indeed , and I don't trust anyone ears to be able to tell the difference.
personally I would like to see some PS measurement too
maybe showing spectral plots of various rectifiers and how they enter the chip amps output. I suspect that 'boutique grade' ultra fast rectifiers are no bueno. snap off energy and all that PS hash.
To infinia, A quote from TI data sheet, the relevant parts on decoupling capacitors and speaker return are in bold.
When designing a layout, it is important to return the load ground, the output compensation ground, and the low level (feedback and input) grounds to the circuit board common ground point through separate paths. Otherwise, large currents flowing along a ground conductor will generate voltages on the conductor which can effectively act as signals at the input, resulting in high frequency oscillation or excessive distortion. It is advisable to keep the output compensation components and the 0.1 μF supply decoupling capacitors as close as possible to the LM3886 to reduce the effects of PCB trace resistance and inductance. For the same reason, the ground return paths should be as short as possible
When designing a layout, it is important to return the load ground, the output compensation ground, and the low level (feedback and input) grounds to the circuit board common ground point through separate paths. Otherwise, large currents flowing along a ground conductor will generate voltages on the conductor which can effectively act as signals at the input, resulting in high frequency oscillation or excessive distortion. It is advisable to keep the output compensation components and the 0.1 μF supply decoupling capacitors as close as possible to the LM3886 to reduce the effects of PCB trace resistance and inductance. For the same reason, the ground return paths should be as short as possible
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yup it's all there in the data sheet ! if only ppl could read the data sheet 1st and ask questions if they don't understand the text.
load ground ( speaker rtn) has the highest currents of all , I still suggest separate path to the stiffest ( biggest caps ) return point . might be worth a test tying it the board PCB decoupling with bigger and bigger PCB caps, but then line related THD might show up more.
consider multi channel amps > active speaker setups where the LF woofer rtn goes to bulk caps and the midrange, or tweeter to progressively smaller caps located on the chip amps PCB.
load ground ( speaker rtn) has the highest currents of all , I still suggest separate path to the stiffest ( biggest caps ) return point . might be worth a test tying it the board PCB decoupling with bigger and bigger PCB caps, but then line related THD might show up more.
consider multi channel amps > active speaker setups where the LF woofer rtn goes to bulk caps and the midrange, or tweeter to progressively smaller caps located on the chip amps PCB.
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you could calculate it to be very low in relation to the speaker impedance at least several octaves before the drivers LF resonance.
sorry I didn't understand yer 1st sentence.
example 4 ohm mid range fs ~100Hz Re ~ 3.3 ohms
Xc aim for 10% Re at least one octave below fs
C= 0.1 *3.3/ 2*pi*50 ~ 1000 uF
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my view on caps and decoupling in 135 are general, the other ideas stem from changing the load return from the bulk filter location to the PCB for an active setup which may or may not improve the sound THD IMD wise, eg the middle range cap value may need to grow depending on the mounted speaker driver. otherwise the small electro is just for PS decoupling and stability of the chip amp circuit.
probably clear as mud
probably clear as mud
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I have grazed through the thread and got more believe its actually possible to measure the subjective listening experience.
Things are starting to get funny in an humoristic way. The thing said that no one in this forum have ever measured the influence of a power supply in a power amplifier. Do you guys are aware that, apart from posting on the forum, some of the members are electrical engineers who measure that kind of things in a daily basis?
Correct me if I'm wrong, You tell me here now that many of the people on this forum can measure absolutely the effect from the power supply on the output from an amplifier?
If this is the case, why I don't see any of this kind of measurements here?
I have my old Vifa basis speakers back and connected them to my amp.hmmmm, I'm confused, the first thing I noticed is a to much bass, my favorite groundation sounds like its to much in low frequency response.
The overall sound stage is very solid but then I got the feeling to get an equalizer to get the nice sound and with the M52's I got the nice sound feeling without thinking about that.
Listening more I find out that with the vifas's the stereo experience is way much less depended on the speaker position...... with the M52's I had to position the speakers precisely in the middle to hear the right sound, with the Vifa's it sounds great even if listening to them way of middle..... really weird.....
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