Why isn't there more digitally controlled analog stuff?

[marcelomd]

Hi,
Is this the right place to ask this?

I was thinking here about the Marshall JMP1 and Mesa Triaxis. Why isn't there more stuff like this? Tube sound with digital control is so neat.

I guess no one needs 100 patches. And musicians are suspicious of anything digital.

[garcho]

I think around here, there is a sentimental attitude to "DIY" from a particular historical snapshot that discludes MIDI and digi controls. That's just the legion of fuzz builders, though. Check out the digital section (just stating the obvious) and plenty of other builders around here doing digi stuff, just not compared to how many are asking about germanium pinouts and if their JFETs are fake.

[Ripthorn]

It's also much more difficult to write all your own proprietary code for the digital control than it is to reproduce something from a widely available schematic and make just a couple of tweaks. I love digitally controlled analog stuff, we have another thread dedicated to it in this very forum section. Lots of great thoughts and ideas are out there.

[toybuilder]

Tube sound with digital control is so neat.

I guess no one needs 100 patches. And musicians are suspicious of anything digital.

I don't know why there isn't more digitally controlled analog stuff now, but I know that stuff was popular in the 1990s. Digitech and Alesis both had some pretty popular products.

I have a Digitech Twin Tube from 1991. It's got some digital effects like delay, flange, and chorus. It's also got digitally controlled tubes and digitally controlled analog effects like compression, distortion, and EQ. Pretty cool unit. Also, 120 user defineable patches!

[Fancy Lime]

Hi,

I think this may, to a certain degree, have to do with when and how the whole DIY pedal thing started to become as popular as it is today. I blame the internet. Unfortunately that was in the 90's when the first generation of affordable digital effects were on the market. And a lot of those were, lets say "underwhelming". That goes especially for the overdrive/distortion/fuzz sounds, which are easy to get right analog but quite tricky to do digitally without sounding a bit ...meh. Reverbs, delays and so on were good almost from the get-go in the digital multieffects. So along came the "boutique builders" and built super expensive germanium fuzzes from 60's schematics that did indeed sound better than the fuzz from a Zoom 505 Guitar. And then people realized that they can buy 2$ worth of parts, take their granddads soldering iron and build something in half an hour that certain boutique builders (not naming names here, there are too many) charge north of 300$ for. And that's where it stops for most people. They build their super duper dream fuzz and their happy.

But I think that among the people who stick with this hobby for longer and geek out about it more, there is no shortage of examples for digitally controlled analog or fully digital projects. Me personally, I find analog electronics more interesting to design than digital. But that only goes for the audio path and only because I do a lot of coding for my job, so analog electronics are my escape from more coding. I have been tinkering a bit with digitally controlled analog effects and even started a thread here some time ago. Was quite interesting:
https://www.diystompboxes.com/smfforum/index.php?topic=122337.0

I need to invest more time to exploit the full potential, though. It takes more thought and original developing than slightly tweaking yet another big muff, that's for sure.

Cheers,
Andy

[marcelomd]

I actually found about this stuff (Triaxis, JMP1, etc) while looking into clean power amps for a preamp project.

Speaking about commercial products, I imagine the target demographic would be studio people, or guys who play 5 hour sets of covers in events. They need to have every tone possible. Then came good enough digital emulation, Kemper, Fractal, or even a Mac with Plugins and the market vanished. Just a hunch. I really don't know.

For us, DIYers, I understand it can be too costly and involved to simply play with. One project/effect/tone and ok, done, next. I get a lot of satisfaction from understanding simple circuits. But also there is an element of creating YOUR sound. Which is usually comes in no more than 3 flavors (clean, crunch, solo). No need for 100 patches.

I find analog electronics more interesting to design than digital. But that only goes for the audio path and only because I do a lot of coding for my job, so analog electronics are my escape from more coding.

I used to write embedded software (device drivers, protocols for telecom equipment, etc). Last thing I want is to write a device driver in my free time. Analog stuff keeps my hardware skills in shape and takes my mind off code. That's why I'm not touching DSP. Had too much of that already.

A simple controller for switching things in and out of audio path is ok tough.

[roseblood11]

This thread is about digitally controlled analog effects:
https://musikding.rocks/wbb/index.php/Thread/419746-Digital-gesteuertes-FX-Interesse-an-einem-Forumsprojekt/?pageNo=5

[Ripthorn]

My sound involves tons of different flavors of stuff, so I love to have all kinds of presets and patches. That might be why I have 8 drive pedals along with my Boss MS-3 and a 5 loop, midi controllable switcher that I designed and built and wrote all the code for...

[amptramp]

I think a number of people have issues with digital clock noise and the trouble they have eliminating it.  If you have a PIC / Arduino / Raspberry Pi, you have a clock superimposed on the internal DAC and ADC signals.  You also have to program it and although these devices allow you to generate a schematic very early in the design, making it actually do something useful requires software that works and software is difficult.  Random logic (CMOS or TTL gate-level design) does not allow you to generate a schematic as easily but once you do, you have the finished product and possibly no clock noise.

I like the idea of a volume control based on a DAC0808 or DAC1208 using the multiplying DAC function to attenuate the signal by a digital factor while keeping the signal analog.  This is what I consider to be digitally controlled analog as the thread title says.

A lot of people do not need digital control.  If you have a potentiometer, you can remember or mark where it should be set.  What kind of input would you use for a digitally-controlled signal?  It would have to be stored parameters.  I could ask the complementary question - what is the benefit of digital control when you can just turn a pot or flip a switch to get the effect you want?

[quad4]

An analog potentiometer provides three things:
- A variable resistance
- An always available user input mechanism to change the value
- An always available display of the current value

A digitally controlled resistance only provides the first. 

If you want all three,  you'll also need an encoder (more expensive than a pot) and an indicator (more expensive and takes more space than a knob pointer).   

From there you quickly descend into menus and deep editing/viewing which is not "always available" for all settings at once.  This changes the UI and the feel of the device.

[I also agree with the prior comments.]

[Mark Hammer]

Chase Bliss uses the PWM outputs of PICS to control vactrols in their pedals.  This provides a number of advantages. 
First, it permits more variety and complexity in modulation.
Second, it permits storing of settings and presets. 
Third, it permits easy assignment of expression-pedal control to different parameters and in different directions.
And, not to be overlooked, it takes up much less space than what an all-analog version would require.

The Electric Druid and MoltenVoltage chips have also been implemented in pedals that offer digital control of an analog signal path.  And pretty much anything that offers tap tempo is also using digital control, as is anything that offers multiple modulation waveforms.

[marcelomd]

Just found these guys:

http://www.distopiksound.com/ . They create custom digital controllers for gear. Then they hook said gear to a web app, https://mixanalog.com/, which lets you mix and process audio over the internet.

Really really awesome.

How do they do it?

[ElectricDruid]

"Why isn't there more digitally-controlled analog gear?"

I think the answer is at least partly "because it's more complicated than either analog-only or digital-only gear".

There was a time when digital was first coming in when it had the power to provide memories and settings and so on, but there wasn't the processing power or know-how to do full digital effects, so there was a brief period of digitally-controlled analog. The same thing happened in the synth world. There was only five years between the 1978 introduction of the Prophet 5 (the first fully programmable polyphonic analog synth) and the 1983 introduction of the  fully-digital Yamaha DX7. The DX7 looked at the time like the end of analog synths and the beginning of digital (although we know now it didn't work out like that, it still killed off practically every analog synth builder of that era).

It's easy to build analog circuits, since everywhere where you want something variable, you just stick a pot in! Simple! In fact, as some/many people here might know, it's often difficult to stop yourself putting a pot on every single option and finishing up with a knob-fest instead of a pedal.
For digital, its simple because as RG says "It's a simple matter of programming!". It is often the case that the hardware can be very simple - a ADC input, a processor, and a DAC output. You don't need much more than that. The rest is indeed just programming.

Digitally controlled analog is a whole other ballgame. You've got to develop good-sounding and versatile analog circuits. Then you've got to work out how to control those using one/some/all of the available technologies, including but not limited to PWM+vactrols, multiplying DACs, DACs+VCAS, digipots, and analog switch arrays. The final stage is to then do the Digital side that will control all that mess, and read the interface and provide feedback to the user. Ideally without making the whole experience painful to use, avoiding the typical pitfalls of "painting the hallway through the letterbox" and "menu diving to 200m without oxygen".

All that said, digitally controlled analog synths have made a massive comeback because they offer the best of both worlds - the flexibility and control of digital coupled with the power and sound of analog. The same can be true of effects, so I wouldn't be surprised to see some more things in this line in the next few years, especially with the sudden arrival of many analog audio chip options (Coolaudio, Alfa, Sound semiconductor) which didn't exist a few years ago.

[bartimaeus]

I think digitally-controlled analog is the best of both worlds. But for my own uses, it usually isn't worth the time to work out how to digitally control all the parameters on a drive pedal I'm building, compared to just taking photos of my favorite settings. For something like a Memory Man clone, you're getting towards a level of complexity where digital control seems justified. But it also takes even more time to wire that up for digital control, and usually if the pedal is working correctly I just want to start playing. More complexity = more time, and sometimes it's just not worth it.

[amptramp]

The only use I could see for digitally controlled analog is if you are at a gig and you don't want to set each control individually between songs.  You could just have a bunch of settings stored for song 1, another set for song 2 etc. but who does that?  Most people leave the settings unchanged throughout a gig and if they do change something, it's usually by hitting a stompswitch to add or cut certain effects.  The added complication of going digital and the added noise with clocked CPU's does not add value to the musician's equipment for the vast majority of people who never change their settings during a gig.

[ElectricDruid]

The only use I could see for digitally controlled analog is if you are at a gig and you don't want to set each control individually between songs.  You could just have a bunch of settings stored for song 1, another set for song 2 etc. but who does that?  Most people leave the settings unchanged throughout a gig and if they do change something, it's usually by hitting a stompswitch to add or cut certain effects.  The added complication of going digital and the added noise with clocked CPU's does not add value to the musician's equipment for the vast majority of people who never change their settings during a gig.

I don't think that's quite fair. Most of the reason almost no-one changes settings during a gig is because it's *hard* to do that and it involves tweaking every bl**dy thing at your feet for two minutes between tracks. Not great. It's the same reason keyboard players in the 1970's travelled with about half a dozen keyboards (one organ, one electric piano, one clavinet, a couple of monosynths set to different lead sounds, a string synth, etc etc. - how many could you afford?) As soon as it became practical to have all of those sounds instantly switchable in one instrument, that's what people chose to do. Switching pedals in and out to get different tones is a "budget" version of having programmable presets on your pedalboard.

Perhaps people wouldn't need three or four drive pedals on their board if they could actually have a different knob settings for every song at the touch of a button? Or they wouldn't need to add a boost in front of it for the solo, because they could just press the button for the "solo" preset that turns up the drive on the pedal and tweaks the tone controls instead.

[cloudscapes]

I completely agree with ElectricDruid.

Plenty of great reasons to do it! Presets are just scratching the surface of its potential. Stuff like digital lfos/wavetables can add complex modulation to your delays/flangers/filters/tremolos that are way too complex to do with an analog circuit. It's difficult to completely run out of ideas if you expand the creativity of your effects beyond your traditional three-knobbed fuzzes and simple delays. So what if it's niche? There's also tap-tempo as well sequencing.

MCU clock noise isn't the biggest issue if you're careful with decoupling, star-grounding, ground planes, where you route your traces.

There's a difficulty curve, but you can learn it in time without even a minute of formal electrical engineering training.

I started with humble basic-programmed stamps and 8bit MCus like most everybody who do digital, to control analog circuits. And moved on to 32bit to do both control/modulation and sampling. Now I'm sort of (slowly) working on a digital/analog hybrid polysynth. Lots and lots of digital control of VCF/VCA chips in that.

[Ben N]

After putting some thought into making a digitally controlled analog overdrive with MIDI input (PC), I saw [urlhttps://www.elektron.se/products/analog-drive/]these[/url] on blowout and ordered one. (Don't have it yet.) I expect it to knock 3-4 dirtboxes off my board.

[garcho]

Presets are just scratching the surface of its potential.

So true. They're also more complicated than some other digi stuff in guitar pedals. Maybe if more of us realize the PT2399 is digital, some of the fear will subside. There doesn't seem to be any shortage of projects around here using that IC. Digital doesn't have to mean designing a GUI. It doesn't even have to include coding. Think of all the builders around here make completely fine pedals without understanding much of the electronics. I imagine there will be more digi controlled analog projects bouncing around here in the future once someone who knows more about coding, digi pots etc., makes a good entry level DIY project that people can build without having to understand the nitty gritty.

It's the same reason keyboard players in the 1970's travelled with about half a dozen keyboards

and a half dozen techiess and roadies

As soon as it became practical to have all of those sounds instantly switchable in one instrument, that's what people chose to do.

DX-7, the Grim Reaper. Guess what the 'D' stands for? Think of all the gigs that happened because some dude could schlepp a DX on the train.

[Ripthorn]

I imagine there will be more digi controlled analog projects bouncing around here in the future once someone who knows more about coding, digi pots etc., makes a good entry level DIY project that people can build without having to understand the nitty gritty.

I've got couple just such projects that I am finishing up that I will be posting full documentation on. No reason to be scared, there are so many great resources now!