One big amp vs 2 smaller ones

Discussion in 'Amp Central Station' started by gpasq, Jan 29, 2013.

  1. zippie

    zippie TDPRI Member

    Posts:
    69
    Joined:
    Jun 26, 2012
    Location:
    new york
    isn.t there an old saying...two equals one...one equals none.

    i think the best real world advantage is that with two amps you always have a backup.
     
  2. Deaf Eddie

    Deaf Eddie Friend of Leo's

    Posts:
    3,050
    Joined:
    Mar 17, 2003
    Location:
    Beautiful Idyllwild, CA
    I'll give you a real world example, and you can draw your own conclusions (same as I did in that other thread):

    I used to gig with two Princeton Chrous amps. They have dual power amps rated at about 25 watts. So, in effect I had four 25 watt amps. That rig was nowhere near as loud as a 50 watt amp, let alone the 100 watt amp some people think it should be, using not-quite-real-world math. It just sounded like a "full and sweet" 25 watt amp. So, in MY experience, you can't add up the power and get a real idea of how LOUD it will be.

    Based on that, I'd say two AC15s aren't going to be anywhere close to as loud as an AC30. So, you'll still be micing your setup, even with two. If volume isn't the reason for adding the second amp, two small ones will work just fine - but it simply won't make your rig any louder.
     
  3. leebman

    leebman Tele-Meister

    Posts:
    324
    Joined:
    Apr 28, 2009
    Location:
    England
    Aren't those amps solid state amps, they never appear as loud as a valve amps.
     
  4. Deaf Eddie

    Deaf Eddie Friend of Leo's

    Posts:
    3,050
    Joined:
    Mar 17, 2003
    Location:
    Beautiful Idyllwild, CA
    Well, yeah, so? I always play SS amps. The "four" SS 25 watters didn't add up to a single SS 50 watter, to my ear. We're not talking about SS vs tube - we're talking about two smaller amps vs one bigger amp. The comparison still holds, IMHO.
     
  5. fauxsuper

    fauxsuper Tele-Afflicted

    Posts:
    1,688
    Joined:
    Sep 15, 2007
    Location:
    San Diego, CA
    I would like to see the math that proves that one big amp is going to be audibly louder than two amps of the same wattage.

    I'm not trying to be argumentative, I just haven't seen any thing that would justify this. I've designed professional sound reinforcement systems and worked with audio engineers and have never heard this other than here. These systems typically use multiple amplifiers and I've never seem any admonishions to use as few amps as possible to get the "volume boost" a single big amp should provide.
     
  6. telo

    telo Tele-Meister

    Posts:
    411
    Joined:
    Apr 15, 2008
    Location:
    richmond hill
    I'm a Princeton fan (the amp), but one of the limitations of most low wattage combos is the size of the cabinet. You can play two Princetons simultaneously, but it's not all of a sudden going to emulate the properties of a bigger 1x12 cab of a Deluxe. And I'm pretty sure we all know how much the physical size of a cab has can affect sound.

    As Wally says, it's difficult to find an amp that has the same 'sonics' as another amp that's double the power. The closest thing that I can think of is the Dr Z Maz Jr (18w) and the Maz Sr (38w). I believe they both use the same iron and while they don't sound identical, they're pretty close. I used to own two Maz Jrs and my buddy still has his Sr. In my experience two Maz Jrs, each with its own 1x12 cab, are definitely louder than one Maz Sr into a single 1x12 cab.
     
  7. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,485
    Joined:
    May 24, 2010
    Location:
    Canada
    One of the geeky ones here (I consider fauxsuper, a geeky one also) and yes we went through this a while back. Fauxsuper's example of two amps into two speakers or one amp of twice the volume in the same speaker is a good example on how the two are equally loud. Mind you that assumes the amps were designed with the same dynamic capabilities as Wally pointed out, the smaller amps operate the same way as the bigger amp, they just were shrunk down in the wash.


    As far as the 50W amp having more headroom than a 25W amp, not likely. Say we have an amp (head not combo) with a pair of EL84's and one amp with four EL84's. The manufacturer basically increased the size of the output and power transformer to get a 30W amp from a successful 15W design. In this case the limiting factor are the tubes in how much power can be produced. Two tubes will do 15W, use double the tubes and you get 30W. Quite simple actually. If the 15W amp has 1dB of headroom the 30W amp will also have 1dB of headroom. So if the smaller amp has X watts of headroom the bigger amp will have 2X watts of headroom. If you use two 15W amps you will have your 30W plus your 2X watts of headroom.

    If the manufacturer could squeeze more power out of the 30W amp they would have advertized it as having more. Most people would go for the 35W amp over the 30W amp given all else being equal, right? Where bigger amps get their advantage is when mated with more efficient speakers or a pair of them. That is where your added loudness comes in. Take a Peavey C30 and feed it into a single speaker rated at 100W, more than the amp can put out so the speaker is not limiting the volume. Use two of the same speaker on the C30 and you will get an added 3dB in loudness for the same watts out. Cost you another trip to carry the speaker but you gain loudness or headroom if that is what you are after. Use the two speakers with a pair of 15W amps and you will have more volume than if you used the 30W amp and one speaker.
     
  8. printer2

    printer2 Poster Extraordinaire

    Posts:
    6,485
    Joined:
    May 24, 2010
    Location:
    Canada
    You snuck in a post before mine, funny you confirm my last point.
     
  9. willspear

    willspear Tele-Holic

    Posts:
    541
    Joined:
    Apr 29, 2012
    Location:
    portland
    Wattage ratings are a part of volume. But it's not Linear A 15 watt amp is not half the volume. To literally double the volume of a 15 watt amp with the same speaker efficiency and speaker area you'd need something like 150 watts


    If you run a small amp or multiple small amps your representation sonically is increased dramatically by increasing the effective surface area of your speakers. Essentially you are pushing more air.

    Take two amps both the absolute same except one is fed through one 12 inch speaker and the other is fed through 2. In that scenario you are making something that will be perceived as louder by anyone in the room. Odds are if you doubled the wattage of the amp with one speaker it would still get over shadowed by the lower wattage 2 speaker amp.
     
  10. Big_Bend

    Big_Bend Poster Extraordinaire

    Age:
    56
    Posts:
    6,510
    Joined:
    Feb 19, 2010
    Location:
    Houston, TX
    I would MUCH rather play a Twin Reverb or a Super Reverb solo as opposed to two Deluxe Reverbs running in stereo. There is nothing like amazing powerful good clean headroom. Ya the two deluxe reverb amps will also sound great in their own way, but I need my clean clean luscious headroom. I can add dirt later when desired.

    Thats just me tho. Get the larger amp.
     
  11. Wally

    Wally Telefied Ad Free Member

    Posts:
    34,279
    Joined:
    Mar 17, 2003
    Location:
    Lubbock, TX
    +1 with Printer2....

    Big BEnd....if I took two SR's and installed SS rectifiers and put 2 x 12's on each of them....then the comparison with a TR would be valid....just as my initial comparison of two SS rectified DR's against a SS rectified SR through the same speakers is valid. IF we don't get the comparison on somewhat equal footing, then 'this wattage against that wattage' is invalid, imho.
     
  12. fauxsuper

    fauxsuper Tele-Afflicted

    Posts:
    1,688
    Joined:
    Sep 15, 2007
    Location:
    San Diego, CA
    A consider getting called a "geeky one" by Printer2 as a compliment

    A great reference book for this sort of thing is Sound System Engineering, by Don & Carolyn Davis. You can find it in online form here:
    http://books.google.com/books/about/Sound_System_Engineering.html?id=9mAUp5IC5AMC

    Here's another useful link with another link to an SPL calculator:

    http://guitarwtf.com/2012/04/17/wtf-is-the-difference-between-a-50-watt-and-a-100-watt-amp/

    I know, reading this stuff makes me a geek, but I used to deal with this stuff to make a living. It's pretty cut and dried. "How much power does it take to get 64 speakers to fill a large restaurant with a 9 foot ceiling at backgound lvolume levels".

    This is a little more "scientific" explanation than the one I gave above.

    Let’s say we have an 8 ohm loudspeaker that will produce maximum 90Db of output with a white noise signal from an amplifier cable of delivering 15 watts into an 8 ohm load at a level of distortion below 1%.

    Put an identical speaker next to it and feed it with the same signal from an identical 15 watt amp. You’d have two speakers with an output of 90Db.

    These two speakers together would give you an output of approximately 93 Db

    Connect the same pair of speakers in parallel to an amp capable of delivering 30 watts into a 4 ohm load at less than 1% THD, Each speaker will receive 15 watts and will play at 90Db and the total level will be, again 93 Db.

    Again, all things are seldom equal, and there are a number of factors such as speaker and cabinet configuration, manufacturers who base power ratings on what the advertising department would like and a given guitarist’s tolerance of distortion levels.

    If you can point out a major error in the calculations or theory, I’m certainly willing to listen.
     
    Last edited: Jan 29, 2013
  13. homesick345

    homesick345 Poster Extraordinaire

    Posts:
    6,794
    Joined:
    Jan 20, 2012
    Location:
    Beirut, Lebanon
    when I turn my second amp (to use stereo effect), the perceived volume is TWICE AS LOUD

    Enough with that "internal ear compression", & "two-amps-don't-sound-louder" bull....
     
  14. homesick345

    homesick345 Poster Extraordinaire

    Posts:
    6,794
    Joined:
    Jan 20, 2012
    Location:
    Beirut, Lebanon
    What you want really, is that big 6L6 sound. There is no substitute, & this has nothing to do with wattage.
     
  15. leebman

    leebman Tele-Meister

    Posts:
    324
    Joined:
    Apr 28, 2009
    Location:
    England
    That has always been my experience.
     
  16. Lunchie

    Lunchie Poster Extraordinaire

    Posts:
    5,567
    Joined:
    Jun 5, 2012
    Location:
    Downstate Illinois
    The OP's question is any advantages, not about volume however that was brought up later.

    You can utilize a stereo setup which is fun but not always practical. I have a Champ 600 stereo setup and although they are low watts with small speakers, it really can fill up a room.

    All talk about 50 watts vs. 2x 25 watts is all hypothetical and can change with every variance. If you want to compare a AC30 vs 2x AC15's then we could have this discussion but generic amp A vs Generic amp B1 & B2 is pointless.
     
  17. blargfromspace

    blargfromspace Tele-Afflicted

    Posts:
    1,222
    Joined:
    Apr 8, 2010
    Location:
    IRL
    The two 60W light bulbs in my house are nowhere near as loud as my 100W Twin.
     
  18. Lunchie

    Lunchie Poster Extraordinaire

    Posts:
    5,567
    Joined:
    Jun 5, 2012
    Location:
    Downstate Illinois
    you don't buy the noise canceling light bulbs?
     
  19. Tle4

    Tle4 Tele-Afflicted

    Posts:
    1,401
    Joined:
    Dec 28, 2010
    Location:
    Warrington, Pa. USA
    Faux.... Your theory makes sense to me. What if you went more extreme and say had ten 10 watt amps with a 1x12 cab vs one 100 watt amp with 2-4x12 cabs and you where measuring the volume from 200 yards away. Would you hear both amps at the same volume from a distance


    Also assuming we are talking tube amps and are cranking the amps to full volume and distortion... Would that make a difference which is louder
     
    Last edited: Jan 30, 2013
  20. willspear

    willspear Tele-Holic

    Posts:
    541
    Joined:
    Apr 29, 2012
    Location:
    portland
    Clearly the answer is to gig with two twins!
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.