Best would be to reopen your 600W PA thread and add measurements...
The SA2021-NCH is a class H "modulated rail" amplifier which saves power whereas your 600W PA is more like SA2014.
The SA2021-NCH is a class H "modulated rail" amplifier which saves power whereas your 600W PA is more like SA2014.
This was a different one, with modulated rail. Better sound in the mid-high frequency range. But your amplifier is more sophisticated!
some thermal pictures...
Amplifier is running about 2h with 3W@8R output.
Heatsink is a "Cool Tec" ct400 120mm length/ 400mm wide / 40mm high.
RthK about 0.35K/W
Amplifier is running about 2h with 3W@8R output.
Heatsink is a "Cool Tec" ct400 120mm length/ 400mm wide / 40mm high.
RthK about 0.35K/W
Attachments
Attached picture shows THD+N 1Khz 0.0022% @18W@8R (bw. 80) with the worst distortion at the rail crossover region. Below and above 18W@8R (12V rms) the distortion values are decreasing again.
The distortion residual clearly shows the small glitches of the schottky diodes at the rail crossover region.
Maybe these glitches can be reduced using a snubber. and/or faster diodes.
BR, Toni
The distortion residual clearly shows the small glitches of the schottky diodes at the rail crossover region.
Maybe these glitches can be reduced using a snubber. and/or faster diodes.
BR, Toni
Attachments
BTW: The SA2021 NewClassH pcb/schematic is flexible in usage. Just use fewer or no IXYS or e.g. IRFP240/9240 and lower voltage you easily can build power amplifiers e.g. for mid/highs only. Adapt some resistors and you are done... Hmm think a table with tested values should follow ... what do you think?
Last edited:
Hi Toni,
Can I use onsemi MJL21193/MJL21194 instead of Toshiba for the lower output BJT devices?
Can I use onsemi MJL21193/MJL21194 instead of Toshiba for the lower output BJT devices?
The Toshiba TTC5200/TTA1943 are mandatory. The negative feedback loop is designed using these fast transistor types.
Friends,
my story with the SA2014 amplifier has just begun, but due to the unavailability of some parts I am quite limited. Input/VAS stage will soon be complete I'm just waiting for the 2u2 input capacitors to be stocked in TME, ...which will be in a few days and I'll be ordering all the WIMA for SA2014 from Reichelt at the beginning of the week. The question is also the bipolar capacitor, C7 which is unavailable in Mouser and I probably won't order it from Digikey. I think I'll order the exclusive Audio Note from HiFi Collective...
Since this project is quite financially demanding, I have planned it for a period of about 12 - 15 months, so once in a while I will throw some progress here, ... 🙄
I am also thinking about a custom box for SA2014, which will be based on custom coolers from GAMMAaluminium specifically type K400 with height 5U.
I would only use the new 5U bracket from modushop.
my story with the SA2014 amplifier has just begun, but due to the unavailability of some parts I am quite limited. Input/VAS stage will soon be complete I'm just waiting for the 2u2 input capacitors to be stocked in TME, ...which will be in a few days and I'll be ordering all the WIMA for SA2014 from Reichelt at the beginning of the week. The question is also the bipolar capacitor, C7 which is unavailable in Mouser and I probably won't order it from Digikey. I think I'll order the exclusive Audio Note from HiFi Collective...
Since this project is quite financially demanding, I have planned it for a period of about 12 - 15 months, so once in a while I will throw some progress here, ... 🙄
I am also thinking about a custom box for SA2014, which will be based on custom coolers from GAMMAaluminium specifically type K400 with height 5U.
I would only use the new 5U bracket from modushop.
Last edited:
Friends,
A mega-pack from mouser is on its way, ...fun for the winter months 🙂 Due to the lack of good quality large capacitors, I chose KEMET slit foil 10.000uf/80V from the ALC10S series, designed specifically for audio applications. Therefore, I need to know what supply voltage to choose in order to have a sufficient safety margin. I was thinking of lowering it to 65V, ...or can I safely go to 70V as well?
Thanks ☕
A mega-pack from mouser is on its way, ...fun for the winter months 🙂 Due to the lack of good quality large capacitors, I chose KEMET slit foil 10.000uf/80V from the ALC10S series, designed specifically for audio applications. Therefore, I need to know what supply voltage to choose in order to have a sufficient safety margin. I was thinking of lowering it to 65V, ...or can I safely go to 70V as well?
Thanks ☕
First power supply finished, ...
Input/Vas - finished
Output stage - 80% finished (I'm waiting for the first 400*210mm heatsink, probably next week.)
mains inrush - finished
Input/Vas - finished
Output stage - 80% finished (I'm waiting for the first 400*210mm heatsink, probably next week.)
mains inrush - finished
Attachments
Last edited:
Hi HRDSTL,
I have built SA2014 cca one year ago and I am really pleased with its performance. It is definitely the best amp I have ever built. I dont think that it could be outperformed. Especially with kind support from astx you are on the right way to excellent sound. I want to bring to your attention that you can get nice heatsinks from Gamaaluminium and the spreaders from Quickpannel in our country. Pictures from my amp you can find in this thread.
Ladislav
I have built SA2014 cca one year ago and I am really pleased with its performance. It is definitely the best amp I have ever built. I dont think that it could be outperformed. Especially with kind support from astx you are on the right way to excellent sound. I want to bring to your attention that you can get nice heatsinks from Gamaaluminium and the spreaders from Quickpannel in our country. Pictures from my amp you can find in this thread.
Ladislav
