My bugera amp question

[mbengs1]

My bugera 6262 amp loses treble response when the master volume of the channel is between 0-1. sounds kinda muddy at very low volumes. but it sounds fine when louder. sounds really good actually, when boosted with my boss super overdrive. is this normal for my amp? its ok since i set the master volume above 1 for jamming along backing tracks or if ever i record with it.

[WRGKMC]

Welcome to the real world with that discovery. Its normal with many amps, especially Fender circuits which have they're tone stacks after the first gain stages. I discovered that when item when I was 11 years old and bought my first bassman amp. I didn't have a Hi Fi for playing music any more so I plugged my turntable into the amp and discovered the tone controls wouldn't work before the amp was cranked up above 1/4 volume. The amp was designed to produce maximum fidelity for guitar pickups at half volume. The bright switch is also becomes less effective over half volume.

 

If amps could work the way engineers design them on a blueprint you probably wouldn't have the issue.

The problem is those parts on a schematic are no where near mathematically perfect. The individual components themselves have inefficiencies. None of them are perfect and all have built in tolerances. Caps can be off by 20% or more and drift as they age, resistors can be off by 1, 5, 10, and 20%. Tube change value as they age, transformers can vary output depending on they're voltages. Even the test equipment used to measure and calibrate these components to work in a circuit have built in variances.

 

In all you're taking a bunch of components that can be out of specs and you are targeting them to work in a circuit as efficiently as possible. In most tube amps, its where they run at full clean power without any distortion. Your amps EQ works most efficiently there because its designed to work most efficiently there.

 

The components that amplify, the pots that adjust voltages, the components that color the sound, add bass and treble are only linear within a narrow range on the power scale. When you turn the volume way down, the voltages become too low for the caps in the EQ circuits to work properly so what happens is the tone circuit dies out before the volume is completely cut.

 

They could redesign the amp so an amp has tone control at low volume, but then it wouldn't work right at the normal targeted volumes.

 

So what it comes down to is this. You want to play at low volumes you need to use a low wattage amp. You can then run the amps volume control in its ideal range and the tone stack will have its maximum control.

 

There are other amps that have different tone stack designs. Amps like yours and fender have they're tone stacks early in the amplification chain just after the first gain stage. Marshall, Ampeg and others have they're tone stacks after the second and third stages. The signal is much stronger at that point. When you turn the volume way down the tone stack still operates well because the signal feeding those caps and pots is stronger. All the controls on that amp are more linear compared to amps like yours. The tone changes in that process. Because Marshall amp tone stacks are using higher volumes, they have milder changes when cranked to minimum and maximum levels.

 

Again this simply comes down to the limitations of the components - and the cost of building those amps. If you're looking for high fidelity and ultra linear tone responses they make Hi Fi amps designed to do that. They have extended highs and lows and EQ's designed to create a flat response for playing back an entire bands worth of music. A guitar is only one of those instruments.

 

If you plug a guitar straight into a Hi Fi amp the first thing you notice is you have way too much bottom and top end. Guitar pickups need plenty of midrange boost to sound normal because of its pickup design. Same thing when you feed a Hi Fi signal into a guitar amp. It will have just the opposite, way too much mids and not enough highs and lows.

 

A guitar amp isn't designed for High Fidelity and a High Fidelity amp isn't designed for guitar. You're wanting high fidelity from a primitive amp from a primitive amp at low volumes. You got the wrong amp for that.

 

You have discovered they are far from being linear which is an important step in the learning process. You found the spot where it works the poorest. Now you have to target the spot where its works its best and use that spot to get your best string tones.

[mbengs1]

actually, its just the lead channel i'm referring to. the clean channel is just fine.