Doepfer

Hello,

I just picked up 3 used A-140s.  
They seem to be a little older 
than the others I have and they 
have flat-top LEDs versus the
rounded LEDs in my other A-140s.

Did the A-140 go through a design
revision somewhere along the line?
I ask because I like the response
of the flat-top LED modules better
than my others.

Thanks in advance,

Ethan

When I ordered two A-140 ADSRs and two A-145 LFOs  in September ´98, one 
half of the modules were delivered with flat-top and the other half with 
round LEDs. But they have the same version-number, so I don´t know whats 
up with that. Perhaps only a matter of design.
You are right, the response of the flat-tops is much better and they 
look more professional to me. My A-129 vocoder with flat-top LEDs looks 
so clean...

Paul


ethanzer0 wrote:

> Hello,
>
> I just picked up 3 used A-140s. 
> They seem to be a little older
> than the others I have and they
> have flat-top LEDs versus the
> rounded LEDs in my other A-140s.
>
> Did the A-140 go through a design
> revision somewhere along the line?
> I ask because I like the response
> of the flat-top LED modules better
> than my others.
>
> Thanks in advance,
>
> Ethan

Hi Ethan/Paul,
My 140 is marked 'v1 1995' and was bought in 2001 - my guess is that 
it is thus very unikely that there are 2 versions out there (either 
one of you may be able to correct me though!).

As for the round/flat LEDs, I would guess that when Doepfer do their 
designs they would try and stick to parts from a 'preferred parts 
list', which would contain component types that are available from at 
least one manufacturer (I think this is called 'second sourcing'). 
This minimises the danger of not being able to get components of a 
certain type should one manufacturer decide to stop making them (i.e. 
to avoid the situation that exists with certain of the CEM chips!). 
Thus whether LEDs are flat or round probably depends on which type 
they managed to get the best deal on last time they bought some in.

That leaves the question of what might be the cause of any perceived 
difference between units. The circuit is relatively straightforward, 
and with my limited knowledge my guess as to what it might be would 
fall on the capacitors which charge/discharge to give the envelope. 
All three, one for each of the 3 ranges, are 'electrolytic' types, 
which are notorious for having poor tolerances, even within one 
particular brand and nominal value. How much any differences might 
contribute to the shape of the envelope to the extent that they could 
be audibly perceived to be different, I do not know - hooking them 
both up to a 'scope would be the easiest way to _see_ the difference!
(The LED is quite isolated from the envelope generating part of the 
circuit, and so a different LED in itself will not affect the  
envelope!)

Tim


--- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> When I ordered two A-140 ADSRs and two A-145 LFOs  in September 
´98, one 
> half of the modules were delivered with flat-top and the other half 
with 
> round LEDs. But they have the same version-number, so I don´t know 
whats 
> up with that. Perhaps only a matter of design.
> You are right, the response of the flat-tops is much better and 
they 
> look more professional to me. My A-129 vocoder with flat-top LEDs 
looks 

> so clean...
> 
> Paul
> 
> 
> ethanzer0 wrote:
> 
> > Hello,
> >
> > I just picked up 3 used A-140s. 
> > They seem to be a little older
> > than the others I have and they
> > have flat-top LEDs versus the
> > rounded LEDs in my other A-140s.
> >
> > Did the A-140 go through a design
> > revision somewhere along the line?
> > I ask because I like the response
> > of the flat-top LED modules better
> > than my others.
> >
> > Thanks in advance,
> >
> > Ethan

No matter which type of LEDs they have, my A-140s are all marked: 
"version1, 1995", so Doepfer don´t seem to have changed anything.
So your idea of 'second sourcing' makes sense.

Paul


Tim Stinchcombe wrote:

> Hi Ethan/Paul,
> My 140 is marked 'v1 1995' and was bought in 2001 - my guess is that
> it is thus very unikely that there are 2 versions out there (either
> one of you may be able to correct me though!).
>
> Tim

--- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> No matter which type of LEDs they have, my A-140s are all marked: 
> "version1, 1995", so Doepfer don´t seem to have changed anything.
> So your idea of 'second sourcing' makes sense.
> 
> Paul
> 
> 
> Tim Stinchcombe wrote:
> 

I have 5 A-140s.  3 of which 
have flat LEDs.  Of the 3 that 
have flat LEDs, 2 have visably
different components on the PCB.
Different transistors, differetly
marked resistors, etc.  I can 
understand red versus blue transistors
as a sourcing issue, however, the banding
on resistors is supposed to be somewhat 
of a standard. The differences in these 
two seems to identical.

It just so happens that these 2 
are the 2 I like most.

Ethan

I recall reading somewhere that all of the A100 modules originally 
had the flat red LEDs, and the Doepfer converted over completely to 
the round orange-ish LEDs. I don't think any flat LED modules have 
been produced since then, and it affected all of the modules, so it 
didn't coincide with design mods as far as I know.

Its possible, though, that Doepfer has made changes to various 
modules over time that haven't been reflected in version #s.

Maybe in a few years the flat LED modules will be considered a rare 
collectors item ;-)

Joe

--- In Doepfer_a100@y..., "ethanzer0" <ethanzer0@y...> wrote:

> --- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> > No matter which type of LEDs they have, my A-140s are all marked: 
> > "version1, 1995", so Doepfer don´t seem to have changed anything.
> > So your idea of 'second sourcing' makes sense.
> > 
> > Paul
> > 
> > 
> > Tim Stinchcombe wrote:
> > 
> 
> I have 5 A-140s.  3 of which 
> have flat LEDs.  Of the 3 that 
> have flat LEDs, 2 have visably
> different components on the PCB.
> Different transistors, differetly
> marked resistors, etc.  I can 
> understand red versus blue transistors
> as a sourcing issue, however, the banding
> on resistors is supposed to be somewhat 
> of a standard. The differences in these 
> two seems to identical.
> 
> It just so happens that these 2 
> are the 2 I like most.
> 
> Ethan

Hi all,
First a correction - only two of the timing capacitors are 
electrolytics (I didn't take the module completely out of the case, 
so I misidentified them); second, my A140 is also marked 'version 1 
1995' ('v1' was shorthand I used in my notes...).

> I have 5 A-140s.  3 of which 
> have flat LEDs.  Of the 3 that 
> have flat LEDs, 2 have visably
> different components on the PCB.
> Different transistors, differetly
> marked resistors, etc.  I can 
> understand red versus blue transistors
> as a sourcing issue, however, the banding
> on resistors is supposed to be somewhat 
> of a standard. The differences in these 
> two seems to identical.

There are two resistor marking codes generally in use - 4 band and 5 
band, and the same value can appear quite different. For example, a 
10kohm, 5% in 4 band is brown, black, orange, gold; 5 band it is 
brown, black, black, red, gold. However if it's 1%, 5 band, it is 
brown, black, black, red, brown, and so it gets tricky to decide 
which end to start from (the gap between the tolerance colour and the 
rest is wider).

The difference in transistor types is interesting though, and may 
account for some diference in performance - I'd be interested to know 
the difference if you can be bothered to check. On mine, Q1-4 & Q6 
are all BC547C (board marked BC549), and Q5 is a BC559C, same as 
board says.

Tim

*

> I recall reading somewhere that all of the A100 modules originally 
> had the flat red LEDs, and the Doepfer converted over completely to 
> the round orange-ish LEDs. I don't think any flat LED modules have 
> been produced since then, and it affected all of the modules, so it 
> didn't coincide with design mods as far as I know.


The original modules had 'round' bead-like red LEDs. Later 
batches of modules used the 'flat' orangey coloured LEDs 
for a while before they made way for the red ones again. 




Sean. 
analogueman@dsl.pipex.com 


*

I noticed some differences in transistors of my ADSRs, too. Okay, here 
we go (components marked on the PCB in brackets)

A-140 with the flat LED: Q1 to Q4 and Q6: 547 (549);   Q5: 557 (559)
A-140 with round LED:  Q1and Q2: 549 (549);  Q3, Q4 and Q6: 548 (549); 
 Q5: 557 (559)

Paul  (confused)



Tim Stinchcombe wrote:

> The difference in transistor types is interesting though, and may
> account for some diference in performance - I'd be interested to know
> the difference if you can be bothered to check. On mine, Q1-4 & Q6
> are all BC547C (board marked BC549), and Q5 is a BC559C, same as
> board says.
>
> Tim

Hi Paul,
Thanks for the info. I have just simulated the 'attack' part of the 
circuitry in the demo versions of PSpice and Multisim that I'm 
currently evaluating. Admittedly neither has the exact models for the 
BC547/549 (they are demo versions after all...), but using two NPN 
transistors whose parameters looked reasonably different, you 
wouldn't have got a fag paper between the two 'envelopes' output! 
This confirms my initial reaction - the differences in the 
transistors probably don't affect the output that much (which is why 
the two types are considered equivalent). I'd still wager any 
difference comes down to the capacitors - I've been wanting to get to 
the bottom of this for other reasons (the quad osc in the frequency 
shifter for one) but have only recently received a book with some 
info that may help, and it's also partly the reason I am evaluating 
the analogue simulation packages, so that I can model different 
effects and see what happens. This is some way off yet, so I'm about 
all out of steam on this for now! If I do have any other ideas I'll 
of course post them.

Tim

--- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> I noticed some differences in transistors of my ADSRs, too. Okay, 
here 
> we go (components marked on the PCB in brackets)
> 
> A-140 with the flat LED: Q1 to Q4 and Q6: 547 (549);   Q5: 557 (559)
> A-140 with round LED:  Q1and Q2: 549 (549);  Q3, Q4 and Q6: 548 
(549); 

>  Q5: 557 (559)
> 
> Paul  (confused)

Hate to break it to you guys - but the modules on my Analogue 
Systems gear, all of which is new,  all has flat tops.

Every single dang one of them.

So, it's not because of obsolesence.  But your observation is 
correct, not all LEDs are created electrically equal, so saying the 
flat tops respond quicker could be due it's electrical 
charactoristics as opposed to just a difference in luminance 
reflection of the domed lens.  I know from playing around with 
some filters that using LEDS in place of signal diodes within a 
circuit will give different coloring to the sound from one LED type 
to another.  Some sound warmer than others.  As silly as this 
seems, green ones are particularily warm sounding.  

John Blacet is famous for using leds within his circuits, on the 
circuit boards themselves.  He does this for sonic reasons with 
intention of bringing them to the faceplate.

I swear, I'm not making this up!

Peter



--- In Doepfer_a100@y..., "Joe Buechler" <buechlerjoe@t...> 
wrote:
> I recall reading somewhere that all of the A100 modules 
originally 
> had the flat red LEDs, and the Doepfer converted over 
completely to 
> the round orange-ish LEDs. I don't think any flat LED modules 
have 
> been produced since then, and it affected all of the modules, 
so it 
> didn't coincide with design mods as far as I know.
> 
> Its possible, though, that Doepfer has made changes to 
various 
> modules over time that haven't been reflected in version #s.
> 
> Maybe in a few years the flat LED modules will be considered 
a rare 
> collectors item ;-)
> 
> Joe
> 
> --- In Doepfer_a100@y..., "ethanzer0" <ethanzer0@y...> wrote:
> > --- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> > > No matter which type of LEDs they have, my A-140s are all 
marked: 
> > > "version1, 1995", so Doepfer don´t seem to have changed 
anything.

> > > So your idea of 'second sourcing' makes sense.
> > > 
> > > Paul
> > > 
> > > 
> > > Tim Stinchcombe wrote:
> > > 
> > 
> > I have 5 A-140s.  3 of which 
> > have flat LEDs.  Of the 3 that 
> > have flat LEDs, 2 have visably
> > different components on the PCB.
> > Different transistors, differetly
> > marked resistors, etc.  I can 
> > understand red versus blue transistors
> > as a sourcing issue, however, the banding
> > on resistors is supposed to be somewhat 
> > of a standard. The differences in these 
> > two seems to identical.
> > 
> > It just so happens that these 2 
> > are the 2 I like most.
> > 
> > Ethan

Hi Peter

> So, it's not because of obsolesence.  
Maybe AS did put a large amount in stock, or they use a brand, that was not
available, when Telefunken stopped their production.

Florian 

-- 
Florian Anwander                  |ConSol*  HP-Support
Tel.   +49.89.45841-133           |Consulting&Solutions Software GmbH
Fax    +49.89.45841-139           |Franziskanerstr. 38, D-81669 München
email: florian.anwander@consol.de |http://www.consol.de

yep you're right.
I just checked my Analogue Systems modules (I only have 3 VCLFO's 
though) and they all have flat LEDS's.....interesting.
Maybe doepfer couldn't source any, afterall Doepfer are German and 
Analogue Systems are English. What about Analogue Solutions, I have 
only 1 filter (MS20) has no LEDS's but do they use flat ones?
I wonder if American companies use Flat ones.


John.





--- In Doepfer_a100@y..., "(i think you can figure that out)" 
<petergrenader@h...> wrote:
> Hate to break it to you guys - but the modules on my Analogue 
> Systems gear, all of which is new,  all has flat tops.
> 
> Every single dang one of them.
> 
> So, it's not because of obsolesence.  But your observation is 
> correct, not all LEDs are created electrically equal, so saying 
the 
> flat tops respond quicker could be due it's electrical 
> charactoristics as opposed to just a difference in luminance 
> reflection of the domed lens.  I know from playing around with 
> some filters that using LEDS in place of signal diodes within a 
> circuit will give different coloring to the sound from one LED 
type 

> to another.  Some sound warmer than others.  As silly as this 
> seems, green ones are particularily warm sounding.  
> 
> John Blacet is famous for using leds within his circuits, on the 
> circuit boards themselves.  He does this for sonic reasons with 
> intention of bringing them to the faceplate.
> 
> I swear, I'm not making this up!
> 
> Peter
> 
> 
> 
> --- In Doepfer_a100@y..., "Joe Buechler" <buechlerjoe@t...> 
> wrote:
> > I recall reading somewhere that all of the A100 modules 
> originally 
> > had the flat red LEDs, and the Doepfer converted over 
> completely to 
> > the round orange-ish LEDs. I don't think any flat LED modules 
> have 
> > been produced since then, and it affected all of the modules, 
> so it 
> > didn't coincide with design mods as far as I know.
> > 
> > Its possible, though, that Doepfer has made changes to 
> various 
> > modules over time that haven't been reflected in version #s.
> > 
> > Maybe in a few years the flat LED modules will be considered 
> a rare 
> > collectors item ;-)
> > 
> > Joe
> > 
> > --- In Doepfer_a100@y..., "ethanzer0" <ethanzer0@y...> wrote:
> > > --- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> wrote:
> > > > No matter which type of LEDs they have, my A-140s are all 
> marked: 
> > > > "version1, 1995", so Doepfer don´t seem to have changed 
> anything.
> > > > So your idea of 'second sourcing' makes sense.
> > > > 
> > > > Paul
> > > > 
> > > > 
> > > > Tim Stinchcombe wrote:
> > > > 
> > > 
> > > I have 5 A-140s.  3 of which 
> > > have flat LEDs.  Of the 3 that 
> > > have flat LEDs, 2 have visably
> > > different components on the PCB.
> > > Different transistors, differetly
> > > marked resistors, etc.  I can 
> > > understand red versus blue transistors
> > > as a sourcing issue, however, the banding
> > > on resistors is supposed to be somewhat 
> > > of a standard. The differences in these 
> > > two seems to identical.
> > > 
> > > It just so happens that these 2 
> > > are the 2 I like most.
> > > 
> > > Ethan

Dome top on my LFO 1


--- In Doepfer_a100@y..., "jmaddocks1975" 
<jmaddocks1975@y...> wrote:
> yep you're right.
> I just checked my Analogue Systems modules (I only have 3 
VCLFO's 
> though) and they all have flat LEDS's.....interesting.
> Maybe doepfer couldn't source any, afterall Doepfer are 
German and 
> Analogue Systems are English. What about Analogue 
Solutions, I have 
> only 1 filter (MS20) has no LEDS's but do they use flat ones?
> I wonder if American companies use Flat ones.
> 
> 
> John.
> 
> 
> 
> 
> 
> --- In Doepfer_a100@y..., "(i think you can figure that out)" 
> <petergrenader@h...> wrote:
> > Hate to break it to you guys - but the modules on my 
Analogue 
> > Systems gear, all of which is new,  all has flat tops.
> > 
> > Every single dang one of them.
> > 
> > So, it's not because of obsolesence.  But your observation is 
> > correct, not all LEDs are created electrically equal, so saying 
> the 
> > flat tops respond quicker could be due it's electrical 
> > charactoristics as opposed to just a difference in luminance 
> > reflection of the domed lens.  I know from playing around with 
> > some filters that using LEDS in place of signal diodes within 
a 
> > circuit will give different coloring to the sound from one LED 
> type 
> > to another.  Some sound warmer than others.  As silly as this 
> > seems, green ones are particularily warm sounding.  
> > 
> > John Blacet is famous for using leds within his circuits, on 
the 
> > circuit boards themselves.  He does this for sonic reasons 
with 
> > intention of bringing them to the faceplate.
> > 
> > I swear, I'm not making this up!
> > 
> > Peter
> > 
> > 
> > 
> > --- In Doepfer_a100@y..., "Joe Buechler" <buechlerjoe@t...> 
> > wrote:
> > > I recall reading somewhere that all of the A100 modules 
> > originally 
> > > had the flat red LEDs, and the Doepfer converted over 
> > completely to 
> > > the round orange-ish LEDs. I don't think any flat LED 
modules 
> > have 
> > > been produced since then, and it affected all of the 
modules, 
> > so it 
> > > didn't coincide with design mods as far as I know.
> > > 
> > > Its possible, though, that Doepfer has made changes to 
> > various 
> > > modules over time that haven't been reflected in version #s.
> > > 
> > > Maybe in a few years the flat LED modules will be 
considered 
> > a rare 
> > > collectors item ;-)
> > > 
> > > Joe
> > > 
> > > --- In Doepfer_a100@y..., "ethanzer0" <ethanzer0@y...> 
wrote:
> > > > --- In Doepfer_a100@y..., Paul Schulz <dasfonk@w...> 
wrote:
> > > > > No matter which type of LEDs they have, my A-140s are 
all 
> > marked: 
> > > > > "version1, 1995", so Doepfer don´t seem to have 
changed 

> > anything.
> > > > > So your idea of 'second sourcing' makes sense.
> > > > > 
> > > > > Paul
> > > > > 
> > > > > 
> > > > > Tim Stinchcombe wrote:
> > > > > 
> > > > 
> > > > I have 5 A-140s.  3 of which 
> > > > have flat LEDs.  Of the 3 that 
> > > > have flat LEDs, 2 have visably
> > > > different components on the PCB.
> > > > Different transistors, differetly
> > > > marked resistors, etc.  I can 
> > > > understand red versus blue transistors
> > > > as a sourcing issue, however, the banding
> > > > on resistors is supposed to be somewhat 
> > > > of a standard. The differences in these 
> > > > two seems to identical.
> > > > 
> > > > It just so happens that these 2 
> > > > are the 2 I like most.
> > > > 
> > > > Ethan

hi peter,
i tried to contact you off list but i got a "failure
delivery" message...
anyway,i'm glad that you have greek roots!
yasou ki esena!(if you know greek...)
bakis.



--- "(i think you can figure that out)"
<petergrenader@hotmail.com> wrote:
> Dome top on my LFO 1
> 
> 
> --- In Doepfer_a100@y..., "jmaddocks1975" 
> <jmaddocks1975@y...> wrote:
> > yep you're right.
> > I just checked my Analogue Systems modules (I only
> have 3 
> VCLFO's 
> > though) and they all have flat
> LEDS's.....interesting.
> > Maybe doepfer couldn't source any, afterall
> Doepfer are 
> German and 
> > Analogue Systems are English. What about Analogue 
> Solutions, I have 
> > only 1 filter (MS20) has no LEDS's but do they use
> flat ones?
> > I wonder if American companies use Flat ones.
> > 
> > 
> > John.
> > 
> > 
> > 
> > 
> > 
> > --- In Doepfer_a100@y..., "(i think you can figure
> that out)" 
> > <petergrenader@h...> wrote:
> > > Hate to break it to you guys - but the modules
> on my 
> Analogue 
> > > Systems gear, all of which is new,  all has flat
> tops.
> > > 
> > > Every single dang one of them.
> > > 
> > > So, it's not because of obsolesence.  But your
> observation is 
> > > correct, not all LEDs are created electrically
> equal, so saying 
> > the 
> > > flat tops respond quicker could be due it's
> electrical 
> > > charactoristics as opposed to just a difference
> in luminance 
> > > reflection of the domed lens.  I know from
> playing around with 
> > > some filters that using LEDS in place of signal
> diodes within 
> a 
> > > circuit will give different coloring to the
> sound from one LED 
> > type 
> > > to another.  Some sound warmer than others.  As
> silly as this 
> > > seems, green ones are particularily warm
> sounding.  
> > > 
> > > John Blacet is famous for using leds within his
> circuits, on 
> the 
> > > circuit boards themselves.  He does this for
> sonic reasons 
> with 
> > > intention of bringing them to the faceplate.
> > > 
> > > I swear, I'm not making this up!
> > > 
> > > Peter
> > > 
> > > 
> > > 
> > > --- In Doepfer_a100@y..., "Joe Buechler"
> <buechlerjoe@t...> 
> > > wrote:
> > > > I recall reading somewhere that all of the
> A100 modules 
> > > originally 
> > > > had the flat red LEDs, and the Doepfer
> converted over 
> > > completely to 
> > > > the round orange-ish LEDs. I don't think any
> flat LED 
> modules 
> > > have 
> > > > been produced since then, and it affected all
> of the 
> modules, 
> > > so it 
> > > > didn't coincide with design mods as far as I
> know.
> > > > 
> > > > Its possible, though, that Doepfer has made
> changes to 
> > > various 
> > > > modules over time that haven't been reflected
> in version #s.
> > > > 
> > > > Maybe in a few years the flat LED modules will
> be 
> considered 
> > > a rare 
> > > > collectors item ;-)
> > > > 
> > > > Joe
> > > > 
> > > > --- In Doepfer_a100@y..., "ethanzer0"
> <ethanzer0@y...> 
> wrote:
> > > > > --- In Doepfer_a100@y..., Paul Schulz
> <dasfonk@w...> 
> wrote:
> > > > > > No matter which type of LEDs they have, my
> A-140s are 
> all 
> > > marked: 
> > > > > > "version1, 1995", so Doepfer don�t seem to
> have 
> changed 
> > > anything.
> > > > > > So your idea of 'second sourcing' makes
> sense.
> > > > > > 
> > > > > > Paul
> > > > > > 
> > > > > > 
> > > > > > Tim Stinchcombe wrote:
> > > > > > 
> > > > > 
> > > > > I have 5 A-140s.  3 of which 
> > > > > have flat LEDs.  Of the 3 that 
> > > > > have flat LEDs, 2 have visably
> > > > > different components on the PCB.
> > > > > Different transistors, differetly
> > > > > marked resistors, etc.  I can 
> > > > > understand red versus blue transistors
> > > > > as a sourcing issue, however, the banding
> > > > > on resistors is supposed to be somewhat 
> > > > > of a standard. The differences in these 
> > > > > two seems to identical.
> > > > > 
> > > > > It just so happens that these 2 
> > > > > are the 2 I like most.
> > > > > 
> > > > > Ethan
> 
> 


=====
synthfreak(parallel worlds)
athens-greece
[Doepfer_a100] group owner-moderator

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