Did you run into noise issues? I actually haven't tried a digipot in a signal path (they do work great for other controls like LFOs and the delay time on a PT2399), but everything I've read online has told me to avoid it. I'm not hearing any in the demos so clearly it's workable!
Noise was a hard problem as well. In the end what helped us a lot was to keep the FX device in its own case and even solder the digi potis right in place where the real potis had been before. You can see that here:
https://im.static-thomann.de/pics/images/stompenberg/backsta...
The relais modules are on the outside of the case, but on the left you will see a flatband cable (digital) run inside of the case, where the digipoti modules will sit. So all analog signals never leave the original case and the metal housing shields all kinds of external interference.
The digipotis were actually one of the hardest problems for this project. Additional to the many pot values and different tapers, you need to also cover a wide variety of voltages that can even be centered around zero (it is an audio signal after all), so you need to be able to handle negative voltage. DigiPots also have a capacitance, so when you have to replace high values like 1M-Ohm you will wind up with a low pass filter.
We built a bunch of modules for common pot values and do the taper and uncommon values in software. If both sides of a poti are used, we will need to use two digipotis to simulate them.
Super interesting, thanks for taking the time to chime in! I hadn't thought about the capacitance aspect. Was noise not as much of an issue as I've been led to believe?
Many many problems (several revisions), but I cannot go into them, because fortunately I was not part of the hardware design team. Definitely nothing I would recommend as part time project.
Did you consider driving the original pots in place through servos fixed to the pots shafts through shaft extenders?
If yes, were there any drawbacks that made you discard the option?
Our main concerns were a) the conversion process would be much more complicated b) hardware would be more expensive c) the motors would not live as long as the digi-potis
They are self hosted in southern Germany and you connect via WebRTC, so if you are far away from there it will have additional latency, sorry no way around it.
I'm in Spain so probably closer than most others here on HN, the latency is really not that bad. Seems you're related to Thomann/Stompenberg, so just wanted to thank you for this service! Will certainly help me in finding pedals without having to go through the buy/sell process I'm currently doing.
They also are behind the design of Harley Benton branded instruments, which are made in China although under a decent quality control.
I have two HB 5 string basses, the former was the bare minimum I could afford to move to the 5 strings world and see how I adapted to it. That bass wasn't great but it was well set up and tuned, had a decent neck binding, the electronic was really quiet and the sound, although a bit rubber-ish and lacking some sustain, was good enough for playing in a band in which the guitarist played gear that cost 10 times more without anyone noticing.
One year later I purchased one of their HBZ-2005, which besides being a piece of beauty sounds fantastic. I paid it about 220€ years ago, before they bumped the price to about 300€ - bummer, I was considering the purchase of a spare one. Apparently it was too good to be that cheap.
My dream guitar was a Gibson Double Cut Special, because of Johnny Thunders. I finally got one for almost €3000 but hated it and returned. Then, Harley Benton released a similar model for less than €200 and it became my favourite guitar. They're amazing little instruments.
Thomann are a brilliant company, old school customer service, competitive prices, great selection. I hate that Brexit has made buying from them not worth it.
They're still managing to ship to the UK. You lose all the consumer protection (thanks, Conservative party!) and have to pay VAT and import dues (thanks, Conservative party!) but they're managing. They're still a fab company.
afaik they are mostly discouraged because of the various challenges coming with them (like zero crossing at high amplitudes, capacitance, etc), but it's not like it's impossible to deal with all of that.
