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Post by feijai on Sept 24, 2023 20:56:30 GMT
I have recently acquired an old unit with three VCOs and one 2OSC, and have been busy calibrating them. It's not been easy. Some notes: 1. I have a Master IO R2. This unit does not respond to MIDI lower than C-1 or higher than G#3. Don't know about R3 or R4. Note that 0-5V would be C-1 to C3. C3 to G3 is 2/3V extra!
2. The VCOs are good news and bad news. The good news is that the VCOs can be calibrated to track more properly from C0 to A2. Beyond A2 they start getting sharp, to about 25 cents at C3 for example. The bad news is that the VCOs can't do bass AT ALL. On AE's Oscillator Calibration Page it's suggested to callibrate starting at C0, which is supposed to be equal to 1V, and it's clear why: C-1 to C0 is bad. If you calibrate from C0 and up, then C-1 to be over 50 cents (a half semitone) flat! Of course if you can calibrate starting at C-1, everything over C0 will be lost, so that's not going to work.
3. I got all three of my VCOs calibrated more or less identically. But turning the unit off, grabbing dinner, turning it on again and waiting for 30 minutes still had one VCO tracking quite differently from the others. :-(
4. The PWM dial affects the pitch of the VCO even in **sawtooth**: about 10-15 cents. That is not good.
5. The 2OSC calibrate quite poorly as I have heard, but you can use them for bass instead of the VCOs. If you calibrate starting at C-1, you can get about 1.5 octaves before things start going too flat to be usable.
6. 2OSC has 2 CV ins (of course) but only one Bus CV supply (!?!?!). So you can't connect both oscillators to your keyboard without scrounging for another Bus CV on some other module. What?
7. So far I have not seen much voltage loss even with all three VCOs and both 2OSC connected to Bus CV. Maybe I'm doing it wrong? Will do more testing.
I cannot afford new modules, so an OSC2/d is out of the question. But more importantly, I'm surprised that we haven't seen a DCO yet, replacing the VCO (that is, one which has triangle, fine tune, PWM, and ideally sine)
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Post by admin on Sept 24, 2023 23:24:17 GMT
Thanks for this very thorough analysis!
I think the shortcomings of VCO and 2OSC in terms of tracking were, what prompted Robert to develop the 2OSC/d which has digital tracking. But it's still not perfect.
I'm not super concerned about tuning as I just tune things by ear and don't play more than 1 octave usually. However the Wavetables module tracks very well, being a pure digital module. Also Keuerslager Kurt's 555 Oscillator tracks very well over a wide range.
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Post by funbun on Sept 25, 2023 15:53:52 GMT
Yeah, if tuning and tracking are your main concerns, like me, the 555, WAVETABLES and RAINS are your best bet.
Right now my 555 needs repair because I broke the trim pots by twisting them too far.
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Post by feijai on Sept 26, 2023 8:01:47 GMT
Some further analysis.
1. I think the 2OSC is simply beyond hope. The oscillators are too unstable, one of them flakes out a lot, but most importantly the single tuning knobs are EXTREMELY sensitive. Jolt the unit slightly and you're out of tune by 20 cents.
2. All four of the oscillators not only get out of tune when warming up again (of course) but also tend to change tracking (which is bad).
3. I still cannot really tell if using a 4BUFFER for the CVs of the oscillators has much of an effect over just putting them directly on the CV bus. Can anyone tell me if the bus (not other CV sources, the *bus*) is likely to drop in voltage much as more devices get added to it?
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Post by Gaëtan on Sept 26, 2023 12:06:25 GMT
They are usable but I definitely think the basic oscillators are due an overhaul at Tangible Waves by now.
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Post by feijai on Sept 26, 2023 13:50:52 GMT
Another note, if I may, this time regarding SV FILTER.
On my unit at least, CV1 does almost nothing even with the knob full to the right. CV2 has a mild effect, perhaps 1/3 of the filter range. This makes SVFilter not particularly useful as a filter. Is this expected behavior or do I have a bad unit?
On the other hand, CV on the the Wasp filter has a dramatic effect.
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Post by tIB on Sept 26, 2023 14:19:57 GMT
Another note, if I may, this time regarding SV FILTER.
On my unit at least, CV1 does almost nothing even with the knob full to the right. CV2 has a mild effect, perhaps 1/3 of the filter range. This makes SVFilter not particularly useful as a filter. Is this expected behavior or do I have a bad unit?
On the other hand, CV on the the Wasp filter has a dramatic effect.
When you say cv1 does nothing do you mean with something patched to the cv1 input and the cv1 knob fully open? |
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Post by feijai on Sept 26, 2023 15:08:21 GMT
When you say cv1 does nothing do you mean with something patched to the cv1 input and the cv1 knob fully open? Correct. It'd say that a full range 0...5V has about a 1/10 effect on the filter output. It's bad enough that I've taken to attaching CV1 and CV2 to a mult and controlling them both from a CV, which gets me a bit more than 1/3 total range. |
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Post by tIB on Sept 26, 2023 16:09:14 GMT
When you say cv1 does nothing do you mean with something patched to the cv1 input and the cv1 knob fully open? Correct. It'd say that a full range 0...5V has about a 1/10 effect on the filter output. It's bad enough that I've taken to attaching CV1 and CV2 to a mult and controlling them both from a CV, which gets me a bit more than 1/3 total range. Yeah that's not right - there's something up with that. |
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