Attenuator vs Effects Loop Volume Knob

Discussion in 'The Tone Zone' started by Shane Stevenson, Jan 24, 2020.

  1. Shane Stevenson

    Shane Stevenson Well-Known Member

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    I picked up the JHS little black amp box and it’s doing a pretty good job in the loop of my SV20h. It’s definitely worth $45. I’m just wondering about the big differences in tone I might be missing out on by not using an attenuator.

    The JHS does ok but I’m not sure it’s giving me what I need for playing live on those rare occasions where I may need to attenuate. So far I’ve read that attenuators make your power tubes work for the tone where as effects loop volume boxes don’t. I’m just wondering why this is due to the fact that I still have to crank the volumes (loudness) on my amp. Wouldn’t turning the volume on my amp up push the power tubes?
     

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  2. Frodebro

    Frodebro Well-Known Member

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    Turning the volume up won't push the power section if you're bringing it back down again with a second volume control in the loop. It all comes down to the level of the signal that hits the front end of the power amp.

    The volume control is part of the preamp, and controls the signal level that hits the input of the power section.

    The power amp itself does not have its own volume control-it simply amplifies whatever signal it is fed.

    Attenuators are effectively a volume control for power amps, as they control the volume after the power amp.
     
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  3. Shane Stevenson

    Shane Stevenson Well-Known Member

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    Ooooh, I see. the way you explained it makes more sense than anything I’ve found so far lol. Thanks!!
     
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  4. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    That is nothing like a power amplifier attenuator. The little black amp box is nothing more than a potentiometer being placed in an effects loop to act as a Master Volume.

    A volume control in the effects loop allows you to crank the preamp stages while turning the level/signal volume down before the phase inverter stage and power amplifier. I myself would rather use a pedal to do that, like a Boss FV-50H/L or some other settable foot controllable pedal.

    A power amplifier attenuator at the output allows you to crank the entire amplifier while limiting the power to the speakers.
     
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  5. Shane Stevenson

    Shane Stevenson Well-Known Member

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    So I would imagine that the general consensus on retaining the character of an amp when it’s cranked would be a quality attenuator over an effects loop volume box, or even over a volume pedal.
     
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  6. Frodebro

    Frodebro Well-Known Member

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    It depends. Some amps get the bulk of their character from the preamp (such as most Mesa/Boogies), so an attenuator would be less ideal than just using the master volume in those cases.

    I experimented with my Mark V and Rivera Rockcrusher a couple of years ago, comparing the Boogie utilizing its master volume to hard bypassing the master volume (there's a switch for that on the Mark V) and using the Rockcrusher to control the volume. What I found with that particular amp was that while there was a difference in sound between the master volume and the attenuator, it wasn't really a big enough difference to make it worth the effort.

    Oh, and a Mark V with the master volume hard bypassed and the channel volumes all set to noon is loud enough to sterilize a water buffalo from 300 yards.
     
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  7. mickeydg5

    mickeydg5 Well-Known Member VIP Member

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    Actually its whatever you want. It can be both and then some.
     
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  8. Michael Roe

    Michael Roe Well-Known Member

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    I have seen several guys getting those volume boxes for their SV20 amps. It boggles my mind why they would do that???
    The whole point of the SV20 amp is that "Plexi" tone which is hitting those power tubes and getting that amp to sing. You can only do that by letting that power amp section stay wide open like it was designed. An attenuator will retain that power amp sing and quiet the amp but does inject in some other stuff, like losing some treble.
    If you are going to use a volume box then just save your money and get the SC20 amp instead of the SV20. It for the most part works just like that with it's own Master Volume.
     
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  9. Shane Stevenson

    Shane Stevenson Well-Known Member

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    I actually have both, the SV20h and the SC20h, with both matching 2X12 cabs. I love these amps! There are only about 2 venues where I need to attenuate my SV so it’s not that often. I was just wondering if an attenuator would be better for keeping that plexi tone. From what I’m reading it seems like the attenuator is better to use with my SV than the JHS volume box.
     
  10. FracStrat

    FracStrat Well-Known Member

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    Yep
     
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  11. Scumback Speakers

    Scumback Speakers Well-Known Member Sponsor

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    Here's what the Scumback DBL attenuator sounds like. Courtesy of Sirloin on the TGP forum.

     
  12. tce63

    tce63 Well-Known Member Premium Member

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    I have the Weber Mini mass 50, and it works great, I also use it with my SV20H in small venues Live.
    For 135$ or so it is great.
     
  13. Shane Stevenson

    Shane Stevenson Well-Known Member

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    Only problem with the mini mass is finding one for sale. I saw one on Reverb a while back but it didn’t last long. I guess I could see what it takes to order one directly from Weber.
     
  14. South Park

    South Park Well-Known Member

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    I have 2204 clone and 4 12 cab and some one gave me a kustom single 10 cab 8 ohm I plugged it in it sounded good half as loud as that as the 4 12
     
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  15. Madfinger

    Madfinger Well-Known Member

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    I don't see any point in having a attenuator for home use if your running SV20H @ 5w mode through a 1x12 when a volume box in the loop will do. I don't see any point in buying a 2x or 4x12 cab then needing to attenuate in a 20w gig situation. Most guitars have volume knobs & tone controls so unless your doing high gain thrash dimed or simply can't play a clean note. Pointless IMO.
     
  16. WellBurnTheSky

    WellBurnTheSky Well-Known Member

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    Nope. The parallel channels vs cascaded channels makes it different amps in the way the sound and feel. We might have to agree to disagree on that, but that's my opinion, and the reason why I got the SV over the SC.

    And YES, I use a volume box in the loop for gigs, and it works for me.
    I actually used my Captor to check out how much the volume box takes away, compensating to loss in output from the volume box with the output level on the Captor, so as to match levels. And the truth is, unless you totally wind down the volume box (at which point you indeed neuter the amp...but then again, at whisper volumes speakers don't move air either and don't sound like they're supposed to, which is why to me using a load/IRs solution at home will always work much better for late night playing), what you lose is mostly compression. Which should be obvious to whoever has used these amps: over 3-ish on High Treble volume, you don't really get more volume, mostly saturation and compression. Which you can get back by other means (pedals, that is). But most of the time it isn't the total slaughtering of tone that some seem to think it is.

    And in turn, if you're using delays in the loop, you're getting back some clarity. EQs/volume boosts in the loop also start working more like you expect them to.
    Which TO ME (and again, that's really what matters, as that's my rig, my way of using it, and ultimately my money...and tools used for earning it too btw) is an acceptable trade-off. Might work for you, might not.
    But I wouldn't make blanket statements about it not working, or even painting it as borderline heresy, as some tend to do.
    To me, as I wanted THAT tone and THAT feel that only a "Plexi" provides, making it work for my needs, it was either a volume box or a load/reamp device. In that scenario the volume box works as expected, and frankly that's all I really care about.

    It always pays off to think outside the box a little, and experiment to find what works for you and what doesn't. Other people's opinions only get you so far.
     
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  17. Michael Roe

    Michael Roe Well-Known Member

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    I guess that came out a bit wrong. I was trying to say that if you were comparing both amps and think that a volume box is the answer to tame loudness on an SV amp, it might not be the most favorable option to retain the tone of that amp. A lot of guys compare the SV and SC. They can be very similar in tone but I personally think the SV wins that battle.
    Obviously, it is just my opinion! I just would not want to steer a guy into thinking that a volume box and an attenuator do the same thing. Yes, they both will quiet the amp but in different methods. In a live situation where you just need to cut a little db off, the volume box could be perfect. If you are in a bedroom and think the volume box will achieve the same thing as an attenuator on an SV and retain all that "Plexi" vibe, well, you are misinformed, IMHO.
     
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  18. WellBurnTheSky

    WellBurnTheSky Well-Known Member

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    No worries Michael ! I definitely agree that an attenuator and a volume box are not the same thing, and depending on what you need and how you use the amp, one will work better for you that the other. And yeah, using a volume box to get to bedroom level won't work for all the reasons you pointed out. Though I stand by my opinion that even an attenuator won't get you the full picture either, as no matter what you'll miss a HUGE part of the equation, which is the speakers actually moving air. Which is why at that point using a load and IRs sounds better (to my ear) than a real cab. No replacement for displacement, right ? ;)

    As for the SV/SC comparison, yeah, I get your point. But to me the parallel vs cascaded preamps make for two different amps with different vibes and (most importantly, to me at least) feel in the way that it reacts to your playing. Even though they can be made to sound very close to each other, one reacts better to playing dynamics to the other.
     
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  19. Michael Roe

    Michael Roe Well-Known Member

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    I agree with you that the Load box/IR route is probably the best you can get to capture a recorded tone in a quiet environment. I do this myself and even own a website that sells IRs for that purpose :)
    Interestingly, I own a Kemper and the hardest amp to get it to profile accurately is...….a NMV plexi!
     
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  20. SkyMonkey

    SkyMonkey Well-Known Member

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    I just got the LBAB, and it is a fine piece of kit.
    I am no cork sniffer though.
    Plus I am generally skint most of the time.
    It does the job for my VS65R.
     
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