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-10dB or -20dB Pads enough?

rumblinbass

rumblinbass

Aug 22, 2003
1,118
196
Wimberley, TX
#1
Seems like most preamps have 1, maybe two, Pad settings. IME, -10 and/or -20dB seem to be the most prevalent.
Is that adequate? Would you like to see more settings? For example, -6 to -18dB in 3dB steps or possibly continuously variable with a pot. Thoughts?
 
#3
Pads, volume controls and gain knobs tend to all do the same thing to the signal, except pads are fixed attenuation and that sometime the gain control actually changes the gain of a stage.

I agree that a fixed pad is only really needed if you have a really hot bass and the first preamp stage doesn't have the headroom to give you the sound you want.
 
#4
Many amps have both a Gain knob along with an input pad switch.

I agree: only use the input pad if absolutely necessary. On a cheap amp, the pad will suck tone. I'm skeptical this is true on quality amps, but IME a quality amp should handle most basses (including actives) without the use of the pad.
 
#5
I had a GK RB700 and I liked the way the Pad worked. The input stage had a fixed gain (+20dB I think). The pad was merely 20dB less gain. I liked that because for Signal-to-Noise performance you want as much gain as far up the signal chain as possible (without clipping of course). I generally don't like passive attenuation pads because they degrade noise performance, particularly with high impedance inputs.
 
#6
mrmills said:
Pads, volume controls and gain knobs tend to all do the same thing to the signal, except pads are fixed attenuation and that sometime the gain control actually changes the gain of a stage.

I agree that a fixed pad is only really needed if you have a really hot bass and the first preamp stage doesn't have the headroom to give you the sound you want.
Click to expand...
Fuzzbass said:
Many amps have both a Gain knob along with an input pad switch.

I agree: only use the input pad if absolutely necessary. On a cheap amp, the pad will suck tone. I'm skeptical this is true on quality amps, but IME a quality amp should handle most basses (including actives) without the use of the pad.
Click to expand...

What that pad does is change the impedance on the input, which does effect your tone.
 
#7
Fuzzbass said:
Many amps have both a Gain knob along with an input pad switch.

I agree: only use the input pad if absolutely necessary. On a cheap amp, the pad will suck tone. I'm skeptical this is true on quality amps, but IME a quality amp should handle most basses (including actives) without the use of the pad.
Click to expand...

In my previous example (GK 700RB) the "Gain" knob was really a level pot following the input stage.
 
#9
rumblinbass said:
I agree...unless someone can point me to an input pad that doesn't either alter the load applied to the source or input impedance of the amp. I am just saying that I don't prefer them because they degrade noise performance.
Click to expand...
I would say they shouldnt be used at all, unless your signal is clipping your amp no matter what you do. I run every bass, active or passive, with out the input padding.
 
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#13
rumblinbass said:
so, then...maybe one pad setting wouldn't be enough? you would want to pad the signal (or reduce gain) only enough that you weren't clipping the input stage.
Click to expand...

If a -15 or -20 in conjunction with a gain knob isnt fixing a clipping issue, it isnt the amps fault. It is user error.

If you have the gain set all the way to zero and are still clipping the input, a -15db pad should solve the clipping. At that point I would think you would have to bring the gain up a tad to adjust for the ~-10db that the pad overshoots.

If you bass isnt clipping the amp with the gain set all the way to zero, then using the pad is a bad idea.

I wish my amps didnt even have the pad. I dont want multiple pad options, I want none. They are a waste.
 
#14
I have some basses that people generally seem to think are "hot". A G&L L-2500, G&L SB-2, and my EBMM Sterling all come to mind. I have had numerous other active basses, also. My amps include a vintage SVT, a B-15R (the reissue), and a vintage ('73) Traynor YBA-3.

I have NEVER needed to use input padding to get a clean sound (with the bass volume dimed, I might add). I'm inclined to agree with CL400Peavey.

At least, that's my opinion. Can anyone offer up an example of a bass and amp combination that really does actually require input padding to allow you to get a clean sound with the bass volume dimed? I don't mean to sound like a know-it-all. I'm curious if there is some bass that is SO hot that it really can cause one of my amps to clip, no matter how much input gain I dial in. Or, maybe some amp that has so much gain on the input that a normal "hot" bass than drive it to clip, no matter how much input gain you use.
 
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#15
rumblinbass said:
Seems like most preamps have 1, maybe two, Pad settings. IME, -10 and/or -20dB seem to be the most prevalent.
Is that adequate? Would you like to see more settings? For example, -6 to -18dB in 3dB steps or possibly continuously variable with a pot. Thoughts?
Click to expand...

If you only use active bases (as I do), a pot right at the front end of the preamp works great for optimizing headroom and signal/noise. IME most people do not want to mess with doing that every time they tweak a tone control setting though, or deal with having three gain/volume controls...Link Removed
 
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#17
Dave W said:
+1.

I never ever use the pad and I too have some very hot basses.
Click to expand...


+1 that pads are rarely needed. The impedance change of a pad is a moot point with an active bass though, but can impact a passive bass, where input impedance can change the top end response of the instrument. Regardless of that, it is usually not an advantage to place additional electronic components in your signal path that are not really needed. It is a very rare situation where a gain control cannot be adjusted to get a clean input signal into the preamp.

Also, per the original question, most 'active' inputs or pad switches apply an extreme level of attenuation (10 or 15db down, which is massive). Glockenklang takes a more 'professional' approach to input padding, using a variable input pad like the ones used in professional sound/PA board applications. That being said, I never used it!
 
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#18
KJung said:
+1 that pads are rarely needed. The impedance change of a pad is a moot point with an active bass though, but can impact a passive bass, where input impedance can change the top end response of the instrument. Regardless of that, it is usually not an advantage to place additional electronic components in your signal path that is not really needed.

Also, per the original question, most 'active' inputs or pad switches apply an extreme level of attenuation (10 or 15db down, which is massive). Glockenklang takes a more 'professional' approach to input padding, using a variable input pad like the ones used in professional sound/PA board applications. That being said, I never used it!
Click to expand...

10, 15, or 20dB down is a bit much IMO...which is the reason for starting this thread. Wanted to know if multiple smaller steps or continuous control would be preferred.
Professional sound/PA board applications? Can you expand on that?
 
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#19
StuartV said:
I have some basses that people generally seem to think are "hot". A G&L L-2500, G&L SB-2, and my EBMM Sterling all come to mind. I have had numerous other active basses, also. My amps include a vintage SVT, a B-15R (the reissue), and a vintage ('73) Traynor YBA-3.

I have NEVER needed to use input padding to get a clean sound (with the bass volume dimed, I might add). I'm inclined to agree with CL400Peavey.

At least, that's my opinion. Can anyone offer up an example of a bass and amp combination that really does actually require input padding to allow you to get a clean sound with the bass volume dimed? I don't mean to sound like a know-it-all. I'm curious if there is some bass that is SO hot that it really can cause one of my amps to clip, no matter how much input gain I dial in. Or, maybe some amp that has so much gain on the input that a normal "hot" bass than drive it to clip, no matter how much input gain you use.
Click to expand...

You are correct that it is very rare. However, it does happened. Some piezo loaded instruments/DB pickups have massive, massive output that needs to be padded on almost any amp. Another interesting example is the original Reverend basses. They were passive, but had output that was the hottest I've ever experienced. An input pad with the bass volume turned all the way up seemed to be more transparent than significantly rolling down the bass volume with an unpadded input.

There are also some guys with massively aggressive technique that can turn the output level of a 'normal bass' into a VERY hot output.

All these situations are quite rare though, so +1. One of the most confusing things to players who aren't that interested in gear is that they assume they need to use the 'active' input for an active bass, which of course is not the case at all. I wish amp manufacturers would stop using the 'active/passive' label for the 'padded/unpadded' inputs.

Edit: I really liked the approach Genz Benz took with this issue. They had an input gain design that could easily handle virtually any bass output, but then put a 'boost' button for those who wanted the ability to overdrive the tube input of their preamps. Much more useful for the vast majority of players, and more 'intuitive' to the player also IMO
 
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#20
mrmills said:
Buffered pads would not change the load impedance, can't give you any amps that are designed like that off the top of my head though.
Click to expand...

There are some amps that use different input impedance on the active/passive inputs, with a higher impedance input on the passive input, and lower on the active (I think). Epifani, older Walter Woods amps and a few others do this. So, putting a passive bass in the 'active' input with some amps would result in a combined loss of gain and top end attenuation (I think!). +1 though, minor issue that wouldn't impact active basses at all anyway, as far as I understand how this all works.

'Passive' input or 'no pad' would be the default setting for the vast majority of players and virtually all instruments (other than the very unusual uber hot output pickups/preamps, or in some cases, hot piezo pickups, etc.)
 

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