Buchla 259 vs 261e Audio Comparisons

[REwire]

These are 5 each patch comparisons of my Buchla 259 and 261e. Each is a 320mbps mp3 file about 15 - 30 seconds each. No routing through a filter, just a Plan-B Model 13 Multi-timbral Gate, a vactrol based copy of the 292e.

Main Osc - Pure Sine Waves, All Knobs at CCW
259 Sine
261e Sine

Main Osc - Sweeping each of just the Timbre Knobs.
259 Timbre Sweep
261e Timbre Sweep

Main Osc - Sweeping all three parameters of the Main Osc.
259 Tweaking
261e Tweaking

Assigning the Mod Osc to Amplitude and Pitch of Main Osc. The 261e Mod Osc has no Sawtooth so can't slam like the 259 because the 259 has Vactrols in it's internal VCA, like the 292. I used a tight rectangle on the 261e to get close:
259 Amp n Pitch Mod
261e Amp n Pitch Mod

The Modulation Osc at Pitch Levels. For 259, using switch between Saw, Pulse and Tri. 261e has waveshaper between Sine and Rectangle
259 Modulation Osc
261e Modulation Osc

My conclusion. They are definitely the same breed and go into similar sonic territory. The 261 has a more functional modulation Osc but no actual sawtooth. The main osc on the 261 can go many more sonic places but can't make a heavy analog sound like 259's meaty sawtooth. Had I a whole Buchla system I'd do the opposite of what I did and get an Plan-B Model 15 Osc in a little box and patch it in.

[cbm]

Thanks a lot for posting these comparisons. I've been wanting to hear them back to back for a while.

One major difference that this brings out is that on a 261e, the FM from the mod osc is always a sine wave, no matter what the waveshaper says. I like this decision, at least at audio rates, but no internally routed square wave modulation is possible.

Even though your "261e Modulation Osc" example illustrates it, I thought it was worth pointing again out that the wave shaper on the Mod Osc smoothly changes from Sine -> to a sort of triangle-ish wave -> Square -> PWM, a little like a fancier version of the morph section of a Plan B Model 15.

[Nosferatu]

Brilliant. splendid. Many thanks.

However short Wav's could be idea since as MP3 can
make some artefact's on certain clean waves.

Interesting the 261e arent much a sine it can even be heard that it has
several odd harmonics att high level.I dont think its the coding
of the MP3 thats the cause.

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[Peake]

Yes, thank you very much for the comparisons!

The 261e sine does indeed sound closer to a triangle than a sine (but that's not extremely important, and likely helps add to the modulation results).

The 259 sounds like it can crap out at certain extremes, which might be nice for machine music. The 261e is more controlled and smoother and goes farther.

Very interesting.

[Nosferatu]

REwire!

Would you mind taking a picture from the backside of the VCOs
so one could see the PCB?

Please!

[Nosferatu]

P Shreiber had some photos of the 258 VCO waves!
http://www.synthtech.com/pix/buchla/b258/

[mono-poly]

The pcb looks quite simple.
How many rare parts are there in it?

[norman phay]

I was thinking that myself!

Also, on this pic:

http://www.synthtech.com/pix/buchla/b258/b258_1.jpg

I notice the little knurled potshaft for fine tuning to the RH side of each osc, but never noticed the similar one on the left. What's that for, I wonder?

[cbm]

[Nosferatu]

[cbm]

[REwire]

Chris, you should know this: What about the trims inside the holes on the 261e under the freq knob. The one page I got from Buchla says these are for "Strectch Tuning." Not sure what that means. Is it a Scaling Offset?

[cbm]

They are for tuning the oscillator's V/Oct response. I suppose you could tune them so that they go a little sharp for something like stretch tuning.

[ultrashock]

Dear all!
First, thank you very much for the 261 and 259 comparison since there came 259e which is a far more advanced 261 but a bit confusing from my point of understanding.

Kindly ask you to clarify the TIMBRE / HARMONICS section in these osc.
since I dont have paper documentation of them (except schemes, but they are still yet sophisticated for me).

From my point of understanding the routing is the following:

-259a:
First, the selected wave from the principal ocs. goes thru the Harmonics section where there are two voltage controlled modifiers: Symmetry and Order.
Do I mean right that the Symmetry section acts like the crossfader beetween the wave that have only odd harmonics (square wave) and the wave which has even (like a sine wave) harmonics?
Neverless, any crossfade beetween sine wave and other one will give the "saturation"-like effect or so.. - exactly when you mix some sine to the other wave.
The order section acts as a voltage controlled crossfader within fixed HPF to make the spike-like waveform as we saw it in the Easel 208 (spike is actually the square wave run thru the fixed hpf)?

Then, from my understanding, the signal goes to the timbre block (some sort of warp of so) and then sinal goes to the final outputs.
Do I understand correctly that principal ocs outputs jacks (sine and pulse) do not passed thru the timbre/harmonics block and their outputs are crear waves?

261e has all this 3 types of modifiers (tibmre, order, symmetry) with individual pot for every one (+ one "amount" pot for control voltage input for timbre). But in what sequence all these 3 modifiers are ordered? The same as in 259a/b? first goes the "symmetry", then the "order" and then the "timbre"?

The 259e is far more sophisticated. almost digital inside and outside with memory banks.
Still there is WARP control (timbre) and Morph is like a symmetry - since the waves for crossfading could be selected within the memory.

That's only my vision of this control. I would be very apreciate if you could correct (or even contradict) with them.

KR,

[TekniK]

From Mark Verbos:

The 148 makes the odd harmonics using a circuit that folds a triangle wave much like the circuit in the 259 or 208. It's not a circuit that you just send in a sine wave and get out all the harmonics though. It doubles the triangles using a full wave rectifier and multiplies by 3, 5 , 7 and 9 using wave folders. Then converts all of those to sines individually.

and more from Buchla-tech:

christopher said...
Could you describe the controls of the 259 Dual VCO a little? I think I understand the "Timbre" control, as compared to the Serge Wave Multiplier; and I believe the "Symetery" control is likely a sine/tri wave shaper, yes?

But I'm curious about the "Harmonics/Order" control. Would you talk about this some?


wavedeform said...
The symmetry control smoothly changes the wave from having symmetrical top and bottom halves, to asymmetrical halves.

The high order is sort of like a high pass filter, although it also adds harmonics.

and more here:

http://electro-music.com/forum/topic-40614.html

[ultrashock]

Teknik, thank you for the hints!

So, according to the Buchlatech
http://buchlatech.blogspot.com/2008/10/music-easel-oscillator.html
and
Manuals - Programming and Meta-Programming the Electro Organism (page 5, 2nd column)
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/PaMtEO_05.gif
only sine and triangle waves (in 259 - only sine either) pass to the TIMBRE block.
This is evident since routing square or similar odd waves to Timbre will not give the considerable result.
SO, I suppose the SQUARE in 259a goes to the ORDER section (for making spike-like waves), and Symmetry could be just the morphing beetween them (saying "morphing" I mean the scrossfade - the nature is different but the result could be the same). aren't you?

[TekniK]

i don't know,am noob in electronics.

[ultrashock]

okay, so, the question is to all - how do you think, what is the order of timbre and harmonics modules arranged in 259 or they interact simultaneously (OMG!).
as for my understanding for now I see the following simplified scheme

as for the 208 complex osc. (Easel) the scheme could be rewritten in the following way:

I can assume that TIMBRE module is at the end of the ring and SQUARE and SPIKE waves also pass thru the TIMBRE but it doesn't bring fundamental change in the square wave.
(but this assumption contradicts the Buchla Tech statement:
"The wave folder's effect disappears at the full CW position of this control."
But then, if we put the Timbre only on SINE wave how timbre could affect the TRIANGLE wave? do we need 2 tibre modules for each one?

as you see, there is no ORDER section in the 208 since the 208 has the dedicated SPIKE waveform.
Generally, the SPIKE waveform is not presented in Buchla exclusively (the nature of it is the square wave thru the fixed HPF and overtones increase as a result).
Such type of wave I've met at Roland Systems 700 description and.. (SUDDENLY!) in Roland JP8000 (TRIANGLE MOD wave at OSC1 gives the similar result).
That's all are only my assumptions and I will be very glad if you could correct them

[ultrashock]

just to update the topic, according to my studying the Easel 208 circuits:
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2080_9_200.jpg
only sine wave goes to the timbre. Other 3 waves (tri, sq and spike) are selected via the switch (actually 4016 logic) and mixed with sine in a crossfader (board/sheet 8 at the schematic):


This is actually very feasible for me and confirms the Buchla Tech description but with at least one doubt I mentioned before:
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/PaMtEO_05.gif
in this paragraph is described that only sine and TRIANGLE (wft?) goes thru the Timbre.

[TekniK]

why you just not check out the 259 schematics?

[ultrashock]

eeeem... well, nice idea, either....
taking into account that there is nothing clear at all with the 259...
okay, I'll try.
let's start from the end.
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2590_4_200.jpg
here at the timbre output stays ORDER section with the vactrol crossfader (some part of scheme cut M. Verbos to show the individual crossfader scheme at his simple-answer site). then the signal goes the section with VCAs (modulation index).
before it:
http://rubidium.dyndns.org/~magnus/synths/companies/buchla/Buchla_2590_3_200.jpg
first goes the waveshaper section, in which goes triangle and pulse (yes, the outs from the ordinary triangle vco-core). so, the symmetry acts at this section in the process of making the sine wave. then the sine wave goes to the timbre and you know what is further.
Thus, we have the following scheme:


p.s.: I didn't really want to do this description since I understand there could be errors! please, check it!

[TekniK]