I have a PCM56P chip in my yamaha 510 CD player.
Figured its a good one to experimenting fet-izator mod on it.
Except I find it has 1 output Vout from pin 9 and Iout from 11-12-13 sent to common ground ?
Now I could pick up the output in the opamps and replace that with fets in there, but my opamps are the long strip kind, they say BA715 and I cant figure out which pin is which on it, and worse, there is far too many of em ... maybe the closest to the output will be it.
Can someone point out to me what could be the correct pins from the dac chip, or the opamp pins.
Thanks.
Srinath.
Figured its a good one to experimenting fet-izator mod on it.
Except I find it has 1 output Vout from pin 9 and Iout from 11-12-13 sent to common ground ?
Now I could pick up the output in the opamps and replace that with fets in there, but my opamps are the long strip kind, they say BA715 and I cant figure out which pin is which on it, and worse, there is far too many of em ... maybe the closest to the output will be it.
Can someone point out to me what could be the correct pins from the dac chip, or the opamp pins.
Thanks.
Srinath.
IC110 is the opamp I need to fet-izator.
BA715 - Let me see if I can find lin outs.
Thanks.
Srinath.
BA715 - Let me see if I can find lin outs.
Thanks.
Srinath.
Here is the data sheet to the PCM56P
http://www.ti.com/lit/ds/sbas149/sbas149.pdf
Here you will find the Dual opamp BA715,
http://www.digchip.com/datasheets/parts/datasheet/406/BA715-pdf.php
jer 🙂
http://www.ti.com/lit/ds/sbas149/sbas149.pdf
Here you will find the Dual opamp BA715,
http://www.digchip.com/datasheets/parts/datasheet/406/BA715-pdf.php
jer 🙂
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Thanks geraldfryjr. That BA715 I think I should replace it with fets etc ... I'll see what there is on this and other sites about the pcm56p for fet-izating it.
Cool.
Srinath.
Cool.
Srinath.
What confuses me about the pcm56 - and I would think all other dacs is that the output is 1 pin, How can we get stereo with 1 point of output unless something else is there behind it to de code it. I should get the output after it turns into stereo right ? Like at the opamp.
Thanks.
Srinath.
Thanks.
Srinath.
Perhaps it has two sample/holds after the chip? The very earliest Sony players worked like that, timesharing the DAC between the two channels.
After the dac it uses NJM2068s and TC4053bp (that is a multiplexer - I suspect it makes up the "stereo")
I need to modify this, so I dont screw up a real CD player with good sound.
Thanks.
Srinath.
I need to modify this, so I dont screw up a real CD player with good sound.
Thanks.
Srinath.
You can get the service manual over at HifiEngine. The schematic from there shows a YM3619 (or YM3404) digital filter which generates the sample pulses for left and right.
Yes - you're right the 4053 mux allocates the samples between the two output channels.
Yes - you're right the 4053 mux allocates the samples between the two output channels.
I have the hifiengine manual. The 1 chip and the MUX like you said do manage to sound very decent though. That's the surprise IMHO.
Anyway the BA715 is the spot I am going to cut into the signal. I'll find the specs for the fet and resistors and try it.
Cool.
Srinath.
Anyway the BA715 is the spot I am going to cut into the signal. I'll find the specs for the fet and resistors and try it.
Cool.
Srinath.
Most of the time when multiplexer chip is used with mono pcm56 (old Aiwa first line ;eg), the voltage output is used ! The current mode is better with an i/v conversion with a wirewound non inductive resistor... Some german specialist here with passive i/v conversion and passive filter after to avoid glitch... But you need to find an another pcm56... CD player with it are not expensive in second hand here (around 20 euros) in France, I surmise the market is 4x bigger in USA !
I can't work out if the YM3619 is doing oversampling - the DAC must be running at least at 2X OS to get both channels out during one sample period.
I reckon you can upgrade by taking the current output into a CFB opamp (to get a low impedance drive to the mux) and then into passive filters for the two channels. The opamp on the PCM56 itself is likely to be rather slow..
I reckon you can upgrade by taking the current output into a CFB opamp (to get a low impedance drive to the mux) and then into passive filters for the two channels. The opamp on the PCM56 itself is likely to be rather slow..
I am just going to try fet-ing that opamp.
I dont even understand your point above abraxalito.
Eldam - CD players around here are 5-10 bucks working, and almost free if not. I have many many cd players I payed under $1 for and repaired (belt, or cleaning or percussive maintenance) ... But looking for one with a particular chip - forget about it.
Let me look at that other site begining with diy and see what they have, they just let me in ... boy are they going to be overwhelmed with this much ignorance ...
Cool.
Srinath.
I dont even understand your point above abraxalito.
Eldam - CD players around here are 5-10 bucks working, and almost free if not. I have many many cd players I payed under $1 for and repaired (belt, or cleaning or percussive maintenance) ... But looking for one with a particular chip - forget about it.
Let me look at that other site begining with diy and see what they have, they just let me in ... boy are they going to be overwhelmed with this much ignorance ...
Cool.
Srinath.
Can you say more about the fet-izator mod ? shematic ?
For the future if you need looking for an another dac chip on the second hand market to experiment further:
CD-Player-DAC-Transport List
For the future if you need looking for an another dac chip on the second hand market to experiment further:
CD-Player-DAC-Transport List
The Fet-i-zator mod page is here: http://lampizator.eu/LAMPIZATOR/FETISHIZATOR/fetishizator.html
I am not an electronics expert. I have a limited ambition. I may kill this CD player and that's fine, as long as I learn from it.
I'm wanting to built the fet setup on the opamp and that is all. The second pcm chip will require me to put a whole separate board etc etc, the cd player doesn't have the space to even do that and I dont have the knowledge. In fact I want to put the original outputs to use in the new fet-izated setup, basically simple and easy I hope.
Cool.
Srinath.
I am not an electronics expert. I have a limited ambition. I may kill this CD player and that's fine, as long as I learn from it.
I'm wanting to built the fet setup on the opamp and that is all. The second pcm chip will require me to put a whole separate board etc etc, the cd player doesn't have the space to even do that and I dont have the knowledge. In fact I want to put the original outputs to use in the new fet-izated setup, basically simple and easy I hope.
Cool.
Srinath.
Thanks,
Me too, my understanding is very limited, I learned step by step and kill myself many cdplayers. I begann like many tweakers with mods with caps and powersupply and hope knowing more now than before... enough to survive with this delicious hobby.
Me too, my understanding is very limited, I learned step by step and kill myself many cdplayers. I begann like many tweakers with mods with caps and powersupply and hope knowing more now than before... enough to survive with this delicious hobby.
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Ok this cd player isn't getting modded. The multiplexer and the TC chip and the opamp etc is all too tangled up in making the "stereo" sound.
I'll get onto my Onkyo dx-110c next.
Last year I modded one of those and ended up with a ton of RF in the amp even when the cd player wasn't playing. If it was powered on and connected to the amp, it was hissing.
I have to do a better job now. Oh yea, atleast I tapped into the correct circuit ...
Cool.
Srinath.
I'll get onto my Onkyo dx-110c next.
Last year I modded one of those and ended up with a ton of RF in the amp even when the cd player wasn't playing. If it was powered on and connected to the amp, it was hissing.
I have to do a better job now. Oh yea, atleast I tapped into the correct circuit ...
Cool.
Srinath.
Hé Don't give up !
There are always little things thing to do: for example just playing with caps. Ok the result is less than if you work on IC and shematic/ powersupply but it can change the sound enough to have fun and pleasure.
Try to play wiyh caps before and after regulators, put Panasonic FC or better polymerSEPC/SEPF/SEP caps around the digital chip, put nichicon KZ muse for outputs circuits (digikey)... Use serzch engine on diya to learn how some experienced diyers made DAC with this dac chip...
Just tweaking, not state of the art but better than nothing, you always learn something. That just my humble opinion...
And don't forget to have a good iron and a good pump to desolder... good investment not to break chips like the eprom which are fragile and break with hot temperature or electric discharge...
2 cents...
There are always little things thing to do: for example just playing with caps. Ok the result is less than if you work on IC and shematic/ powersupply but it can change the sound enough to have fun and pleasure.
Try to play wiyh caps before and after regulators, put Panasonic FC or better polymerSEPC/SEPF/SEP caps around the digital chip, put nichicon KZ muse for outputs circuits (digikey)... Use serzch engine on diya to learn how some experienced diyers made DAC with this dac chip...
Just tweaking, not state of the art but better than nothing, you always learn something. That just my humble opinion...
And don't forget to have a good iron and a good pump to desolder... good investment not to break chips like the eprom which are fragile and break with hot temperature or electric discharge...
2 cents...
Actually I like cutting off the shorting caps at the output, I will do that on this, but this isn't a great player to put in much more time and effort into.
I've got better ones ... that onkyo I am on next is better, TC9417 dac chip and a couple of JRC45590 or something like that opamps. I'll swap em with the socket type and do that one instead as practice.
Cool.
Srinath.
I've got better ones ... that onkyo I am on next is better, TC9417 dac chip and a couple of JRC45590 or something like that opamps. I'll swap em with the socket type and do that one instead as practice.
Cool.
Srinath.
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