Juno 106 chorus input mod!

[sorgenkind]

Hi guys

yesterday night a friend and I replaced the jack board and did a mod on my juno 106, "hacking" the patch shift input of the jackboard in order to use it as a input to feed sounds into the chours circuit of the juno 106.
I ordered a jackboard for my juno by http://www.synthsnstuff.com/ in amsterdam. Joep is a very nice and friendly guy and helped me a lot. Check him out if you need any spare / replacement parts for your synths!
Chorus sounds better now (that's why i wanted to replace the jackboard), and being able to route whatever I want into the juno chorus is a very nice plus. I like to chorus of the juno a lot.kfhkh

here the pics:

http://www.flickr.com/photos/61068278@N03/

[AK]

I looked at em ( nice pics ) but I don't know what the fck I'm supposed to know whilst looking. Is it working now?

[sorgenkind]

i thought the pics speak for themselves.
it is working now, yes, I'll post samples as soon as I'll go back to the studio.

easy man.

[hydrogen]

I think it's a cool mod! The 106 chorus is noisey as fck Did u come up with the plans yourself?

[sorgenkind]

my friend (he has the soldering skills, I don't yet) found infos on the net.
The main reason of changing the jack board was the noisy chorus, which is doomed to be noisy because of relatively cheap components, specifically the chips delivering the clock to the BDD chips (Bucket Brigade Delay chips).
With the new board the floor noise is only 2 dB lower, not a big improvement, but venturing into re-calbring the clock chips and recapping is a costy operation with no guarantee that the noise floor will be better, so I tried with a new jack board, following the precious and skilled advices of joep @ synths and stuff .com (link above).

The chorus on the new board sound way better than the old one, I'll post samples next week after hitting the studio again.

Luckily the chorus on my alphajuno2 is very silent, so we might venture into doing the same mod if it's possibile. ON the juno is possible since there are 2 "test poinst" where you can feed audio in the chorus, possibly this was done to give technicians an easy way to do some tests.

I'll give you more info about this as soon as I'll have them -I can't find the damn link now.

EDIT:

here the link:

http://www.vintagesynth.com/forum/viewt ... 97&start=0

[NoAffiliation]

i checked the pictures and the ones after, is that your studio? Do you have every synth ever made or something?

[sorgenkind]

no, the big serie of pictures are from a synth museum we have here in switzerland. Unfortunately these are not my synths.
The nice thing about this museum is that you can actually play with every synth. I lost some hours in the room where the ARP2500 is... a crazy place.

[lem]

I might have to come to switzerland!!

Modding an alpha juno is definitely possible. At the end of the day they are mostly modular in design, the only thing that could be an issue are levels. But that can be solved fairly easily.

BBD's are renowned for getting noisy with age. I'm not sure if the alpha's use BBD's. Although, knowing the era, im not sure what else they could use?

I know some synths that receive noise around BBD boards, wether its the BBD or surrounding ciruitry I don't know.

Did you test the BBD circuit outside of the synth?

I read somewhere about putting plastic (like an ice cream tub or something) over a circuit with a layer of tin foil around it. I have never tried it, but if its still unfitted it might be worth a go?