Shaan, you and your Indian friends were quite pleased with 6 BJT VSSA as seen in local forums, many amps reproduced. You can always go to a little more complex as with cap multiplier or so, but the beauty of VSSA basic design is lost for just a fraction of an improvement.
Major step forward in SQ you will not see in this thread.
Major step forward in SQ you will not see in this thread.
Andrej.
Stop posting baits.
Stop copying other peoples' work.
Stop being a horrible person to others.
Stop using nonsense posts to push links to commercial sector.
Stop insulting other people and their passion.
Stop being a bully.
Stop being a know-it-all.
Stop the self-gratification.
or don't...
An image, once established is your best weapon, be it self-deluding.
Stop posting baits.
Stop copying other peoples' work.
Stop being a horrible person to others.
Stop using nonsense posts to push links to commercial sector.
Stop insulting other people and their passion.
Stop being a bully.
Stop being a know-it-all.
Stop the self-gratification.
or don't...
An image, once established is your best weapon, be it self-deluding.
Well said!!!
Some DIY-er do forget the fact he copied the circuit from other sources. Commercial or not, give thank you and respect where it do! Please.
I never ever saw the Japanese version of the amp.
The basic circuit I posted on the forum with a minimal modification I have it almost 32 years. I got it from a Hungarian engineer! I do not know if he copied or not I care less.
I do not brag about that!
We should help each other (that is why the forum called community) or at least not to disturb and bully etc. 
VSSA sound very nice even with mediocre measurements. Let's be fair 6 BJT can't do much, it's more about the parts chosen and fine tuning their values. PCB layout is as much as important as you already found out. Correct GND connections makes all the difference.I never said that an amplifier with the best measurements is the best sounding one.
Yes BD139/140 or many others, and output can be BJT... DIY is fun you can do anything what do you want to do.
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Here the cap multiplier transistors have very little voltage across them and fairly low current. So it's dissipation is very low. BC546B/556B or equivalent is sufficient . They also have higher gain than the BD series and so the 'multiplied cap' is greater. If I remember right the effective capacitance is hfe* Transistor Base capacitance !
VSSA was an open project for the masses, track record of all the copies followed around the world are well documented by the Google. Few hundreds modules of mine traveled the globe, according to feedback there are many satisfied customers. My intention was to start promotion of CFA amplifiers since all what was present at that time in majority sites was classic Linn LTP topology. Master plan worked very well as you can see from the variety of threads evolved on DIY audio, including this one. Basic schematic is so tempting that once seen, one could not resist to try. What's best, the result is amazing compared to stakes involved...
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...Happy VSSA builds to all of you.
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Shaan, I'm always here if you need some advice or help.
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VSSA sound very nice even with mediocre measurements. Let's be fair 6 BJT can't do much, it's more about the parts chosen and fine tuning their values. PCB layout is as much as important as you already found out. Correct GND connections makes all the difference.
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Adding cap multiplier is really good idea, low noise LDO combined with shunt regulator is even bolder step towards better PSRR. Not to mention using advanced CCS wherever clear and constant high impedance current source/sink is needed.
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Dear Andrej pretty sure we can agree if hole audio chain is medio line or higher in quality level then a simple change of wire type even its a short peace inside power amp or be it change a capacitor from one brand to another brand is audioable, but not shure we can measure data change with the budget present for gear over here but members enjoy to diy and learn about stuff plus judge for themselves if its worth invest in more costly components or amp kits or laboratory gear.
It seems a bit that whatever improvement is discovered here than your designs have always some even better and that is probably right and your FO amps look really great, but please regarding pro measurements documentation verse what you call mediocre measurements give some links because have not seen anything presented at diyA since you did benchmark FO v1.2 via a Creative Labs soundcard on home computer and isn't that actually a mediocre measurement.
I mean all hype about your latest designs seems based on subjective reviews and old mediocre measurements therefor miss some real pro AP measurement documentation and that stuff that for example compare real input signal to FO amps is reproduced completely correct or at least better than most other amps at speaker terminal, because nobody really knows if your clever new amp designs and recommended expensive PSU plus electrolytic power banks really improve on all parameters in electric minimum phase domain and reproduce more correct than any other amp or its just a pleasant difference.
Time will tell if above hinders me to buy your FO v1.4 when they get released in small module version, but think its fair critics that either your builds need to improve on own mediocre measurements or stop accuse others and maybe help them instead and cooperate a bit.
Have best and happy Christmas, including FO sales.
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Today I discovered something... bad news, my eyes are not good, many times going back and watching some of the pictures added in this thread to rethink things.. and only now I saw those very very thin lines and ellipses in those amp pictures...
Thimios, can you please increase the line thickness, if you use Microsoft Paint program then please change according to attached picture so we with a bit older and lousy eyes can see better, it makes discussion easier when something is pointed out in pictures.
Happy CFH7 builds to all of you. MEW!
Thimios, can you please increase the line thickness, if you use Microsoft Paint program then please change according to attached picture so we with a bit older and lousy eyes can see better, it makes discussion easier when something is pointed out in pictures.
Perhaps a reminder is in place for this gentleman, we are not in the VSSA thread, this is the CFH7 thread in case a certain persons/cats memory is fooling him/her-self, hence, we are sure he/she most probably meant:
Happy CFH7 builds to all of you. MEW!
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Ok maico i will take care.Today I discovered something... bad news, my eyes are not good, many times going back and watching some of the pictures added in this thread to rethink things.. and only now I saw those very very thin lines and ellipses in those amp pictures...
Thimios, can you please increase the line thickness, if you use Microsoft Paint program then please change according to attached picture so we with a bit older and lousy eyes can see better, it makes discussion easier when something is pointed out in pictures.
Perhaps a reminder is in place for this gentleman, we are not in the VSSA thread, this is the CFH7 thread in case a certain persons/cats memory is fooling him/her-self, hence, we are sure he/she most probably meant:
Happy CFH7 builds to all of you. MEW!
We here do not have nothing to hide
You have a curve tracer? Cool!
All I can do is match Hfe.
That keeps thermal drift low when tied together but matching curves gives ultimate low HD performance.
Matching hFE is exactly what you need to do. Matching Vbe doesn't help you at all, and with transistors from the same lot that match hFE, the Vbe will probably match as well.
Using a curve tracer to match parts would be one unpleasant job. You could use that to add some extra verification if you wanted.
-Chris
Using a curve tracer to match parts would be one unpleasant job. You could use that to add some extra verification if you wanted.
-Chris
Given the new layout revisions - as soon as Idefixes has time to update layouts I can get the GB #2 going with the new improved PCB. In the meantime, for those with gen 1 boards it looks like simply cutting two traces, adding a pair of jumpers on the ground and a pair of resistors is all that is needed. The data Thimios provided showed 50Hz peak at -112dB for a main audio signal level of 0dB. So you should not hear the hum at all.