The 33uf suffices. For the sake of experimentation you could try a ladder of 100nf(poly), 1uf(tant), 33uf(electr) and hear what happens 😉
I did that with 100uF electro bypassed with (a big) 1uF polypropylene bypassed with 100nF also polypropylene. You know something - I can't hear a difference! Maybe my speakers or source are not resolving enough, maybe my ears are not resolving enough, maybe there is no diference at all. Going back to the single eletro.
One thing that a made a difference is the input and feedback caps. I started with a Nichicon Muse ES bipolar (supposedly good for coupling job) and I didn't like the highs. Then I went with a 4.7uF Wima MKS2 and it was better but the highs still not that good. Then I put two wet tantalum back-to-back and the highs became marvelous! For the feedback cap I used so far: Lelon - clean but extremes rolled off, Panasonic FM -very clean and dynamic however I'm not sure about the tonal balance, Nichichon Muse ES - slow, grainy, not good at all, Nichicon KZ - nice warm mids and punchy bass but etches the highs to much, Elna Cerafine - shouty and grainy, Elna Silmic II - I really wanted to like it!!! but the midrange and highs are too soft and lifeless.
The problem is that these caps have a sound signature and I would much prefered if they were neutral - let the sonic signature remain in topology alone!
In the end, the Panas FM and Lelon were the most neutral, but not sure if tonaly correct. Needless to say, the SYMEF sounds wonderful with any of these caps - I'm being very picky and perfectionist here! 😉
By any chance, does the formula takes into account the different sonic signature of caps and gives the best combination? It would be great if it did, if it besides topology and harmonic spectra would also considered parts. 😉
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Very nice. Thats some serious research your doing. With every line you provide a wealth of information to the world.
The formula takes into account a certain set of variables, however it can be expanded to include component types. What you are doing now is providing those expanded variables. 🙂
The formula takes into account a certain set of variables, however it can be expanded to include component types. What you are doing now is providing those expanded variables. 🙂
about high filter
hi paulo,
about incorporating that cap.you are talking for filtering high frequency,it is refering to signals generated during rectification process that are going to be injected at amp.this can be done by puting capacitor in parallel with the rectifier diode and by placing also at the output of power supply.value is from .01 to .1uf
regards,
joel
hi paulo,
about incorporating that cap.you are talking for filtering high frequency,it is refering to signals generated during rectification process that are going to be injected at amp.this can be done by puting capacitor in parallel with the rectifier diode and by placing also at the output of power supply.value is from .01 to .1uf
regards,
joel
about sources...
Hi Paulo,
Are you still using your computer as your source of music?be aware that some files converted from original have losses.Get one original cd look at how much files in MB per song and how much they have compressed it. and turn off the equalizer of your player coz this can overdrive signal.you can notice that while using headphones.
My settings in input capacitor, I have used polypropylene(4.7uf) and and electrolytic cap on NFB.(100UF).my source is a dvd player and mixer with bass, mid ,treble.I have used a yamaha tower speaker 6 ohms(2-6" and tweeter dome).
As you can see I have compare it to optimos and carver and SYmef is ahead of mid and bass is more controlled and you can feel its presence.Best way to experiment is to have a good source.
regards,
joel
Hi Paulo,
Are you still using your computer as your source of music?be aware that some files converted from original have losses.Get one original cd look at how much files in MB per song and how much they have compressed it. and turn off the equalizer of your player coz this can overdrive signal.you can notice that while using headphones.
My settings in input capacitor, I have used polypropylene(4.7uf) and and electrolytic cap on NFB.(100UF).my source is a dvd player and mixer with bass, mid ,treble.I have used a yamaha tower speaker 6 ohms(2-6" and tweeter dome).
As you can see I have compare it to optimos and carver and SYmef is ahead of mid and bass is more controlled and you can feel its presence.Best way to experiment is to have a good source.
regards,
joel
Thank you, Harrison! 🙂
Joel:
Yes, the source is very important. These days I use the desktop pc as my main source. All music is in the hard drive in losseles FLAC format. The special effects for games like THX are all disabled for better transparency. It's just so pratical to have the pc as music source that I seldom use the CD/DVD player for music.
I'm now experimenting with 4 x 1uF paraleled Evox-Rifa PHE 450 bypassed by a 100nF Vishay MKP 1837 as input cap and a 47uF Black Gate FK as NFB cap. It's sounding good so far but it's to soon for me to tell what I like best. Perhaps a mix of different brands like the sharp Muse KZ and the soft organic Silmic II would give the best results. It would be nice to correlate these subjective perceptions with mesured data from the caps (ESL, DA, loss tg, etc) so it could be possible to arrive to a matrix that correlating with topology would tell which cap is best for which place.
keep it up...
thanks in advance for you will save us time and money.your research will be highly appreciated.This amp. deserves a space in my home, and to all Filipinos you can count on SYMEF.It is well documented back up by simulation and listening test and has proven its stability.
regards,
joel
thanks in advance for you will save us time and money.your research will be highly appreciated.This amp. deserves a space in my home, and to all Filipinos you can count on SYMEF.It is well documented back up by simulation and listening test and has proven its stability.
regards,
joel
Yes, that's why I have now 2 x 47uF. 47uF it's the highest value I have.
More findings:
The Lelon REA has a mid-bass glow that can be used to fix the Silmic's lack of mid range energy. It's also very fluid. Better tonal presentation than the Pana FM. Just the lows and highs are rolled off.
All the electrolytics have influence in the sound except for PS decoupling wich I can't perceive a difference. The black gate FK is very clean, fluid, detailed but a bit thin sounding. Again, the Lelon can be usefull here.
For input cap the best way is polypropylen. No wet tant, no electro, no polyester, only polypro.
The NFB capacitor behaves better and has less influence on the sound quality if it has no voltage across it. No DC voltage. No AC voltage.
If you use the NFB cap to roll off your bass response then the NFB cap must have some voltage across it, otherwise it cannot act as your bass filter.
If you want good bass then ensure the NFB cap has no voltage across it when the amp is passing audio signals.
You do not need decoupling at the PSU. It cannot do anything to the sound.
Oscillation at the PSU will affect the sound. Remove all oscillation at the PSU, not add useless decoupling.
If you use the NFB cap to roll off your bass response then the NFB cap must have some voltage across it, otherwise it cannot act as your bass filter.
If you want good bass then ensure the NFB cap has no voltage across it when the amp is passing audio signals.
yes, the local decoupling should be at the amplifier and particularly right next to the main current consumers that can change demand rapidly.
You do not need decoupling at the PSU. It cannot do anything to the sound.
Oscillation at the PSU will affect the sound. Remove all oscillation at the PSU, not add useless decoupling.
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it is called high frequency cap.
according to sloan page 203 paragraph 4,these capacitors are last defense at eliminating any rf components that could be applied to the amplifier circuitry.rf components can originate with the bridge rectifier or be inductively coupled into the power supply through the line cord or other external rf source.
regards,
joel
according to sloan page 203 paragraph 4,these capacitors are last defense at eliminating any rf components that could be applied to the amplifier circuitry.rf components can originate with the bridge rectifier or be inductively coupled into the power supply through the line cord or other external rf source.
regards,
joel
The local decoupling caps are of most importance, I didn't mean to minimize their role. What I wanted to say is that in that place - maybe because these caps are away from the signal path - the influence of using this or that brand of cap is less contributing to the sonic signature. I couldn't tell apart a Panasonic FM from a Muse KZ in the decoupling places.
The bigger the cap the less voltage has across it's terminals and the lower it's cut-off frequency. The ideal would be an infinite capacitance cap. Because I don't have a Black Gate higher than 47uF, to minimize the roll off I placed two of these in paralel, giving-me 94uF, close to 100uF prescribed.
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Thank you
Hi Joel,
These are only my subjective perceptions. I wish I could have access to a spectrum or distortion analyser (or whatever device appropriate) to back up these perceptions with objective data. And yes, the SYMEF is some very special amp! 🙂 It deserves to be built with the best parts for the job so it can shine in all it's glory! 🙂
Filipino? I tought you were american!😉 Your english is very good! Much better than mine.🙂
Hi Joel,
Thank you for your words of encouragement!🙂
These are only my subjective perceptions. I wish I could have access to a spectrum or distortion analyser (or whatever device appropriate) to back up these perceptions with objective data. And yes, the SYMEF is some very special amp! 🙂 It deserves to be built with the best parts for the job so it can shine in all it's glory! 🙂
Filipino? I tought you were american!😉 Your english is very good! Much better than mine.🙂
I'm sorry, it is obvious this complement was meant for Harrison and not for me. The thing is that I'm so excited trying different caps and ways to bring this wonderful design to full glory that I miss read Joel's post. This is a very sweet design backed up by Harrison's scientific research,formula and - I can only imagine- many hours of hard work that is trully remarkable! I have to thank Harrison not only for all his work and amp but also for the enjoyment and excitment that this amplifier is bringing to me in all this process of trying different caps and tweaks! I'm having a great time doing this! Thank you Harrison!
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you may find that an ordinary industrial grade 220uF or 330uF will match or even exceed the performance of the paralleled yet too small Black Gates.
The bass and the treble should be controlled at the input. Those passive input filters should do all the out of audio band shaping of the electric signal.
The NFB cap should only be used to block DC voltage and as a result reduce DC gain to ~1times (-0dB).
completely wrong.
Adding a low esr cap across the PSU or across the transformer or across the rectifier or across the diodes can introduce more ringing in the supposedly DC supply.
It is the added resistors that perform the snubbing function (damping of the oscillation) to reduce the ringing.
The impedance should be halved with two paralleled capacitors. I though that was good thing... 😕 I'm going to try your sugestion.
high frequency filters
Electrolytic capacitors are usually used due to high capacity at low cost and low size. Smaller non-electrolytics may be paralleled with these to compensate for electrolytics' poor performance at high frequencies.
regards,
drowranger
Electrolytic capacitors are usually used due to high capacity at low cost and low size. Smaller non-electrolytics may be paralleled with these to compensate for electrolytics' poor performance at high frequencies.
regards,
drowranger