Explendid amplifier designed by Michael Bittner, our MikeB

4x PCB sysasym V5-2 arrived

Hello MikeB,

you wrote, you want to see the PCBs.
I make some pictures and you can see the here.

Thank's for your comments ! ;)
 

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Toshiba drivers are nice, the plastic ones are wonderfull.

I made some experiences,and sounded a bit better than MJ340/350.

Well guys....Symassym sounds good the way you construct it...only severe bad luck will turn you deceptive.

The amplifier is reliable, well designed, deeply tested, revised, ugraded, updated, tweeked, misadjusted, underbiased, overbiased, with good supply, bad supply, with good speaker, bad speaker.

The only way it has to sound bad is if you make some cuts in your speaker.... introduce sand inside the gap of give a kick directly in the middle of the voice coil.

Can be bad too if you crash your car (bad mood)...if your mother in law decide to go to leave with you (tragedy)...if your wife decided to change you by someone more young or if you install a high distorted portable radio...with low voltage batteries....and insert all volume in the Symassym input.

Also, be attention if you have not a small dark cloud following you at all time long...raining over you and never touching others...if you use to cut yourself when shaving each morning...if your tires use to be flatten, your new car explode the motor or exaust the brand new battery...or the only bird that use to fly over your town.... made something that crashes directly over your head...hehe....bad luck maybe.

Other sittuations...do not worry and be happy!...if not sounded good....change parts, check parts, if continue to sound bad...change input source...continuing to sound bad...sorry man...nobody told ya....but i have some small suspections that there are a small possibility that you have listening problems.

Icnoclastic was interesting Hugh, very subtle information.....was deep that...i had to search hystory book.... well, well.

regards,

Carlos
 
HI Carlos,
yes, the plastic toshiba is what I have, to save me a trip to the basement, do you remember what you used?
the sanken are the 2922 and whatever the pnp is.

I believe in the amp, but I believe the pcb can use some work.
I really have no clue about pcb design and I don't have distrortion measurement gear to help me in the decision making.
I have heard about putting in a gnd plane and other things but I had mixed results with gnd planes.

I think we can all agree that a pcb that gives lower distortion on the same exact design would sound better (unless all the distortion turns into 5th or higher harmonic).
 
Or for just matching some small signal bjts a much simpler version... (see attachment)
You only need one of these constructions, it's identical for npn and pnp.
I used a dip8-socket for placing the transistors, the whole thing fed by a 9v battery.
The vbe is simply measured by checking the voltage between base and emitter, the hfe is calculated by simple math:
Re = one of the 1k at emitter side
hfe = V(Re)*100/V(R3)

V(Rx) = voltage across resistor. Not the perfect accurate one, but built quickly.

Mike
 

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Grataku was answered by direct mail...well guys!

Always Germans..... always!

You have special intelligence in my point of view, because i had many examples...i will start to eat those vegetables...Krau....something alike, to have that acid fosfóricum, or some bissulfitum intelectualibus...something to make me more clever.

Many monthes without understand a lot of things that Bittner explained me...as he is thousand years advanced related me!...there are posts that seems Japanese, and i know to read some words in Japanese, and they seem easier to me.

Well...there are people that have better school, better education and maybe some faster intelligence, better memory or something alike that......well...i can feel Germans very clever.

The Bias circuit is clever, really smart, as you can decide the real voltage and the real current, to test your gain with the current and voltage the circuit will need...so...measurement will be better, more realistic, and more precise.

Yeah!...Germans....very good...i will have another sausage...maybe i can turn more clever.

Zier gut!

Carlos
 
Thanks Mike and Uwe! See attached my board, done with a gutted scanner as glass fixture, some traces have small holes (can be checked well by holding against a 100W light bulb), I will use some solder for that.

Oh destroyerX, Mike is smart, and you are heartful (new word... I mean hearty).
 

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Yes, that worked out. I used 3 min but maybe will up to 4, because it needs to heat up or sth and after 2 min it has maybe 80% maximum light output. I developed ~ 3min. Was not too clever and wiped the board dry with toilet paper after developing and rinsing, that left some resist in some areas where it shouldnt belong. But all in all worked and was fun :nod:. This hobby is so many-sided :smash: