setting pre-amp gain

[NHM]

Does anyone have a 'top tip' for setting the right input gain on their amp to maximise efficiency without under- or over-loading the signal? Amps don't seem to come with 'clipping lights' any more, so how can you tell that you're not overloading other than by listening for distortion (i.e. trial and error)? 

[Dad3353]

44 minutes ago, NHM said:

...so how can you tell...

I would humbly suggest that listening for distortion would be about the best way possible, 'clipping lights' or not. 

[Bolo]

1 hour ago, Dad3353 said:

I would humbly suggest that listening for distortion would be about the best way possible, 'clipping lights' or not. 

This.

[Bassalarky]

3 hours ago, Dad3353 said:

I would humbly suggest that listening for distortion would be about the best way possible, 'clipping lights' or not. 

+ 1 from me too.

[PaulWarning]

I use a Trace Elliot with clipping lights and passive P bass, I have the gain turned right up and the red clipping light doesn't come on, don't know whether that's any help or not, but it depends on the amp, they're not all designed the same

[xgsjx]

I've always set it by bringing the input up to just clipping & then backed off a bit.  And like Dad says, listening for any unwanted distortion.

[NHM]

Thanks for the replies. So it looks as though setting a correct input level is down to listening / trial and error if there isn't a meter or clipping light (so, most amps I've come across).

I don't understand why a fairly critical electronic interface between guitar and amp is so arbitrary. If you inadvertently over-load the signal I assume you could damage the amp (as well as spoil your guitar's natural sound); if you under-load, then you're wasting the potential power of the amp (although this probably isn't critical).

Do the electronics of an amp perform differently if you under-load the input signal?

 

[Dad3353]

43 minutes ago, NHM said:

Thanks for the replies...

Fundamentally it's the assumption that's false. There's nothing a bass can put out that can damage the amp before one's ears warn of the potential danger. A meter or clipping indicator is fine, but redundant, which is why most amps don't have one. Some do, of course, and it's a good selling point, but I doubt that many musicians watch their amps just in case the light flickers on, or the meter goes into the red.
Signal is not 'wasted', either, if the volume goes down. Some players use this to add dynamic content to their playing. Less signal is not a Bad Thing. Not enough signal is different, but, again, one's ears are usually sufficient to detect such a case.
Hope this helps.

Edited April 28, 2018 by Dad3353

[NHM]

that's really clear, thanks very much Douglas (now my friend!).

[Dad3353]

[The59Sound]

20 hours ago, xgsjx said:

I've always set it by bringing the input up to just clipping & then backed off a bit.  And like Dad says, listening for any unwanted distortion.

 

[drTStingray]

I haven't owned or used an amp in the last 15 yrs or so that doesn't have either an input clipping light or meter - they are quite useful to get a feel for whereabouts your signal is in terms of load. 

I always set mine so that it's just under the point of clipping - then I don't worry about it and control the output volume from the amp output and bass volume. 

I only use active basses and contrary to what has been said there are vast variations, just based on the intensity of playing - a low B string changes things as well. 

Having the input at a level where it will clip if you play really hard is quite useful (I certainly found it so using a Stingray and getting that really gritty sound where required). 

Also, using Ashdown ABM I always found that using the active/passive button can cut the input unnecessarily, based on what the meter said - probably only necessary for 18 volt electronics. 

 

[SpondonBassed]

On 27/04/2018 at 07:48, NHM said:

Does anyone have a 'top tip' for setting the right input gain on their amp to maximise efficiency without under- or over-loading the signal? Amps don't seem to come with 'clipping lights' any more, so how can you tell that you're not overloading other than by listening for distortion (i.e. trial and error)? 

Unless your hearing is damaged, listening is the best way.

Bear in mind that eq affects output level as well as gain.  I'm not sure that clipping indicators operate right across the frequency range of the instrument but my Ashdown combo's old school VU (Volume Unit) gain metering seems to detect cuts and boosts across all three eq bands on my bass.

[naxos10]

Do the comments above suggest that if you have an amp with passive and active inputs it does not really matter which one you use? I ask as I have an Ashdown Retroglide with both but run my passive bass through a DHA VT1 Spitfire and use the passive input. I don't get the indicator lamp lighting up as I keep the input level below the required threshold.

Would there be any benefits to using the active input instead?

Unfortunately I do have hearing loss so hence the question.

[SpondonBassed]

1 hour ago, naxos10 said:

Do the comments above suggest that if you have an amp with passive and active inputs it does not really matter which one you use? I ask as I have an Ashdown Retroglide with both but run my passive bass through a DHA VT1 Spitfire and use the passive input. I don't get the indicator lamp lighting up as I keep the input level below the required threshold.

Would there be any benefits to using the active input instead?

Unfortunately I do have hearing loss so hence the question.

Try it and see.  You will not damage your amp with a passive bass plugged into either of the inputs.  Exercise caution if you want to plug an active bass into a passive input.

If you start from zero output set on your bass you will spot any overload well in advance.  If you're not sure, press gang some volunteers into a listening session to establish your benchmarks.

My active basses are both 9V.  The max output is not a great deal more than my passive basses at max.  I can plug into either input (Passive or Active) with only a slight difference showing on the VU meter.  I'd expect there to be more output from an 18V active output but I can't say from personal experience.

May I ask what frequencies you hear best?

Edited April 29, 2018 by SpondonBassed

[naxos10]

Low level is best, I have lost the high and part of the mid frequencies of my hearing.

[SpondonBassed]

11 minutes ago, naxos10 said:

Low level is best, I have lost the high and part of the mid frequencies of my hearing.

You might not hear the beginnings of distortion from overload then.

Some trials with a trusted friend observing during sound check might help.  Compare notes after to see if you're letting excess top end through.  I can't see it being a problem unless you inhabit the guitar zone.  Just make sure you aren't adding top to compensate.

[drTStingray]

1 hour ago, naxos10 said:

Low level is best, I have lost the high and part of the mid frequencies of my hearing.

I'm sorry to hear that.

FYI I agree with SpondonBased - my 9 volt active (Stingray; Sabre) do not cause a problem plugged into the active input on my Ashdown - it goes into the red more if it's a 5 string or with 18 volt electronics - or with very hard playing.

FYI and as a rule of thumb, with these basses, clipping is under control if the input is set between say 9 o clock and 11 o clock (either Ashdown (meter) or MarkBass (light)). The MarkBass is provided in jam sessions as well and everything from Rics to P and J are ok at say 11 o clock on the input - 18 volts or players with very strong plucking/picking need to be backed off a bit. Similarly back off if the output volume only needs to be 9 o clock. 

Thus all assumes a relatively flat EQ on the amp. 

As SpondonBased says, get someone to help you set the output volume and ensure you aren't permanently clippings or distorting - I think you would hear distortion anyway. I usually do this anyway to ensure my volume isn't overpowering further back in the venue (if not through PA or with sound people). 

Edited April 29, 2018 by drTStingray

[naxos10]

Thank you SpondonBassed and drTStingray I will carry out a few experiments with the aid of our guitarist. I will just have to take into account any additional distortion from the DHA VT1 valve 'output'.

[Jus Lukin]

-

Edited March 1, 2022 by Jus Lukin

[drTStingray]

I have no recent experience of using valve amps, but by setting the input on amps I've used to just below clipping level, by playing (a Stingray) on selected notes or passages hard I have been able to get sufficient distortion to be audible, but to produce a clean sound the rest of the time - this has been quite a useful extension of creating dynamics (an additional feature of moving the position or changing the intensity of your plucking action).

Regarding setting the amp output high and the input low, I have found backed off input level to affect the overall volume quite a bit (rather like turning the entire EQ to full cut on an active bass). I guess it will vary a lot amongst different amp designs as well? 

As you will guess I'm coming at this more from a practical experience rather than theoretical viewpoint - so it will include my perceptions/what I hear - which may differ from others!! 

Edited April 29, 2018 by drTStingray

[SpondonBassed]

I've never run my Ashdown at full volume.

It's never done a gig.  I might have a play with the full volume low gain approach next practice... just for a laugh.

[Dad3353]

The 'Master volume max'd' approach does have the inherent risk of a fault or error somewhere getting through at full volume. We've all heard those nasty thumps and blips (or worse...) from PA systems, where the FOH amps are often set up 'full tilt', and someone unplugs a mic without muting. A small risk, maybe, but risk just the same.
Just sayin'.

[Jus Lukin]

-

Edited February 26, 2022 by Jus Lukin

[Jus Lukin]

-

Edited February 26, 2022 by Jus Lukin