You could use the pairs 9-10 up to and including 21-22 and 25-26 up to and including 29-30 for the critical capacitors and the other pairs for the less critical capacitors. You have a good match between left and right and accurate first RIAA poles then.
Thanks Marcel. 🙂 🤚
I did as you suggested.
This is a possible combination of the pairs.
Is it possible to do better?
I did as you suggested.
This is a possible combination of the pairs.
Is it possible to do better?
Sel n° | More Critical (C17, C18) | Values (uF) | Less Critical (C19, C20) | Values (uF) |
1 | 9-10 | 7,02 – 7,01 | 31-32 | 6,58 – 6,57 |
2 | 11-12 | 7,00 – 7,00 | 33-34 | 6,57 – 6,55 |
3 | 13-14 | 7,00 – 6,99 | 3 5-36 | 6,55 – 6,55 |
4 | 15-16 | 6,99 – 6,98 | 37-38 | 6,55 – 6,53 |
5 | 17-18 | 6,98 – 6,97 | 39-40 | 6,52 – 6,52 |
6 | 19-20 | 6,97 – 6,97 | 1-2 | 7,08 – 7,06 |
7 | 21-22 | 6,96 – 6,96 | 3-4 | 7,04 – 7,04 |
8 | 25-26 | 6,70 – 6,68 | 5-6 | 7,03 – 7,03 |
9 | 27-28 | 6,66 – 6,63 | 7-8 | 7,03 – 7,03 |
10 | 29-30 | 6,63 – 6,60 | 23-24 | 6,94 – 6,73 |
Thanks for this Nick. There's only one schematic in that article https://imrad.com.ua/userdata/modul.../banner/cy-xxi-v-7-karta-naprug-jpg6TT9F0.jpg
It's a bit hard to read but is the "transadmittance cascade at the output" a pnp common emitter output stage with a constant current load?
The input FETs are 'sorta' cascaded by npn BJTs but that's not the output.
Yes it is
, - open collector of CE stage loaded with CC in class A (and later T-shaped overall RIAA NF network with neumannpole+tau1...tau4 5-75-318-3180-7950 us). The main advantage of using such a transadmittance output @ riaa-preamp with overal NF deep RIAA EQ 40 dB from 20 hz to 20 kHz FR is almost constant loop gain from 0.5 Hz to 50 kHz [ https://photos.app.goo.gl/yDRBsG5rEvZtPotL9 ] : ultralow THD with large overload margin, good RIAA accuracy, no THD increase @ LF, no problems with HF stability.
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The effect is bound to be negligible but if you are very perfectionistic, you could try to combine the highest values for the more critical capacitors with the lowest values for the less critical capacitors and the other way around. That is:
More critical: 9-10 with less critical: 39-40
More critical: 11-12 with less critical: 37-38
More critical: 13-14 with less critical: 35-36
More critical: 15-16 with less critical: 33-34
More critical: 17-18 with less critical: 31-32
More critical: 19-20 with less critical: 23-24
More critical: 21-22 with less critical: 7-8
More critical: 25-26 with less critical: 5-6
More critical: 27-28 with less critical: 3-4
More critical: 29-30 with less critical: 1-2
Has anyone checked the distortion of the signal in an LP which gets worse toward the center.
The OPA 1656 may reduce EQ Distortion to 0.001% however the DIP8 NJM2068 is giving 0.008% thd. Is there an audible difference other then noise. A 2 chip solution may only reduce EQ THD by half.
Noise performance is 20+ dB below surface noise.
The OPA 1656 may reduce EQ Distortion to 0.001% however the DIP8 NJM2068 is giving 0.008% thd. Is there an audible difference other then noise. A 2 chip solution may only reduce EQ THD by half.
Noise performance is 20+ dB below surface noise.
Compared to vinyl + cartridge distortion and groove noise, everything related to an opamp is negligible. It is just a mental training, nothing about resulting sound.
Thanks Marcel,
Mostly for your patience. 😉
But this answer is useful not so much for pursuing perfection, but more for understanding the logic of an optimal pairing.
And since the boring work has already been done (measuring the capacitors and reporting the values), choosing which group to solder is the easy part.
I attach screenshots of the optimized pairings.
(I haven't yet found a way to copy a table and paste it here. In the one above I had to enter the data one by one...)
Mostly for your patience. 😉
But this answer is useful not so much for pursuing perfection, but more for understanding the logic of an optimal pairing.
And since the boring work has already been done (measuring the capacitors and reporting the values), choosing which group to solder is the easy part.
I attach screenshots of the optimized pairings.
(I haven't yet found a way to copy a table and paste it here. In the one above I had to enter the data one by one...)
New update.
I received the pcb of MarcelvdG's design a while ago, but preparing a simple metal case which could become the final one, took a bit of time. Only yesterday I was finally able to do the first rough tests, with an improvised set-up, just to get a taste of the behavior.
This is the set-up:
Pro-ject Xpression iii turntable, Cambridge Audio Azur 640p Phono preamp, Klipsch RF-52 tower speakers (all from Barbara, my partner) and my own class D amplifier.
Before connecting Marcel's preamp I wanted to try the default system with the Azur 640p Phono preamp, which has a small metal case and the classic small separate 12V AC power supply, without the ground conductor.
Apart from the fact that it seems to sound very good, the noise level with the arm raised and the volume at maximum is really low.
From two meters away it is inaudible and it is only a slight buzz, if you put your ear close to the speakers.
After 15 minutes of pleasant music, I turn everything off and connect the Phono MvdG preamp.
I am happy, it sounds (probably good), but the ground noise level is very high.
With the volume at 11 o'clock (for a normal listening level) the buzz is almost as loud as the music.
I try to disconnect the ground wire of the TT from the preamp side, and the noise is reduced only a little.
The choice to connect the ground point of the IEC socket to the "Phono" ground point, between the preamp inputs, was not a good one.
An hour later I read that these two ground points must always be separated...
Moving the ground connection point to one of the fixing screws of the IEC socket, does not change the noise level, which is slightly lowered only by leaving the ground point disconnected, but for obvious safety reasons, it cannot be the solution.
I recently found this guide by Pro-Ject on ground management.
https://www.project-audio.com/wp-co...mer_Techinfo_Turntable-hum-issue-guide-EN.pdf
As summarized in the two images below, according to them the ground connection on the Phono preamp should be avoided.
Thinking about it a bit, I remembered Rod Elliott's "Ground Loop Breaker" circuit.
https://sound-au.com/earthing.htm
I don't have 10R/5W resistors, so I ordered them.
About the 100nF capacitor, what kind would be suitable?
I really want this Phono preamp to perform at its best.
Any suggestions are welcome.
I received the pcb of MarcelvdG's design a while ago, but preparing a simple metal case which could become the final one, took a bit of time. Only yesterday I was finally able to do the first rough tests, with an improvised set-up, just to get a taste of the behavior.
This is the set-up:
Pro-ject Xpression iii turntable, Cambridge Audio Azur 640p Phono preamp, Klipsch RF-52 tower speakers (all from Barbara, my partner) and my own class D amplifier.
Before connecting Marcel's preamp I wanted to try the default system with the Azur 640p Phono preamp, which has a small metal case and the classic small separate 12V AC power supply, without the ground conductor.
Apart from the fact that it seems to sound very good, the noise level with the arm raised and the volume at maximum is really low.
From two meters away it is inaudible and it is only a slight buzz, if you put your ear close to the speakers.
After 15 minutes of pleasant music, I turn everything off and connect the Phono MvdG preamp.
I am happy, it sounds (probably good), but the ground noise level is very high.
With the volume at 11 o'clock (for a normal listening level) the buzz is almost as loud as the music.
I try to disconnect the ground wire of the TT from the preamp side, and the noise is reduced only a little.
The choice to connect the ground point of the IEC socket to the "Phono" ground point, between the preamp inputs, was not a good one.
An hour later I read that these two ground points must always be separated...
Moving the ground connection point to one of the fixing screws of the IEC socket, does not change the noise level, which is slightly lowered only by leaving the ground point disconnected, but for obvious safety reasons, it cannot be the solution.
I recently found this guide by Pro-Ject on ground management.
https://www.project-audio.com/wp-co...mer_Techinfo_Turntable-hum-issue-guide-EN.pdf
As summarized in the two images below, according to them the ground connection on the Phono preamp should be avoided.
Thinking about it a bit, I remembered Rod Elliott's "Ground Loop Breaker" circuit.
https://sound-au.com/earthing.htm
I don't have 10R/5W resistors, so I ordered them.
About the 100nF capacitor, what kind would be suitable?
I really want this Phono preamp to perform at its best.
Any suggestions are welcome.
Nice and tidy build. Too bad about the ground loop issue.
Are you talking about which kind of plastic (or ceramic) material (like MKP/C/T, etc.) or safety spec (X/Y rated)?
I have used this ground breaker too, but without the diodes, and just put an MKT in of what I had lying around.
My reasoning was that this circuit does not seem to be designed for safety purposes. It is not breaking the ground from the inlet to the chassis in any way. I think the diodes are overkill, assuming you use a transformer for the secondary voltage, and we all do that. Can those diodes be some carry over from a tube era and transformerless mains supplies? They could put the chassis live when you plugged in the mains plug the wrong way around.
In any case, the diodes will limit any voltage across the cap to max. 1,4 V. If you are anxious, put in a Y2 rated cap, but neither Merlin Blencow in his Tube Amp books neither Rod Elliot pay any attention to the specs of the cap.
Another option is to seperate the supply in a plastic enclosure and don't ground that.
Are you talking about which kind of plastic (or ceramic) material (like MKP/C/T, etc.) or safety spec (X/Y rated)?
I have used this ground breaker too, but without the diodes, and just put an MKT in of what I had lying around.
My reasoning was that this circuit does not seem to be designed for safety purposes. It is not breaking the ground from the inlet to the chassis in any way. I think the diodes are overkill, assuming you use a transformer for the secondary voltage, and we all do that. Can those diodes be some carry over from a tube era and transformerless mains supplies? They could put the chassis live when you plugged in the mains plug the wrong way around.
In any case, the diodes will limit any voltage across the cap to max. 1,4 V. If you are anxious, put in a Y2 rated cap, but neither Merlin Blencow in his Tube Amp books neither Rod Elliot pay any attention to the specs of the cap.
Another option is to seperate the supply in a plastic enclosure and don't ground that.
These ground loop isolators are only useful when a three wire mains connection is in use; otherwise they serve no purpose. The ground loop occurs when the PE (safety ground / third wire) which must be connected to chassis forms a parallel path for signal return currents, forming a loop. The loop will pick up E/M stray fields and add them to signal returns.
In ordinary situations, keeping the mains wiring small and local, by plugging everything into a single power outlet strip, is enough to avoid audible issues. If gear is plugged into random (however convenient) mains wall outlets, the loop gets very large - back and forth to breaker panel - and likely will cause issues.
The stacked diodes used provide a small voltage threshold before conduction, giving some isolation for small intrusive voltages. The resistor attempts to swamp various stray leakages, to maintain resting voltage across the stacked diodes near zero volts. The capacitor should probably not be used, or at least moved to the input jacks. Diodes must be able to withstand a catastrophic failure in the signal path to chassis, for long enough to open the mains fuse. This whole arrangement may or may not be code, or even legal, in various places in the world. Done properly it's probably as safe as lots of other things done in DIY, but it'll never get UL approval.
For a phono equalizer, batteries are an attractive option. All good fortune,
Chris
In ordinary situations, keeping the mains wiring small and local, by plugging everything into a single power outlet strip, is enough to avoid audible issues. If gear is plugged into random (however convenient) mains wall outlets, the loop gets very large - back and forth to breaker panel - and likely will cause issues.
The stacked diodes used provide a small voltage threshold before conduction, giving some isolation for small intrusive voltages. The resistor attempts to swamp various stray leakages, to maintain resting voltage across the stacked diodes near zero volts. The capacitor should probably not be used, or at least moved to the input jacks. Diodes must be able to withstand a catastrophic failure in the signal path to chassis, for long enough to open the mains fuse. This whole arrangement may or may not be code, or even legal, in various places in the world. Done properly it's probably as safe as lots of other things done in DIY, but it'll never get UL approval.
For a phono equalizer, batteries are an attractive option. All good fortune,
Chris
Hi arjen6t8,
Thank you for your comments and moral support. 😉
Yes, speaking of the 100 nF capacitor, I meant the type of dielectric, ceramic, rather than MKT, MKP.
What minimum voltage should be considered?
Anyway...
Yesterday was the day of discouragement, but the night brought advice.
An important connection was missing, which I had overlooked and which Rod Elliott has mentioned 100 times, in his projects.
The ground connection at the output of the dual regulated circuit, for which I had specially prepared 3 possible soldering pads.
I added a wire between the ground output of the power stage and the chassis.
Suddenly everything became silent.
I was almost disappointed!
Is it possible that I solved it with so little?
Maybe the fact of being a Muggle, justifies me a little... 🙄
But I will still try the Ground Loop Breaker circuit, to see if the residual noise is further reduced.
I also found a different version of the Ground Loop Breaker circuit, also by Rod Elliott.
This one:
https://sound-au.com/project127.htm
In cases like this (a Phono stage), which version would be more suitable?
I will do some more careful comparisons soon....
And I think that between today and tomorrow I will receive the PCBs of Nick's RIAA pre design.
I already have an identical case and power stage ready, to try that circuit as well.
Thank you for your comments and moral support. 😉
Yes, speaking of the 100 nF capacitor, I meant the type of dielectric, ceramic, rather than MKT, MKP.
What minimum voltage should be considered?
Anyway...
Yesterday was the day of discouragement, but the night brought advice.
An important connection was missing, which I had overlooked and which Rod Elliott has mentioned 100 times, in his projects.
The ground connection at the output of the dual regulated circuit, for which I had specially prepared 3 possible soldering pads.
I added a wire between the ground output of the power stage and the chassis.
Suddenly everything became silent.
I was almost disappointed!
Is it possible that I solved it with so little?
Maybe the fact of being a Muggle, justifies me a little... 🙄
But I will still try the Ground Loop Breaker circuit, to see if the residual noise is further reduced.
I also found a different version of the Ground Loop Breaker circuit, also by Rod Elliott.
This one:
https://sound-au.com/project127.htm
In cases like this (a Phono stage), which version would be more suitable?
I will do some more careful comparisons soon....
And I think that between today and tomorrow I will receive the PCBs of Nick's RIAA pre design.
I already have an identical case and power stage ready, to try that circuit as well.
That was an easy fix, luckily!
The difference between the two circuits is that the one you drew has double diodes is series/parallel, and the second circuit single parallelled diodes. I think it is a matter of convenience what people choose, plus the fact that you read every sort of 'heavy duty' warning for these diodes, ranging from 3 A, 6 A to 35 A. Probably the circuit with the 35 A bridge rectifier is also a matter of convenience, because if you want to opt for 35 A diodes, a bridge rectifier is easy to get and cheap.
Regarding the cap again, it is your own build, so do go overboard if you want to, with multiple multilayer ceramics in parallel. 😛 If you still need to order one, why not get a Y2 100 nF MKP cap? They're rated for mains voltage (250V~) are fail safe, designed for interference suppression and cheap. And if you have a habit of taking stuff apart, you might even find one lying around in one of your boxes.
The difference between the two circuits is that the one you drew has double diodes is series/parallel, and the second circuit single parallelled diodes. I think it is a matter of convenience what people choose, plus the fact that you read every sort of 'heavy duty' warning for these diodes, ranging from 3 A, 6 A to 35 A. Probably the circuit with the 35 A bridge rectifier is also a matter of convenience, because if you want to opt for 35 A diodes, a bridge rectifier is easy to get and cheap.
Regarding the cap again, it is your own build, so do go overboard if you want to, with multiple multilayer ceramics in parallel. 😛 If you still need to order one, why not get a Y2 100 nF MKP cap? They're rated for mains voltage (250V~) are fail safe, designed for interference suppression and cheap. And if you have a habit of taking stuff apart, you might even find one lying around in one of your boxes.
Thanks Chris..! 🤚
arjen6t8, thanks for the suggestions.
I already have 100 nF X2 capacitors at home, but not Y2.
I saw that they have opposite uses (between the lines, or between line and ground), but for this application a Y2 would be needed.
Can you explain to me why, for the same value, an X2 costs 30 cents, while a Y2 costs over 2 euros?
And it is also particularly large, 30x12x19 mm. for the kemet available from Reichelt. As an alternative to the Y2, could a Wima MKP still be good?
Like this one, for example: https://www.reichelt.com/it/en/shop/product/mkp10_pp_pulse_capacitor_100_nf_10_400_vdc_rm_15-173227
Finally, a couple of hours ago the postman delivered.
Here is a photo with the two RIAA-Pre versions.
Marcel's HPF Version (assembled in the last few days), next to Nick's, just arrived.
arjen6t8, thanks for the suggestions.
I already have 100 nF X2 capacitors at home, but not Y2.
I saw that they have opposite uses (between the lines, or between line and ground), but for this application a Y2 would be needed.
Can you explain to me why, for the same value, an X2 costs 30 cents, while a Y2 costs over 2 euros?
And it is also particularly large, 30x12x19 mm. for the kemet available from Reichelt. As an alternative to the Y2, could a Wima MKP still be good?
Like this one, for example: https://www.reichelt.com/it/en/shop/product/mkp10_pp_pulse_capacitor_100_nf_10_400_vdc_rm_15-173227
Finally, a couple of hours ago the postman delivered.
Here is a photo with the two RIAA-Pre versions.
Marcel's HPF Version (assembled in the last few days), next to Nick's, just arrived.
This MKP-Y1 100N at Reichelt is only € 0,61.
That's a tiny pre-amp (the Schukov one). I see it is also a single op-amp design. Did you have a seperate topic on that? I've missed that.
That's a tiny pre-amp (the Schukov one). I see it is also a single op-amp design. Did you have a seperate topic on that? I've missed that.
I've been listening to music through MarcelvdG's preamp for about ten days now.
To get there, I first had to resolve some ground noise issues, due to my wiring mistakes.
Then I had to fix the speed selector on the turntable I was going to use for listening, a JVC QL-F4 purchased a few months ago.
When switching from 33 to 45 rpm, the speed struggled to stabilize, or wouldn't stabilize at all.
I opened it and sprayed a little deoxidizer inside the speed selector.
The rest (mechanism, main PCB, and components) seemed to be in good order. I reassembled it and tested it.
The speed is now accurate and stable, judging by the stroboscope.
Finally, I had to prepare the stylus (AT-VM95C/H) with the overhang required for this turntable, namely 15 mm.
I was eager to try the whole thing, also to start the new stylus's break-in, so I didn't check anything else andwent straight to listening (with tracking force and anti-skating set to about 1.9 g).
Unfortunately, the sound was slightly attenuated, but still "not right."
I concluded that it was time for a more thorough check.
Using an arc template generator, I played around with the settings, concluding that the 15 mm overhang for the 220 mm effective arm length was probably calculated with a Stevenson alignment. Switching to a Lofgren A alignment, the overhang became 17.59 mm.
Even the azimuth didn't seem right by eye. Using the mirror confirmed this.
With a little patience, I managed to adjust it to the level where I couldn't tell in which direction to make further adjustments.
With the azimuth corrected, I moved on to adjusting the new overhang, using the printed arc template.
I managed to adjust it fairly accurately, although I think it could be further optimized by lengthening it by 1-2 tenths of a mm.
But with the new overhang, I also had to correct the tracking angle, which was no longer aligned with the headshell.
Once I achieved a fairly correct angle, I didn't feel like trying to lengthen the fateful 1-2 tenths, for fear of losing alignment again.
But I still plan to try correcting that distance, also to see if and to what extent a difference of 0.1-0.2 mm on the effective length of the tonearm is audible.
With these new adjustments, I was ready to listen to MarcelvdG's preamp.
...But first, I was curious to listen to the background noise at full volume, with the TT on and the needle raised.
I'm happy; now the residual noise is really low, barely audible from a meter away.
It's not unlikely that a different case configuration than mine could perform better, but it's already a good result.
I'll try adding the Ground Loop Breaker soon to see if it improves further.
Moving on to the music, the first feeling is that everything is finally in the right place.
And despite the occasional pops and clicks, caused by less than clean records, the music flows smoothly, with a good rhythm.
As stocktrader200 predicted, yes, I really like this cartridge. I find it better every day that passes.
Overall, I think the MarcevdG preamp does a splendid job.
Right now I'm listening to Arbour Zena, and Charlie Haden's bass comes out deep and clean, seemingly more realistic than when I listen to it on CD. The input capacitance on the preamp is set to its minimum value, 15 pF.
I've listened for several hours with both the 2nd- and 3rd-order filters, but so far I haven't heard any particular differences, just scattered impressions, like that with the 3rd-order filter it sounds damn good!.
In the last few days, Nick Sukhov's preamp has also been added.
They both have the same case and power supply, but the smaller space Nick's preamp takes up allows for a more rational layout and less cluttered wiring.
The sound is beautiful, smooth, and at least as clean as Marcel's preamp.
Just a little while ago, I tried listening to two or three tracks with Nick's preamp (15 pF input), then I listened to the same ones again with Marcel's preamp (also 15 pF, 3rd-order filter). If there are any differences, I struggle to discern them.
Both sound very, very good.
I have the feeling that they could both sound splendid, even in systems far superior to mine.
To get there, I first had to resolve some ground noise issues, due to my wiring mistakes.
Then I had to fix the speed selector on the turntable I was going to use for listening, a JVC QL-F4 purchased a few months ago.
When switching from 33 to 45 rpm, the speed struggled to stabilize, or wouldn't stabilize at all.
I opened it and sprayed a little deoxidizer inside the speed selector.
The rest (mechanism, main PCB, and components) seemed to be in good order. I reassembled it and tested it.
The speed is now accurate and stable, judging by the stroboscope.
Finally, I had to prepare the stylus (AT-VM95C/H) with the overhang required for this turntable, namely 15 mm.
I was eager to try the whole thing, also to start the new stylus's break-in, so I didn't check anything else andwent straight to listening (with tracking force and anti-skating set to about 1.9 g).
Unfortunately, the sound was slightly attenuated, but still "not right."
I concluded that it was time for a more thorough check.
Using an arc template generator, I played around with the settings, concluding that the 15 mm overhang for the 220 mm effective arm length was probably calculated with a Stevenson alignment. Switching to a Lofgren A alignment, the overhang became 17.59 mm.
Even the azimuth didn't seem right by eye. Using the mirror confirmed this.
With a little patience, I managed to adjust it to the level where I couldn't tell in which direction to make further adjustments.
With the azimuth corrected, I moved on to adjusting the new overhang, using the printed arc template.
I managed to adjust it fairly accurately, although I think it could be further optimized by lengthening it by 1-2 tenths of a mm.
But with the new overhang, I also had to correct the tracking angle, which was no longer aligned with the headshell.
Once I achieved a fairly correct angle, I didn't feel like trying to lengthen the fateful 1-2 tenths, for fear of losing alignment again.
But I still plan to try correcting that distance, also to see if and to what extent a difference of 0.1-0.2 mm on the effective length of the tonearm is audible.
With these new adjustments, I was ready to listen to MarcelvdG's preamp.
...But first, I was curious to listen to the background noise at full volume, with the TT on and the needle raised.
I'm happy; now the residual noise is really low, barely audible from a meter away.
It's not unlikely that a different case configuration than mine could perform better, but it's already a good result.
I'll try adding the Ground Loop Breaker soon to see if it improves further.
Moving on to the music, the first feeling is that everything is finally in the right place.
And despite the occasional pops and clicks, caused by less than clean records, the music flows smoothly, with a good rhythm.
As stocktrader200 predicted, yes, I really like this cartridge. I find it better every day that passes.
Overall, I think the MarcevdG preamp does a splendid job.
Right now I'm listening to Arbour Zena, and Charlie Haden's bass comes out deep and clean, seemingly more realistic than when I listen to it on CD. The input capacitance on the preamp is set to its minimum value, 15 pF.
I've listened for several hours with both the 2nd- and 3rd-order filters, but so far I haven't heard any particular differences, just scattered impressions, like that with the 3rd-order filter it sounds damn good!.
In the last few days, Nick Sukhov's preamp has also been added.
They both have the same case and power supply, but the smaller space Nick's preamp takes up allows for a more rational layout and less cluttered wiring.
The sound is beautiful, smooth, and at least as clean as Marcel's preamp.
Just a little while ago, I tried listening to two or three tracks with Nick's preamp (15 pF input), then I listened to the same ones again with Marcel's preamp (also 15 pF, 3rd-order filter). If there are any differences, I struggle to discern them.
Both sound very, very good.
I have the feeling that they could both sound splendid, even in systems far superior to mine.
How about this Panasonic MKP metalized polyprop with 7.5mm "crimped" lead spacing; 17L x 11W $1.25USD
https://www.mouser.com/ProductDetail/Panasonic/ECW-FD2W225J4?qs=qeco7YeAuFDKfzn70jQuSQ==