[sdiy] Looking for schematics

[Pete Swarbrick]

I repaired a DB9 a few years ago. I am sure it has a transistor ladder
and if I remember correctly the 3080 just to the right of your photo is
used as the diff amp, picking off the 4th stage of the ladder. I would
think that tracing the inputs to this OTA should confirm this and give
you a relatively easy place to add your selector switch.
I had not seen a DB9 before this faulty one and was quite impressed with
the sound; it has a CEM3340 VCO and the aforementioned ladder filter
plus a 3080 based VCA I think. Anyway, my pal got it in broken condition
for a few pounds and I fixed it for a few more - everybody happy!
 
Apologies if my memories are incorrect, but I think you could have an
easy hack here

Best
Pete


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Heitor Alves
Sent: 17 January 2009 21:27
To: harrybissell at wowway.com; Synth DIY List
Subject: Re: [sdiy] Looking for schematics

Hi Harry, and list

I've uploaded a photo of the mainboard (analog circuit) and there are 2 
possible places to be the diode/transistor  ladder... but without the 
schematics i'm affraid of mess something... i'll keep on trying to find
it, 
if i cant find it i'll leave the idea alone ;o)

photo: www.atomlabs.biz/DSCN2497.JPG

thanks for the help anyway, i've already made a .txt with harry's 
explanation on the mod :o)

regards

Heitor
----- Original Message ----- 
From: <harrybissell at wowway.com>
To: "Heitor Alves" <theatomlabspt at gmail.com>; "Synth DIY List" 
<synth-diy at dropmix.xs4all.nl>
Sent: Saturday, January 17, 2009 5:58 PM
Subject: Re: [sdiy] Looking for schematics


> Hi Heitor
>
> if it is truly a transistor or diode ladder, copy the
> buffer circuit from the top of the ladder and add it
> at the second cap up from the bottom. DO NOT move the resonance
> circuit. Select A or B with a switch. If it is an IC
> based filter, it should be easy to tap the second stage...
>
> H^) harry
>
>
>
> If it is a laOn Sat, 17 Jan 2009 16:41:43 -0000, Heitor Alves wrote
>> Hi All!
>>
>> I'm looking for service manual or schematics of a DeepBass Nine (DB9)
>> . I cant find any online, and infos about it are almost none. I know
>> that it was built in the UK, very few were built in fact. My goal is
>> to transform the 24dB filter in to 12dB filter, kinda of mod it to
>> be able to select the filter kind. Is it possible? I believe this
>> synth is another clone of the TB303, but without the manual i wont
>> risk it ;o)
>>
>> thanks in advance
>>
>> Heitor
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>
> Harry Bissell & Nora Abdullah 4eva
> 

_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

checked by CanIt4