These are beautiful measurements, of which there are many. However, there is a discrepancy between the measurements and subjective perception. In your posts, you describe a lack of power. Now, technically, with continuous excitation such as sine waves analyzed with FFT, there will be no difference whether your switching power supply is oversized or not. The linked report also measures with an ohmic load, which is standard but also silly, as passive speakers almost always present complex loads and therefore the amps are differ in how well they can handle them. In this sense, these measurements are not very indicative of how 'powerful' an amplifier is perceived to be. When it comes to noise, it's a similar issue. We hear impulses and not tones - that's the current scientific opinion on hearing in the frequency range from about 1kHz. So, the noise in a circuit only presents itself as very slight distortion of the signal and is often hardly detectable in the continuous signal through the feedback circuit of the amplifier - in the measurement often represented in the form of the background noise detected by the FFT, usually without attributing the background noise of the measurement chain without the amplifier. This means that while measurements can demonstrate the function of an amplifier, we do not have suitable measurement methods to measure the quality criteria that we hear subjectively. To test my thesis, I did as always: in simulation, it is possible to make disturbing electrical effects visible and suppress them through electrical filters. The simulation can also simulate impulse behavior, as well as very complex noises. Based on these simulations and objectives, I optimized the circuit and built several variants, testing them on different speakers, sources, and listening rooms with different subjects to minimize the psychological effects of listening. After all, humans have a learning ear and therefore a fundamentally subjective individual interpretation. Nevertheless, this means that general effects are described quite similarly by different individuals.
Good evening,
Just some nice info.
The small Wima 1uF MKP capacitor for the Q17-Mini is now available from Mouser.
Film Capacitors MKP 2 1.0uF 63VDC 11x16x7.2 PCM 5
https://www.mouser.fr/ProductDetail/505-MKP2C0411NMN
Just some nice info.
The small Wima 1uF MKP capacitor for the Q17-Mini is now available from Mouser.
Film Capacitors MKP 2 1.0uF 63VDC 11x16x7.2 PCM 5
https://www.mouser.fr/ProductDetail/505-MKP2C0411NMN
Hello,
New LTSpice for le Q17-Mini and Q17-Turbo files uploaded to the Github repository.
Q17-Mini 1.3
Q17-Mini 2.1
Q17-Turbo 1.0
https://github.com/stefaweb/Q17-Amplifier/tree/main/Q17-LTspice
Have fun.
Stef.
New LTSpice for le Q17-Mini and Q17-Turbo files uploaded to the Github repository.
Q17-Mini 1.3
Q17-Mini 2.1
Q17-Turbo 1.0
https://github.com/stefaweb/Q17-Amplifier/tree/main/Q17-LTspice
Have fun.
Stef.
If I turn up the sound, I consume around 150mA per peak per rail.
The sound is dynamic on my small 4R speaker (Triangle Titus 202).
Unfortunately, I do not have a transformer to output the 66Vdc needed to power the sigma with the 60V that I would need to properly power the Turbo. My lab power supply only does 60V-3A max.
EDIT: modified wrong consumption numbers.
The sound is dynamic on my small 4R speaker (Triangle Titus 202).
Unfortunately, I do not have a transformer to output the 66Vdc needed to power the sigma with the 60V that I would need to properly power the Turbo. My lab power supply only does 60V-3A max.
EDIT: modified wrong consumption numbers.
Last edited:
When I turn up the sound, for watching a movie through Q17 modules, I feel the bass just like being nearby a helicopter flying from the ground. I need realistic sounds so the power consumption goes very high. A RMS wattmeter showed 200W of power, in the primary of the transformer. And the transformer is heating very much because was not a good design by me. So I'll wait for the SMPS and Sigma to put them together and hope to rise the power up to 400W per channel. Imagine 16 channels how it sounds on Dolby Atmos.
I don't have the equipment to actually test everything to its limits.
Something that annoys me. Q6 heats up more than the others. It doesn't come from MOSFETs. I paired them. I also tried IRF530NPBF and IRF9540NPBF. Same story.
Measured on the TO-220 screw (it's more reliable).
Q6=46.5°C
Q7=29.6°C
Q8=29.5°C
Q9=26.1°C
However, I forgot to measure the 0R47 resistors before soldering them.
Some good manners.
The 6V difference between the input and the output MUST be respected, otherwise there is a risk of stalling (the negative starts flashing).
Adjust the sigma to the correct voltage with a passive load corresponding to the "iddle" consumption of the amp before connecting it to the amp. Otherwise, the positive starts flashing when you turn TR1 and the lab power supply trips to the positive (500mA max in current protection).
The heatsinks are at 30°C after an hour of music. This gives an idea of the sizing of the heatsinks necessary in reality. Take a margin of 30% minimum. Sigma does not like MOSFETs to be overheated (0.5V positive/negative offset).
Something that annoys me. Q6 heats up more than the others. It doesn't come from MOSFETs. I paired them. I also tried IRF530NPBF and IRF9540NPBF. Same story.
Measured on the TO-220 screw (it's more reliable).
Q6=46.5°C
Q7=29.6°C
Q8=29.5°C
Q9=26.1°C
However, I forgot to measure the 0R47 resistors before soldering them.
Some good manners.
The 6V difference between the input and the output MUST be respected, otherwise there is a risk of stalling (the negative starts flashing).
Adjust the sigma to the correct voltage with a passive load corresponding to the "iddle" consumption of the amp before connecting it to the amp. Otherwise, the positive starts flashing when you turn TR1 and the lab power supply trips to the positive (500mA max in current protection).
The heatsinks are at 30°C after an hour of music. This gives an idea of the sizing of the heatsinks necessary in reality. Take a margin of 30% minimum. Sigma does not like MOSFETs to be overheated (0.5V positive/negative offset).
Hello,
I changed the 0R47R R16 on the Sigma and all is fine now with Q6 temp. The value was too high (0R60 instead of 0R47).
I also upgraded the sigma to a larger heatsink. This way of putting the board on is much more practical.
I downloaded in my Github repository, a new diagram of the Sigma with the voltage values measured in real life. This roughly corresponds to the simulation.
I'll also have some new stuff for the Q17 amps. Some component values changed for improved bandwidth linearity, floor noise and sensitivity to ground loops (thanks to Spice simulation). This does not require any changes to the PCB. I'll tell you more when I've taken the measurements.
Good Sunday.
Stef.
I changed the 0R47R R16 on the Sigma and all is fine now with Q6 temp. The value was too high (0R60 instead of 0R47).
I also upgraded the sigma to a larger heatsink. This way of putting the board on is much more practical.
I downloaded in my Github repository, a new diagram of the Sigma with the voltage values measured in real life. This roughly corresponds to the simulation.
I'll also have some new stuff for the Q17 amps. Some component values changed for improved bandwidth linearity, floor noise and sensitivity to ground loops (thanks to Spice simulation). This does not require any changes to the PCB. I'll tell you more when I've taken the measurements.
Good Sunday.
Stef.
Attachments
Hello,
Good news with the new settings that I am experimenting with on the Q17.
The turbo (2 pairs) did not work perfectly below 58V. There was a problem with the square signal.
With the new settings, the problem has disappeared.
The Q17-Turbo can now be used below 60V.
I'm waiting for a component that I'm missing and as soon as I receive it, I can do full tests with the new settings.
Stef.
Good news with the new settings that I am experimenting with on the Q17.
The turbo (2 pairs) did not work perfectly below 58V. There was a problem with the square signal.
With the new settings, the problem has disappeared.
The Q17-Turbo can now be used below 60V.
I'm waiting for a component that I'm missing and as soon as I receive it, I can do full tests with the new settings.
Stef.
Attachments
Hi Stef,
I have received the SMPS800RE from Ireland and I tested today, at low power but soon I'll make a university lab test to measure the ripple at high amps.
The good news, until now, is that there is noise at all, I can't hear any noise on pause, neither on low volume. There is no hum, no ground loop ... but if it will deliver the bass or not, well, that remain to be seen in the near future when I'll mount it inside my metal box modules. It is a lot of work therefore I want to make a lab test first.
I can modify the output voltage between 57 and almost 63V+-. I also have 12V+- with two separate grounds.
I added a cooler (it came without because I didn't ordered that).
I made the tests with the older chinese Quad 405-2 modules, because already the Q17 are mounted inside the metal boxes and I am already enjoying listening music.
If the final power test will prove that SMPS can really offer 800W continuous up to 1150W for short bursts ... then, this was a succesful replacement of the 3 kg heavy 300W torroidal transformer. I'll be back with the lab results as soon as possible, in a week or two.
I have received the SMPS800RE from Ireland and I tested today, at low power but soon I'll make a university lab test to measure the ripple at high amps.
The good news, until now, is that there is noise at all, I can't hear any noise on pause, neither on low volume. There is no hum, no ground loop ... but if it will deliver the bass or not, well, that remain to be seen in the near future when I'll mount it inside my metal box modules. It is a lot of work therefore I want to make a lab test first.
I can modify the output voltage between 57 and almost 63V+-. I also have 12V+- with two separate grounds.
I added a cooler (it came without because I didn't ordered that).
I made the tests with the older chinese Quad 405-2 modules, because already the Q17 are mounted inside the metal boxes and I am already enjoying listening music.
If the final power test will prove that SMPS can really offer 800W continuous up to 1150W for short bursts ... then, this was a succesful replacement of the 3 kg heavy 300W torroidal transformer. I'll be back with the lab results as soon as possible, in a week or two.
