-10dB or -20dB Pads enough?

[rumblinbass]

Separate sensitivity inputs is generally identical circuit-wise to inserting a pad, just looks different from the outside.

I don't know why you would think series resistance is bad, there are only 2 ways to use resistance in any circuit... series and parallel, both can be good, bad, and/or necessary depending on the circuit.

I don't typically design for musical instrument applications.

 

[KJung]

So, have two knobs to control the gain on the input (as most amps already have one knob to control input gain)? I've read all the posts here and I'm still unclear on how the one knob would be different than the other knob.

And, actually, I said most amps already have one knob to control input gain, but don't they actually ALL have a knob for that. It's just some amps that don't also have a Master Volume knob, which controls something in the output stage versus the input. Like my vintage SVT, for example. It just has one volume knob (per channel), but that knob really controls input gain, right?

See Andy's post. There are a number of reasons. However, I'm with you. For the vast majority of players, a pad switch, an 'active input', or a 'variable pad' in addition to a well designed gain control is a useless option.

I do like the 'gain/volume/master' design of the Genz circuit, but again, for those who don't massively crank their gain for overdrive, not that useful.

So, I guess, in general, +1. A well designed audiotaper gain control is going to satisfy virtually every player with any type of bass for the most part.

Edit: Per your single knob edit, yes, back in the day, you had no choice other than have massive volume if you wanted to overdrive the preamp for some grind and grit. I remember jumping for joy when guitarists started getting Marshall's with a master volume control. With bass, if you want a relatively clean tone, +1, more of a 'signal/noise' sort of thing than anything super valuable.

 

[tech21nyc]

Examples of boards that have this?

I've been between bands for a little while now, so I haven't used my Presonus StudioLive board in a while, but I don't remember it having that. It just has a gain knob at the input and then a channel fader for the output. And my previous board, a Yamaha analog board was the same. And the Mackie boards I've looked at are also the same setup.

I think.

The Presonus as well as many Mackie boards can be set to pad the input via the input trim. The Presonus can be set for -16/-20dB, I think the Mackies are -15/20dB depending on the board.

 

[KJung]

I enjoy this topic, so one more point to reinforce one of the reasons Andy posted for needing a pad switch with a good dose of attenuation in some cases. For those who aren't 'gear heads' (i.e., kids at Guitar Center or whatever), there is a lot of 'listening with your eyes' going on. How many times have we heard a young player or one of our students say, that 'x brand' amp kicks **s. I had the master on 9 o'clock and it was slammin'.

Many times, players have reviewed amps with very nicely designed non-linear gain and/or master pots/circuits, and reported, 'this amp seems underpowered'. They didn't realize that some amps (some of the Genz models, the Glock stuff, some of the EA stuff) have pots that allow for very even, linear like increases over almost the entire range of the control (the non-linear way we hear volume increase results in the somewhat counterintuitive situation where you need a 'non-linear' gain/master pot taper to result in a more linear relationship between knob position and perceived volume). The bad news in a marketing sense is the amps won't get loud until those pots are cranked to a high level.

So, amps like some of the Mesa stuff, the GK stuff and others, that have a much more linear pot design results in most of those amps' volume to be achieved at very low gain/master settings. If you play that game as a company, then you actually need a secondary pad control so that the poor guy with gorilla technique and/or a hot output bass, doesn't go from 'off to blazing' within the first 10% of the gain or master taper.

 

[agedhorse]

The Presonus as well as many Mackie boards can be set to pad the input via the input trim. The Presonus can be set for -16/-20dB, I think the Mackies are -15/20dB depending on the board.

This is more common when the smallest possible control surface is used, the drawback (and a major one for some users) is that the mixer can not handle high level inputs that are common in the pro world. It also compresses all of that gain adjustment range into a fixed amount of rotation leading to touchy adjustments. It's not an issue with a digital console that uses a continious rotary encoder in place of a 270 degree pot as the software will control gain and pad as needed automatically (think Yamaha M7's head amp gain switching).

Interesting historical note, Greg Mackie's early Tapco mixers included a design feature called "auto pad" (IIRC) that adjusted volume and gain together so the scaling was proportional to desired level. This came at a small noise penalty, though a great concept for the intended application.