turntable is a Maplenoll Apollo, which uses two refrigerator air compressors to support the air-bearing platter and air-bearing tonearm. The Maplenoll’s air pumps are located in a separate room and are on a dedicated 15A circuit. The turntable and speed controller (Pyramid’s SG-4 sinewave generator) are plugged into a homemade power distribution box which is connected to a Furman AC-215A power conditioner. The other components connected to the power distribution box include my preamp (Aleph P 1.7), phono preamp (Pearl / Ono), DAC (Schiit Bifrost Uber) and music server. The Furman AC-215A is plugged into its own dedicated circuit.
The “fluttery” sound was less evident last night, but there were other sounds in the background. I noticed a significant increase in the background noise when the turntable’s air pump was turned on, and a slight increase in the background noise when the speed controller was turned on. With both the air pump and speed controller turned on, the volume of the background noise was about the same as I had heard over the weekend but the noise itself was different. With the air pump and speed controller turned off, the background noise was significantly diminished.
I found an ancient Blue Point Special but did not install it last night or perform any of 6L6’s or Vince’s suggestions (which I can still try), as I was preoccupied by a child-like fascination with turning on and off a variety of electrical devices in my house to see what impact they had on the phono stage background noise. For the record (small pun intended), I previously found that connecting a ground wire to either my phono preamp or the turntable increased the background noise.
I don’t know which device in my house causes the “fluttery” sound, but the problem now seems simpler to me: how do I block all of the electrical noise infiltrating my system?
Regards,
Scott
The plot thickens. A little background may be helpful: my turntable is a Maplenoll Apollo, which uses two refrigerator air compressors to support the air-bearing platter and air-bearing tonearm. The Maplenoll’s air pumps are located in a separate room and are on a dedicated 15A circuit. The turntable and speed controller (Pyramid’s SG-4 sinewave generator) are plugged into a homemade power distribution box which is connected to a Furman AC-215A power conditioner. The other components connected to the power distribution box include my preamp (Aleph P 1.7), phono preamp (Pearl / Ono), DAC (Schiit Bifrost Uber) and music server. The Furman AC-215A is plugged into its own dedicated circuit.
The “fluttery” sound was less evident last night, but there were other sounds in the background. I noticed a significant increase in the background noise when the turntable’s air pump was turned on, and a slight increase in the background noise when the speed controller was turned on. With both the air pump and speed controller turned on, the volume of the background noise was about the same as I had heard over the weekend but the noise itself was different. With the air pump and speed controller turned off, the background noise was significantly diminished.
I found an ancient Blue Point Special but did not install it last night or perform any of 6L6’s or Vince’s suggestions (which I can still try), as I was preoccupied by a child-like fascination with turning on and off a variety of electrical devices in my house to see what impact they had on the phono stage background noise. For the record (small pun intended), I previously found that connecting a ground wire to either my phono preamp or the turntable increased the background noise.
I don’t know which device in my house causes the “fluttery” sound, but the problem now seems simpler to me: how do I block all of the electrical noise infiltrating my system?
Regards,
Scott
Attachments
Vince:
I have wondered if the problem is DC on my AC line; if so, perhaps a snubber in the power distribution box would resolve the issue. But that box is powered by the Furman AC-215A, which I had previously thought would address that issue. Perhaps not.
By "AC network adaptor," do you mean the powerline adaptors I use to connect my server to the house router? That's an interesting thought. I believe the powerline adaptor in my music room is on a different circuit than the Furman conditioner and the power distribution box but, as my experience with the turntable's air pump demonstrates, the fact that two different circuits are involved may mean nothing. I'll look into that tonight.
tiefbassuebertr (and 6L6):
Yes, I'll short the inputs to the phono preamp to see if that makes a difference. There have been no unremarked changes to the phono preamp, but perhaps other changes to my system have created a ground problem. More investigation is needed.
Thanks for the counsel! I'll report back in due course.
Regards,
Scott
Folks:
Gadzooks -- youse guys is good!
Vince was spot-on: the powerline adapter used to connect my music server to the house router is creating some of the background noise (rather weird noise, in fact). Shorting the inputs left me with a quiet, rushing sound but none of the other artifacts I'd been hearing.
Is the quiet rushing sound something that can be ameliorated by replacing all of the caps on the Pearl and Ono boards, or is that noise something I should simply learn to live with?
Is there a filter I should install, presumably in the power distribution box, that will kill or quiet the sounds leaching in on the AC line?
Much appreciated,
Scott
Gadzooks -- youse guys is good!
Vince was spot-on: the powerline adapter used to connect my music server to the house router is creating some of the background noise (rather weird noise, in fact). Shorting the inputs left me with a quiet, rushing sound but none of the other artifacts I'd been hearing.
Is the quiet rushing sound something that can be ameliorated by replacing all of the caps on the Pearl and Ono boards, or is that noise something I should simply learn to live with?
Is there a filter I should install, presumably in the power distribution box, that will kill or quiet the sounds leaching in on the AC line?
Much appreciated,
Scott
Scott,
How loud is the rushing sound with the inputs shorted? Do yo need to turn up the volume of the preamp to hear it? Are you merely listing to the noise floor of the Pearl? It's a phonostage, it will have a floor that's audible if you crank it.
It could be that the caps are aged, but I very highly doubt it... Lots of other stuff to look at first.
Here's some good info on DC blocking
Mains DC and Transformers
How loud is the rushing sound with the inputs shorted? Do yo need to turn up the volume of the preamp to hear it? Are you merely listing to the noise floor of the Pearl? It's a phonostage, it will have a floor that's audible if you crank it.
It could be that the caps are aged, but I very highly doubt it... Lots of other stuff to look at first.
Here's some good info on DC blocking
Mains DC and Transformers
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.