Doepfer

Hello all,
I just recieved my Doepfer rack (digging it by the way)
My question is about the clock noise at low delay times
on the A-188 1-B (1024 stage) analog delay.
I had read Ingo's message # 9525 about filtering
clock noise before I bought the A-188 1-B.
But I didn't realize the noise was as bad as it is.
I need to use the delay at slower speeds for the
dubby stuff I do and hate to have to use a low pass filter
just to clean it up. Any other fixes or mods?
Soy Sos

You have to use a filter to reduce the clock noise until 100 %!
It has been heavily discussed whether a filter should have been build in, but many users want to have the dirty sound you describe as "bad". I recommend the A-105 VCF to blow the clock noise away. I think, after using a filter you'll get the dub sound as it is requested by most of the dubbing fans.
best regards
Axel 
  "djsoysos" <djsoysos@yahoo.com> schrieb: 
Hello all,
I just recieved my Doepfer rack (digging it by the way)
My question is about the clock noise at low delay times
on the A-188 1-B (1024 stage) analog delay.
I had read Ingo's message # 9525 about filtering
clock noise before I bought the A-188 1-B.
But I didn't realize the noise was as bad as it is.
I need to use the delay at slower speeds for the
dubby stuff I do and hate to have to use a low pass filter
just to clean it up. Any other fixes or mods?
Soy Sos

 

[Non-text portions of this message have been removed]

Axel,
thanks for your reply. I experimented with the 2 filters I have,
the A-121 multimode  filter  and A-101-1 vactrol multi mode filter.
But in order to remove clock noise I end up rolling off everything at
what sounds to my ear around 200-300 hz. That's a considerable
dulling of the sound. Not something I will always want.
Dont get me wrong this thing sounds great for doing
modulated fx like chorus, flange ect. I just a bit of an echo freak.
Soy Sos


> You have to use a filter to reduce the clock noise until 100 %!
> It has been heavily discussed whether a filter should have been build in, but many users 
want to have the dirty sound you describe as "bad". I recommend the A-105 VCF to blow the 
clock noise away. I think, after using a filter you'll get the dub sound as it is requested by 
most of the dubbing fans.
> best regards
> Axel

Hello Soy Sys, I *guess* the 1024 BBD stage version of the A188 uses 
a MN3007 chip. Accord. to it's data sheet the delay time ranges from 
5.12ms to 51.2ms. If the A188 can be set for longer times there's a 
trade off in massive quality leakage. It results in the "bad" sounds 
mentioned by Axel many on this list opted for. The MN3007 is rather 
a reverbation and chorus chip than an echo device in it's true sense.

--- In Doepfer_a100@yahoogroups.com, "djsoysos" <djsoysos@...> wrote:
>
> Axel,
> thanks for your reply. I experimented with the 2 filters I have,
> the A-121 multimode  filter  and A-101-1 vactrol multi mode filter.
> But in order to remove clock noise I end up rolling off everything 
at
> what sounds to my ear around 200-300 hz. That's a considerable
> dulling of the sound. Not something I will always want.
> Dont get me wrong this thing sounds great for doing
> modulated fx like chorus, flange ect. I just a bit of an echo 
freak.
> Soy Sos
> 
> 
> > You have to use a filter to reduce the clock noise until 100 %!
> > It has been heavily discussed whether a filter should have been 
build in, but many users 
> want to have the dirty sound you describe as "bad". I recommend 
the A-105 VCF to blow the 
> clock noise away. I think, after using a filter you'll get the dub 
sound as it is requested by 

> most of the dubbing fans.
> > best regards
> > Axel
>

That's impossible without a lowpass on principle. E.g. if the clock rate is
500Hz you need a lowpass that supresses this frequency. The suppression will
we the better the higher the slope of the lowpass (6/12/24/48...dB/Oct). For
a lowpass with a small slope (e.g. 6 or 12 dB) the frequency has to be even
smaller (e.g. 200 or 300Hz) for a satisfactory suppression. Consequently the
sound will become more "dull" because of the missing higher frequencies.
This is a general drawback of all analog delays. Consequently for analog
delay applications the longest BBD should be used (i.e. MN3005/4096 stages).

The planned (probably dual) SC filter will be a suitable supplement to the
BBD modules as it will probably include two 30dB filters with common
frequency control. One of the filters can be used for the audio input (if
desired), the second for the audio output of the A-188-1.

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von djsoysos
> Gesendet: Sonntag, 23. Juli 2006 00:55
> An: Doepfer_a100@yahoogroups.com
> Betreff: [Doepfer_a100] clock noise A-188 1-B (1024 stage) analog delay
>
>
> Hello all,
> I just recieved my Doepfer rack (digging it by the way)
> My question is about the clock noise at low delay times
> on the A-188 1-B (1024 stage) analog delay.
> I had read Ingo's message # 9525 about filtering
> clock noise before I bought the A-188 1-B.
> But I didn't realize the noise was as bad as it is.
> I need to use the delay at slower speeds for the
> dubby stuff I do and hate to have to use a low pass filter
> just to clean it up. Any other fixes or mods?
> Soy Sos
>
>
>
>
>
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>

I just wanted to say thanks to everyone for the
helpful information. I'm really enjoying my new
Doepfer stuff. This user's group is a great resource
Soy Sos

Hello Dieter

> The planned (probably dual) SC filter will be a suitable supplement 
to the
> BBD modules as it will probably include two 30dB filters with common
> frequency control. One of the filters can be used for the audio input (if
> desired), the second for the audio output of the A-188-1.

How about a dual SC hi pass filter to eliminate unwanted low 
frequencies. Just a common freq control (20 - 200 Hz) and some 
really steep slopes. That would be great for protecting monitors, 
cleaning up a mix or splitting up a bass sound.

By the way: really enjoying the BBD module, it's madness

Greetings,

Anton

Anton,

we already have a 24dB highpass filter A-123. As the sales of this module
are very poor we will stop production as soon as the stock is sold out. I
don't think that we will offer a dual 30dB highpass as I assume that the
sales will be even worse than for the A-123.

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von Anton Coops
> Gesendet: Freitag, 4. August 2006 08:45
> An: Doepfer_a100@yahoogroups.com
> Betreff: Re: AW: [Doepfer_a100] clock noise A-188 1-B (1024 stage)
> analog delay
>
>
> Hello Dieter
>
> > The planned (probably dual) SC filter will be a suitable supplement
> to the
> > BBD modules as it will probably include two 30dB filters with common
> > frequency control. One of the filters can be used for the audio
> input (if
> > desired), the second for the audio output of the A-188-1.
>
> How about a dual SC hi pass filter to eliminate unwanted low
> frequencies. Just a common freq control (20 - 200 Hz) and some
> really steep slopes. That would be great for protecting monitors,
> cleaning up a mix or splitting up a bass sound.
>
> By the way: really enjoying the BBD module, it's madness
>
> Greetings,
>
> Anton
>
>
>
> Yahoo! Groups Links
>
>
>
>
>
>
>

> Anton,
> 
> we already have a 24dB highpass filter A-123. As the sales of this module
> are very poor we will stop production as soon as the stock is sold out. I
> don't think that we will offer a dual 30dB highpass as I assume that the
> sales will be even worse than for the A-123.

I think you're right. Thanks and greetings,

Anton