Low watt amps and compressors

Discussion in 'Glowing Bottle Tube Amp Forum' started by DannyStereo, Jul 29, 2019.

  1. Asmith

    Asmith Friend of Leo's

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    I got a boss cs3, I tried it in store liked it but after a while I couldnt stand it. I wanted something to give me some extra sustain without adding distortion but it removed too much attack. I ended up replacing the tone control with a mix knob so I could blend the compressed signal with the original, worked a treat. I use low wattage amps but I struggle to see what relevance it has with the matter
     
  2. Geo

    Geo Friend of Leo's

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    I use one in a Route 66 V2 some mainly for clean boost (compression turned down or off),
    EQ change and some mild compression. You can barely tell compression is there but it does what
    it is intended too very well. Even with compression turned up all the way there is no rubbery sound
    like the old MXR or EH ones.
     
  3. William Pugh

    William Pugh TDPRI Member

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    I picked up a Maxon CP101+$$ for a Peavey Bravo that I hated. Had never heard of a compressor before.

    He said he couldn't say what it did, but he never turned it off.

    I set it up, turned it on and wasn't sure it was working. Then I turned it off and found that things didn't sound quite as good somehow.

    I turned it back on and haven't really tried playing without it.

    Both knobs set between 9 and 10 o'clock.

    Wish I could say more, but that's my experience.
     
  4. DannyStereo

    DannyStereo Poster Extraordinaire

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    Maybe not ALL low watt amps, but in my experience, AC or Marshall style low watt amps do hit the ‘I’ve run out of clean and I’m compressing’ pretty much around 11 o’clock or noon. Some people call it ‘edge of breakup’, I call it then amp is starting to shelve off the top and bottom of the sine wave.
     
  5. Asmith

    Asmith Friend of Leo's

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    Are you aiming to use the compressor as a limiter, to squash down the attack and set the maximum clipping?

    Thats not how I use mine personally, I don't like the sound of a squashed attack but obviously it has its uses.
     
  6. Alex W

    Alex W Friend of Leo's

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    IMO you're using the wrong word here. Compression is not overdrive or distortion. You can use a compressor to modulate the attack of the note and the sustain of the note, and these are independent of the amp being clean, overdriven, or on the edge of breakup.
     
  7. DannyStereo

    DannyStereo Poster Extraordinaire

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    I politely disagree. Compression, by its definition, IS distortion. You’re altering the initial input signal by shelving the peaks and adding makeup gain for the valleys.

    Same concept applies to a Distortion Pedal or Fuzz. You’re squaring the wave hard at that point.

    Where tube amps come into the equation is in the issue of headroom. The less headroom you have, the easier you’re gonna get to that ‘shelving’ level, hence why a Twin will stay round and full and keep getting louder while an AC15 doesn’t actually increase volume past a certain point, it just sounds more driven And, you guessed it, compressed.

    So, at least as I understand it, compression IS distortion and distortion IS compression. Now, how you arrive there is where the question lies - do you add gain to push your amp into natural breakup and/or compression, or do you compress your signal BEFORE it enters your amp’s input. And, what I’m specifically considering is - should one do BOTH, or is that too MUCH compression?

    Hope I’m explaining myself well :)
     
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  8. Asmith

    Asmith Friend of Leo's

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    Compression/distortion in an amp is different to a compressor pedal. In a compressor there's no clipping, it just modulates the volume to even it out and there isn't any harmonic distortion. In an amp it's a little more complex because the clipping can be fairly soft but if the amp is overdrive then there generally is clipping (what guitarists call distortion). I would use a compressor when clean but not with an overdriven amp (regardless of amp wattage).
     
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  9. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    NO!

    Compression does NOT distort the signal. Reading through the thread it sounds - respectfully - like you don't really have a clear understanding of compression, limiting, distortion etc.

    A compressor might CAUSE your signal to distort if you dime its output, essentially using it to "overdrive" the first preamp gain stage. This way you are using the compressor NOT as a compressor, but as a signal booster, hitting the first preamp section with too much gain for it to maintain a clean signal - so the PREAMP distorts....not the compressor.

    The function of a stompbox compressor is to reduce the dynamics of your signal by leveling the input amplitude and "equalizing" it. Your attack, if slightly varied, is "squashed" AND boosted at the same time, evening out the starting point of each note or chord. It then maintains that level - to a point - increasing sustain somewhat.

    This is where stompbox compressors normally start to have problems - the background noise is raised along with the guitar signal, and because it's initially lower it's raised a bit more. This is the dreaded compressor hiss that bothers so many players....and soundboard workers. A limiter, OTOH, only levels the input signal, with no signal increase as the note(s) fade (but with the same loss of picking dynamics).

    Compression does NOT create a distortion-type square wave signal. That is a specific signal processing action, normally combined with more jagged distortion waveforms. But for years country players have used compressors to control their attack, add some "snap" to their playing and provide an even, clean, sustained sound. All a compressor will do to the input signal is lower the high-amplitude levels, raise the lower amplitude ones, and send a level-equalized signal to the preamp.

    If it's a clean signal being sent to the compressor, the compressor will send a clean signal to the preamp.

    If you stick a distortion pedal in front of the compressor, it will send a distorted signal to the preamp.

    However, the compressor creates NO distortion of its own.

    But as previously noted it DOES have a detrimental affect on dynamics, as every note, double stop and chord has the same volume - unless you use a newer compressor that allows you to mix your "dry" signal" with the "squashed" one.

    I hope that clarifies the true function of a stompbox compressor.

    And to just touch on the subject briefly - players do not add studio compression. Studio compression is handled completely by the engineer and producer - normally drums and bass have a slight amount added and entire tracks are compressed during the mixdown - finally, mastering of CD's involves different compression to equalize the levels of all instrument/vocal tracks, with (in the past, and making a comeback!) different compression and equalization for CD's than mp3's, AM radio, FM radio....or LP's (or cassettes in the old days). Each requires different compression and equalization.

    FWIW the studio info is from my oldest son, who was a ProTools, Logic and 16-track tape engineer at NRG Studios in N. Hollywood (Matchbox Twenty, Stone Temple Pilots, Linkin Park & others - using Universal Audio LA-3A and Gates Sta-Level levelers, Neve 2254 & 3046 compressors etc.) until digital home recording changed the entire industry.
     
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  10. DannyStereo

    DannyStereo Poster Extraordinaire

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    A quick google search - “Distortion is any change in the content of an electrical signal or the shape of a sound wave during its transmission. It could also be described as information either lost or added relative to the original signal. Audio distortion can be placed in two broad categories. Type 1 — linear, altered amplitude content. Type 2 — nonlinear, added frequency content.”

    Again, Distortion NOT meaning gain. So, I maintain my previous post. You simply cannot Compress without distorting the signal, since you’re ACTIVELY altering the amplitude of your signal by applying a compressor pedal or pushing your amp into its own compression - or quieting the loudest parts and making the quietest parts louder.

    WHERE the compression occurs is up to you.
     
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  11. Asmith

    Asmith Friend of Leo's

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    You can argue that the terminology is the same but type 1 and 2 sound is completely different. If I'm using a Princeton reverb (12 Watts) and want a clean country tone I might use a compressor but I won't overdrive the amp.
     
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  12. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    That is output stage saturation. Where you are exceeding the clean sound capabilities of a combination of the output transformer and tubes. The signal compresses AND distorts - but while they happen concurrently, they are not the same thing.

    Distortion is NOT part of compression. I have no idea where you think you found audio engineering information that stated that, but You misinterpreted something or think you read something that isn't true.

    Have you ever taken a class in acoustical foundations of music, taken a certification program in studio recording, or read technical; articles written in layman's language that explain compression? My impression is that you haven't - or misunderstood the material.

    Try starting here: https://music.tutsplus.com/tutorials/the-beginners-guide-to-compression--audio-953

    I'm not trying to be mean or overly critical, but it's impossible to discuss compression at all - whether in amplifiers, pedals or recorded tracks - when there's a misunderstanding of "Compression 101".

    Let me give you one more example - bass tracks are virtually always compressed on commercial recordings. But only rarely are bass signals distorted, and normally because the player sends a distorted signal direct to the track (think "Jack Bruce").
     
    Last edited: May 26, 2020
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  13. DannyStereo

    DannyStereo Poster Extraordinaire

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    I don’t think you’re overly critical. It’s good to talk it out.

    I did shadow a local engineer for a bit for a college project. That’s one thing he drilled into me - any time you change the original signal in ANY way, you’re ‘distorting’ it. Maybe I’m wrong, but I think it’s worth the discussion.

    I did some rearranging of pedals and I think I will take more time with the compressor set low.

    Normally, I can open up my amps a bit and they sound so good, but I did record some worship for a livestream this past week with a church, and I had to turn down quite a bit because of the room we were recording in. THAT is where I missed the compressor. The amps were not pushing, so it just felt... flat. They were not singing like I normally set them (I run a two amp setup - this week it was an Orange OR-15 and a Tone King Falcon).

    All this to say, I’m not dogging on compressors or folks who use them. Just like with anything else guitar related, I’m not an expert and all I can offer is my opinion :)
     
  14. DannyStereo

    DannyStereo Poster Extraordinaire

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    Oh and for reference here is the old board - Aria > Ruby Red > Iron Horse > Volume pedal > Tuner > Boost > Caverns > PS-6 > Timeline > Flint

    These are the settings I arrived at on the comp side of the Aria also
     

    Attached Files:

  15. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    I'm
    I think there was simply a misinterpretation of what he was saying

    Many times you'll hear that the *reverse* is true - a distorted signal is always somewhat compressed - but , OTOH, a compressed signal is NOT always distorted.

    You can read the material I linked and move on to more advanced tech data. It's all consistent: distortion is compressed; compression is NOT usually distorted.

    It's a subject also covered in college electronics and the previously mentioned acoustical foundations of music - in both textbooks and lab work. If you ever ran signals through an oscilloscope you'd have empirical proof in minutes.
     
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  16. DannyStereo

    DannyStereo Poster Extraordinaire

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    I THINK we are saying the same thing (maybe) in different ways. Lol

    Regardless, at the end of the day, it’s all about what that means for TONE. I am gonna commit and try a very low amount of compression up front. I’m playing at two different churches this week, so I’ll get a chance to really put the Aria through its paces with the low comp settings.
     
  17. Modman68

    Modman68 Tele-Holic

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    Would you consider altering your guitar’s volume “distorting” the signal?


    Sent from my iPhone using Tapatalk
     
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  18. DannyStereo

    DannyStereo Poster Extraordinaire

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    Depends on what you define as ‘input’ signal. If you’re measuring the electrical flow from the strings or from the first stage at the pedalboard or amp. If you’re talking about strictly from your strings on, then yes, a volume pot will alter the signal. Try turning on your spigot only halfway and tell me it’s the same ‘signal’ as turning it on full blast.

    I tend to think of the signal starting at my first pedal, since that’s what we are talking about here - pedals and amps. Everything between my cable and the speaker will affect the signal and ‘distort’ it. Hell, we could get nit picky and say that even if you plug straight in, the cable itself is adding its own effect to the signal. Or the power in your house. Or the weather. Or how long your nails are. Or how calloused your finger tips are. Or whatever.

    So whether you feed the amp 50% or 100% of your signal, that’s what I count as ‘input’ signal.

    I don’t think we can fully avoid having an effect on the origin source, and I think that’s what makes music so beautiful. All the little distortions along the way.
     
  19. DannyStereo

    DannyStereo Poster Extraordinaire

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    I will also note I am not looking for y’all to convert to my point of view. We can disagree and still be friends :)

    After all, we all hear things differently and that’s just a-ok with me.

    Hell, I’m not above admitting I could be full of manure here. Hahaha
     
  20. Silverface

    Silverface Poster Extraordinaire Platinum Supporter

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    I don't know why I didn't ask this earlier.

    Why are you using a compressor at all? Most players I know that use them do so because they are stuck with an overpowered amp that they have to run at low volume level, and they're trying to get some kind of "imitation output stage saturation" like they wood with a a low-powered tube amp that can be run right at the headroom limit with their guitar controls rolled off 20% or so.

    I spent over 25 years playing progressive "rock band" worship music - 3-4 sets a week plus my other "normal " gigs and sessions) and only used a compressor for electric 12 string (which otherwise sounds like a sitar falling down stairs!:lol:)

    But I used tube amps that could be run as mentioned - right at the headroom limit with guitar controls rolled back. This left me enough control at the guitar to increase level for solos and with a last "push" slide into smooth output stage saturation.

    In most churches we ran baffles in front of the amps (which were miked)to control stage and "first row" volume, and I'd use a tweed bandmaster clone with a half-power switch or a Holland running at roughly 18 watts (a boutique amp with multiple tube options.

    In a couple churches with no baffles I used a Champ with a 12" speaker cab. At club jobs ' use a Deluxe Reverb, the Bandmaster on "full", or the Holland at 35 watts loaded with EL34's.

    Other local players a did the same thing - used the lowest-powered amp they could run clean to saturated without blowing out the crowd's eardrums. No bigger amps (haven't seen a Twin except on large stages with touring bands in 15 years) - and nobody uses compressors anymore, unless they play electric 12 or they want to use one on a couuntry tune or two for that "snap" at the front of the note.

    But they're so detrimental to playing dynamics that even the ones used today have the capability of mixing in some "dry" sound to regain SOME dynamics. I use a Janglebox JB3 (handy because of both the mix and a separate clean boost section) - and use the boost 90% more than the compressor.

    But unless you play 12 string, why in the world would you compress the sound of a low-powered amp? I don't understand your application at all - it's actually something I used to teach students to very specifically NOT do!
     
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