Vintage Revolution - Pedal Pro

[tnijland]

Je zag onlangs zelfs dat de lui bij Fractal Audio ook al nieuwe profiling-achtige features introduceerden voor de Axe FX 2 (of zo werd het tenminste gebracht).

Daar kan ik je mee uit de droom helpen. Ik heb samen met een kameraad geprobeerd om met 2x SM57beta mijn OD100 sound te capturen maar het resultaat leek slechts een verre benadering van het orgineel. Ik mag hopen dat de Kemper dat beter doet. Het gekke was dat ik er overigens wel een goed bruikbare sound aan overhield. Ik denk dat je deze functie moet zien als een leuke extraatje waarmee je een statisch filter maakt.

M.b..t de Pedalino moet ik gezien de aversie je gelijk geven omtrent de keuze wel of geen MIDI die niet handig lijkt uit te pakken ondanks de voordelen van een verbeterd protocol. Dat gezegd hebbende wil ik er gelijk aan toevoegen dat ik in mijn verleden het meest blij werd van een footcontroller die mij de juiste functionaliteit gaf en maakte het protocol uiteindelijk niet zoveel uit (behalve dat je makkelijk een andere controller kunt kopen). In de praktijk wordt ik juist het meest blij van een footcontroller die ik als preset & als pedal board tegelijkertijd kan gebruiken. De meeste controllers die dat goed deden waren bijna altijd proprietary. Hierbij denk ik aan een Lexicon MPX G2 R1 controller, een Line6 FBV longboard. Sterker nog, ik vond de Rocktron Midi access etc. klotedingen waar je altijd veel zoekwerk voor nodig hebt om het ding te laten doen wat jij wilt (en ik heb notabene al veel ervaring met MIDI, maar probeer maar eens een handig preset/pedalboard combinatie met midi te maken, je eindigt vrijwel altijd met een compromis). Zelfs de Axe-Fx II heeft een dedicated pre-programmed board en ondanks dat ik er ook een simpele MIDI controller op aan zou kunnen sluiten kies ik liever voor het bijbehorende MFC-101 board dat functioneel al goed is voorbereid en voor 99% al doet wat ik wil. Kortom, hoofd en bijzaken scheiden.

De Padalino is perfect gebouwd, heeft een prettige werking en schakelt supersnel. De preset/favorites keuze setlist is ook uiterst doordacht. Het control pedaal werkt vloeiend op de parameters en benadrukt de kwaliteit van de combinatie met de PedalPro. Als binnenkort de combinatie preset met pedaal board (virtual board) komt is het voor mij goed genoeg.

Zou ik de VR designers toch een extra tip moeten geven, dan zou ik voor wat meer pads gaan (ca. 2x4 stuks) waarbij de bovenste rij (iets verhoogd) de effecten schakelt en de onderste rij de presets in bank-setjes zoals het nu al werkt. Een global solo boost switch blijft natuurlijk ook altijd handig.

Amen.

[massi1234]

Triaxis is a good example of digitally controlled device. All the controls are implemented using opto resistors.
Opto resistors are great sounding components but have two main problems.
1) The resistance range between each components may vary 200-300%.
2) LDR (opto resistor) are slow components. From low resistance to high resistance, due to the dark current, the transition may take 500ms !

So LDRs are good for certain slow real time controls that do not require fast transition. (Eg. Tone, gain).
Using MIDI cc to control LDR currents is fine as long 128 levels resolution offers enough resolution (tone and gain controls)

The problem is that each technology used to control an analogue parameter (eg. digital pot, LDR) should to be selected according to their limitation and drawback.
Example:
If you try to control Tempo with LDR you will end up facing thermal drift.
If you try to control Tempo using a digital pot, you will not have enough resolution.

PedalPro is much more then LDRs and digital pots.
It is a waveform synthesizer capable of producing up to 8 modulation waveforms and real time controls that can be synchronized with a very high resolution and insensitive to temperature swings.

So if you need to span 16 bits for Tempo, 10bits for filter frequency, 8 bits for effect depths using midi RPN it would lead to a convoluted programming + latency .
Standard midi cc would be good for latency but poor from resolution point of view.

Thanks to the ADES protocol the user does not have to think about resolution and latency. He can modify the analogue parameters according to its measurement unit (eg. Hz for frequency, dB for gain, percentage for depth, BPM for tempo) and set the appropriate range without thinking about how max and min limits will be mapped.
For example with Pedalino you can set the Tempo of the tremolo to span between 100.0 BPM to 300 BPM in no time. Further you can see on the display when the expression is approaching to 200 BPM.

To conclude, Midi protocol was not designed for real time control of analogue parameters but for midi keyboards.

[peter_heijnen]

Good luck tonight Max!

I'll be serving an italian menu tonight, forza italia!

[massi1234]

There are 4 micro processors in the PedalPro!? Holy cow! Can you elaborate on that (I know programming MCU's and digital electronics so I wouldn't mind if you get really technical ;-) ).

More general I would really love to hear more on how the PedalPro works at a technical level. Why you made the choices that you did. Recently we talked about digital pots (PM) and how they do not stand up to the job, yet you do use them in the main volume. Why?

Ciao,
about the 4 processors:
When I started the architecture and the feasibility study, I had in mind always a multiple-waveform synthesizer.
This is the real big difference with rest of the digital controlled devices.
If you have an analogue pedal, the waveforms that you can generate are very limited.
Thanks to this flexible architecture, each processor can be loaded with up to 16/18 different waveforms.
So that the waveforms used for the chorus can be different for the phaser, wah, and tremolo.
Further I always want it to reproduce the compression curve of a Vary-mu (Fairchild).
So, the secret is the PedalPro is not only in the component selection but also in the way we control the waveform generators.
Keep in mind that I want it to have no limitation in number of simultaneus waveforms and the ability to synchornize tjhem all with 4 values of relative phase (0 90 180 270).
If you want to have more info, I will be happy to answer more questions on the matter.

Regarding Digital Pot and volume controls, the PedalPro has 4 ways of controlling the volume. Each of them relates to a different technology and placed in different chain position.
1) VCA voltage controlled amplitude of the compressor using compression parameter. By increasing the attack to 85ms, you can transform your compressor in a powerful volume control/saturation control (if used to drive a distortion). This VCA (compressor) is placed in the beginning of the chain. Technology matched pair transistors
2) Opto resistor changing the gain control of the boost. Range -6dB: 25dB also placed in the beginning of the chain but after compressor and pre loop. Technology LDR
3) You can also use the VCA in the Tremolo as a volume control, by activating the function FOOTC. Technology matched pair transistor
4) Main stereo volume control via digital potentiometer placed at the end.
Technology dual potentiometer

@ Peter. We need a lot of luck tonight and no catenaccio!!!

[obiwanjacobi]

Triaxis is a good example of digitally controlled device. All the controls are implemented using opto resistors.
Opto resistors are great sounding components but have two main problems.
1) The resistance range between each components may vary 200-300%.
2) LDR (opto resistor) are slow components. From low resistance to high resistance, due to the dark current, the transition may take 500ms !

So LDRs are good for certain slow real time controls that do not require fast transition. (Eg. Tone, gain).
Using MIDI cc to control LDR currents is fine as long 128 levels resolution offers enough resolution (tone and gain controls)

The problem is that each technology used to control an analogue parameter (eg. digital pot, LDR) should to be selected according to their limitation and drawback.
Example:
If you try to control Tempo with LDR you will end up facing thermal drift.
If you try to control Tempo using a digital pot, you will not have enough resolution.

PedalPro is much more then LDRs and digital pots.
It is a waveform synthesizer capable of producing up to 8 modulation waveforms and real time controls that can be synchronized with a very high resolution and insensitive to temperature swings.

So if you need to span 16 bits for Tempo, 10bits for filter frequency, 8 bits for effect depths using midi RPN it would lead to a convoluted programming + latency .
Standard midi cc would be good for latency but poor from resolution point of view.

Thanks to the ADES protocol the user does not have to think about resolution and latency. He can modify the analogue parameters according to its measurement unit (eg. Hz for frequency, dB for gain, percentage for depth, BPM for tempo) and set the appropriate range without thinking about how max and min limits will be mapped.
For example with Pedalino you can set the Tempo of the tremolo to span between 100.0 BPM to 300 BPM in no time. Further you can see on the display when the expression is approaching to 200 BPM.

To conclude, Midi protocol was not designed for real time control of analogue parameters but for midi keyboards.

Sorry, I still don't get it

But I wont bore every one with going on about it.

Ciao,
about the 4 processors:
When I started the architecture and the feasibility study, I had in mind always a multiple-waveform synthesizer.
This is the real big difference with rest of the digital controlled devices.
If you have an analogue pedal, the waveforms that you can generate are very limited.
Thanks to this flexible architecture, each processor can be loaded with up to 16/18 different waveforms.
So that the waveforms used for the chorus can be different for the phaser, wah, and tremolo.
Further I always want it to reproduce the compression curve of a Vary-mu (Fairchild).
So, the secret is the PedalPro is not only in the component selection but also in the way we control the waveform generators.
Keep in mind that I want it to have no limitation in number of simultaneus waveforms and the ability to synchornize tjhem all with 4 values of relative phase (0 90 180 270).
If you want to have more info, I will be happy to answer more questions on the matter.

Regarding Digital Pot and volume controls, the PedalPro has 4 ways of controlling the volume. Each of them relates to a different technology and placed in different chain position.
1) VCA voltage controlled amplitude of the compressor using compression parameter. By increasing the attack to 85ms, you can transform your compressor in a powerful volume control/saturation control (if used to drive a distortion). This VCA (compressor) is placed in the beginning of the chain. Technology matched pair transistors
2) Opto resistor changing the gain control of the boost. Range -6dB: 25dB also placed in the beginning of the chain but after compressor and pre loop. Technology LDR
3) You can also use the VCA in the Tremolo as a volume control, by activating the function FOOTC. Technology matched pair transistor
4) Main stereo volume control via digital potentiometer placed at the end.
Technology dual potentiometer

I think syncing waveforms is great but do you need an individual processor for each waveform output? What MCU do you use (are they small)?

Thanx.

[peter_heijnen]

@ Peter. We need a lot of luck tonight and no catenaccio!!!

If spain plays that well, even all the luck in the world isn't enough. They played as real masters, italy was second best this year!

Quality does it!

[massi1234]

Spain was by far superior.
At least now I can concentrate on the software upgrades
Take care Peter,

[massi1234]

Sorry, I still don't get it

I think syncing waveforms is great but do you need an individual processor for each waveform output? What MCU do you use (are they small)?

Thanx.

Ciao,
when the aim is to have absolute zero noise addded on your effects, the clock frequency of your processor becomes a seriuos issue.

As a digital designer you may think to go up with the clock frequency so that the time sharing of tasks is not a issue and it can be neglected.

If you go up with the clock frequency (>20 MHz), the crosstalk + EMC + radiation will propagate through the air and get in to your analogue circuit.
Even if you make the best layout and keep all the device as close as possible, every processor pin will be a source of noise and will get in your analogue modulators though your digipot,VCA etc...

Since for me silence (no noise) is a MUST, I choose the higher clock frequency (20MHz) that allows for -130dBu of isolation between analogue and digital section. Thus in order to generate multiple waveforms I need to parallel multiple processors.

In this way you achieve ultra low noise, neglectable latency, and phase lock between each waveform.

[obiwanjacobi]

Thanx. I do get that.

[tnijland]

Mooi technische verhaal Max maar waar het uiteindelijk om draait is de sound.

ik heb dit weekend gelukkig weer wat tijd gehad om eens lekker te spelen met de Pedalpro. Ik blijf me iedere keer als ik het apparaat aanzet verbazen over de kwaliteit en ben er inmiddels ook behoorlijk enthousiast over. Wat me het meest opvalt is dat de effecten alleen al een puurheid bevatten en daardoor helemaal niet meer uitnodigen om er nog een extra effect toe te voegen. Less is more is hier zeker van toepassing. Van ieder effect zijn er ook meerdere presets die subtiel van licht naar zwaardere en andere modulatie veranderen. Er zit er altijd wel eentje bij die nog mooier is dan de vorige.

Ik hou zelf enorm van de meer standaard vintage effecten zoals bijv. phaser, tremolo, chorus en delay en iedere keer als ik een tijdje met een preset speel effect kan ik me niet onttrekken aan het gevoel dat ik op het beste effectpedaal van de wereld speel. Er is veel zorg besteed aan het ontwerp van dit apparaat en ik zou bij deze Max dan ook een welgemeend compliment willen geven voor het maken van zo'n prachtige effectunit.