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

Master volume amps and attenuators

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

  1. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    So I've seen similar statements in the documentation of a few different master volume tube amps in describing the controls:

    "MASTER VOLUME - Controls the overall volume of the tube output stage. Running the amplifier with the Master Volume control wide open essentially takes the control out of the signal path."

    So...

    For getting the best sound out of a master volume tube amp, would you be better off diming the MV, and using an attenuator to control overall volume, or would there be no difference in just using the MV to control the levels?
     

  2. MMARSH

    MMARSH Tele-Meister

    359
    Jun 21, 2015
    CA
    Depends on whether you prefer the sound of preamp distortion or the sound of power tubes cooking. I prefer the latter, so I generally run my MV at full volume and use Vol/Gain for overall loudness. I use dirt pedals in front and like that sound a lot.

    Some amps sound great with the front end maxed out as well. I would try both on your amp and see what you like.
     
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  3. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    Fair enough! At this point it's just a hypothetical, but it got me to thinking about it. Your answer definitely makes a lot of sense.

    I have a feeling based on my sound preferences that I'd prefer power tube distortion rather than preamp, since I like a little bit of grit, but not high gain distortion.

    Thanks for checking in!
     

  4. clintj

    clintj Friend of Leo's

    Apr 4, 2015
    Idaho
    I've got two amps with master volume, and generally run it wide open unless I need low volume crunch at night or for practice, for example.

    When the power section starts to overdrive, you start to get that sag/bloom effect with tube rectified amps. Power tube and speaker distortion also has a different sound, and I think feel, as well. More touch sensitive and organic to my ears, and easier to ride with the guitar.
     
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  5. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    Neither. You get the best tone by turning an amp up near the top of headroom with no attenuator. Then you're driving the speakers enough to get full frequency response. If you always have to use either an attenuator or master volume to control the amp you probably have an amp with too much output for the music you play. Neither of those methods get you optimum amp sound.
     
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  6. Lucky Day

    Lucky Day Tele-Afflicted

    Age:
    43
    Feb 24, 2014
    Vancouver, WA
    "Best sound" is 100% subjective. The trick is to try and see what you prefer, in EVERY CASE.
     
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  7. MMARSH

    MMARSH Tele-Meister

    359
    Jun 21, 2015
    CA
    Yeah, this is true. I rarely get that chance unless at a gig sometimes, and between the two options the OP posted MV wide open is my choice.
     

  8. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

    Age:
    65
    Mar 2, 2003
    Lawndale CA
    True - but nearly every player I've worked with and serviced amps for prefers to run a smaller at a a high clean level than any larger amp throttled back - regardless of whether it's through use of a MV, attenuator or just turning it down.
     
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  9. charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

    Age:
    56
    Mar 17, 2003
    Spring City, Pa
    So...does a master volume have the same affect as a hotter pickup by hitting the front end harder or does a hotter pickup effect both stages?
     

  10. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    That being understood, let's assume that the amp is what it is, and no option to choose another, lower powered one...

    If you NEED lower volume, MV or attenuator for better tone? Or does this still fall under the "try them both and see" method?

    Thanks for all the replies!
     
    Owensv likes this.

  11. MilwMark

    MilwMark Poster Extraordinaire Ad Free Member

    Apr 29, 2013
    near Arnold's
    Neither is ideal. Personally, I prefer just using the MV over an attenuator. Less work. Less risk. Built right into the amp already. And I don't understand the tech at all, but every attenuator I've tried makes things sound a bit dark and dull and unresponsive to me.

    I don't know if it's technically an "attenuator" (so I may be contradicting myself) but I do find some "1/2" power switches useful. They don't tend to cut the power in half. But they do reduce headroom. They also make the amp just a bit darker and less lively IMO. But not as bad as an attenuator. The one I have says "pentode - triode switch" in the manual. The Orange I used to have said the same thing. The feature worked about the same in both amps for me.

    So with my Ampeg GVT 15, if I'm too loud with the master wide open on full, I'll bring that down and the gain up. Then switch to 1/2 power and run the master wide open.

    Which "mode" will sound better at the right volume for any gig is hard to predict.
     
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  12. charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

    Age:
    56
    Mar 17, 2003
    Spring City, Pa
    I think your impressions of attenuators are shared by at least 1 manufacturer who includes a treble control (or boost) to keep things less dark.
    I kind of like a master volume, but only to inch me a little closer to break-up...not to actually get it, if that makes sense.
    It's like when you're with company and only eat half as much as you'd be embarssed to.
    I'm still happiest with a preferred boost pedal to put me on the edge of break-up when I have too much amp for the situation.
     

  13. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    Slightly off topic, but how is a Master Volume DIFFERENT from an attenuator?

    It all sort of leads back to my initial question, and the statement from the manufacturers - Shouldn't taking the MV out of the signal path have SOME effect on tone that would benefit the sound?
     

  14. NashvilleDeluxe

    NashvilleDeluxe Tele-Holic

    606
    May 10, 2007
    Laurentians, Quebec
    This is straight from Mark Bartel, in the owner's manual for my Tone King:


    "There are many different approaches that can be used to generate overdriven and
    distorted tones as a low volume. For example, master volume circuits, or a power
    reduction scheme such as London Power Scaling have both been used successfully on
    various amp models of other brands. However, for the more vintage sounding tones
    that the Falcon is designed to achieve, a good quality attenuator such as the built-in
    Ironman is the best way to preserve tone and feel at very low volume, because it allows
    the output stage to operate the same way at any level of attenuation.

    The attenuation control determines the amount of power sent to the speaker, but does
    not affect the operation of the output stage of the amplifier itself. The attenuator
    absorbs and dissipates any excess power generated by the output tubes that is not sent
    to the speaker."
     
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  15. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    Thank you! Nice summary, and the kind of info I was looking for.

    Much appreciated!
     

  16. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    Weber?
     

  17. brogh

    brogh Super Moderator Staff Member

    Jun 26, 2010
    italy
    The master volumes dimes the power sent to the speakers at the final stage, the attenuator is usually put between the output jack and the speakers lowering the signal while power tubes run at maximum volume ( if you want to )

    I prefeer master volume because it's more versatile and so i don't have another box to haul around.
     
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  18. charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

    Age:
    56
    Mar 17, 2003
    Spring City, Pa
    I'm thinking that a speaker being pushed hard has a lot more to do with that sound we love than a lot of people imagine.
    I'm pretty sure the amplifier doesn't know the difference between one load and another (speaker or attenuator), so the difference would be in how hard the speaker is being driven.
     
    MilwMark likes this.

  19. Hexabuzz

    Hexabuzz Tele-Afflicted

    Dec 13, 2014
    Northeast PA
    That's clearly a large component of the sound, and something you have to live with regardless of what's creating the lower output level reaching the speaker (MV or attenuator).

    My logic keeps telling me that not having the MV on full is (at least for me) creating a less desirable tone by reducing power tube output.

    That's just me, though - I'm sure lots of guys would love to have maxed out preamp gain, and work the MV for the final output.
     

  20. VintageSG

    VintageSG Tele-Afflicted Ad Free Member

    Mar 31, 2016
    Huddersfield, UK
    My favourite setting is having the pre-amp set so that when I brang a chord out, it crunches, when I am more gentle, it's clean(ish). Hit the front with an overdrive/boost as and when needed.
    I don't like too much pre-amp gain. Hairy cleans, not lairy gain.
    Set the master volume so the power stage is compressing a little, then when it gets hit with a bigger signal, it shows. Have the MV too high, and the difference is much less obvious. It's just compression. Imagine riding a motorbike and holding the revs just below where it comes on cam ( or pipe for stinkwheels ), then quickly roll the throttle on. The bike takes off. Having it at peak power all the time achieves nothing. Give it room to expand and the amp comes to life.
    Sadly, this is too loud for my family. Boo!. This, for me, is where the attenuator comes in. It's not quite the same as moving air. Nothing is, but it can come close. Give the valves some headroom, use the dynamics and rein it in with the attenuator.
     
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