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another dumb tube amp question... low watts into 2 215's

Discussion in 'Amps and Cabs [BG]' started by MattZilla, Mar 27, 2015.


  1. Hah! no.

    4 vote(s)
    36.4%
  2. tried it. kinda, sorta, almost as loud.

    7 vote(s)
    63.6%
  3. toe mah toe

    0 vote(s)
    0.0%
  1. MattZilla

    MattZilla

    Jun 26, 2013
    CNY
    So, apparently I have to have at least 4 feet in cab height to Rock with tubes regardless of whether I go full svt vr or bug 1960. 4' of cab is not going to fit in my compact 2 door. I don't currently have trailer/truck/van for hauling, but when I do get another one, it's going to be a while before I can afford another amp, so I've been toying with the idea of building a case for my b15 head and building a couple of 215's that'll each be essentially two thiele cabs stuck together. I figure that since the b into my sunn d140f loaded 215 was loud enough for a rock drummer with restraint and a guitarist with a 50w marshall into a 112, and my sunn was at least shooting sound into my thighs rather than just my shins (Im kinda tall), then a vertical set of 4 beta 15a's powered by that b15 would possibly hold down with a pair of 50w 112/212 guitar doods and a heavy handed drummer in a medium club with vox/kick-only foh and would be shooting sound from as high as my shoulder down and, as such, should at least keep a level stage volume for medium-loud rock.
    I've already sketched up some cabs and see that the shortest that I could make the stack while having it have the appropriate volume per speaker is a few inches under 6'. I am a bit over 6' so I consider it a slight win in the not-looking-absolutely-ridiculous-onstage department. I'll have to do a mockup, but I think I might be able to tweak the dimensions to fit one in the trunk and one in the back seat.

    TlDr: 30 tube watts into a vertical column of 4 15" speakers- to those of you as crazy as me to try 2 215's in any configuration with less than 60w, is it loud enough to actually compare to a v4 cranked into a single 115?

    To those who read my last dumb thread and are maybe thinking "dude, you were just asking about 300w into a 212, now you're wanting to do a giant full stack with as little watts as possible?" Yeah. I'd like to keep my options open and my tone awesome. ...and I have a demented need to be different for the sake of being different.
     
    Last edited: Mar 27, 2015
  2. Tube amps don't see a power increase due to impedance load, so your increase in output has to come from more speakers.
     
  3. will33

    will33

    May 22, 2006
    austin,tx
    Some simplified spl/power math says they'd end up about the same, though the 4-speaker stack would feel "bigger", and probably percieved as louder due to speakers up around ear level.

    Example, say you have a 97db@1 watt speaker. 100 watts would make 117db.

    4 of those same speakers @ 1 watt would be 103db. Add 20 watts and you're at 116db.


    That's pretty simplified, but you're using low power levels, so, probably close enough to get an idea.
     
    Downunderwonder likes this.
  4. MattZilla

    MattZilla

    Jun 26, 2013
    CNY
    Hah, sweet. So if I want v4 -> 215 volume I just fire up 8 15's via the b15 (not really ever gonna happen but it's fun to think about how much dough I save doing it this way :) [edit] :( before i figure in the cost of a trailer/bigger vehicle).

    Super glad the five minutes spent figuring out a switch for isolating each speaker / putting them in series with a parallel out wasn't a waste lastnight.

    Just measured- my sunn cab is uselessly too large, but the twin-thiele 215 design will fit in both the trunk and the back seat. I win! Where do I get some nice 5-7 ply birch?
     
  5. higain617

    higain617

    Sep 12, 2013
    WA
    I temporarily ran a 150W tube head in to a single SWR SOB 1x15. It held its own against two 120W tube guitar amps. It definitely sounded 'bigger' in to a 2x15.
     
  6. hdracer

    hdracer

    Feb 15, 2009
    Elk River, MN.
    for the price of one efficient 215 cab you could buy a used SVT or other 300 watt tube amp and melt peoples faces off with one 215.
     
    mbelue, button and Sid Fang like this.
  7. Sid Fang

    Sid Fang Reformed Fusion Player Supporting Member

    Jun 12, 2008
    I like this, but it makes my back throb just thinking about it.
     
    shawshank72 likes this.
  8. hdracer

    hdracer

    Feb 15, 2009
    Elk River, MN.
    and moving 2-215's doesn't? even with neo's it would be a pain.
     
  9. Sid Fang

    Sid Fang Reformed Fusion Player Supporting Member

    Jun 12, 2008
    Don't know. Never owned a 215, and my Neo 212s are really no problem, weight-wise. On the other hand, I do own a vintage SVT head+810, and have come to really resent how they remind me that I'm no longer 25. :dead:
     
    MattZilla and Jim C like this.
  10. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Let's face it...the 100w amp will be considerably louder. I have regularly run my B-15 with two 115 cabs in the past, and it's only 25w and it ain't bad at all. Seriously doubt it'll work in your situation. The 415 idea is fine, but you would do much better with a 215 or twin-115 rig with modern speakers that can handle a lot of power and more wattage than a 415 and very low wattage. D140 was great for its time but there are some excellent 15"s out there now that blow it away for power handling.
     
    allredtillblue likes this.
  11. SanDiegoHarry

    SanDiegoHarry Banned Supporting Member

    Aug 11, 2008
    San Diego, CA
    Rather depends on the cabs and the amps... but while 4 of any type of speaker will move more air than one, if you don't have enough power to drive those speakers, you'll not hear much anyhow!
     
  12. friendlybass

    friendlybass

    Jul 19, 2012
    Colorado
    Quadrupling speaker size will give you 6 more dB. Also I've got a serious bass boner for a 415 mega rig, but a much bigger head would probably do it more justice. I dont know the minimum impedance on a B 15 but if you were to do it that'd be a concern. If you do this pleeeease post a build thread for your cabs
    Edit: As to your original question, in theory itd be approximately the same, but with power and volume relationships we all know its not so simple.
     
    MattZilla and allredtillblue like this.
  13. button

    button

    Aug 16, 2007
    Los Angeles
    Go back to 300w into 212s!!!!!
     
    MattZilla and allredtillblue like this.
  14. MattZilla

    MattZilla

    Jun 26, 2013
    CNY
    @JimmyM re:d140 I don't know if it's the speakers or the cab that they're in, but I really don't like them at all. Since I replaced the stock speaker in the b15 with a beta 15a and reeeeally like how that sounds, I was planning on using four of those (I was also considering using the beta 12a's as they seem to have similar enough characteristics according to Eminence's site and the stack size would be a bit less ridiculous). Would I be wrong to think that kappalites, while being more efficient for exponentially bigger amps, would only be being tickled by my amp into being even a smidge quieter than the beta's?

    @friendlybass I really want to do this just to do it now:) Worst case scenario I'll have a couple of neat 215's already then I can focus on getting a booger 60 or v4 to power them.
     
    friendlybass likes this.
  15. friendlybass

    friendlybass

    Jul 19, 2012
    Colorado
    You could even go modular and get a little weird with it! Do 4x4ohm 115s and daisy chain 2 for each parallel out (which unless I'm mistaken gives you 4 ohms total load) that way you could just what you needed for the gig!
     
  16. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Matt, sorry but I have no idea about the Kappalites vs the Betas. I would assume you're right based on the specs, but I have no idea how that plays out in real life.
     
  17. The Beta 15a's have a peaked bass and peaked upper mids and highs. You almost cannot get serious peaking in the bass from the Kappalites, and they have much tamer upper mids and highs. So if you like the Beta 15a's, you're not likely to be as pleased with the Kappalites (3015 and 3012HO). What the Kappalites have going for them, that might interest you, is greater sensitivity: 3-4 db per driver. The peaking in the bass and treble (of the beta's) would somewhat reduce the audible difference in sensitivity between the Beta's and the Kappalites. The two 2x15 cabs loaded with Beta 15a's that you are considering would be a formidable stack for a low power tube rig.
     
    MattZilla likes this.
  18. MattZilla

    MattZilla

    Jun 26, 2013
    CNY
    20150329_201707. I think that this one is right... this lets me either have each cab in series, together linked in parallel for a single 8 ohm load, to power just a single cab with the two outs of the amp powering each speaker seperately or just one amp out into one speaker if there's a situation where I should've just brought the stock b15 cab and two speakers are one too much.
     
    Last edited: Mar 29, 2015

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