Double Bass What is digital? Amp classification discussed

[Ric Vice]

Where I would define "digital" is if the amplifier uses digital processing to implement the controls. Everything else is rather mundane, but digital controls are interesting. Virtually any control function could become a matter of writing software instead of designing circuitry. The knobs are simply digitized and used to compute control parameters for the software. This is really where I think the benefits of digital would accrue.

F Deck,
Very nicely done indeed. Personally, even if the preamp and signal processing were digital. I would prefer an amplifier that used a "traditional" user interface in it's design as you suggest with knobs. I find a computer style interface with presets and menus very difficult to access and tweak in real time. In live performances they can actually create more problems than they solve IMHO.

Ric

 

[Tom Baldwin]

This is all quite fascinating, even if for me in a kind of trivial way. Thanks to everyone for all the input!

Where I would define "digital" is if the amplifier uses digital processing to implement the controls. Everything else is rather mundane, but digital controls are interesting. Virtually any control function could become a matter of writing software instead of designing circuitry. The knobs are simply digitized and used to compute control parameters for the software. This is really where I think the benefits of digital would accrue.

Now that you mention that, don't the new powered cabs from Bergantino operate this way? Except that there are no knobs to control the chip - it's just preprogrammed and you get what you get.

 

[fdeck]

This is all quite fascinating, even if for me in a kind of trivial way. Thanks to everyone for all the input! Now that you mention that, don't the new powered cabs from Bergantino operate this way? Except that there are no knobs to control the chip - it's just preprogrammed and you get what you get.

That's right.

 

[fdeck]

F Deck,
Very nicely done indeed. Personally, even if the preamp and signal processing were digital. I would prefer an amplifier that used a "traditional" user interface in it's design as you suggest with knobs. I find a computer style interface with presets and menus very difficult to access and tweak in real time. In live performances they can actually create more problems than they solve IMHO.

Ric

I also prefer a tactile interface -- one of the reasons why we play upright bass, after all. You can control a knobby interface in the dark, or adjust a control without looking away from... whatever you are looking at.

One possibility (I think the Ashdown Superfly was of this nature) is that you set it up at home with an elaborate PC interface, assign the knobs to desired control functions, then just use the knobs at the gig.

 

[seanm]

The RNC from FMR Audio has an analog signal chain with a digital interface. However, the digital interface is controlled via knobs.

From the FMR Audio site:

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[drurb]

I realize that this is somewhat of an aside but it seems to fit the flow of the thread. It is often the case that digital processing of a signal is not the best alternative. I mention this because many circuits involve the A/D conversion of signals, after which the processing/conditioning is in the digital domain, after which the signal is passed through a D/A converter. Now suppose you want to attenuate the signal (reduce its level). One might think that it is a simple matter of scaling the bits down. Well, it is, but reducing level in such a manner also reduces the precision of the sampling and increases the relative amount of noise. The preferred way to accomplish this is via a good old resistor network or a change in the gain of analog device (assuming signal-to-noise ratio is properly maintained). This is, in fact, the way laboratory devices actually work. So it's actually digital control of analog devices and an analog signal. Maybe no one here cares about all of this. I mention it, however, because when you are choosing a device either for sound reinforcement or recording, it's worth checking into how the device actually works.

Sorry if this is too geeky a post.

 

[bassbrock]

I realize that this is somewhat of an aside but it seems to fit the flow of the thread. It is often the case that digital processing of a signal is not the best alternative. I mention this because many circuits involve the A/D conversion of signals, after which the processing/conditioning is in the digital domain, after which the signal is passed through a D/A converter. Now suppose you want to attenuate the signal (reduce its level). One might think that it is a simple matter of scaling the bits down. Well, it is, but reducing level in such a manner also reduces the precision of the sampling and increases the relative amount of noise. The preferred way to accomplish this is via a good old resistor network or a change in the gain of analog device (assuming signal-to-noise ratio is properly maintained). This is, in fact, the way laboratory devices actually work. So it's actually digital control of analog devices and an analog signal. Maybe no one here cares about all of this. I mention it, however, because when you are choosing a device either for sound reinforcement or recording, it's worth checking into how the device actually works.

Sorry if this is too geeky a post.

I wonder if this is how the SansAmp PSA 1.1 works.

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Tech 21 describes it this way:

To program, you just tweak the knobs and save. Parameters are adjusted in real time with traditional analog potentiometers. The digital memory stores the positions of the pots. With 256 incremental steps, each rotary control increases and decreases in a smooth linear fashion.

Before this thread, the whole "digital front-end" controlling an "analog back-end" made absolutely no sense to me.

 

[drurb]

I wonder if this is how the SansAmp PSA 1.1 works.

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The link describes it as a completely analog signal path. That would mean no A/D-D/A involved.