The operation is to bypass the TDA1541 DAC output from the first OpAmp (OPA2134 is now permanent), from first opamp output a wire is soldered to a set of coupling capacitor then to extra set of RCA plug. Sounds simple, but when you look at the PCB?..confusion is assured :-). Things getting better when I got a CDP950 schematic explaining connections in the DAC-Audio ouput area. Why this operations? the old CDP950 will sounds much better!, less parts & damage to the signals,..so Mr. Fikusz said. And after more than 1 year doing DIY Audio & hearing friends CDP hard for me not to agree. Now is my turn to hear the tweak my self.
step 1 , identifiying pins on PCB (opamp output & ground)
step 2, soldering wire to first opamp output
step 3, soldering ouput capacitor (phillips MKC 2.2uF) , RCA plug & ground. I like to keep the original fixed RCA for comparison
step 4, Now I can test the new sound!, and ? ...wooww..all I can say is that I could not believe that I have spent >17 years listening on this garbage CDP. I never liked the CD sound anyway, that is why I never upgrade to new CD player. Liked the old vinyl best. Now this almost trashed garbage player is my tweak darling.
I'm not just stop here, I know the sound can always be better and there are another steps to CD audio nirvana : making this 4 fold oversampling DAC to a non-oversampling or NOS DAC, then add a pair of tube buffer..long way..
But first just experimenting with coupling caps, better wiring, and variable output also bypassed. Coupling caps of the DAC also a tweak target using salvaged mylar caps from thrashed Blaupunkt Bremen car set. Another ways of reusing parts & save mother earth. Below, trying the sound of Russian Paper in Oil 2.2uF K75y-24 (the green thing).
above : harvesting result & Blaupunkt PCB, the mylar caps are 100nF, just the right value!
Final selection of coupling caps, I settled with paralleled yellow Phillips MKC 2.2uF, Blue metalic EroFoli 0.22uF, Back to back unknown electrolite 47uF (guess them Epcos?), in total of ~26 uF. These caps, especially after adding the electrolite, sounds very open-transparent , balanced low-mid-high. Overall the new sounds are very sweet, fluidic & analogue, now my Thorens TD320MK2-BlackPearl MM Cartridge-Cambridge Audio Azur Pre-MM have to fight very hard I must say.
final selection
Other tweaks are changing the diode rectifier to a ultra fast ones (BYV27), changing the old motorized pot to the sweet sounding little 50k ALPS green, replacing PSU Caps of DAC to Elna Cerafine, also a mishap of my tweak frenzy..a lesson learnt on my account. Changing DAC coupling caps the original 100nF ceramic cap//100nF mylar to Wima// mylar & a pair of (Auri?) MKT at the MSB pins. Theoretically the sound must improve since the Wima's and the MKT are better parts, the resulting sounds are worst. Details are lost, far from airy..well, once you get the correct sound, you must restrain yourself, except if you've got 14pcs of Black Gate NX of course!. Off with the wima's!, luckily I still able retain the sound I liked, just clean the solder pads thoroughly with acetone. I heard scary stories that you may not be able to go back to 'original' sound.
Diode, ALPS & tweak mishap
I'm completely astonished by the sound, and it's not even using 'better' op-amp than OPA2134, not NOSed yet & no Tubes. Thank you to all my DIY friends & cheers to Mr. Lukasz Fikus. Do not believe me, just try it yourself!.
step 4, Now I can test the new sound!, and ? ...wooww..all I can say is that I could not believe that I have spent >17 years listening on this garbage CDP. I never liked the CD sound anyway, that is why I never upgrade to new CD player. Liked the old vinyl best. Now this almost trashed garbage player is my tweak darling.
I'm not just stop here, I know the sound can always be better and there are another steps to CD audio nirvana : making this 4 fold oversampling DAC to a non-oversampling or NOS DAC, then add a pair of tube buffer..long way..
But first just experimenting with coupling caps, better wiring, and variable output also bypassed. Coupling caps of the DAC also a tweak target using salvaged mylar caps from thrashed Blaupunkt Bremen car set. Another ways of reusing parts & save mother earth. Below, trying the sound of Russian Paper in Oil 2.2uF K75y-24 (the green thing).
above : harvesting result & Blaupunkt PCB, the mylar caps are 100nF, just the right value!
Final selection of coupling caps, I settled with paralleled yellow Phillips MKC 2.2uF, Blue metalic EroFoli 0.22uF, Back to back unknown electrolite 47uF (guess them Epcos?), in total of ~26 uF. These caps, especially after adding the electrolite, sounds very open-transparent , balanced low-mid-high. Overall the new sounds are very sweet, fluidic & analogue, now my Thorens TD320MK2-BlackPearl MM Cartridge-Cambridge Audio Azur Pre-MM have to fight very hard I must say.
final selection
Other tweaks are changing the diode rectifier to a ultra fast ones (BYV27), changing the old motorized pot to the sweet sounding little 50k ALPS green, replacing PSU Caps of DAC to Elna Cerafine, also a mishap of my tweak frenzy..a lesson learnt on my account. Changing DAC coupling caps the original 100nF ceramic cap//100nF mylar to Wima// mylar & a pair of (Auri?) MKT at the MSB pins. Theoretically the sound must improve since the Wima's and the MKT are better parts, the resulting sounds are worst. Details are lost, far from airy..well, once you get the correct sound, you must restrain yourself, except if you've got 14pcs of Black Gate NX of course!. Off with the wima's!, luckily I still able retain the sound I liked, just clean the solder pads thoroughly with acetone. I heard scary stories that you may not be able to go back to 'original' sound.
Diode, ALPS & tweak mishap
I'm completely astonished by the sound, and it's not even using 'better' op-amp than OPA2134, not NOSed yet & no Tubes. Thank you to all my DIY friends & cheers to Mr. Lukasz Fikus. Do not believe me, just try it yourself!.
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