Emitter followers are the most stable output stages and there is a way to do them. The symef series of amplifiers had the right output stage from the word go. An output stage even without any feed back applied and with no voltage gain stage does its best to keep the output at zero. This can present challenges to a quasi complementary stage due to phase lag and this is even before we apply feedback. Even with the latest series of symef designs, we hit a home run yet again, this design has even surprised me by defying time. I however believe that my recent improvements to the quasi complementary offerings in the 1diffqc series will pay off. Output stage oscillation is a beautiful thing to behold, its fast and even the polite glow of onboard fuses doesnt save output devices from mating collector to emitter of the output devices that are doing their best to keep the output voltage at zero but alas the current draw is too much.
https://www.pcbway.com/project/shareproject/SYMEF_Audio_Power_Amplifier_8bb70aa8.html
Service update:
1. ZD1,ZD2 changed from 1N5230B to 1N5234B
2. R8,R47 changed from 2k7 to 4k7
3. This version is unity gain stable
Service update:
1. ZD1,ZD2 changed from 1N5230B to 1N5234B
2. R8,R47 changed from 2k7 to 4k7
3. This version is unity gain stable
The SYMEF has soft clipping and regularly compared to a tube amplifier, however I have also found that SYMPHONY has even softer clipping ,to prototype and also enjoy this lovely amplifier, let me know what you hear, is your other amplifier as addictive? please use quality parts, the BOM is a guide only! substitute some generic parts with better parts, check post https://www.diyaudio.com/community/threads/symphony-amplifier.408203/post-7576197
good morning, OnAudio, I'm taking a look on your Symef just now, I'm interested... it's possible to get (by link too) the last schematic, and the measured specifics , please? I can't find them. thanks, regards
Ros
Ros
Hi Ros, have just seen this. You can use this, there are even downloadable pcb files, good luck https://www.pcbway.com/project/shareproject/SYMEF_type_S_e5e73a51.html
When evaluating and measuring audio we sometimes forget the brain is its own computer that applies its own correction mechanisms, mappers and filters to a certain extent and thus determines what each individual finally perceives, not forgetting the room and speakers, do you like what you perceive
good morning OnAudio,and to everyone.
I find it a very interesting project.
Have a nice day.
Ros
I find it a very interesting project.
Have a nice day.
Ros
good morning OnAudio, I downloaded the documentation on pcbway, the schematic is on a black background, and it's easy to get confused; where can I find the same schematic (I think it's the latest updated, right?) but on a light background which is more readable for me? thanks in advanced e again un saluto Ros
amplifiers have many dimensions, the most important being semiconductor, capacitor and other components quality. if these are held constant we then go into fashion aspects, music type, speakers etc. It looks like 15% IMD isn't so bad. There are many dimensions to amplifier acceptability including soft clipping and dynamic behavior. Just pick what you like. Those that got blown away by the symef and were comparing it to their Bryston amplifier or McIntosh amplifier weren't far off. In an AB test telling apart a McIntosh MC303 from a symef type s might be quite a task.
Perceptions complement measurements, different people and different setups have different perceptions, heres more data to try explain how symef politely dethrones almost all amplifiers
When it comes to amplifiers there are many cockerel and bull stories that differ from ground truth
Although no ranking system is completely fair, this is just a rough draft, scientific methods are presumably more objective than commercial advertising ranking systems used for marketing, its also not cheap to get on those ranking lists. There may be errors and unfairness in this list due to the fact that an amplifier with more head room despite having hard clipping is actually better than a soft clipping amplifier with no headroom. So this list will change as more objective scientific methods are used, feel free to contribute your ideas
Here's an attempt to rank the amplifiers. No ranking system is pristine, bias and focus on certain metrics skews ranking. Component and parts quality and provenance supersedes the ranking. Feel free to share your own perceptions both subjective and objective.
