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Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups

Master volume amps and attenuators

Discussion in 'Glowing Bottle Tube Amp Forum' started by Hexabuzz, Oct 5, 2017.

  1. Lucky Day

    Lucky Day Tele-Afflicted

    Feb 24, 2014
    Vancouver, WA
    Just for the sake of understanding the terminology, technically speaking a master volume IS an attenuator. An attenuator is a device that reduces the signal.
    In common use, a device that we put between the amp's output and the speaker's input is just called "an attenuator" because it's descriptive and the isn't applied to all the other attenuating components (pretty much every pot on the amp, for example) of an amp. Sometimes attenuators are called "power soaks" or "load boxes" because they do in fact absorb the output power of the amp and dissipate it somewhere other than the speaker's voice coil.
    Doctorx33 likes this.

  2. MilwMark

    MilwMark Poster Extraordinaire Ad Free Member

    Apr 29, 2013
    near Arnold's
    You might be over-thinking this one. Get the amount of breakup you want at the volume you need, use a MV if you have one. Part of it is speakers, I totally agree with @charlie chitlin. Power tube vs. preamp tube? Who knows. Are you really hearing power tube distortion? Or speaker compression/breakup/frequency range (caused by volume), phase inverter, etc.?

  3. charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

    Mar 17, 2003
    Spring City, Pa
    I've never heard that.
    Means 2-stroke, I suppose.

  4. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

    Mar 2, 2003
    Lawndale CA
    If you're stuck I'd go the attenuator route - at least you end up driving the entire amp fully - except speakers, obviously. When preamps alone are driven fully the sound is inherently thinner.

    If the amp is a single-12 I recommend one of the Eminence variable-gap speakers in lieu of other attenuators. The speaker is still driven to some degree with volume controlled well. Otherwise I recommend the Weber MASS, which uses an actual speaker voice coil as the "guts" of the attenuator. Those are the only two methods I'd use.

    But - if you are consistently in situations that require attenuation your amp *is* too big IMO - or you need a second (or third) amp to cover lower volume situations. Nearly every gigging player I know has multiple amps to cover different types of venues (and basically use the settings I outlined above). If you play small clubs and larger places (or outdoors) it's virtually impossible to get consistent tone with only one "gig" amp (plus I assume you have a backup amp!).
    Hexabuzz likes this.

  5. MilwMark

    MilwMark Poster Extraordinaire Ad Free Member

    Apr 29, 2013
    near Arnold's
    Keep in mind, many great sounds have been made using preamp gain from MV amps.

  6. Wally

    Wally Telefied Ad Free Member

    Mar 17, 2003
    Lubbock, TX
    I have owned many amps with MV controls. I am lucky enough to have owned...and rue the day I sold original Jim Kelly FACS amp with the attenuator. The only ‘new’ amp that moves me to acquire is a Tone King Imperial MKII, which has the Ironman II attenuator that can function on both channels or can be assigned to only the Lead channel. The Tone King attenuator many levels. The MKII is imho a great amp, of the most musical and usable that I have come across. If the Kelley had been the FACS Line amp, which also could assign the attenuator, I might never have turned loose of it. That amp is worth four times what I got for it in 2002.
    There is a distinct difference between MV and attenuators. There are also differences in the results that different attenuators yield. I find more usefulness for a good attenuator than I do for a MV....but I can find a way to utilize both.
    Hexabuzz likes this.

  7. codamedia

    codamedia Friend of Leo's

    Apr 4, 2009
    Western Canada
    I see a couple of answers to this, but the simplicity is lost!

    Master Volume... Attenuates the signal after the pre-amp, before the power tubes. There are several ways to implement it, but that is the general idea. When you turn down the MV, the power tubes get less signal, but the pre amp is still working hard!

    An Attenuator is placed between the amp and speakers. Your entire amp (including power tubes) are working hard you are just turning down the sound before it reaches the speaker.
    Wally and Hexabuzz like this.

  8. Hexabuzz

    Hexabuzz Friend of Leo's

    Dec 13, 2014
    Northeast PA
    That explains a lot, and makes a lot of sense - Thanks!

  9. Sounds Good

    Sounds Good Tele-Holic

    Oct 2, 2017
    Luton UK
    I asked about this the other day on another thread and no one answered, because in my manual it states never go above around 2 o'clock with channel volumes, and one needs to if playing at lower volumes on say a crunch channel so to distort things a little more to get the break up.

    I am no amp expert so not sure which is the best way for the care of the amp, so i just use my ears to judge the sound. Using the two but not pushing the channel volume to far.
    Last edited: Oct 10, 2017

  10. codamedia

    codamedia Friend of Leo's

    Apr 4, 2009
    Western Canada
    What a silly manual :lol:. Ignore that completely and use your ears to get the sounds you want.
    Doctorx33, Sounds Good and Wally like this.

  11. mad dog

    mad dog Friend of Leo's

    Jun 27, 2005
    Montclair, NJ
    I don't think "hypothetical" works. And "best sound" is a moving target.

    My assumption was attenuators would be better. In practice, hasn't happened. They're all different. I have yet to try the most expensive, most hyped choices, so it could be just that I've tried the wrong ones.

    Whereas a good MV, that does work for me. Not with every amp. Some circuits seem to respond much better to a MV. Some are way better than others. Hard to predict.
    Hexabuzz likes this.

  12. Doctorx33

    Doctorx33 Tele-Afflicted

    Jun 8, 2014
    I like attenuators, and have built several of them. I only have one amp with a master volume, an AC30CC.

    There is a marked difference in tone between using a master volume vs attenuator. Different kinds of distortion. Something I've experimented with is using both of them. Dial the master down a bit then use the attenuator to dial down a bit more. It's a good compromise.
    Last edited: Oct 10, 2017
    Wally and Hexabuzz like this.

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