cool way of taming the snappyness of the ba6110

[aminoacid]

hi.


i have disliked the way the xoxbox/ba6110 snapps when gating and accenting.

ive tried different setups with all transistors around the gate circuit and the vca.

but i just made some saom random experiment just now.


when applying a pad between the collector of q1 and the cv input of the ba6110 i found out that thoose fast rock hard transients get smoothend out. the accent doesnt fly as high above regular gated notes and the overall output gets damped aswell, making the signal less distorted as you otherwise can find it sounding when the filter is fully open with out resonance and full accents pushing high frequency transisents into a crushed ugly sound.

the pad is a 100k resistor but you could prob use anything from 47k and up.

i have to admit that im doing this with a pair of cheaper sennheiser headphones so i might hallucinate some, but you professors out there should really give it a look.

its like having a smooth compressor in there!!!

i even tried with 1meg resistor and that was like baby cream and much lower output signal.

[guest]

how do you connect the resistor to q1

[phono]

how do you connect the resistor to q1

i think by pad he means attenuate so q1 collector to 100k to ground i guess

or not :S reading it again its q1 collector to cv input of the ba6110?

[aminoacid]

sorry for being so unclear. i got a bit carried away and wrote a bit sloppy.

i conected a resistor in between the middle pin of q1 and to whatever pin that is going on the ba6110. i dont seem to understand the pin config from the shematic actually...

no conections to ground.

i have thoose transistor socketed so i just pulled the leg out and inserted a resistor with two aligator clips and a piece of wire.



now i just recorded 4 different resistor setups:
-no resistor inserted
-100k
-200k
-300k

from my daw program i can clearly see some small differences.
-dynamics are reduced
-overall output is lowerd
-after 200k, the accent of the voulme is almost neutralised, but more of the sound in the middle/end of the notes gets more pronaunced.

[guest]

excellent
so thats the same as cutting the collector trace
and inserting a 200k resistor

i am a bit suprised it makes a difference
but not too much
that part of the circuit is there to compensate for the ba6110
and if you look at the usual current source for the ba662
there is a 220k resistor in series with the current source

[aminoacid]

yes, simple operation.

i have a ml303 with a ba662 and a xoxbox with the 6110.

the dynamics are quite different i think. and i dont like the way the 6110 sounds snappie in the start and thin afterwards if you get what im saying.

this is why i started to experiment a bit.

[aminoacid]

the usual current source you are talking about, is that of the tb303?

im out of town but when i get back im gonna try inserting a cap to ground in that area aswell. and make recordings of both my machines to see if i can match thoose dynamics some.

[guest]

q31 is the vca control current source for the tb303
and that has a 220k r131 on it

[aminoacid]

hi again!

back in town and made some experimenting this evening.

i tried to insert resistors on more places in the ciruit but the one i was talking about did give me what i was after finaly. refering to my ml303 and to what my ears was looking for.

100k as mentioned, between middle pin of q1 (collector) and to the pin of ba6110 where that was going, although something like 70k or 80k would be good too. the biggest effect here is the accent really. i might have exaggerated this before, sorry for hyping stuff.

and a 47nf cap between middle pin of q1 and ground(emitter of q3 and q4) made the fastest dynamics go away and at the same time no more clicks. the 47nf felt just about to big here but sounded totally okey. a 33nf would probobly be better i think. i used a polypropylene but any film cap will prob work.

i have some audio samples here recorded while syncing to my daw.

although i have no web hotell or what ever is needed to upload samples and i am not the best with internet... if anybody else would like to upload i can send the files. they are 48khz 24bit. four of them. two without the mod and the same two with the mod.

good night!

[aminoacid]

i just found a fault in my box. c33 in the vco was 1nf instead of 10nf.

i found this because i changed some of my nichicon polyester caps for polystyrene caps today. i changed c10,c33,c20,c21,c25 and c27. i changed c10 and c33 in the same time and that made a whole lot of difference with my box. i got a new high freq dimension that i wanted to find now for some time and that was my plan with the polystyrene caps. i love it. the overall sound is less transient and more full, wide and soft.

however this makes my former tests a bit useless...

but still, adding a resistor and a cap will get your accents down and get ridd of clicks/pops. im currently using an 82k resistor and a 22nf cap. my xox is actually 1db less hot then my ml303 now and it doesnt make thoose crackling distortions when playing with full resonance , half cutoff and accents.

hope im not making a mess here

[guest]

wow
how did you tune it with a 1nf c33
that would make all your notes 10x the frequency

glad you got it all sorted

[aminoacid]

no problem tuning it...

maybe you are thinkig about c34..?

i think that a bigger cap in c33 would filter out some high freq before the fet.

im feeling really silly finding this kind of fault. since it was caused by my self!

[antto]

isn't C33 a lowpass filter on the sawtooth?
my silly calculator suggests it's some high frequency when 0.01uF, having it 0.1uF would be lower frequency

[aminoacid]

im thinking lp filter aswell. i must of thought the wrong way just before.

as i had smaller cap in c33 i should filtered out less actually... right?

strangest thing is that i got more high freq harmony when swithcing to a bigger cap (polystyrene).

maybe i should be a good boy and switch c33 again with the right capacitance but back to nichicon poly films, and see what that sounds like before i just say that polystyrene is the way to go.

my pcb is starting to grumble

[antto]

C33 should be 0.01uF
what did you had in before, and what did you put afterwards?
and uhm, experimenting with that cap would most likely change your square wave also