I'm sure it'll come to that; I programmed in LabView, which was basically a data flow connection diagram with functions picked from a pallette. Need analog in from a USB connected ADC? Just pick the function, tell it the sample rate, gain etc. Need a filter? ALL of them were available, in fact any mathematical function you could think of was available.
I've seen data flow diagram programming environments that werent LabVIEW and their patent cant last forever. It will come to that, just a matter of time. Forget MOV R0, R1+ or having to deal with anything at assembly level.
I think that DSP is becoming more accessible to DIY as well, if someone is really interested in getting a good quality hardware platform there are kits available on the market. After that it`s a question of either doing low level coding or working in a GUI environment..or a combination of both. Not everyone`s cup of tea though..I spend too much time at work in the digital world, and coding in assembly language..well lets just say it has been decades!
On a pretty basic level, but the Spin FV1 DSP has a lot of built in features for I/O that could integrate pretty well into a guitar amp preamp.
There are some examples of distortion coding and limiter coding that could be of interest. There is a GUI that is available called Spin-CAD that you can string together blocks of code as modules. I think for the wave shaper menu they have cubic distortion function, and Keith Barr wrote some example code (on Spin Semi website) for soft limiting. Cubic distortion curve would be odd order harmonics, but with some digital offsetting of the signal you can bring in even harmonics. You could also code for a squared function that would give principally even harmonics, and soft limit when the signal goes over a certain level.
There are some examples of distortion coding and limiter coding that could be of interest. There is a GUI that is available called Spin-CAD that you can string together blocks of code as modules. I think for the wave shaper menu they have cubic distortion function, and Keith Barr wrote some example code (on Spin Semi website) for soft limiting. Cubic distortion curve would be odd order harmonics, but with some digital offsetting of the signal you can bring in even harmonics. You could also code for a squared function that would give principally even harmonics, and soft limit when the signal goes over a certain level.
I visited their website - oh, how I would have loved it 20 years ago. News entries in 2007, 2008, 2009? I wonder what happened to them; no yearly cadence of chip "spin"?
Sadly Keith Barr the co-founder of Spin and designer of the FV-1 passed away in 2010. Chip is still in use and production as far as I know. Keith Bar also co-founded MXR and Alesis. There are some newer all-in-one DSP platforms that could be a bit more pricey for DIY though.
With this chip I designed my chorus, reverb and echo effect pcbs using the factory presets. Did anyone here create own custom programs?
I was going to order up some FV-1 for a couple of projects I had in mind, then the pandemic hit..they went out of stock in most places with very lengthy lead times. Mind you there were a lot of basic electronic components that went into back-order too. During that time I ended up designing and building a couple of FET based preamps/boosters, because I had a quite an assortment of JFETs and Mosfets already on hand. One of the designs ended up being pretty good, according to my ears and a few people who tried it ended up buying them from me. The other project is more of a full preamp which I discussed a little on this thread. Once I get the details ironed out on that one, I will probably post it up in this forum as a new thread.
What about newer class d amplifier chips? Some of them have DSP and might be possible to use digital out for recording on some of them?
Cheers!
Cheers!
That may be very useful for cabinet simulation. If you have a module that can do both DSP filter function and Class D amplification, usually the DSP is there to flatten out speaker responses, but that may be a good way to "un-flatten" a speaker designed for full range audio, to get a guitar amp speaker response.
Finally got mine. So far, pretty disappointed. I so wanted it to just be right.
I'm hoping I can blame the monitors (weeny Behringer 3030As) as the "marshall" channel certainly doesn't match the valve version + 1 x12", even at low volumes. Likewise the other amps I know are a bit Meh. Not bad like a Zoom pedal, just a bit lifeless.
And I don't understand the out of the box set up: why are all the channels set to different gains ? Very frustrating!
I need to give it another go (and probably adjust all the presets so I can compare apples with apples between channels ), particularly with a decent speaker + a few dozen clean watts.
Any suggestions on how to get this to sing?
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Bit of an update: I set up the Flamma with 60W of hifi amp into a (sealed) 1x12 with a typical guitar amp speaker (Celestion G12-70MD).
A major step in the right direction!!! (Insert happy dancing penguins here). It shouldn't have made that much of a difference but it did. There's something going on there above and beyond just the cabinet size/shape. It's got some life at last & channel 4 sounds mostlly like my Marshal clone, even if I haven't gotten my head around mapping the knob settings, (which is quite hard as you don't know where they're set until you change them. And where's the presence knob gone 😉 )
Phew!
Next I'm going to go through all the presets and adjust gain & volume so that I'm not going from eh? to blowing-ones-head-off swapping between amps & channels. Then, time for some serious knob twiddling. Oh, and I'll need to add a spring reverb after and vibrato pedal before.
A major step in the right direction!!! (Insert happy dancing penguins here). It shouldn't have made that much of a difference but it did. There's something going on there above and beyond just the cabinet size/shape. It's got some life at last & channel 4 sounds mostlly like my Marshal clone, even if I haven't gotten my head around mapping the knob settings, (which is quite hard as you don't know where they're set until you change them. And where's the presence knob gone 😉 )
Phew!
Next I'm going to go through all the presets and adjust gain & volume so that I'm not going from eh? to blowing-ones-head-off swapping between amps & channels. Then, time for some serious knob twiddling. Oh, and I'll need to add a spring reverb after and vibrato pedal before.
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I am working on my fourth JFet booster building for a friend who plays bass. He has an Ampeg "real amp" along with the Ampeg SCR-DI floor pedal preamp that is solid state. He is using the pedal on some gigs where he can't bring in his big amp, just plugging in to the mixer board.
The Ampeg pedal has a built-in Scrambler circuit for distortion, and he doesn't like that part. He just wants to add a bit of warmth and grit. So the Jfet boost with the adjustable soft limiting is what we are going with. The preamp part of the SCR-DI works well, but as we have discussed it sounds too clean and clinical. With the JFet booster in front of the preamp, the gain can be adjusted, then lower the output level so it doesn't overload the Ampeg input. We don't want to overdrive the preamp input in this case. There will be a switch to select the soft limiter. One thing to note is that e-bass guitars generally have a lot more signal output than e-guitars. Some very big peaks can happen.
The Ampeg pedal has a built-in Scrambler circuit for distortion, and he doesn't like that part. He just wants to add a bit of warmth and grit. So the Jfet boost with the adjustable soft limiting is what we are going with. The preamp part of the SCR-DI works well, but as we have discussed it sounds too clean and clinical. With the JFet booster in front of the preamp, the gain can be adjusted, then lower the output level so it doesn't overload the Ampeg input. We don't want to overdrive the preamp input in this case. There will be a switch to select the soft limiter. One thing to note is that e-bass guitars generally have a lot more signal output than e-guitars. Some very big peaks can happen.
One time they asked me to evaluate an early Tek digital sampling oscilloscope. I brought my bass into work. It was fun capturing the biggest peak I could get. This was 35 years ago, so all I can remember was that the bass (Gibson EB0 - cant remember if I had the Dimarzio in it yet) put out way more peak voltage than any audio input was designed to handle. For sure multi 10s of volts...
I have been planning to put some Zener diode clamps in front of the first Jfet stage, just as a protection against any peaks such as that! Cheers
What about adding a series resistor of 1 to 10 ohms (and "appropriate" power rating, 10w or more)? Tube amps have higher output impedance (dunno what it would be offhand)/low damping factor, and it surely affects tone. The solid-state Peavey Rage 158 has a feedback circuit to raise the amp's output impedance, they wouldn't do that if they didn't think it made a difference.
Better look at the schematic of that Peavey amp. The feedback is from a small value (I forget, one ohm or less?) resistor in series with the speaker's ground wire, it makes it more of a current-drive amp. The easiest thing is just put a larger resistor in series with the speaker.
If you do that the "larger" series resistor will have a huge voltage drop across it, the output power will be reduced and most of it will be wasted in that series resistor.
"Mixed mode" feedback is more sensible because voltage drop and power dissipation in the low-ohm "current sampling" resistor remain low while ratio of feedback, established with a circuit that does not "load" the amp, adjusts how much effect the "current feedback" will have.
"Mixed mode" feedback is more sensible because voltage drop and power dissipation in the low-ohm "current sampling" resistor remain low while ratio of feedback, established with a circuit that does not "load" the amp, adjusts how much effect the "current feedback" will have.