[sdiy] Where is the DIY spirit? was: Filters

[harry]

Not only that... we're so jaded that we will now roast Rene
(toaster mode on ... just kidding ;^)

René Schmitz wrote:

> Hello everybody,

Hi Rene...

>
>
> I'm asking myself if we can't offer better advice to novices as where to
> buy the kits. I mean building a kit is mainly only improving your soldering
> skills.

That depends. I remember being a novice and building a PAiA 2720. Then noticing
that the filter didn't work too well, and expanding the range (discover the
twin-tee).
Then tracking down every bug that I could find. The bleedthrough from the UJT
reset circuit in the AD generator (which actuallt took a re-design of the whole
thing).

But at first, the kits were a good starting point...

>
> IMO the challenge in DIY lies somewhere else. Its in understanding how these
> circuits operate, and why they sound like they sound. That means to learn
> some
> electronics on your way. The fun when you have reached such a state, is in
> being
> able to tailor your synth to your taste, rather then just being able to
> pick from
> whats available off the shelf as a kit.

OTOH.... I was pretty accomplished when I first built the PAiA 2720... I had and

could operate a scope, etc.  Trips to the college library yielded the Journal of
the
Audio Engineering Society... etc.  So eventually I did figure how to make a
synth to
my taste.

There are newbies and newbies. I correspond with a lot of them off-list.  Those
I
talk to have one thing in common, they are tenacious in dogging the problems
until
they are gone. Might take time but they WILL prevail.

I also see some new DIYers that expect instant gratification.  These folk are
best
served with the kit. Most bugs are worked out already.

Some just want a synth for cheap. They (honestly) should go out an buy a ready
made synth... possibly repair a commercial one.  DIY ? Stay home... its really
NOT easier to build your own synth.

> I'm fearing that on the long run this community is starving, because the
> oldhanders merely sell kits and the newbees simply put them together,
> without learning how they work. (To say it more drastically: If all the
> gurus here only had built kits, this community wouldn't be existant. Ok,
> this is a bit exaggerated, but I hope you see my point.)

OTOH there are Guru's and Guru's...  I got a real kick out of your dual-fet
reset for the VCO. I'm at the point where seeing something like that really
gets the juice flowing. "Wow I can use this to...."

> So much ranting, and now for the questions:
>
> The IMO best sounding four pole filter is the SSM2040, followed by the moog
> ladder, both give a classic sound. If I had to choose between one of them
> I'd clearly prefer the 2040.
> I'd also prefer having a four pole instead of a two pole filter if I needed
> to choose,
> although a two-pole state variable has more sonic possibilities, but then I
> find myself often only using the lowpass mode anyway.

I like lots of filters. For me the kits were a good starting point. In a couple
of hours
I could find out what they sound like... (sort of) and decide if I want to
persue
them.  The one I have not done yet is JH's (or your) 2040 clone.

Listening to a MonoPoly currently in my possession, with the real 2040... I'm
underwhelmed.  I don't hear anything too special. Tin ear, perhaps ?

I like the State Variable Filter a lot. Bright and buzzy... it sounds more like
a synth
to me. I'm influenced more by early ARP than Moog...

The Korg styles are new to me. They are TOO buzzy IMHO.... They remind me of
touch-tone telephone sounds.

The Moog ladder is a good all around filter. This is the one filter I LIKE to
overdrive.

> For VCOs I'm not having much preferences, except that the circuit should be
> stable, either thru tempco or heater compensation.

Amen !

> And it should have good
> tuning precision.

Amen !

> There is nothing worse than a VCO that gets flat above a
> certain frequency, if you do FM or ringmodulation between two oscillators,
> or just run them in unison, it sounds unpleasant to crap. A basic setup
> could do with just saw and pulse, but tri and sine are handy too.

Triangle is very nice. Sine is better left to LFO use (as you say later)... or
in
one Yahama archetecture where the sine bypasses the VCF and goes
direct to the VCA.  That lets you sweep the filter and never attenuate the
fundamental !!!!

> Much
> better if your oscillators can span from LFO-range to the audio range, you
> don't need specific LFOs then. For LFO use the circuit really should have
> sine and tri.

I'd rather have specific LFO's which can be a lot cheaper and less stable or
precise
and still be good.

> For VCAs I'm a fan of the diff-pair VCAs because they have better control
> rejection then the VCAs with OTAs, also better noise performance. The
> minimoog VCA is such a circuit.

Amen !  To this day... the PAiA 2720 VCA remain in my modular. They have
not gotten stale as my tastes moved from beer to champagne... (so to speak...)

> Just a quick rundown, I hope that we can get the discussion into depth on
> these issues.

Yeah. Lets have a flamewar. Its been SO long... c'mon.... please....   ;^P

H^) harry

>
>
> Cheers,
>  René
>
> --
> uzs159 at uni-bonn.de
> http://www.uni-bonn.de/~uzs159
>
>

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