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Replacing the BA6110 with a BA662

PostPosted: Jan 31st, '17, 15:59
by mymaracas
Hello everyone,

I need to replace the BA6110 with a BA662, can't really find the pinout anywhere though.

All i could find was this:
1 CV1
2 -IN1
3 +IN1
4 Not labeled but appears to be CV2 *EDIT: According to the original 808 schematic this seems to be the Input Bias? See below*
5 -V
6 OUT1
7 IN2
8 OUT2
9 +V

from here: http://analogue-heaven.1065350.n5.nabbl ... 48876.html

Can anyone confirm this?

Thanks

Re: Replacing the BA6110 with a BA662

PostPosted: Jan 31st, '17, 21:41
by Altitude
BA662 is not a drop in replacement for BA110

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 1st, '17, 16:25
by mymaracas
Sorry, do you mean it's not a drop in replacement because the pinout is different or because it can't be used in exchange? I wired it up as in the original post, and it seems to work, however the noisefloor is really high...

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 1st, '17, 17:25
by mymaracas
just saw this thread: http://mutable-instruments.net/forum/di ... nd-sh-2/p1

if the 6110 needs extra circuitry to behave like a 662, would i be right in assuming this is present in the yocto, and if so, could this circuitry be bypassed in order to be able to use the 662 in place of the 6110?

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 1st, '17, 17:31
by antto
the two have some differences
i don't understand, and i haven't looked into it

the x0xb0x for example has the option to use either one of them, but the circuit has been designed with that in mind, you can check it out in the schematic in the VCA section
normally the x0xb0x comes with BA6110 because it's less rare, and you put it on one slot, with 4 additional transistors
alternatively, if you use BA662 in the x0xb0x, you put it on the other slot, and don't put those 4 transistors

so there certainly is a difference and you may need to adapt it if the circuit wasn't meant for it

is there any reason you want to put BA662 in your yocto?

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 2nd, '17, 12:19
by mymaracas
ah thats great to hear, thanks for the tip antto.

the person i built it for said the clap sound wasn't quite right, and wanted to try with the 662. I was doing some of the other mods so said I'd do it at the same time.

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 2nd, '17, 23:14
by mymaracas
So I had a look at the original schematics and they ARE almost identical to the Yocto, however there are a few small discrepencies:
- R334 is 100k in the 808, and 150k in the Yocto
- R200' doesn't seem to exist.
And finally the one which seems to have been causing all the problems:
- The BA6110s Input bias (3rd pin) doesn't seem to be grounded in the Yocto schematic (infact it doesn't seems to be unconnected in my files), however in the 808 schematic the BA662's 4th pin (appears to be the input bias from this schematic) IS grounded. So I grounded the 4th pin of the BA662 and voila! Seems to be runnning perfectly!


Here's the 808 schematic file I used:
Image

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 4th, '17, 16:01
by BedroomMusic

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 6th, '17, 13:50
by rv0
BedroomMusic wrote:https://shop.re-303.com/product/ba662-clone/


that clone is an estimation. might not work for every use of the ba662.
its "fine" in a x0xb0x/303 clone, but not sure about the yocto.

Re: Replacing the BA6110 with a BA662

PostPosted: Feb 9th, '17, 15:46
by mymaracas
rv0 wrote:
BedroomMusic wrote:https://shop.re-303.com/product/ba662-clone/


that clone is an estimation. might not work for every use of the ba662.
its "fine" in a x0xb0x/303 clone, but not sure about the yocto.


that is the chip i used, i don't have a ba662 to check unfortunately. if i do come across one, i will try it and post an update