MOTM

Hi,

now that a good number of people have shown interest in this project, I'm
ready to take pre-orders.

The 36dB Filter is a spin-off of the Variable Slope Filter / Phaser, using
the same PCB, but only half the components.

Same order form, therefore.

(See
http://www.jhaible.de/varislope_filter_phaser/varislope_filter_phaser.html

for details about the project.)

Pricing is EUR 27.00 per board

plus a single EUR 6.00 shipping flat charge for worldwide shipping,

regardless how many boards you are ordering and where you live.

It does *not* include any customs fees or tax that you may (or may not) have

to pay in your county.

What you get is a double-sided printed circuit board with component overlay,

approx. size 160mm x 100mmm.

You have to buy the electronic components for this, and build the device,

yourself. (Check the above website regularly for updates and building hints,

bill of matrials etc.)

If you want to place a pre-order, please send me an email to the following

adress:

jhaible@...

and use the FOLLOWING FORM (fill in your data instead of [],

for instance: "2 Boards" instead of "[quantity] Boards")

===== Start of Email Order Form ===============

Email Subject line: 36dB Varislope order: [quantity] boards

Email text:

I'm ordering [quantity] pieces of the 36dB VCF and Variable Slope
Filter/Phaser PCB

for EUR 27.00 per board + EUR 6.00 single shipping flat charge for any

number of boards.

I'm aware that I may have to pay additional amounts of customs and tax in my

country.

I'm aware that I'm only buying blank PCBs that may help me building an

electonic module - I'm *not* buying a diy kit, not a "project" - just pieces

of FR4 with copper traces.

I know how to build electronic circuits and I am trained in electrical
safety matters.

The seller of these PCBs will not be held responsible for any damage that
results

from these PCBs, directly or indirectly.

My shipping adress is

[Your Name]

[Your street, number, city, ZIP code, in exactly the form

that is generally used in your country]

[your country]

My paypal adress is [your paypal adress].

I===== End of Email Order Form =========

Looking forward to hear fom you :)

JH.

On 2009-05-18 08:21 +0200, JH. wrote:

> now that a good number of people have shown interest in this
> project, I'm ready to take pre-orders.
>
> The 36dB Filter is a spin-off of the Variable Slope Filter /
> Phaser, using the same PCB, but only half the components.
>
> Same order form, therefore.

Okay, I'll ask the obvious question : why two order forms ? If
someone plans to build one phaser and one filter, is it a problem
to just order two of either item ?

--
André Majorel <URL:http://www.teaser.fr/~amajorel/>

It's the *same* PCB, and the *same* order form.

I just sent two emails because some people who are into phaser shopping may
overlook it when they read filter, and vice versa.

JH.

----- Original Message -----
From: "Andre Majorel" <aym-htnys@...>
To: "JH." <jhaible@...>
Cc: "analog heaven" <analogue@...>; <synth-diy@...>;
"MOTM List" <motm@yahoogroups.com>
Sent: Monday, May 18, 2009 12:32 PM
Subject: [motm] Re: [sdiy] Taking pre-orders for JH. 36dB/oct LPF now


On 2009-05-18 08:21 +0200, JH. wrote:

> now that a good number of people have shown interest in this
> project, I'm ready to take pre-orders.
>
> The 36dB Filter is a spin-off of the Variable Slope Filter /
> Phaser, using the same PCB, but only half the components.
>
> Same order form, therefore.

Okay, I'll ask the obvious question : why two order forms ? If
someone plans to build one phaser and one filter, is it a problem
to just order two of either item ?

--
André Majorel <URL:http://www.teaser.fr/~amajorel/>


------------------------------------

Yahoo! Groups Links

On 2009-05-18 19:19 +0200, JH. wrote:

> It's the *same* PCB, and the *same* order form.
>
> I just sent two emails because some people who are into phaser
> shopping may overlook it when they read filter, and vice versa.

Thank you. I hope the pre-order phase is not closed because I'm
still busy trying to wrap my head around that project. Here's
what I've got so far :

- varislope_filter_phaser_sch1.pdf is the "meat" of the project,
the phaser/filter itself,

- varislope_filter_phaser_sch2.pdf is the PSU and the (very
elaborate) modulation source that consists of Q11 + U18 = noise
generator, U17B + C31 = S&H, U13 + C19 = LFO, U15 + U16 + U17A =
wave shapers + scanner (I think).

The difference between the filter-only version and the full
version is that the modulation source is omitted and the 6 DG419
switches are replaced by straps.

I guess a third way to build the varislope would be to omit the
modulation source but keep the DG419 so it can still be a phaser
or filter.

Personally, I'm not sure about this modulation source. I suspect
that, on my unit, the waveform pot would be permanently stuck in
pure sine position, making the scanner redundant. The other
sources I see myself using (velocity, EG and sawtooth LFO) all
have to come from other modules anyway.

In theory, each pole could individually be switched between
all-pass (phaser) and low-pass (filter) under voltage control. If
all poles are sonically interchangeable, a single CV could be
used with the number of LP poles being 6/5 of the CV. No idea how
to do that, nor how useful it would be.

--
André Majorel <URL:http://www.teaser.fr/~amajorel/>

>> I've ordered the boards from the factory already, but I always
>> get more than I've ordered (and have to pay them: small print of
>> contract that I have to take over-production),
>
>Interesting commercial practice.

I think it's pretty standard in that business. They have to make more PCBs
than I ordered, in order to make sure they'll have enough that test good (my
PCBs are tested with a needle adapter). And when they have more good ones
than I ordered (which is to be expected), I have a chance to sell them, but
*they* could only throw them away.

>> The waveform crossfading ("scanner") is arranged ina way that
>> S&H is adjoining "square" on the left side, and
>> "self-modulation" on the right side. That means, in S&H position
>> you have true random staircases. Turn the waveform pot slightly
>> to the left, and you get a tad of regular rectangle mixed in:
>> the steps become less random in a way that large steps are more
>> likely. Turn the waveform pot slightly to the right, and the
>> random S&H gets mixed with the dirt of an audio-rate
>> self-modulated filter. That's especially impressive at high
>> resonance settings. I got the idea for this from the Prophet 5's
>> Poly-Modulation and the CS-50's and Minimoog's external
>> modulation input, and - for a phaser application - from the EMS
>> Synthi HiFli.
>
>Thanks for the explanations. Where does the self modulation comes
>from ? lfo_mod seems to be in the wrong direction. Perhaps AUX
>MOD IN should be normalled to something else than ground ?

Sure. In my prototype, I've hard-wired it to the "DRY" output (pre-amplified
input signal).

>This is what I had in mind :
>
>CV Pole 1 Pole 2 Pole 3 Pole 4 Pole 5 Pole 6
> ~ 0.42 V LP LP LP LP LP LP
>0.42 V ~ 1.25 V LP LP LP LP LP AP
>1.25 V ~ 2.08 V LP LP LP LP AP AP
>2.08 V ~ 2.92 V LP LP LP AP AP AP
>2.92 V ~ 3.75 V LP LP AP AP AP AP
>3.75 V ~ 4.58 V LP AP AP AP AP AP
>4.58 V ~ AP AP AP AP AP AP
>
>The idea is that the higher the CV, the more high frequency
>content there is.
>
>Looks like it could be done with an LM3914-type circuit.

> But the 6 stages are interchangeable only with the "Slope" (or
> pole spread) potentiometer at ccw position. When the poles are
> spread apart, it makes a difference which one gets the
> complementary zero (= switchet to all pass), and which one
> doesn't.

I see. Yes, you should be able to add this (off-board) with a couple of
comparators.
But then again, the "SLOPE" parameter already lets more high freq contents
in, gradually.

JH.