Korg Minilogue

[Daags]

check the thread, it was clearly labelled so you won't just have to click on every a/v link looking for it.

Isn't it the one you posted yourself you are referring to, Daags? Here I bookmarked it:

https://www.youtube.com/watch?v=E1N8f3fVWSk

yep, pretty sure that's the one.

[ghettosynth]

Maybe Arp truly wanted to keep the new filter secret, or maybe they just wanted to continue potting the filters to somehow prove to the world, "See, we are still potting filters. We definitely weren't potting filters simply because we were infringing on Moog." Or maybe potting was somehow good for the filter circuits, though that seems a far stretch.

I'm pretty sure that they were just trying to hide their new design from competitors.

After Arp, Moog and EML, everybody and his brother started making small runs of obscure mono synthesizers. Probably Arp didn't want to make it any easier than it had to, with public circuit hints which would give a leg up to all the garage-based competitors crawling out of the woodwork at the time.

Yes, I think that's all that it was.

So anyway that 3900 has always been an odd duck, but very interesting chip that can do things which most conventional opamps cannot. Very rugged. Very ancient design. Sometimes called "3900 automotive amp" possibly because it was intended for various slow automotive and industrial logic in unfriendly environments, dunno.

Not suited to extremely high frequencies. Fairly noisy. But what made it unique was that the inputs were basically ground referenced current mode "naked" differential transistor pair.

Right, it doesn't seem like the stuff that new designs are made from. It would be like using
3080s today, except for availability, ok, better example, like using 741s.

Also, the difference in cost from an LM13700 based design is probably minimal at best. He points out in the interview where the real costs savings come from, labor. It seems very unlikely to me that you would end up at an LM3900 based design today when starting from ground zero if you weren't already inspired by an existing design.

It is just a cute chip because it can do so many tricks ordinary opamps can't, but rarely used for audio because most functions can be better done by conventional opamps. PAIA and some others in the early days would use 3900's in synth kits which did not get much respect, because the nature of the chip made it possible to create very low parts count circuits. In fact, because the 3900 was used in some inexpensive "toy" synth kits, might have made some folks back then prejudiced that it is too cheezy a chip to use in a serious "high quality" product.

Serge really knew how to use them. The PAIA Gnome is a bit of an odd duck, it seems to use the LM3900 in some places to reduce parts count and then goes to sort of high count discrete circuits elsewhere.

I don't know if a 3900 would be useful for a precise-tracking audio frequency VCO,

But of course, that's what a filter is when oscillating, or, that's what it should be. In fact, Paul Schreiber once commented that in some ways a VCF is every bit as demanding as a VCO with respect to design for that reason. It's not hard to make a VCF oscillate, but if you want it to be on pitch, that's a different kettle of fish.

I never used a 3900 to make an envelope generator, but suspect it might make a very good core for low-parts-count discrete ADSR circuits. That is a common 3900 usage in industrial context so far as I know, large-voltage slow analog circuitry with un-used sections of the chip useful as fairly-high-current-drive slow digital logic.

See the Gnome schematic for an A/R envelope.

I have a fascination with minimalist circuits that work well. That's what led to my rework of the Ody VCO. It would be fun to see how much more minimal one could get with that (the Gnome) design.

[JCJR]

So anyway that 3900 has always been an odd duck, but very interesting chip that can do things which most conventional opamps cannot. [snip] Not suited to extremely high frequencies. Fairly noisy. But what made it unique was that the inputs were basically ground referenced current mode "naked" differential transistor pair.

Right, it doesn't seem like the stuff that new designs are made from. It would be like using
3080s today, except for availability, ok, better example, like using 741s.

Yep, 741 or 1458 is a great analogy.

I don't know if a 3900 would be useful for a precise-tracking audio frequency VCO,

But of course, that's what a filter is when oscillating, or, that's what it should be. In fact, Paul Schreiber once commented that in some ways a VCF is every bit as demanding as a VCO with respect to design for that reason. It's not hard to make a VCF oscillate, but if you want it to be on pitch, that's a different kettle of fish.

Yep temp stable 1 v/octave tracking was a challenge in filters and VCOs as well.

A (possibly incorrect) reason for doubting 3900 as a promising precise-tracking audio frequency VCO--

3900 slew rate is fairly slow. Maybe not such a problem if the VCO is running 1 volt peak-to-peak or whatever. But some VCO's ran higher output voltages, where ramp wave reset slew rate might be problematic for wide-range tuning over 8 or 10 octaves. Was assuming that a vco would run at several volts peak-to-peak, but there is no law that a VCO would have to run that hot.

Perhaps the linear-to-exponential converter could be made tweakable far enough out-of-kilter to compensate for a tendency to track flat at high frequencies, because of limited reset slew rate.

[IncarnateX]

Dear Customer

Thank you for your email. We expect the first shipment of the minilogue to be in stock on 05.03.2016. However we have a very large number of backorders - these will be fulfilled chronologically.

Therefore it is unlikely that your order will be fulfilled from the first shipment. We expect the next one on 05.04.2016.

[Uncle E]

We're actually expecting another shipment of Minilogue's within the next couple weeks. It will be very small, though.

[IncarnateX]

We're actually expecting another shipment of Minilogue's within the next couple weeks. It will be very small, though.

[Sendy]

Another reason why I took the risk with buying straight away. Get that sucker while it's available. I think I pretty much got the last one from that batch.

This synth is freaking awesome

[Sequent]

Same here. Very happy with this synth so far

[3ee]

https://www.youtube.com/watch?v=Oldx5QEMSCk

[Daags]

Sequent & Sendy ... you're happy with the synth, but clearly you're doing it wrong... you need to be running this thing through oscilloscopes and spectograms with the filter closed and comparing the results with a jupiter-8 ... now THAT's how you use and ultimately enjoy a synth.

[DJ Warmonger]

https://www.youtube.com/watch?v=Oldx5QEMSCk

Great demonstration. This is how synths should be made!

[Mutant]

https://www.youtube.com/watch?v=OYGBiYUAK6g

https://www.youtube.com/watch?v=4xwKO08H6Q4

[yul]

Argh I'm debating to let go of my JX-8P to get this one I can't make up my mind. I mean I have pretty much all I will ever want out of software. It's just a question of if the Mini will be more inspring than the JX for those unplug the PC sessions...I already own a minibrute and BS2.

[Uncle E]

Argh I'm debating to let go of my JX-8P to get this one I can't make up my mind. I mean I have pretty much all I will ever want out of software. It's just a question of if the Mini will be more inspring than the JX for those unplug the PC sessions...I already own a minibrute and BS2.

The JX-8P is a truly lovely and underrated instrument, the perfect pad machine. Furthermore, for the simple fact that you won't get anywhere near what it's worth, I say keep it.

The Minilogue does have it beat in terms of versatility but they're hard to compare beyond that.

[ghettosynth]

Argh I'm debating to let go of my JX-8P to get this one I can't make up my mind. I mean I have pretty much all I will ever want out of software. It's just a question of if the Mini will be more inspring than the JX for those unplug the PC sessions...I already own a minibrute and BS2.

The JX8P is a decent pad machine, and Uncle E is right, it's not worth much. That cuts both ways though. I don't see the price shooting up anytime soon. So, the thing to consider are the advantages and disadvantages of both.

The 8P has 6 voices, the Korg 4, for pads, this is a real compromise, the 8P has 61 full size keys, the Korg has smaller keys and their are fewer of them. I'm not sure that there are many more disadvantages to the Korg.

The Korg is VCO, the 8p DCO. The Korg has a great sounding filter, I'm not as swayed by the IR305 filter which is in the later model Rolands. The korg has a great U/I, the 8p not so much.

I have a JX10, which is a 12 voice version of the 8P. They don't go for much more than the JX8p, but, they are better pad machines because of the 12 voices.

In any case, I would consider selling a JX8p, especially if I didn't have the PG-800. I think that synths like the Korg are going to put pressure on the prices of some of the less popular vintage gear.

I think that you have to decide what it is you want to do when you use the synth. If you like to program sounds, the Korg will be a LOT more fun. If you just like to choose sounds and play them, the Roland will be more enjoyable.