Doepfer

Hi all,

My tapped bbd module suddenly has a limited range, it can now only 
do short delaytimes, probably 25-40% of the range it should have. In 
other words: it can't produce the aliasing sound anymore. The first 
time I fired it up it was ok, second time it had this problem. Any 
ideas? 

greetings, Anton

> Hi all,
>
> My tapped bbd module suddenly has a limited range, it can now only
> do short delaytimes, probably 25-40% of the range it should have. In
> other words: it can't produce the aliasing sound anymore. The first
> time I fired it up it was ok, second time it had this problem. Any
> ideas?
>
> greetings, Anton

Sounds like a fault. Probably the "heater" of the temperature controlled
logarithmic converter of the HSVCO is defective. If you are able to replace
an integrated circuit we can send you a new one. As all circuits are
equipped with sockets no soldering is required but only removing the old
circuit and inserting the new one.

Please tell me your postal address (directly to me, not to the Yahoo group)
and we will send you the spare part if you agree. Otherwise please send the
module for repair.

Best wishes
Dieter Doepfer
(hardware@doepfer.de)

I get a similar problem all the time!!!!

Happens on a very intermittant basis.  While using an envelope as 
clock source, I smack a key and can get that typical repeating and 
pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" noise, and 
then when it feels like it, it stops responding.

Also, depending on how I have the delay clock knob position, I'll 
get this extremely high resonant noise.  Sometimes it's more subtle 
like the frequency it's producing is so high that it's not in the 
audible spectrum, but its enough to hurt my ears.  I fear that I've 
even damaged a bit of my high-end with this....

Is this a defect in the unit, or is that the clock noise that the 
manual talks about generally requiring an LPF?  And if it is, where 
exactly should the LPF be inserted?


--- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
>
> > Hi all,
> >
> > My tapped bbd module suddenly has a limited range, it can now 
only
> > do short delaytimes, probably 25-40% of the range it should 
have. In
> > other words: it can't produce the aliasing sound anymore. The 
first
> > time I fired it up it was ok, second time it had this problem. 
Any
> > ideas?
> >
> > greetings, Anton
> 
> Sounds like a fault. Probably the "heater" of the temperature 
controlled
> logarithmic converter of the HSVCO is defective. If you are able 
to replace
> an integrated circuit we can send you a new one. As all circuits 
are
> equipped with sockets no soldering is required but only removing 
the old
> circuit and inserting the new one.
> 
> Please tell me your postal address (directly to me, not to the 
Yahoo group)
> and we will send you the spare part if you agree. Otherwise please 
send the

> module for repair.
> 
> Best wishes
> Dieter Doepfer
> (hardware@...)
>

I meant 4096 stages, not 2096

--- In Doepfer_a100@yahoogroups.com, "regimental1200" 
<regimental1200@...> wrote:
>
> I get a similar problem all the time!!!!
> 
> Happens on a very intermittant basis.  While using an envelope as 
> clock source, I smack a key and can get that typical repeating and 
> pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" noise, 
and 
> then when it feels like it, it stops responding.
> 
> Also, depending on how I have the delay clock knob position, I'll 
> get this extremely high resonant noise.  Sometimes it's more 
subtle 
> like the frequency it's producing is so high that it's not in the 
> audible spectrum, but its enough to hurt my ears.  I fear that 
I've 
> even damaged a bit of my high-end with this....
> 
> Is this a defect in the unit, or is that the clock noise that the 
> manual talks about generally requiring an LPF?  And if it is, 
where 
> exactly should the LPF be inserted?
> 
> 
> --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> >
> > > Hi all,
> > >
> > > My tapped bbd module suddenly has a limited range, it can now 
> only
> > > do short delaytimes, probably 25-40% of the range it should 
> have. In
> > > other words: it can't produce the aliasing sound anymore. The 
> first
> > > time I fired it up it was ok, second time it had this problem. 
> Any
> > > ideas?
> > >
> > > greetings, Anton
> > 
> > Sounds like a fault. Probably the "heater" of the temperature 
> controlled
> > logarithmic converter of the HSVCO is defective. If you are able 
> to replace
> > an integrated circuit we can send you a new one. As all circuits 
> are
> > equipped with sockets no soldering is required but only removing 
> the old
> > circuit and inserting the new one.
> > 
> > Please tell me your postal address (directly to me, not to the 
> Yahoo group)
> > and we will send you the spare part if you agree. Otherwise 
please 

> send the
> > module for repair.
> > 
> > Best wishes
> > Dieter Doepfer
> > (hardware@)
> >
>

Hi,

You might need to expand on a the first problem little further. When
you say using an envelope as a clock source, presumably you are
modulating the HSVCO with an envelope, not clocking the BBD with an
envelope generator?

Regarding the high pitched noise, it sounds like you are describing
clock noise which is quite normal and does require a LPF to be placed
at the output of the BBD module in order to remove it. The obvious
drawback of this is the potential loss of high end audio frequencies. 

Cheers,
Adam-V
--- In Doepfer_a100@yahoogroups.com, "regimental1200"
<regimental1200@...> wrote:

>
> I meant 4096 stages, not 2096
> 
> --- In Doepfer_a100@yahoogroups.com, "regimental1200" 
> <regimental1200@> wrote:
> >
> > I get a similar problem all the time!!!!
> > 
> > Happens on a very intermittant basis.  While using an envelope as 
> > clock source, I smack a key and can get that typical repeating and 
> > pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" noise, 
> and 
> > then when it feels like it, it stops responding.
> > 
> > Also, depending on how I have the delay clock knob position, I'll 
> > get this extremely high resonant noise.  Sometimes it's more 
> subtle 
> > like the frequency it's producing is so high that it's not in the 
> > audible spectrum, but its enough to hurt my ears.  I fear that 
> I've 
> > even damaged a bit of my high-end with this....
> > 
> > Is this a defect in the unit, or is that the clock noise that the 
> > manual talks about generally requiring an LPF?  And if it is, 
> where 
> > exactly should the LPF be inserted?
> > 
> > 
> > --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> > >
> > > > Hi all,
> > > >
> > > > My tapped bbd module suddenly has a limited range, it can now 
> > only
> > > > do short delaytimes, probably 25-40% of the range it should 
> > have. In
> > > > other words: it can't produce the aliasing sound anymore. The 
> > first
> > > > time I fired it up it was ok, second time it had this problem. 
> > Any
> > > > ideas?
> > > >
> > > > greetings, Anton
> > > 
> > > Sounds like a fault. Probably the "heater" of the temperature 
> > controlled
> > > logarithmic converter of the HSVCO is defective. If you are able 
> > to replace
> > > an integrated circuit we can send you a new one. As all circuits 
> > are
> > > equipped with sockets no soldering is required but only removing 
> > the old
> > > circuit and inserting the new one.
> > > 
> > > Please tell me your postal address (directly to me, not to the 
> > Yahoo group)
> > > and we will send you the spare part if you agree. Otherwise 
> please 
> > send the
> > > module for repair.
> > > 
> > > Best wishes
> > > Dieter Doepfer
> > > (hardware@)
> > >
> >
>

Sorry, I'm at work now and was just not refering to the correct 
jack.  I basically take the output of an envelope and I stick it 
into CV2 of the BBD module.  I also dial-in a bit of feedback.  
Beyond that, only the MIX OUT is connected.


--- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@...> wrote:
>
> Hi,
> 
> You might need to expand on a the first problem little further. 
When
> you say using an envelope as a clock source, presumably you are
> modulating the HSVCO with an envelope, not clocking the BBD with an
> envelope generator?
> 
> Regarding the high pitched noise, it sounds like you are describing
> clock noise which is quite normal and does require a LPF to be 
placed
> at the output of the BBD module in order to remove it. The obvious
> drawback of this is the potential loss of high end audio 
frequencies. 
> 
> Cheers,
> Adam-V
> --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> <regimental1200@> wrote:
> >
> > I meant 4096 stages, not 2096
> > 
> > --- In Doepfer_a100@yahoogroups.com, "regimental1200" 
> > <regimental1200@> wrote:
> > >
> > > I get a similar problem all the time!!!!
> > > 
> > > Happens on a very intermittant basis.  While using an envelope 
as 
> > > clock source, I smack a key and can get that typical repeating 
and 
> > > pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" 
noise, 
> > and 
> > > then when it feels like it, it stops responding.
> > > 
> > > Also, depending on how I have the delay clock knob position, 
I'll 
> > > get this extremely high resonant noise.  Sometimes it's more 
> > subtle 
> > > like the frequency it's producing is so high that it's not in 
the 
> > > audible spectrum, but its enough to hurt my ears.  I fear that 
> > I've 
> > > even damaged a bit of my high-end with this....
> > > 
> > > Is this a defect in the unit, or is that the clock noise that 
the 
> > > manual talks about generally requiring an LPF?  And if it is, 
> > where 
> > > exactly should the LPF be inserted?
> > > 
> > > 
> > > --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > My tapped bbd module suddenly has a limited range, it can 
now 
> > > only
> > > > > do short delaytimes, probably 25-40% of the range it 
should 
> > > have. In
> > > > > other words: it can't produce the aliasing sound anymore. 
The 
> > > first
> > > > > time I fired it up it was ok, second time it had this 
problem. 
> > > Any
> > > > > ideas?
> > > > >
> > > > > greetings, Anton
> > > > 
> > > > Sounds like a fault. Probably the "heater" of the 
temperature 
> > > controlled
> > > > logarithmic converter of the HSVCO is defective. If you are 
able 
> > > to replace
> > > > an integrated circuit we can send you a new one. As all 
circuits 
> > > are
> > > > equipped with sockets no soldering is required but only 
removing 
> > > the old
> > > > circuit and inserting the new one.
> > > > 
> > > > Please tell me your postal address (directly to me, not to 
the 

> > > Yahoo group)
> > > > and we will send you the spare part if you agree. Otherwise 
> > please 
> > > send the
> > > > module for repair.
> > > > 
> > > > Best wishes
> > > > Dieter Doepfer
> > > > (hardware@)
> > > >
> > >
> >
>

Regarding an LPF at the output of the BBD module, I've tried that, 
and exactly like you mentioned, you filter out too many of the 
goodies, so it's useless.  It's just a matter of modifying DELAY 
CLOCK until it goes away.

--- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@...> wrote:
>
> Hi,
> 
> You might need to expand on a the first problem little further. 
When
> you say using an envelope as a clock source, presumably you are
> modulating the HSVCO with an envelope, not clocking the BBD with an
> envelope generator?
> 
> Regarding the high pitched noise, it sounds like you are describing
> clock noise which is quite normal and does require a LPF to be 
placed
> at the output of the BBD module in order to remove it. The obvious
> drawback of this is the potential loss of high end audio 
frequencies. 
> 
> Cheers,
> Adam-V
> --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> <regimental1200@> wrote:
> >
> > I meant 4096 stages, not 2096
> > 
> > --- In Doepfer_a100@yahoogroups.com, "regimental1200" 
> > <regimental1200@> wrote:
> > >
> > > I get a similar problem all the time!!!!
> > > 
> > > Happens on a very intermittant basis.  While using an envelope 
as 
> > > clock source, I smack a key and can get that typical repeating 
and 
> > > pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" 
noise, 
> > and 
> > > then when it feels like it, it stops responding.
> > > 
> > > Also, depending on how I have the delay clock knob position, 
I'll 
> > > get this extremely high resonant noise.  Sometimes it's more 
> > subtle 
> > > like the frequency it's producing is so high that it's not in 
the 
> > > audible spectrum, but its enough to hurt my ears.  I fear that 
> > I've 
> > > even damaged a bit of my high-end with this....
> > > 
> > > Is this a defect in the unit, or is that the clock noise that 
the 
> > > manual talks about generally requiring an LPF?  And if it is, 
> > where 
> > > exactly should the LPF be inserted?
> > > 
> > > 
> > > --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > My tapped bbd module suddenly has a limited range, it can 
now 
> > > only
> > > > > do short delaytimes, probably 25-40% of the range it 
should 
> > > have. In
> > > > > other words: it can't produce the aliasing sound anymore. 
The 
> > > first
> > > > > time I fired it up it was ok, second time it had this 
problem. 
> > > Any
> > > > > ideas?
> > > > >
> > > > > greetings, Anton
> > > > 
> > > > Sounds like a fault. Probably the "heater" of the 
temperature 
> > > controlled
> > > > logarithmic converter of the HSVCO is defective. If you are 
able 
> > > to replace
> > > > an integrated circuit we can send you a new one. As all 
circuits 
> > > are
> > > > equipped with sockets no soldering is required but only 
removing 
> > > the old
> > > > circuit and inserting the new one.
> > > > 
> > > > Please tell me your postal address (directly to me, not to 
the 

> > > Yahoo group)
> > > > and we will send you the spare part if you agree. Otherwise 
> > please 
> > > send the
> > > > module for repair.
> > > > 
> > > > Best wishes
> > > > Dieter Doepfer
> > > > (hardware@)
> > > >
> > >
> >
>

The joy of BBD delays!

--- In Doepfer_a100@yahoogroups.com, "regimental1200"
<regimental1200@...> wrote:

>
> Regarding an LPF at the output of the BBD module, I've tried that, 
> and exactly like you mentioned, you filter out too many of the 
> goodies, so it's useless.  It's just a matter of modifying DELAY 
> CLOCK until it goes away.
>

Seems a bit strange to me. 

I would start from scratch and just patch a VCO into the BBD input and
monitor the BBD output whilst manually tweaking the delay time to
check the basic functionality of the module. Then I would try an LFO
to modulate the delay time to determine that the CV2 input is
functioning correctly. If that works then I would re-try the envelope
generator just to be sure I had actually connected it properly. Then I
would try a different envelope generator or perhaps recheck the
envelope generator settings.

One other thought, the feedback isn't set to a point that the BBD is 
self-oscillating is it?

Perhaps one of the other members can offer up further ideas.

Cheers,
Adam-V
--- In Doepfer_a100@yahoogroups.com, "regimental1200"
<regimental1200@...> wrote:

>
> Sorry, I'm at work now and was just not refering to the correct 
> jack.  I basically take the output of an envelope and I stick it 
> into CV2 of the BBD module.  I also dial-in a bit of feedback.  
> Beyond that, only the MIX OUT is connected.
> 
>

as said in the BBD manual... when doing clock filtering (LPF at the BBD output) use the CV 
OUT of the BBD to modulate the LPF... Its true that you LOSE a bit of high freq. (but then 
its the point of the operation basically) but it does give GOOD RESULTS... 

and I agree with Adam that starting from very basic is a good way to understand and work 
out such module... it took me a bit of time just studying it very closely with just basic 
signal in, cv's, filters before and after... one or two inputs, etc...

same remark with A106 is valid too... as many of the controls really work together and 
gives very different result depending even on the order the parameters are changed over 
time...


if that helps...


Best,

A

--- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@...> wrote:

>
> Seems a bit strange to me. 
> 
> I would start from scratch and just patch a VCO into the BBD input and
> monitor the BBD output whilst manually tweaking the delay time to
> check the basic functionality of the module. Then I would try an LFO
> to modulate the delay time to determine that the CV2 input is
> functioning correctly. If that works then I would re-try the envelope
> generator just to be sure I had actually connected it properly. Then I
> would try a different envelope generator or perhaps recheck the
> envelope generator settings.
> 
> One other thought, the feedback isn't set to a point that the BBD is 
> self-oscillating is it?
> 
> Perhaps one of the other members can offer up further ideas.
> 
> Cheers,
> Adam-V
> --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> <regimental1200@> wrote:
> >
> > Sorry, I'm at work now and was just not refering to the correct 
> > jack.  I basically take the output of an envelope and I stick it 
> > into CV2 of the BBD module.  I also dial-in a bit of feedback.  
> > Beyond that, only the MIX OUT is connected.
> > 
> >
>

hello,
yes, but Anton meant the a188-2 tapped bbd module.
so, it seems that his problem is not the same as in
your module. Anton probably has a defective unit that
needs repair. (as indicated by Dieter.)
as for your unit, i also have the 4096 bbd module and
have not noticed any wierd behaviour in mine...
but, maybe, all you have to do is filter the clock
noise? for this, just insert a steep slope LPF module
before the bbd module's audio input and after the bbd
module's audio output.
best regards,
Bakis.


--- regimental1200 <regimental1200@yahoo.com> wrote:

> I meant 4096 stages, not 2096
> 
> --- In Doepfer_a100@yahoogroups.com,
> "regimental1200" 
> <regimental1200@...> wrote:
> >
> > I get a similar problem all the time!!!!
> > 
> > Happens on a very intermittant basis.  While using
> an envelope as 
> > clock source, I smack a key and can get that
> typical repeating and 
> > pitch shifting
> "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" noise, 
> and 
> > then when it feels like it, it stops responding.
> > 
> > Also, depending on how I have the delay clock knob
> position, I'll 
> > get this extremely high resonant noise.  Sometimes
> it's more 
> subtle 
> > like the frequency it's producing is so high that
> it's not in the 
> > audible spectrum, but its enough to hurt my ears. 
> I fear that 
> I've 
> > even damaged a bit of my high-end with this....
> > 
> > Is this a defect in the unit, or is that the clock
> noise that the 
> > manual talks about generally requiring an LPF? 
> And if it is, 
> where 
> > exactly should the LPF be inserted?
> > 
> > 
> > --- In Doepfer_a100@yahoogroups.com, <hardware@>
> wrote:
> > >
> > > > Hi all,
> > > >
> > > > My tapped bbd module suddenly has a limited
> range, it can now 
> > only
> > > > do short delaytimes, probably 25-40% of the
> range it should 
> > have. In
> > > > other words: it can't produce the aliasing
> sound anymore. The 
> > first
> > > > time I fired it up it was ok, second time it
> had this problem. 
> > Any
> > > > ideas?
> > > >
> > > > greetings, Anton
> > > 
> > > Sounds like a fault. Probably the "heater" of
> the temperature 
> > controlled
> > > logarithmic converter of the HSVCO is defective.
> If you are able 
> > to replace
> > > an integrated circuit we can send you a new one.
> As all circuits 
> > are
> > > equipped with sockets no soldering is required
> but only removing 
> > the old
> > > circuit and inserting the new one.
> > > 
> > > Please tell me your postal address (directly to
> me, not to the 
> > Yahoo group)
> > > and we will send you the spare part if you
> agree. Otherwise 
> please 
> > send the
> > > module for repair.
> > > 
> > > Best wishes
> > > Dieter Doepfer
> > > (hardware@)
> > >
> >
> 
> 
> 


Bakis Sirros - Parallel Worlds
[Doepfer_a100] group owner
http://www.parallel-worlds-music.com
http://www.myspace.com/parallelworldsmusic
http://www.shimarecords.co.uk
http://www.rubber.gr
Athens-Greece

__________________________________________________
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i would start testing without using a modulator and only with
a very simple input signal (a single vco wave).

first reduce the feedback to zero.
dial in a very short delay time and you should not hear
any clock noise coming through. then decrease the delay time
manually and write down the knob setting when the clock noise
gets audible (knob should be around 12 o'clock position).
if you get a different result then please post your
knob setting here.

after that you should try a slow modulator (f.e. an lfo)
as adviced by adam-v.
one important point regarding envelopes, some env modules
spill out up to +10 volts, so sometimes it is necessary to
attenuate the envelope signal, otherwise the hsvco may
reach frequencies where the bbd chip starts doing strange things.
this is of course also depending on the type of bbd chip,
not all chips show the same reactions.

if you want to filter out the clock noise, then use the
cv output of the bbd module and feed it into the cv input of a
lowpass filter. feed the bbd output into the filter input and use
the filter output as your new delayed signal. use the steepest
lowpass filter that you have in your system. the steeper the
filter the more high fequencies are left in the signal.
if you want to get more clean results, then you can use
another lowpass in the same manner to filter the bbd input signal.
this reduces aliasing noises, but has nothing to do with the
clock noise.

best wishes

ingo



--- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@...> wrote:
>
> Seems a bit strange to me. 
> 
> I would start from scratch and just patch a VCO into the BBD input 
and
> monitor the BBD output whilst manually tweaking the delay time to
> check the basic functionality of the module. Then I would try an LFO
> to modulate the delay time to determine that the CV2 input is
> functioning correctly. If that works then I would re-try the 
envelope
> generator just to be sure I had actually connected it properly. 
Then I
> would try a different envelope generator or perhaps recheck the
> envelope generator settings.
> 
> One other thought, the feedback isn't set to a point that the BBD 
is 

> self-oscillating is it?
> 
> Perhaps one of the other members can offer up further ideas.
> 
> Cheers,
> Adam-V
> --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> <regimental1200@> wrote:
> >
> > Sorry, I'm at work now and was just not refering to the correct 
> > jack.  I basically take the output of an envelope and I stick it 
> > into CV2 of the BBD module.  I also dial-in a bit of feedback.  
> > Beyond that, only the MIX OUT is connected.
> > 
> >
>

If you modulate the CV input of the VCF (which you placed after the
BBD) with an EG or envelope follower, it is possible to keep the
characteristic BBD sound for exactly the time desired, after which the
clock is slowly filtered out entirely in the time set by the "release"
control of the EG.
This way, you can use the VCF as a kind of 'noise'(clock) gate for
your bbd.

Hope this helps, regards
Joost


--- In Doepfer_a100@yahoogroups.com, "regimental1200"
<regimental1200@...> wrote:

>
> Regarding an LPF at the output of the BBD module, I've tried that, 
> and exactly like you mentioned, you filter out too many of the 
> goodies, so it's useless.  It's just a matter of modifying DELAY 
> CLOCK until it goes away.
> 
> --- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@> wrote:
> >
> > Hi,
> > 
> > You might need to expand on a the first problem little further. 
> When
> > you say using an envelope as a clock source, presumably you are
> > modulating the HSVCO with an envelope, not clocking the BBD with an
> > envelope generator?
> > 
> > Regarding the high pitched noise, it sounds like you are describing
> > clock noise which is quite normal and does require a LPF to be 
> placed
> > at the output of the BBD module in order to remove it. The obvious
> > drawback of this is the potential loss of high end audio 
> frequencies. 
> > 
> > Cheers,
> > Adam-V
> > --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> > <regimental1200@> wrote:
> > >
> > > I meant 4096 stages, not 2096
> > > 
> > > --- In Doepfer_a100@yahoogroups.com, "regimental1200" 
> > > <regimental1200@> wrote:
> > > >
> > > > I get a similar problem all the time!!!!
> > > > 
> > > > Happens on a very intermittant basis.  While using an envelope 
> as 
> > > > clock source, I smack a key and can get that typical repeating 
> and 
> > > > pitch shifting "Daaaaaaaa-daaaaaaaa-daaaa-da-da-da-da da" 
> noise, 
> > > and 
> > > > then when it feels like it, it stops responding.
> > > > 
> > > > Also, depending on how I have the delay clock knob position, 
> I'll 
> > > > get this extremely high resonant noise.  Sometimes it's more 
> > > subtle 
> > > > like the frequency it's producing is so high that it's not in 
> the 
> > > > audible spectrum, but its enough to hurt my ears.  I fear that 
> > > I've 
> > > > even damaged a bit of my high-end with this....
> > > > 
> > > > Is this a defect in the unit, or is that the clock noise that 
> the 
> > > > manual talks about generally requiring an LPF?  And if it is, 
> > > where 
> > > > exactly should the LPF be inserted?
> > > > 
> > > > 
> > > > --- In Doepfer_a100@yahoogroups.com, <hardware@> wrote:
> > > > >
> > > > > > Hi all,
> > > > > >
> > > > > > My tapped bbd module suddenly has a limited range, it can 
> now 
> > > > only
> > > > > > do short delaytimes, probably 25-40% of the range it 
> should 
> > > > have. In
> > > > > > other words: it can't produce the aliasing sound anymore. 
> The 
> > > > first
> > > > > > time I fired it up it was ok, second time it had this 
> problem. 
> > > > Any
> > > > > > ideas?
> > > > > >
> > > > > > greetings, Anton
> > > > > 
> > > > > Sounds like a fault. Probably the "heater" of the 
> temperature 
> > > > controlled
> > > > > logarithmic converter of the HSVCO is defective. If you are 
> able 
> > > > to replace
> > > > > an integrated circuit we can send you a new one. As all 
> circuits 
> > > > are
> > > > > equipped with sockets no soldering is required but only 
> removing 
> > > > the old
> > > > > circuit and inserting the new one.
> > > > > 
> > > > > Please tell me your postal address (directly to me, not to 
> the 
> > > > Yahoo group)
> > > > > and we will send you the spare part if you agree. Otherwise 
> > > please 
> > > > send the
> > > > > module for repair.
> > > > > 
> > > > > Best wishes
> > > > > Dieter Doepfer
> > > > > (hardware@)
> > > > >
> > > >
> > >
> >
>

I'll try to run those basic tests.  I'll also try different patch 
cables in case it's a matter of bad connectors; sometimes I can't get 
a response somewhere in the system and by nudging the cable, it then 
works.

As for the feedback, I have already eliminated that because the same 
intermittant problem was occuring with no feedback.

--- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@...> wrote:
>
> Seems a bit strange to me. 
> 
> I would start from scratch and just patch a VCO into the BBD input 
and
> monitor the BBD output whilst manually tweaking the delay time to
> check the basic functionality of the module. Then I would try an LFO
> to modulate the delay time to determine that the CV2 input is
> functioning correctly. If that works then I would re-try the 
envelope
> generator just to be sure I had actually connected it properly. 
Then I
> would try a different envelope generator or perhaps recheck the
> envelope generator settings.
> 
> One other thought, the feedback isn't set to a point that the BBD 
is 

> self-oscillating is it?
> 
> Perhaps one of the other members can offer up further ideas.
> 
> Cheers,
> Adam-V
> --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> <regimental1200@> wrote:
> >
> > Sorry, I'm at work now and was just not refering to the correct 
> > jack.  I basically take the output of an envelope and I stick it 
> > into CV2 of the BBD module.  I also dial-in a bit of feedback.  
> > Beyond that, only the MIX OUT is connected.
> > 
> >
>

If memory serves me well, I followed the manual one time and used its 
CV output to control an LPF...forget if it gave me the result i 
wanted.  I'll try again and see if there's a difference from having 
the filter controlled by a seperate envelope.  Thanks!

--- In Doepfer_a100@yahoogroups.com, "bellenger_a" <bellenger_a@...> 
wrote:
>
> as said in the BBD manual... when doing clock filtering (LPF at the 
BBD output) use the CV 
> OUT of the BBD to modulate the LPF... Its true that you LOSE a bit 
of high freq. (but then 
> its the point of the operation basically) but it does give GOOD 
RESULTS... 
> 
> and I agree with Adam that starting from very basic is a good way 
to understand and work 
> out such module... it took me a bit of time just studying it very 
closely with just basic 
> signal in, cv's, filters before and after... one or two inputs, 
etc...
> 
> same remark with A106 is valid too... as many of the controls 
really work together and 
> gives very different result depending even on the order the 
parameters are changed over 
> time...
> 
> 
> if that helps...
> 
> 
> Best,
> 
> A
> 
> --- In Doepfer_a100@yahoogroups.com, "Adam-V" <adam-v@> wrote:
> >
> > Seems a bit strange to me. 
> > 
> > I would start from scratch and just patch a VCO into the BBD 
input and
> > monitor the BBD output whilst manually tweaking the delay time to
> > check the basic functionality of the module. Then I would try an 
LFO
> > to modulate the delay time to determine that the CV2 input is
> > functioning correctly. If that works then I would re-try the 
envelope
> > generator just to be sure I had actually connected it properly. 
Then I
> > would try a different envelope generator or perhaps recheck the
> > envelope generator settings.
> > 
> > One other thought, the feedback isn't set to a point that the BBD 
is 
> > self-oscillating is it?
> > 
> > Perhaps one of the other members can offer up further ideas.
> > 
> > Cheers,
> > Adam-V
> > --- In Doepfer_a100@yahoogroups.com, "regimental1200"
> > <regimental1200@> wrote:
> > >
> > > Sorry, I'm at work now and was just not refering to the correct 
> > > jack.  I basically take the output of an envelope and I stick 
it 

> > > into CV2 of the BBD module.  I also dial-in a bit of feedback.  
> > > Beyond that, only the MIX OUT is connected.
> > > 
> > >
> >
>