Symphony, the best of two worlds, joining Symasym from Bittner

[destroyer X]

With the Dx Blame, that also came from Doctor Self, the Blameless.

I continue to search for perfection, even knowing this does not exist.

Friends have asked me to try to join the bass and dinamics from Symassym to the superb treble reproduction we have in the Blame...the low distortion too.

I have made (simulated only) the Symphony.

It uses the Symassym 5 input, a current sink was added.

The voltage amplifier is enhanced, Self style, and using the same differential alike style used by Bittner... the main difference is the second stage is feeded by bootstrap.

I have not assembled... i cannot do that now a days, i am still healing from a surgery..but i will do that and dead line will be Christmas....uncle Charlie's gift for the Dx Corporation friends.

I may use the Electrocompaniet idea to feed drivers using CCS, alike i did at Precision II and also in the published Troyan...but i have to listen with and without to evaluate that a little bit more.

Distortion is the smallest i have obtained..less than 0.0018% THD...but i have to see how this sounds and the harmonic distribution.

The amplifier is under research, the topologie will be the one shown, with drivers CCS or not.

The output power will be decided too.

Attached the Symassym schematic Bittner did...i would like to remember friends i have worked helping Bittner, and i know this amplifier performance very well, as it is well accepted by the forum, alike the Dx Blame..then i will join them together.

regards,

Carlos

[destroyer X]

attached,

regards,

Carlos

[lineup]

Well, there are a couple of strange things in that topology.
But I guess you will sort it out when your work progress.
Especially the VAS looks like it would not work.
Good luck, destroyer!

[destroyer X]

at least in the simulator it works great..this seems there's a huge chance it will work real life.

Good luck Line up.

regards,

Carlos

[wahab]

Originally Posted by destroyer X

at least in the simulator it works great..this seems there's a huge chance it will work real life.

Good luck Line up.

regards,

Carlos

No doubt it works, thanks to the LIN kindness, but all the work
is made by half of the VAS..
The other half is not functionnal but don t stop the active part
from settling the DC loops correctly...

This is because the current mirror is NOT a voltage mirror,i.e,
the AC voltage amplitude is not the same in each leg of the current mirror..

[destroyer X]

I have spent just one hour in front of the computer....but here you see it is a nice promisse of performance.... or course, if you believe small numbers sounds....you know im not the one loves numbers..but some folks believes on them.

The Symphony was not tuned, so numbers will change, and i will make it better in distortion than the Dx Blame.

You can see the harmonic distribution and the THD up the page.... Omar have asked (Metal), so i have sent him something..but really, i had not worked on the Symphony to reduce these numbers..but i will do it... as i told you, there are several folks that believes good numbers represents good sonics....not always in my point of view..but sometimes this is truth...happened with the Blame..where good numbers resulted in good sonic too...but have not happened with the standard Dx amplifier, that sound great and distortion is high (0.023% THD)

The Symasym 5 had this same numbers when simulated... well... almost the same (0.021% THD)

regards,

Carlos

[destroyer X]

Some friends asked me to go ahead and not delay till the Christmas....i cannot...i have to wait people form group buy's to assemble..there are more than 90 guys in Brazil starting to assemble the Blame...i have to wait them finish before to release a new amplifier.

Also we have Rudi in this forum.... boards are arriving and i do not know if he will open a new turn to group buy or not...so...the next monthes are the time needed to allow this people to build.

Because of that i will have time to tune it using calm... to test it with several speakers.

Simulators allow us to produce 20 different amplifiers each day...but untested and untuned things...i want to make it right!

regards,

Carlos

[BV]

"Left half" of VAS (schematic in post 2) is without any function, outside signal path, connected only to +- Ub and GND. You can omit 3 transistors, 3 resistors and 1 capacitor, compensation capacitor should be in "right half" of VAS . And than it is "blameless"(without dif. input degradation) with bootstraped VAS. Or??
P.S
Only now I noted post 5 by wahab..

[destroyer X]

higher distortion.

Here is how it looks today.

But thanks by the input..left VAS half has not function as you said..but the removal resulted not fine...at least for a while.

I got what you mean... and i already have realised this...thank you BV.

regards,

Carlos

[destroyer X]

Not a good idea to make exactly as Blameless because i already did..also not a good idea to make alike Symasym.... this was already done.

I have another idea to explore.

Here is the topologie under research as plan B

regards,

Carlos