Studio.h DPO // 258e

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cyberdine
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Studio.h DPO // 258e

Post by cyberdine » Wed Nov 01, 2017 8:15 pm

So for those people that have the new DPO/258e, what do you think? My initial impression of it from playing only a few hours is that it’s warmer and softer than the 258r but still capable of some gritty, biting sounds. Having the index CV is cool, especially because you can CV modulate at audio rate at a range much greater than the 259e. And it goes so high, all the way to G9...

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missingtwin
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Post by missingtwin » Sun Nov 24, 2019 6:54 am

I love the DPO/258e :goo:

Did you know that in MIDI mode the big frequency knob becomes a
midi note offset in semi tones?

This is a powerful feature for cross modulation.

Set both sides to midi mode and cross mod one to another (or both). Using the midi offset trick, because the midi notes are perfectly in tune, can lead to some rich and unexpected timbres.

Play some Debussy midi files into it, guaranteed not to sound like Tomita.

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Post by elmerfudd » Sun Nov 24, 2019 9:22 am

Thank You!
I did not know that, and look forward to exploring that feature! I was just happy that I had an e osc that tracked cv!

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Post by missingtwin » Mon Nov 25, 2019 11:13 am

The Studio H Control Signal Router (CSR) can make any "e" oscillator track very well. My sequencers are first scaled by the CSR before hitting the oscillators.
Having everything in tune is like a buchlachristmasmiracle.

The 250e is particluarly bad. The thing is not even close to being quantized. It's a joke! Why put a quantized output when it's nowhere near correct?

Anway, the CSR fixes it.

:party:

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ArguZ
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Post by ArguZ » Mon Nov 25, 2019 2:09 pm

The thing is, none of the e stuff is "particularly bad"
The problem is neither INs not OUTs of most e modules are buffered.
And that is bad.
Not if you connect one to another e, the impedance matches.
But as soon as you start feeding them clone modules, or even worse try to use e CV with clone Oscis you get voltage drops up to 0.25v or 2-3 half notes.

I will make a video soon to illustrate the problem.
For generic modulation the system is sufficient, but if one thinks one could use a 256e to transpose something with accurate pitch, that will not happen.
Or use a 250e CV out to drive 4 oscillators...
The 218e has the same problem...they all have..
But with a buffer in between and some clever patching it is totally possible to patch a 259e or 261e to track 5 octaves...

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Post by missingtwin » Mon Nov 25, 2019 3:49 pm

Image

The 250e is particularly bad. Check out this table that dougcl made. By only 3v, the output is already off by a semitone.

Yes, by attenuating the cv input, you can get any of the e oscillators to track for several octaves. The problem is that you’ve corrected for one sequencer and one only. As you said arguz, any attempt to transpose an entire sequence by, say, an octave (eg by throwing 1.2v at it from the 251e) is not possible in any predictable way. I just find it annoying that the 250e pretends to have a quantized mode.

It doesn’t.

Anyway, the table shows how the CSR can correct the tuning so that everything is standardized and plays in tune.

I had three sequencers transposing each other in an orgy of in-tuneness to one target oscillator. It was a little disconcerting.

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Post by ArguZ » Mon Nov 25, 2019 6:33 pm

This table is exactly what i found as well and also the explanation why Doug's 210 is so much better than the rusty old one.
So what we need is a small module that holds and buffers the CV on its inputs.
A buffered mult..lol
I am sure someone will claim ownership of the idea.

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Post by missingtwin » Tue Nov 26, 2019 7:02 am

It would also help to have the quantizer - actually put out quantized values. You can buffer the input but that won’t help anything if the quantized values are off to begin with.

The CSR changes the CV span (by expanding or contracting the CV span) reducing this error, and making it effectively quantized.

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Post by ArguZ » Tue Nov 26, 2019 12:21 pm

It actually gets worse the more you connect to one output..

I just tried with a 250e on 2V (2.055 measured) and into the 259e which brings it down to 2.01 which is what it is intended to do...
But if you run another patch cable from the 259e to the other port in the dame 259e it drops to 1.98.
And if i go then to a 256e we are down to 1.95 and after a 2OC we are down to 1.89
Not a big deal you might think, but in the grand scheme of things its drops an A to a G flat
And that is in the 2-4V range
In the 6-8V range the values are even worse...
Instead of 6.2V it starts at 6.1V with just one 259e and with all four we land at 5.85V

I am gonna see if we can mod this thing to have a buffered out.
Normally it is enough to move the feedback resistor input to include the output resistor.
That would force the opamp to compensate for a voltage drop.

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Post by cyberdine » Tue Nov 26, 2019 12:46 pm

ArguZ wrote:It actually gets worse the more you connect to one output..

I just tried with a 250e on 2V (2.055 measured) and into the 259e which brings it down to 2.01 which is what it is intended to do...
But if you run another patch cable from the 259e to the other port in the dame 259e it drops to 1.98.
And if i go then to a 256e we are down to 1.95 and after a 2OC we are down to 1.89
Not a big deal you might think, but in the grand scheme of things its drops an A to a G flat
And that is in the 2-4V range
In the 6-8V range the values are even worse...
Instead of 6.2V it starts at 6.1V with just one 259e and with all four we land at 5.85V

I am gonna see if we can mod this thing to have a buffered out.
Normally it is enough to move the feedback resistor input to include the output resistor.
That would force the opamp to compensate for a voltage drop.
If there's a little H panel that can deal with the quantization issues you're describing, that would be very useful. 8-)

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Post by ArguZ » Tue Nov 26, 2019 5:33 pm

You mean a six channel voltage buffer ?
That would be something ;)
Maybe something you can actually mix and merge voltages to transpose without a massive loss ?
hmmm...wonder what that could be..

Oh wait..it's the first thing we built :-D

Image

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cyberdine
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Post by cyberdine » Tue Nov 26, 2019 5:53 pm

ArguZ wrote:You mean a six channel voltage buffer ?
That would be something ;)
Maybe something you can actually mix and merge voltages to transpose without a massive loss ?
hmmm...wonder what that could be..

Oh wait..it's the first thing we built :-D

Image
Well now, isn’t that useful...

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Post by missingtwin » Thu Nov 28, 2019 5:02 am

The studio h CSR is both a CV buffer and can be a
CV span scaler (for accurate pitch).

The module was conceived as such as it has the ability to save the scaling on any particular node. The ability to save a node’s max cv for accurate tuning (CV scaling), is implemented w/in the module itself. Meaning that you can scale the node perfectly and save that node’s tuning to the CSR internally. So if you want accurate 1.2v oct tuning, just select the node and press the encoder. It pops back in tune.

This ability to save the scaling of nodes is within the CSR itself and in addition to the normal e series preset manager functionality that it also has.

Of course the module is much more than this, but the CV section of the module was conceived with this functionality in mind.

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Post by missingtwin » Sun Dec 01, 2019 4:21 am

Another source of interesting sounds via the DPO under midi control:
Run both oscillators of the DPO in midi mode into the 285e Frequency shifter reference and signal inputs.

Using the midi note offset trick mentioned above, some interesting sounds can be had.

Using the CSR to mix in various other morphing sound sources (259e, 262v) with this harmoniously frequency shifted DPO into the carrier or signal input of the 285e is my current buchla obsession.

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