Explendid amplifier designed by Michael Bittner, our MikeB

[PMA]

Dear Hugh,

I have respectfully read your standpoint and I have absolutely no need to dispute with you.

Probably if you ever read my thoughts about influence of HF interference, D/A residuals etc. you would not call me an iconoclast.

But it is your attitude and why should I quarrel about?

Yours faithfully,

Pavel Macura

[dx.master]

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 !

[destroyer X]

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

[grataku]

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).

[PMA]

Look at the distortion images and see that there are almost only even harmonics of low orders, odd harmonics appear at the moment when the amp is pushed hard ....

I think it is a pretty puzzle what the new PCB will do with the sound ....

[MikeB]

Grataku, Sanken sc2922/sa1216 are the ones Carlos uses, so your outputstage would be identical to his. The PCB needs some work with the powergnd, i have no clue how the sound will change. Like Pavel said, a puzzle. As the distortions are mostly even order, there is the danger that they did "improve" sound, but i hope not.

Mike

[PMA]

Hi Michael_K,

I have prepared one image especially for you

Pavel

[MikeB]

Pavel, you may explain which curve of the 3 phaseplots represents which node ?
Mike

[mikeks]

Originally posted by PMA
Hi Michael_K,

I have prepared one image especially for you

Pavel

Image of what...?

[12 Cents]

dx master, you wrote that you have done a matching tool, can you show that to me? Right now I only have this: