I was just wondering what is the point of copper film/foil placed around the electrolytic capacitors in my PD9700 CD player. Looking at the schematics they are around all the digital power supply smoothing caps, not the analogue. The copper is not connected to ground so I can't see the point in it?
You can't see it from the outside of the player and it's not mentioned anywhere so they must think it's of some benefit?
Keep well,
Will
You can't see it from the outside of the player and it's not mentioned anywhere so they must think it's of some benefit?
Keep well,
Will
The Pioneer PD-95 has copper foils on all the capacitors 
An externally hosted image should be here but it was not working when we last tested it.
My personal opinion is sugarpill.
I tried copper sheets on top of surface mount 1704 DAC's and was able to easily notice more relaxed sound. There's even bigger difference with DIL chips, like TDA1541A, if using copper sheets sandwich: one plate beneath, the other on top. The connection between these two plates, as well as connection of this sandwich to PCB ground plane, makes the difference as well. This is easy to notice especially on NOS DAC which is very revealing of EVERYTHING.
I haven't tried copper-wrapped capacitors, but from the experience above, I recon there should be audible difference in sound, all for better. I suppose the only way would be to try and see...
Extreme_Boky
I haven't tried copper-wrapped capacitors, but from the experience above, I recon there should be audible difference in sound, all for better. I suppose the only way would be to try and see...
Extreme_Boky
I don't see how this might help. There is more than one difference between caps and ICs. The case of the latter doesn't provide any electrical shielding at all.
The outer can of elcaps is made of aluminium (not that much a worse conductor than copper BTW) which is usually connected to the negative wire/pin. I don't see how an unconnected copper shielding could have any effect then - apart from looking cool.
Regards
Charles
The outer can of elcaps is made of aluminium (not that much a worse conductor than copper BTW) which is usually connected to the negative wire/pin. I don't see how an unconnected copper shielding could have any effect then - apart from looking cool.
Regards
Charles
I think the trick is in using copper which has natural, warm sound full of harmonics and texture, instead of aluminum can only. This approach was very popular with beautifully rich sounding CD players made by TEAC. They were full of copper-wrapped capacitors. What beats me is the fact that the copper wasn't connected to ground(???) Injecting the jitter purposefully to smooth-out the sound?
Extreme_Boky
The copper is not bonded to any ground on these players. Like everything else Pioneer does - it's marketing only. Fleecing the pulic again.
The copper vs aluminum sound .... oh god, let's not debate this now. I knew some just had to launch this while reading through the thread. It would have been me if peranders hadn't jumped on it.
-Chris
The copper vs aluminum sound .... oh god, let's not debate this now. I knew some just had to launch this while reading through the thread. It would have been me if peranders hadn't jumped on it.
-Chris
Well I won't get into copper vs alu sound. But adding a layer of copper will increase the rfi/emi shielding effectivity (theoretically) Since the thickness of a shield is a factor.
Also since you have in effect 3 layers of different materials you have created a form of constrained layer damping since aluminium is very resonant and copper would constrain slightly I suppose those resonances.
The question in my mind is now only this...does it matter enough to hear the difference?
Good question. Now consider how many people are listening to CD players with worn disc motor bearings that cause vibration. Now what's the BLER rate on the disc? Never mind that everything is shaking inside the unit. Worse on the first few tracks BTW.
Then I have to ask, is oxidized copper foil more effective than shiny lacquer covered foil? The shinny stuff takes a better picture. A metallic putty might then be the perfect treatment.
Not enough research has gone into this and Pioneer released the product prematurely. I wonder if Microsoft has an interest in Pioneer?
OKay, I am kidding. If there is a technical benefit, that's not why Pioneer did this. It's marketing.
-Chris
Then I have to ask, is oxidized copper foil more effective than shiny lacquer covered foil? The shinny stuff takes a better picture. A metallic putty might then be the perfect treatment.
Not enough research has gone into this and Pioneer released the product prematurely. I wonder if Microsoft has an interest in Pioneer?
OKay, I am kidding. If there is a technical benefit, that's not why Pioneer did this. It's marketing.
-Chris
Actually I do not really wish to comment much about the copper foil shielding since it is getting a bit controversial.
For the record, I did shield the capacitors of my cd player with copper foil some years back and I did hear a difference in the playback.
The easiest way to find out if this copper foil shielding is a hoax is to try it yourself - if you have the time anyway.
For the record, I did shield the capacitors of my cd player with copper foil some years back and I did hear a difference in the playback.
The easiest way to find out if this copper foil shielding is a hoax is to try it yourself - if you have the time anyway.
If you know your capacitor jacket colors you can tell what they as the copper doesn't cover the top. The copper isn't connected to anything as the caps have a thin plastic film over them and it's not run to GND! It would have been easy to run a drain wire down to the PCB and hook it up to GND if they wanted.
It does look nice
Pioneer have put some copper shield around some of the IC's which IS connect to GND which I can understand has decent theory behind it. The pcb layout and all the power supplied and a couple of mains transformers is all good practice and well implemented.
It's not mentioned in any marking blurb. And you can't see it without taking the lid of, which, what, 0.001% of owners would do...
Will
It does look nice
Pioneer have put some copper shield around some of the IC's which IS connect to GND which I can understand has decent theory behind it. The pcb layout and all the power supplied and a couple of mains transformers is all good practice and well implemented.
It's not mentioned in any marking blurb. And you can't see it without taking the lid of, which, what, 0.001% of owners would do...
Will
The copper foil creates eddy currents as a result of magnetic fields produced by the capacitor foils. The resultant solenoidal field is mirrored by the copper foil. As any magnet physicist knows, if you create a mirror over a magnetic construct, you reduce it's inductance.
To test if this is what they are doing, the capacitance of the lytic has to be tested out to 20 Khz. If the foil makes a difference, it will reduce the dielectric starving which is caused by the eddy current induced skinning which occurs axially along the capacitor.
If they connected to both foils at the inner end of the foils, the copper will make no difference, there will be no skinning or solenoidal field..if they spaced the connections to match the lytic external connection spacing, that will cause non cancellation of magnetic field.
Check out the dc to 20Khz capacitance curve for large lytics..some of them drop down to half the capacitance...ever wonder why??
Cheers, John
To test if this is what they are doing, the capacitance of the lytic has to be tested out to 20 Khz. If the foil makes a difference, it will reduce the dielectric starving which is caused by the eddy current induced skinning which occurs axially along the capacitor.
If they connected to both foils at the inner end of the foils, the copper will make no difference, there will be no skinning or solenoidal field..if they spaced the connections to match the lytic external connection spacing, that will cause non cancellation of magnetic field.
Check out the dc to 20Khz capacitance curve for large lytics..some of them drop down to half the capacitance...ever wonder why??
Cheers, John
Hi John,
The dissipation factor does down the toilet first. Phase angles shift. Generally unpleasant stuff with a cap. Electrolytics without a DC bias do far worse things ( hysteresis). Ceramics suffer from the same thing.
Of course, the effects become more pronounced as the frequency increases. At any rate, I have doubts that the copper wrap truely helps in any meaningful way. But they take a great picture!
-Chris
The dissipation factor does down the toilet first. Phase angles shift. Generally unpleasant stuff with a cap. Electrolytics without a DC bias do far worse things ( hysteresis). Ceramics suffer from the same thing.
Of course, the effects become more pronounced as the frequency increases. At any rate, I have doubts that the copper wrap truely helps in any meaningful way. But they take a great picture!
-Chris
tubee said:
Of concern is: why the large parasitic inductance?
If the foils are wrapped so as to increase the solenoidal field, the inductance will go up fast..and, the foils will enter skin effect current redistribution faster, therebye starving the inner electrolyte area of current.. Such is the tradeoff of lead placement along the foil construct.
Cheers, John
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.