Cleaner headroom for Matchbox D-30

Seven2Eleven said:
I'm simplifying a bit but master volumes on tube amps are a gain stage. They control the gain of the power amp tubes specifically. There are higher and lower headroom tubes and circuits can be designed for maximum headroom, but volume in a tube amp is never 100% transparent.

The other thing too is that it's very easy to run the modeled volume knob higher in a modeler than you would ever run it on a real amp because the real amp would be so painfully loud that's unusable.

When I first got into modelers, I tried to dial some basic fender clean tones. Most of the classic Fender amps are non-master volume but I just followed the conventional wisdom that Fenders are always clean and that "cranked = more good". In the Helix and Fractal, they would always be way more distorted than I wanted with the volume just on 5. I thought there was something wrong with the modeling but then I thought back to the times I've used real Fender amps and on most of them, I couldn't turn the volume past 3 before it got painfully loud and unusable. Between 2-3 was usually the sweet spot for me in terms of a clean tone.I discovered that the Fractal Amp models worked the same, which is to say they were accurate.
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Master volumes are not gain stages. They control the power tube section volume and are used to reduce overall amp volume when preamp tubes are driven to natural distortion.

It’s a moot point because the wiki notes on the fractal model for the DC30 states that the master volume function has been bypassed in the model. I’m guessing the MV that we see in Edit is acting as a dedicated single volume for the power amp stage.
 
I have one of the first SC30s ever made and I can tell you that the Fractal model is very close to my amp. Matchless C30 amps have a defeatable MV where you pull the pot to remove it from the circuit but most people seem to just use it all the way up or slightly dialed back.

The amp doesn't have a whole lot of headroom, especially if you're using humbuckers but that's the magic. Don't get me wrong, it can do clean loud but it's not a Twin Reverb style, crystalline clean. The amps can be strident and very loud, even in half-power mode which can make you play with a lighter touch to bring out the cleaner sounds. I use the EF86 channel the most and things start warming up around 9-10 o'clock on the volume.

As others have said, roll back the input trim and MV. Also, you may just need to set the gain lower than you think.
 
One additional note on the Matchless DC sound as well is the fact that it comes with a set of mismatched speakers on purpose. (Not the HC or SC obviously). It’s a Greenback paired with a G12H30 from the factory. I would think you would want to run two different cabs panned stereo to get that same effect in the Fractal model.
 
Dangeroso said:
One additional note on the Matchless DC sound as well is the fact that it comes with a set of mismatched speakers on purpose. (Not the HC or SC obviously). It’s a Greenback paired with a G12H30 from the factory. I would think you would want to run two different cabs panned stereo to get that same effect in the Fractal model.
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York Audio has a ESD212 matchless IR pack that captures both of the dis-similar speakers. It sounds delicious with these models!
 
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I’ve been working on a Matchless preset using both models. On the EF-86, it is pretty dark to me. The DC-30 is a little brighter. I’m liking it so far. Does anyone know what FAS did with the EF-86 in regards to the tone cap selector switch on the real amp?
 
skolacki said:
I’ve been working on a Matchless preset using both models. On the EF-86, it is pretty dark to me. The DC-30 is a little brighter. I’m liking it so far. Does anyone know what FAS did with the EF-86 in regards to the tone cap selector switch on the real amp?
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From the Wiki:

While the real amp has a six-position Tone switch, the model has a continuously variable tone control. Note that the Tone control is mapped to the Bass control in Ideal mode as the Tone switch is essentially a bass cut control."
 
EL-84 amps are not known for being clean. They are typically biased as "Class-A" using cathode biasing and no feedback. The power amp transfer function is therefore very nonlinear resulting in distortion even at low input levels.

You can clean up the power amp by increasing the Negative Feedback.
 
this is exactly how these amps are in real life...I've had 3.

if you are cranking the MV then the power section is cooking and you aren't getting headroom, like others have said, turn it down then adjust gain to get what you want.

That being said, these aren't exactly clean platform amps, they are maybe the best edge of breakup amps ever made, though.
 
That EF-86 channel model is pretty addictive. Great touch sensitivity. I've not spent a ton of time with the Matchless models. I've been missing out.
 
FractalAudio said:
EL-84 amps are not known for being clean. They are typically biased as "Class-A" using cathode biasing and no feedback. The power amp transfer function is therefore very nonlinear resulting in distortion even at low input levels.

You can clean up the power amp by increasing the Negative Feedback.
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Thanks for that tip. I did experiment with the negative feedback and I was able to get cleaner. I also tried a number of other suggestions in this thread but have come to the conclusion that the trade offs to get cleaner aren't worth it. They all affect the magic in one way or another and I love the tone as is. I've got other vox inspired models that get a bit cleaner and I can use them if I need more clean headroom.
With MV on 10 gain at 1.50 and trim at .300 I get it fairly clean with out compromising the tone magic of this model.
However negative feedback adjustments on my deluxe reverb presets made some favorable improvements. Increased it slightly for the clean channel and decreased slightly for the grit channel.
 
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After several hours of playing and adjusting this amp today, it became one of my favorites for EDGE sounds. It also has a good Crunch sound. Especially when playing on a Strat, the EDGE sounds are amazing.
 
having played the real amps for years, the Fractal models are dead on....only thing missing is being able to jump the two channels.

This amp, like many EL84 amps, can produce a lot of power amp distortion. to clean it up use input trim to simulate the low input or turn the MV down. On the physical amp you can actually pull the MV knob to remove it from the circuit altogether.

It's one of the greatest EOB amps of all time, and that's where it shines. You be surprised at how clean it sounds in a mix or on stage even with some of that hair. That's it's thing, it's dynamic cleans, as I like to say. Play lightly you get clean, dig in you get dirt.
 
FractalAudio said:
If you want to hear what a DC-30 can do listen to "Dulcinea" by Toad the Wet Sprocket. Some of the best EOB guitar tones in history.
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Do you know details on what they used in the studio for that record? Just the DC-30 cranked? Or did they use drive pedals with it? I’d love to hear more insight on that just to learn and associate certain sounds with certain rigs I’m not familiar with!
 
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