How to get rid of/stop clipping

[Alejandrohno]

Hey all, my rig consists of a Fender Bassman 250 head running into an Acoustic BA410 cab, the head is rated at 250w, and the cab at 400w. My amp clips basically whenever I turn the volume up by 1. What can I do to prevent this? Please explain to me like I'm 5.

 

[moles]

You're going to have to define "my amp clips" a bit better. What are you hearing/seeing?

What's your signal chain and gain structure? EQ?

 

[Wasnex]

If the cab is Acoustic B410C, AFAIK it's 8 ohms. The Bassman 250 is rated 250W at 4 ohm. I don't think Fender provides the power rating at 8 ohms. My guess is it probably makes about 175W. This is not a lot of power, unless you are pushing a very efficient cab. AFAIK Acoustic does not post a Sensitivity rating for the B410C.

Here is the amps OM: https://www.fmicassets.com/Damroot/Original/10001/OM_leg_bassamp_Bassman_250__20052010.pdf

The Bassman 250 has two clip LEDs. One is for the preamp and one is for the output section.

The preamp LEDs are on the left. The OM says adjust the volume for the preamp signal LED to flash. Occassional flashing of the clip LED is OK. If the clip LED is flashing prematurely, engage the -6d pad button.

The Clip PWR Amp LED is on the right. It should light when the amp is pushed to full power. The amp should start to distort simultaneously with lighting the LED.

If the Clip PWR Amp LED is lighting before the amp is making very much power, something is wrong with the amp. If the amp is damaged, you are probably better off putting funds towards a better amp than having it repaired. I don't own this amp, so I can't tell how far you should be able to turn up the Master before the amp clips. Also the setting where this occurs will vary with the way the volume and tone controls are adjusted.

If possible, try your amp with another cab. The idea is to determine whether the problem is with the amp or cab. The amp may be developing good power, but the speaker is not effectively translating the power into sound. Or the speaker may be fine, but the amp is not working properly. Try a different speaker cable as well.

 

[Cadillac_Mike]

I actually have a pretty similar setup to that; a 300w G/K head into an Acoustic 4x10.

Are you using an active bass or pre-amp by any chance? If so see if there's a "pad-switch" db cut feature. I just recently learned about that and definitely helped me get a cleaner signal with my active along with less susceptibility to clipping.

Wasnex is also correct about the ohms-wattage which is another thing I recently learned thanks to the Internet lol. I always thought I was getting the full 300w but my amp actually "only" makes around 175-180w into a single 8 ohm cab. Still plenty for jamming in my studio and even most bar gigs.

 

[Alejandrohno]

You're going to have to define "my amp clips" a bit better. What are you hearing/seeing?

What's your signal chain and gain structure? EQ?

My apologies, I was at work and kinda rushed this post.

My fx loop consists of an Ibanez BP10, Digitech Whammy, Morley PFW, Boss DD-8, Boss OC-5, Arion bass chorus, and an EHX Small Stone.

On the head, I've got the bass/low mids at around 2'o clock, high mids at 10'o clock, and treble/fx blend at 2'o clock. (Picture attached)

 

[Alejandrohno]

I actually have a pretty similar setup to that; a 300w G/K head into an Acoustic 4x10.

Are you using an active bass or pre-amp by any chance? If so see if there's a "pad-switch" db cut feature. I just recently learned about that and definitely helped me get a cleaner signal with my active along with less susceptibility to clipping.

Wasnex is also correct about the ohms-wattage which is another thing I recently learned thanks to the Internet lol. I always thought I was getting the full 300w but my amp actually "only" makes around 175-180w into a single 8 ohm cab. Still plenty for jamming in my studio and even most bar gigs.

Yep, a Schecter Stilleto Stealth, one of my personal favorites!

 

[Redbrangus]

Further attempting to narrow things down:

What makes you say it's clipping? Clip lights? Which one, the input or the output clip light? Both?

Do you have all that... uhh... 'stuff' patched into the effects loop on the amp? What happens if you remove all that stuff from the FX loop... still clipping?

Edit: You have an active bass? Are you engaging the input pad?

 

[Alejandrohno]

If the cab is Acoustic B410C, AFAIK it's 8 ohms. The Bassman 250 is rated 250W at 4 ohm. I don't think Fender provides the power rating at 8 ohms. My guess is it probably makes about 175W. This is not a lot of power, unless you are pushing a very efficient cab. AFAIK Acoustic does not post a Sensitivity rating for the B410C.

Here is the amps OM: https://www.fmicassets.com/Damroot/Original/10001/OM_leg_bassamp_Bassman_250__20052010.pdf

The Bassman 250 has two clip LEDs. One is for the preamp and one is for the output section.

The preamp LEDs are on the left. The OM says adjust the volume for the preamp signal LED to flash. Occassional flashing of the clip LED is OK. If the clip LED is flashing prematurely, engage the -6d pad button.

The Clip PWR Amp LED is on the right. It should light when the amp is pushed to full power. The amp should start to distort simultaneously with lighting the LED.

If the Clip PWR Amp LED is lighting before the amp is making very much power, something is wrong with the amp. If the amp is damaged, you are probably better off putting funds towards a better amp than having it repaired. I don't own this amp, so I can't tell how far you should be able to turn up the Master before the amp clips. Also the setting where this occurs will vary with the way the volume and tone controls are adjusted.

If possible, try your amp with another cab. The idea is to determine whether the problem is with the amp or cab. The amp may be developing good power, but the speaker is not effectively translating the power into sound. Or the speaker may be fine, but the amp is not working properly. Try a different speaker cable as well.

Oh bless you, may your iced drinks never water down!

 

[agedhorse]

First of all, eliminate everything from the effects loop and see if the problem goes away. It's possible that something in the effects loop is the cause.

Second, if the amp still distorts without anything in the effects loop, AND you have tried it with a known good speaker and cable (no assumptions that what you tried it with is "good", does the distortion occur with the master volume very low and as soon as you turn up the input volume?

One of my former co-workers designed this amp, internally, it's quite complicated and there are plenty of places where things could go wrong causing similar symptoms.

 

[Kansas]

Old school says:
Crank master to 10 and bring up preamp.
Put short cable in fx loop... out to in.
Check speaker cable for dodgy connection.
If bass is active, don't overdrive front end.
Still distorting? See a good tech.

 

[Pep]

Using no pedals, with the bass turned up at full volume, turn the master down to “0” and turn the input volume up while plucking the open “E” string. When you finally see the clip light, back the input volume down just a touch to make the light disappear.
Now adjust the master volume to an acceptable level. If you can’t get there without turning the input volume up, you’re underpowered and need a more powerful amp.

If you reach an acceptable level without clipping, start with one pedal and get it dialed in without clipping. Continue to add pedals watching the clip light as you dial them in.

Hope that helps.

 

[Ritter667]

My apologies, I was at work and kinda rushed this post.

My fx loop consists of an Ibanez BP10, Digitech Whammy, Morley PFW, Boss DD-8, Boss OC-5, Arion bass chorus, and an EHX Small Stone.

On the head, I've got the bass/low mids at around 2'o clock, high mids at 10'o clock, and treble/fx blend at 2'o clock. (Picture attached)

Turn down the volume and instead turn up the master volume of you amp.

 

[Redbrangus]

In the absence of further data, I'll theorize this: your pedal chain is contributing too much gain and driving the output stage too hard, even though the input preamp is providing only minimal gain. You probably need to address the gain staging in your external processing. The proof would be if you remove the pedals from the effects loop to see if the 'problem' is still there.

Edit: And @Wasnex is right -- if you cab is 8Ω, your amp doesn't really have enough power.

 

[lug]

First question to answer, which clipping light is lighting. input or output?

 

[Redbrangus]

I believe that makes you the fourth person to ask this.

 

[Pep]

Wasnex also brought up a great point. The amp is rated at 250 watts @ 4 ohms. If your cabinet is 8 ohms, you’re probably getting about 125 watts which explains a lot.

 

[agedhorse]

All this speculation without even the most basic troubleshooting steps…