Marshall DSL20HR Treble Control

[fretburner]

I just got a used DSL20HR and turning the treble knob all the way to the left (counter clockwise) seems to boost the mids and bass.

Has my DSL20HR been modified?

I used to own a brand new DSL100H and I cannot recall the treble knob doing that. I own a few other marshalls and all the treble knobs are a simple boost/cut of the high frequencies. They don't affect the mids and bass at all.

I also noticed the DSL20HR's presence knob is more interactive than my other marshalls, i.e., it affects the BMT controls, way more than I'm used to. I'm not complaining about this though. But it makes me turn the presence control at noon or more when I usually set it at zero (with my other marshalls)

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[CK71]

I have a dsl 20 combo, which I also bought used, and have had a similar experience. It seems to take a while longer to dial in a good tone and is a good reminder to adjust controls by ear vs site. Anyways enjoy your new amp!

[GuitarStv]

I'm not familiar with the tone stack used in these amps, but guitar tone stacks are often weird and interactive. This is definitely the case with Fenders, HiWatts, and the Vox amps I've played.

[jeremy]

yeah, im not familiar with how this tone stack is configured but, like stv said, many are very interactive. turning the treble all the way down could absolutely give the impression of more mids and bass. a typical presence control works with the negative feedback loop in the power section, but there is no law that says it has to have anything to do with that so could be anything

[dave74]

Rectifiers are the same way. When you reduce treble it allows more mids and bass through the stack. Most good tube amps do not have active tone stacks. The tone pots are like a line of specific-frequency attenuators.

[fretburner]

yeah, im not familiar with how this tone stack is configured but, like stv said, many are very interactive. turning the treble all the way down could absolutely give the impression of more mids and bass. a typical presence control works with the negative feedback loop in the power section, but there is no law that says it has to have anything to do with that so could be anything

This one is different though... the volume boost is so great it's basically like having a pedal through the fx loop.

It starts between 9 and 10 o'clock.

I actually kinda like it because I like middy amps. I just think it's weird and I cannot help but think that was probably not by design.

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[Wattage]

How do you like the amp otherwise. It is on my shortlist for something Marshall-y without going OTT

[fretburner]

How do you like the amp otherwise. It is on my shortlist for something Marshall-y without going OTT

It is a marshall and is very close to the JCM2000. Although the latter, depending on the cab, sounded more "organic" and thick.

I miss the "crunch" mode in the DSL100H, but the HR does remove the "fizziness" associated with these newer DSLs.

I'm very pleased that you wont lose the low end when you switch to the 10-watt mode, unlike the Orange terror series where its tone changes when you switch to 7-watts and you lose a lot of low end.

I also agree with Ola in that the bass response isn't quite there with the JCM2000 DSL and DSL100H. But for my taste, I really don't see why I need that much bass. The DSL20HR has plenty of bass.

I've plugged it into a 1960A with V30 x G12T-75 and 1x12 DIY mahogany cab with G12-65 and it sounds great!

Also, as mentioned earlier, it's EQ + presence + resonance controls are much more "integrated" than all other marshalls I've tried and had. The BMT reacts greatly to the presence and resonance control. My other marshalls, the BMT are pretty much independent with everything else.

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[Cynical]

I own a few other marshalls and all the treble knobs are a simple boost/cut of the high frequencies. They don't affect the mids and bass at all.

I guarantee you that this isn't correct, unless you own some of the weirder Marshalls (i.e., things such as the Silver Jubilee that aren't based on a 1959/1987/Super Bass/2203/2204). The standard Marshall tone stack has the treble knob doing all sorts of things to lots of frequencies -- as you turn it up it scoops the mids but also moves the mid-range focus more to the low mids. Google "Duncan Tone Stack Calculator" if you want to see exactly what it does to the frequency response.