I am sure that poor Michael would happily comment on Egon, Hertha ... etc. 😀
Don't you mix German and Jewish a little bit, Carlos? 😉
Don't you mix German and Jewish a little bit, Carlos? 😉
I do not know...herta and Eggon ...were German people that i know and lived here.
If i am writing in other language....this do not surprises me...as i do not know to talk correctly in my own language....try to imagine the others!
The difference i have...advantage, is that i am not shy...i try all i can...if people understand good...if not...good too.
More than 40 years ago...in the school, i have studied English,French,Spanish, German and Russian....because they offered for free and i love languages.
I feel very bad because i lost the Latin language... when i was ready for start...they decide to finish to teach that language...so...i tried to learn some words in Catholic Churches...were the cerimony was made in Latin.
Now i am learning Croatian..... Dobidgênia....and i think is dobre in your language.
regards,
Carlos
If i am writing in other language....this do not surprises me...as i do not know to talk correctly in my own language....try to imagine the others!
The difference i have...advantage, is that i am not shy...i try all i can...if people understand good...if not...good too.
More than 40 years ago...in the school, i have studied English,French,Spanish, German and Russian....because they offered for free and i love languages.
I feel very bad because i lost the Latin language... when i was ready for start...they decide to finish to teach that language...so...i tried to learn some words in Catholic Churches...were the cerimony was made in Latin.
Now i am learning Croatian..... Dobidgênia....and i think is dobre in your language.
regards,
Carlos
For those who are interested in this ClassD:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=54248&perpage=10&pagenumber=1
But i have not finished it, and have for now no plans to continue, maybe later...
First, i will completely finish the symasym.
Mike
http://www.diyaudio.com/forums/showthread.php?s=&threadid=54248&perpage=10&pagenumber=1
But i have not finished it, and have for now no plans to continue, maybe later...
First, i will completely finish the symasym.
Mike
dtrif said:
Yes, the PCB seems to need changes, but the circuit is unlikely to change...
Mike
Christer said:
Hi Christer !
This question is not easy to answer... It is not a single "secret", it is all pieces together.
I have put every experience i made with making amps into that circuit. (This includes avoiding of cdoms/millercaps)
First, there is the topology, this dualdiffamp with currentmirror in 2nd stage sounded great from the very first version. Then, i tried to avoid the typical flaws seen in many amps. These are for example high thd for high frequencies, not flat openloop bandwidth and so on, lousy feedbackcompensation. These "unusual quirks" are the final salt in the soup, they heavily improved audible quality.
The mainfeatures of this amp are nearly flat openloop bandwidth, low 3rd and high order harmonics, massive amounts of feedback, but "properly" compensated. Feedback is NOT evil ! Symasym has ~57dB of feedback over the audioband...
The topology has by nature very high CMRR, by adding a ccs to the input-LTP and the 22ohms in the supply i increased PSRR to a quite high value, also this topology is by nature well balanced. Because of the high gain of the 2nd stage the 1st stage has only minor work, keeping it in the linear amplification area, not needing REs.
Adding r-loads to the vas always improved quality in my amps (lowering zout ?), the 330pf c-loads to the vas have 4 purposes:
1, stabilization / feedback compensation
2, lowering zout of vas even more for higher freqs
3, reducing the dynamic phaseshifts by adding a constant value to a dynamic value
4, reducing thd for higher freqs
I believe, paying attention to every detail made the symasym sound so good, i am thinking of this amp as some really "blameless"... 😀 Okay, the PCB is not blameless, it contains one error... (hard to fix)
Also, i think this amp prooves 3 things:
1, Feedback is a good thing (If properly used)
2, The need for high SR is nuts (Symasym has only ~20v/us)
3, High DF is necessary / good (DF=~12000)
Okay, let's begin the flame war !
Mike
Hi Mike,
That's looking cleaner. I may as well build it that way since I haven't been able to build the boards yet.
-Chris
That's looking cleaner. I may as well build it that way since I haven't been able to build the boards yet.
-Chris
Hi Mike !
Did you maybe compare your amp with an inverting GainClone yet ?
The PS is perfect, and i would be very intrested about your opinion in that comparison.
Regards!
Did you maybe compare your amp with an inverting GainClone yet ?
The PS is perfect, and i would be very intrested about your opinion in that comparison.
Regards!
Hi Mike, little notice about grounding : if you can get best results of SNR, you must lead every grounds separate by own wire to geometrical middle of PS : by one wire input ( signal ) ground, by second wire " filtration " ground ( which must be connected in this PCB to geometricel middle between C 12+13 ) and output ground lead directly to geometrical middle of PS. If you make it by this method, SNR will be over 120 dB ....
Hello Mike
I see that your boards are evolving. Great!
The only problem is that I have to build a new one again
I just finished another set of SYM5.2 for a friend. Everything went just fine this time and I will send the pics here soon.
Cortez: I have compared Sym with my LM3886 based inverting gainclone a´la CarlosFM which is very nice amp too but in my opinion SYM is in its own league! If you are thinking of building it I say go for it and be amazed!
Jarno
I see that your boards are evolving. Great!
The only problem is that I have to build a new one again
I just finished another set of SYM5.2 for a friend. Everything went just fine this time and I will send the pics here soon.
Cortez: I have compared Sym with my LM3886 based inverting gainclone a´la CarlosFM which is very nice amp too but in my opinion SYM is in its own league! If you are thinking of building it I say go for it and be amazed!
Jarno
Upupa Epops said:
SNR is over 120 dB right now with old PCB (see my measurements, 50 Hz component comes from CD player that is used as a signal source).
You did not get the point, he tries to decrease rise of THD at frequencies above 1kHz, there is a constant + 6 dB/oct rise (see measurements in my review). Suspected is No.6 distortion according Self, i.e. supply rail induced distortion (not the PSR!)
Ok I have no clue but I liked the first layout. Will Pavel do all the evaluation again?
Lukas
Lukas
Cortez said:
I have myself not compared, but i know of 3 people having compared, one of them at least with a LM3875... All said the same, symasym is another league than chipamps, these are no real competition to symasym.
12 Cents said:
I don't think that Pavel is willing to test every pcb-version i made... Let's see if new PCB is better, if not, i will keep old one.
Mike
LM3875 has differences, a lot, related LM3886, and there's a lot of differences also
If you compare them with Symassym.....
What will be the difference?
hehe...i am not crazy enougth to start a figth with Chippy guys!
.........................................................................................................
Man, Pavel will turn crazy if you change a milimeter!...he will have to calculate everything again....and may result 119 dB only...ahahahahahaha!
Precision is precision.... well....that's the reason why we ask him to come to help us.
regards,
Carlos
If you compare them with Symassym.....
What will be the difference?
hehe...i am not crazy enougth to start a figth with Chippy guys!
.........................................................................................................
Man, Pavel will turn crazy if you change a milimeter!...he will have to calculate everything again....and may result 119 dB only...ahahahahahaha!
Precision is precision.... well....that's the reason why we ask him to come to help us.
regards,
Carlos
