Taurus 1/Modular Sound

[thealien666]

... those thoughts are broken away by the tremendous slam to the ground that is administered by the stampeding bull.

[megavoice]

Now thank you guys so much for the first.
A few minutes I bought my parts and will go on discussing the last what you've written with my tech before installing.
I only need now the two pots (50 kOhm, linear), but with 6,35 mm shafts, as I want to put original Minimoog knobs on.
Years later after buying the T2, NEW, I observed that it hadn't the usual small knobs. It was equipped with Minimoog knobs, strange ?????????

[megavoice]

My experience is that I can't get a square wave out of my T3 because it doesn't have one.

Another revelation from that same email with Bob is that the most other synths don't produce the low end of the T1/T3 because of RC coupling between stages (VCO to VCF to VCA). The RC product is a necessary evil that forms a highpass filter that reduces bass. The -3dB frequency point or lowest frequency depends on the design of that RC product. Are other synths intentionally crippled of bass? I certainly think so when I designed the bass boost mod for the Micromoog years ago. That's one reason why the Minimoog won't make that low end oomph of the Taurus.

Whether a square wave sounds hollow is not dependent on RC product but is a factor is non-linear circuits. Translated, non-linearity is distortion. The most common culprits are the VCF and VCA. Even with the VCF cutoff frequency wide open, the frequency response is FAR from flat. Years ago I tried playing a CD through my wide open Micromoog VCF and it frankly sounded like sh!t. That's a consequence of the class filter required to get high resonance for musical uses. Filter choices are a case of pick your poison, but sometimes imperfections can be a good thing. And not all filters have the same frequency response with the cutoff wide open. VCAs, notably in synths before the mid 1980s, impart their own distortion because they were not high fidelity devices and cost effective high fidelity VCAs were not yet available at the time.

MC,
talked to my tech today and he agrees with all this.
As for the T1 he did the simulation on his PC and said, when going into the VCF with 0 dB, the VCA output shows at 30 Hz -3dB, at 20 Hz -6 dB.
So still he claims there are NO 20 dB enhancement anywhere.
Tht's all what I can tell you about this, I hope as a non tech that I've reproduced everything right.

He said furtheremore, and this is ONLY an assunption !!! the special sound maybe be influenced or even created by the retrace of the sawtooth waveform. He said when looking into the schematics (???) the saw waveform is looking like an assymetrical triangle, the second decaying part of the wave is not that steep and vertical as it should be, and obviously prevails on other synths. This he said, could be a significant influence on the basic sound. And of course, on the T2 the decaying second part is different and steep and will let the T2 sound different and probably not that thick like on the T1.........
This might be also a confirmation about what you've said about the "uncorrect" working of the parts or groups.

I can also confirm especially on the Chroma of the collapsing of the deep frequences on the deep notes like you talked about above, as my tech said its Filter cannot reach the depth of the oscillators (6 or 16 Hz, I cannot remember, sorry)
We decided now experimenting and adding on the bass slider two 10 or 15 nF caps on the upper and lower part.
We both are very interrested in what will happen after, if there's an improvement or not.
The speaker I'm going into is a high quality active RCF monitor NX, 129 SPL

[MC]

Many engineers are skeptical of simulations. Simulations are NOT measurement tools. They are only as good as the component model. The key component in the T1 sonority is the OTA and it is a highly non-linear component. The more non-linear a component is, the harder it is to model accurately. Too many circuits that worked in simulations did not function at all in the real world.

I put more integrity into an actual T1 on a hardware frequency analyzer than any simulation or software tool.

FWIW, I have spent twenty plus years in the measurement industry.

[megavoice]

Many engineers are skeptical of simulations. Simulations are NOT measurement tools. They are only as good as the component model. The key component in the T1 sonority is the OTA and it is a highly non-linear component. The more non-linear a component is, the harder it is to model accurately. Too many circuits that worked in simulations did not function at all in the real world.

I put more integrity into an actual T1 on a hardware frequency analyzer than any simulation or software tool.

FWIW, I have spent twenty plus years in the measurement industry.

Interesting......................

[megavoice]

Many engineers are skeptical of simulations. Simulations are NOT measurement tools. They are only as good as the component model. The key component in the T1 sonority is the OTA and it is a highly non-linear component. The more non-linear a component is, the harder it is to model accurately. Too many circuits that worked in simulations did not function at all in the real world.

I put more integrity into an actual T1 on a hardware frequency analyzer than any simulation or software tool.

FWIW, I have spent twenty plus years in the measurement industry.

My tech says you can approach closely enough with the simulations to achieve the desired results. (???)
He also confirmed of course the phenomenon with the OTA. This could also of course be a main reason, or the single reason.

I soldered now the two 15 nF caps to the bass slider of the Chroma and have now a Taurus 4 on my left hand
Pushing the bass slider upwards nobody in that room needs a haircut for the next time anymore, seriously !

I'm now VERY curious about what will happen after the T2 Mod, first swapping those two resistors, and then adding the two subs after.
I'm still wondering why its outputlevel is so low now in comparison to that of the Chroma ??? But this will change, I hope....

It's a pity, I'd also like so much to add to the T1 two additional fully adjustable oscillators, but as my tech has SO much work to do he "surrendered", although as lovely as he is he would do, of course.
Anyway, I'm hoping that I gonna be happy "only" with the two additional square waveforms......

BTW, I'm almost shocked a little bit about the state that, as you said, the T3 has no squares.....
Maybe the Moog guys wanted to come as close as possible to the T1, or it would have become too expensive at the end.
I'm still wondering.........

[Voltor07]

Megavoice, ask your tech to run a simulation of a MiniMoog filter...if his simulation program is the same as mine, the simulation will not work. In fact, a LOT of Moog circuits don't work in simulations, or work differently in simulations than they do in real life. Simulations are absolute crap.

[megavoice]

Megavoice, ask your tech to run a simulation of a MiniMoog filter...if his simulation program is the same as mine, the simulation will not work. In fact, a LOT of Moog circuits don't work in simulations, or work differently in simulations than they do in real life. Simulations are absolute crap.

Sir,.....there isn't absolutely any reason to make fun of, but I accept that you`re obviously a funny person
My tech uses first, "Circuits Marker", and secondly "LP Spice" and he said he NEVER had any problems with...neither with the Moog filter or anything else........

I can't help pointing out that the phase relationship between the sawtooth and square waves is mighty important for the final output. Also the fact that some synths produce a ramp up sawtooth, versus a ramp down one, will also greatly affect the sound when mixed with other waveforms.

That's quite correct, but on the T1 you have to note that its saw waves are not only declining, like the second saw of the third oscillator of your Minimoog but are also "negative" !
When the wave starts at zero on the x-axes the first part of the shape will drop, and will go straight up back vertically.
If s.o. wants to add square waves, they must also be negative, if not obviously it won't work.......