• Testing TDA1543A and TDA1545A

    andrey.malyshenko07/15/2020 at 20:17 0 comments

    Next to test was 2 classic budget ICs: TDA1543A and TDA1545A. Unfortunately, despite the time spent i failed to make them work properly. I suspect that they could be fakes, since i got them from chinese platform for a price of € 1,6 per 5 pieces, giving € 0,30 a piece. I have no plans to buy them from trusted supplier, since then price leaven no senso of using them in low-budget projects.

    Data format: left justified, stereo output

    Ouput: high-impedance, biased, requires output driver

    Price: ~€0.30 per unit

    So lets call them replicas of TDA154X and see how output  looks like. I've connected both according to original's datasheet, input still the same: mono wav file generated by esp8266 module using ESP8266Audio library modified for LJ format, industry standard 44.1Khz sampling rate. 


    TDA1545A, no output filters, 2KHz

    TDA1545A, no output filters, 10KHz

    Input signal is visible, so i guess data format is OK. However waveform is so messed up, i can't be bothered to connect it to amp and speakers.

    TDA1543A, no output filters, any signal

    I failed to make it work really, it looks like input format is wrong, even it is ok for TDA1545, and they suppose to have same input format. So nothing I really could say about that. 

    I tried few different ICs, from same seller however, so makes not much sense to expect a difference. 

  • Tests of PT8211 IC

    andrey.malyshenko07/14/2020 at 22:16 0 comments

    Next to test is bare naked I2C DAC from unknown to me chinese manufacturer. It is advertized as (not really) direct replacement of TDA1311 DAC ond partially its successors TDA154X series. It requires output driver and i added one using 4558D opamp according to dtasheet application circuit

    Data format: left justified, stereo output

    Ouput: high-impedance, biased, requires output driver

    Price: ~€0.10-0.20 per unit

    Clearly it is here because the price, and it is not expected to have hifi performance, but rather support low-cost audio driver in projects.

    Here is the setup. 

    Only element added to above is output 1uF cap to filter out DC.

    Again, I only have toy oscilloscope, therefore results will be eye measured:)

    Test signal is mono wav file generated by esp8266 module using ESP8266Audio library modified for LJ format, industry standard 44.1Khz sampling rate. 

    1KHz on the output, after driver

    2KHz after driver

    10KHz on the output, after driver

    20KHz on the output, after driver

    As you can be seen, already at 10Khz distortions are huge, and 20Khz is a mess. However up till 20Khz there is no fading out of signal, and despite harmonic distortions i expect it to sound quite nice (for the price). As i said before, this is bad candidate for Hi-Fi sound, but very promisiong chip for less demanding audio applications. I keen to see it in action.

  • Tests of PCM5102A module

    andrey.malyshenko07/14/2020 at 20:11 0 comments

    Next to test is another popular module from unknown manufacturer based on PCM5102A chip. It has a bit strange power schematics compared to datasheet, but nevertheless it is one of my favourites in terms of usage in projects

    Data format: I2S, stereo output

    Ouput: medium-impedance, capable to drive headphones

    Price: ~€4 per unit

    Here is the setup. Test circuit is a module itself, since it has built in output filter. It is identical to my setup, apart of R=470 Ohm, C=2n2, giving same 30KHz cutoff frequency

    Again, I only have toy oscilloscope, therefore results will be eye measured:)

    Test signal is mono wav file generated by esp8266 module using ESP8266Audio library, industry standard 44.1Khz sampling rate. 

    1KHz before filter, after filter

    2KHz before filter, after filter

    10KHz before filter, after filter

    20KHz before filter, after filter

    What can be said here. It has relatively clear output even before filter applied. After filter i see no issues even on 20Khz. Curve is clean and properly leveled for every measured frequency. 

    To compliment more, I listen one of these modules every day in my home audio setup and I perfectly happy with it. Given it's price, no more to ask really.

  • Tests of MAX98357A module

    andrey.malyshenko07/14/2020 at 19:46 0 comments

    First to test is popular ready-to-use module based on MAX98357A chip. 

    Data format: I2S, mono output

    Ouput: 3W D-class amp, low-impedance

    Price: ~€4 per unit, or ~€7 per stage

    Here is the setup and test circuit

    On the output there will be sine tones on following frequiencies: 1K, 2K, 10K, 20K

    Unfortunately i only have toy oscilloscope, therefore results will be eye measured:)

    Amp will be loaded with 10 Ohm resistor and measurment will be done on the output and after first-order low-pass filter set on ~30K cutoff frequency, which would be standard in every DAC's ouput.

    Test signal is mono wav file generated by esp8266 module using ESP8266Audio library, industry standard 44.1Khz sampling rate. 

    1KHz before filter, after filter

    2KHz before filter, after filter



    10KHz before filter, after filter



    20KHz before filter, after filter

    As you can see, output is quite noisy, this is what you expect from low performance D-class amp, even after RC filter line is loaded with noise. Probably you can eliminate it more by adding more ouput filter stages, but since it is already beyond normal out-of-the-box usage of module, i will not do it for now. 

    More importantly alteady at 10Khz signal level is ~3V peak-to-peak, compared to ~4V at 1KHz. This is significant drop, most certainly hearable. 

    20Khz performance is beyond words. Signal is simply vanished.