Erinp

Cuneyt, firtsly you must understand the fow of data in the CD player. Very basicly the data from the laser is sent to the SAA7210. This is the chip that generates the i2s signals. When we perform the non oversampling mod. We are bypssing the SAA7220.(which does the oversampling) We are effectively taking the i2s output from the SAA7210. The 11.2896Mhz crystal is connected also to the SAA7210 and also used by the rest of the CD player to make the motor spin and data to be transfered correctly etc. The TDA1541 does not have a direct connection to the 11.2896Mhz crystal. it uses word clock, data and left right clock information derived from the SAA7210. Dont touch the crystal or your CD player wont work. Of course you could upgrade it with a 1ppm clock upgrade kit []

My understanding of a digital audio recording is that the analog audio goes through an anti aliasing filter prior to going to the ADC and then stored on a recording medium. So when playing back the recording it is not necessary to filter the output because the frequencies that cause aliasing have already been removed. If they had not been removed proir to recording the audio then the alias frequencies would be present on the recording and then hence present during playback even if there was a filter. Correct me if I'm wrong here but output filters are not even need to filter the 44.1Khz sampling frequency from the output because DACs like ADCs use a sample and hold circuit so the 44.1Khz has already been smoothed so that the highest frequency possibly present on the output is 22Khz (if present on the recording). Class D amps on the other hand do need LC filtering because they will have a certain amount of Volts on the output @ high frequency because they use PWM and a product of the mark space ratio is that there will be volts present on the output during the "mark" albeit very briefly, hence the filter needs to be tuned to the frequency that the amp oscillates at to make sure that there is 0Volts DC on the output as well as no HF energy to blow the HF drivers. When a DAC is reading the digital data and if there is data representing silence going into the DAC then the DAC outputs 0 Volts or 0 current.

Well, bearing in mind that the title of this thread was "Have you tried the zero oversampling mod?"- I was just replying to the person who started it and was thanking him for his suggestions,and also agreeing that it is fantastic. I think that being skeptical is a good thing, we certainly should not go around believing everything that we are told. We should go and try things for ourselves. We should have our own thoughts and opinions and experiences. I bothered to try this mod because there are so many people giving positive feedback and reviews of NOS Dacs/CD players on the internet - Google it and see what im talking about. I certainly in no way was suggesting that enjoyable results cant be achieved using oversampling or modern Delta Sigma DAC processing. - I have tried these methods and i personally think that Non Oversampling has the edge (to put it mildly) I was just intending to add to the vast body of feedback. Considering that this mod is easy and that there are so many NOS DACs and kits available why not just try it for yourself? None of them are particularly expensive. Hey you may end up liking it. Anyone else tried it yet? P.S. FYI, im totally agianst all that magic rocks "HIFI" nonsense, mostly because the magic rocks always seem to cost $$$$$$$$$. What i am into, however, is good sound - preferably costing me as little as possible, and that is something that i would never lie about. Thanks

Hi Dr. Who, Well, i wouldn't have believed the improvement either unless i had heard it myself. I'm a qualified electronics technican, so ive learnt about nyquists theorum etc. All the theory says that you should filter the HF "hash". Oversamping moves the "hash" above the hearing frequency etc. etc.blah blah......... Well after years of trying to find a digital player that reproduces "music" instead of reproducing a vague interperetation of music.. i have finally found a way of doing it that works for me.... Ive been listening to the modded cd player for the past two days and i just cant believe how realistic the music is. I mean jaw dropping to the ground.... big smiles.... OMG its that good. HF up to the sky and Bass to the ground, I mean im so happy because i was never happy with the sound of music off CD. I used to mostly like listening to Vinyl because the sound is generally more realistic but its a bit of a hastle and has problems of its own that we will all be aware of..........and so i was depressed that my only option was CD so I just descided to buy various DACs and try this and that and change op-amps capacitors etc... to try to find some digital source that makes music. WELL THIS IS IT!! As for the datasheet... who cares man... let the music flow... oversampling was developed by philips to compensate for their first 14bit audio dac before they developed their 16 bit dac... and i guess they just lost the plot. Remember the 80's,everything had to be "better and better" 4x oversampling 8x oversampling16x oversampling but i guess they justgot confused somewhere along the line and then all the companies started doing it cause its all marketing... if its 8x oversampling then it MUST be better than 4 its the 80's here man could you imagine a company trying to sell a Non overampling CD player for $800-$1200 in the 80's when the other guy is selling an 8x OS.... well thats probably something like how it went. Maybe the engineers did know but couldnt do anything about it because of marketing???? I dont know???? If you are skeptical just try it for yourself.... it will take anywhere from 15min onwards to do this mod. And then you can let me know what you think about the sound. I mean when you look at Viny how on earth could it possiblysound good.. a tiny groove,dust,a diamond stylus.tiny electrical signal,pre amp,tracking error,pre/post echo - but it sounds good!!!!! and thats what matters. Therory says that lots of things shouldnt work but people try them and it ends up working, and thats what matters. Anyway this is my personal opinion which i wanted to share with others for the sake of making the world a better place and music a better experience for all to listen to. Best of luck, peace man :-)

Thanks Lorenzo, I tried your suggestion on my Philips CD460, and..........WOW!!!!!.................... what a huge improvement. Thanks for the clear instructions. I did the mod in about 15 minutes. Its people like you who share their knowledge which makes Hi-Fi Audio (on a budget) a reality for many people. This simple mod turned a dark, average, and congested sounding CD player into a lovely open detailed sounding player. The HF is now alive and very realistic. I suggest and recomend this mod to anyone who has an old CD player with the TDA1541 DAC - its easy and will yeild an immediate and noticeable improvement. Cheers mate!!!!