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First rehearsal with Ampeg B25... so how many watts do we need, again?

Discussion in 'Amps and Cabs [BG]' started by andrus108, Nov 10, 2019.

  1. andrus108


    Mar 11, 2018
    I got back my Ampeg B25 after few weeks at an amp tech's, because it required replacing some parts before things blew completely (like a 50 year old power capacitor....) and a couple of necessary mods (bias control to fit 6L6's, rewinding a power transformer for 230V), and today I had my first rehearsal with it. For further information: it was plugged into a 2x10 with Eminence Delta speakers (101db efficiency), and our rehearsal room is ca. 16m / 50 ft2, ceiling height is maybe 2,5 m / 8 ft, and we play industrial rock, so synths and distorted guitar are present, but my drummer is not heavy handed.

    So how loud was it? I was a touch too loud, but not enough that I was drowning out the rest of the band. BUT that was the limit - I was aiming for the edge of break up, and I wasn't sure where it was at the beginning, so I started turning the volume up only to realize all I have further on is more distortion, of the lovely power valve kind of course, but still :) Also, technically, I still had some room to go louder, because the Ultra Lo switch was on; it was set up like that for recording last week by my producer / drummer's husband, will not digress here about the mixing technique because I personally would prefer my tone with it off, but I decided to leave it on for now just to get that volume drop.

    Anyway, my personal verdict is... if this set up can match a rock drummer's volume then 50 watts is plenty, or at least plenty for me. I like my tone slightly dirty, so that edge of break up is definitely what I want to achieve, and hence such 'low' power gives me exactly that. Now of course, will that be enough for a gig? We play one in 2 weeks in a small local venue (maybe 100-150 capacity) where guitar and bass amps often are left unmiked, so hopefully I will be able to bring this very set up and see for myself; will definitely follow up if that happens, but I guess I'll have to bring a mic just in case, and of course the Ultra Lo switch will be off.

    I don't know how useful this short report is to anyone, but I write it partly because when I was researching my first amp purchase the general consensus seemed to be that you need 300-500 watts and at least a 4x10 to match the volume of other instruments. I then decided to be somewhat 'smart' with my purchases, and decided to go a separate preamp / power amp route, because old heavy power amps are very inexpensive. Eventually I got a QSC USA 900, 2x 450W@4 ohms, so should be more than I'd ever need, but I was still missing a preamp. I stumbled upon a good deal for a GK 400RB, which of course is not just a preamp, it's a 200W head, but then I thought 'well, I have a nice practice amp included'. So off I go to one of my first rehearsals as a bass player, carrying that GK only. So I plug it in to a cab... and my volume never goes up above 9 o'clock yet I am perfectly loud with the others, creating a big question mark in my mind regarding how many watts is required. And hence this experiment, where at worst I'll end up with a really good amp for clean electric guitar or recording bass, not too bad of a place to be in my opinion :)
    Last edited: Nov 10, 2019
    JimmyM, grouse789, coreyfyfe and 2 others like this.
  2. Sorry but I can’t get past the 50 square foot rehearsal space with 8’ ceilings. That is TINY. I’m typically in the ‘You don’t need as much rig as you think you do’ camp - but WOW that is an itty bitty rehearsal space. One of my bands rehearses in a 24’x 60’ garage/pole barn. My GK MB112 is plenty for that country/pop/rock band rehearsal. For gigs I add the matching MBP112 but could do without on most.

    My point? Each situation is quite different.....
    dabis and pcake like this.
  3. andrus108


    Mar 11, 2018
    My bad, 16m2 is ca 170ft2, not 50 :-D
    richntiff and Wisebass like this.
  4. Generally the more speakers you add, the more efficient you get. So if you really like the tone of your vintage amp, I would suggest adding more speakers. For example per WinISD using Delta 10s you should have 121 db with 20 watts into 4 sets of the 2-10s. You need about 100 watts to get to 121 db with a single 2 10. Grab one of the speaker builder simulation programs and try different combinations of speakers and power and you will see what I mean.
    Last edited: Nov 11, 2019
    webmonster likes this.
  5. Wisebass


    Jan 12, 2017
    Lost in Space
    Hi andrus108 :)

    50ft2 => you have to sit on your drummer 's lap! :D

    No wonder he can 't play too loud. :laugh::roflmao:

    4m x 4m = 16 m2 That' s not huge but much better!


    That is bad! When you have to carry the room with your amps on stage you might get problems.

    You can have an awesome sound out front but on stage it will horrible or vice versa. :(

    (due to the room, the placement of your amps, the different amp 's volume etc.)

    Anyway your amp will probabely not be enough to carry the room without FOH support.

    IME it can only work (really good!) when you all keep your stage volume down

    to a strict "only monitor" volume. => bring those mics for your amp and the guitarist' s amp too!

    Get your amps on stands (beer crates can do the job) to get your sound closer to your ears.

    Dial your volume to carry the stage so that you can hear yourself and the guitar (no volume wars!)

    and dial your sound for the room! (don' t use the bedroom boost :D)


  6. andrus108


    Mar 11, 2018
    That particular venue has a crappy vocal only PA, plus some stage monitors. Every time I was there to see a gig and they put bass guitar or kick drum through it, it took away from the vocals. So for that venue my rig will HAVE to provide the sound, but the Dinky Rig thread has me hoping that I can at least scrape by. Plus, usually it's my guitar and synth players who seem to be fighting over low end, and I'm perfectly happy with providing audible mid range to the mix for a change, and for that kind of tone I'm sure 50 watts through a 2x10 is more than adequate. And if that won't work then I'm happy to be proven wrong by experience to inform my future needs.

    As per above, I kind of want to see how much a single 2x10 can get me before I decide where to go next. I expect to not provide any substantial low end with that cab only, but I'm already somewhat set on upgrading to a 2x12 with Basslites to improve this department. But at 118db I should be audible at the least, no?
  7. okcrum

    okcrum in your chest

    Oct 5, 2009
    Verde Valley, AZ
    RIP Dark Horse strings
    You're asking the wrong question.

    The correct question is: So how many dB of SPL do we need, again?

    The cabinet counts. 50w into some modern cabs is bedroom practice volume (see: Fearless).
    Last edited: Nov 11, 2019
    Bboopbennie, Wisebass and Wasnex like this.
  8. Wasnex


    Dec 25, 2011
    My I suggest the correct question is "How many dB do I need?"

    The answer to the question depends upon the situation and one's expectations. I generally like a nice clean and punchy tone and I typically played in auditoriums that seat 800 or more. Sometimes I played in much larger venues, all the way up to outdoor stadiums with an estimated 10,000 people in attendance, so my touring rig had to be able sound great in small venues or large. There is no universal correct answer because we all play in different situations and have different expectations on how an amp should be used, and how it should sound and feel.

    My last touring rig was an Eden D210XLT with a QSC power amp rated for 250W. I am confident an Ampeg B25 would have provided insufficient power for the SPL I needed for many gigs. But if the OP is happy with a B25 :thumbsup:. I am also quite confident many people would think an Eden D210XLT with 250W was pathetic, and totally insufficient for their needs.
    okcrum and Wisebass like this.
  9. Raw N Low

    Raw N Low If I can't hear it, hopefully I'll feel it Supporting Member

    Jul 16, 2009
    Denver, Colorado
    It's extremely relative to what your needs are. I recently used a B15s in a medium to a large venue using the ext. amp out into an SVT DI going in front of the house. It worked for me and I had a great tone. I've also used my B25B with a single Baer 12 and had no problem keeping pace with the band in rehearsal.

    I could do the same thing with the amp and wouldn't hesitate to use the ext amp out on the B25B into a DI. For larger venues, you really should rely on the PA to provide a pleasant signal for your patrons. If it's so loud you don't need a PA, your probably too loud on stage. It's all about a good mix for me.
    Wisebass and Wasnex like this.
  10. BasturdBlaster

    BasturdBlaster Supporting Member

    Feb 19, 2012
    Crandon WI
    For me, the reason I prefer "high" wattage amps isn't because smaller amps aren't loud enough, but because the smaller wattage amps would typically be pretty hot after a 4 hour gig while the larger wattage amps would be only warm after that time period, hehe :):woot:
    Bboopbennie likes this.
  11. Bboopbennie


    Jun 16, 2019
    Gents- its all about head room. You don't crank the 500 watt head up all the way. @ # 4 on the dial you have less distortion /clipping. Rehearsing, I play a bassman 100w - 15 speaker and it is crapping out @ 100 watts. Some of
    the Neo -cabs are so efficient they might be loud @ 50 RMS, and others are bedroom quality at this power level.
    Power is logarithmic, so going from 50 RMS to 350 RMS is just a bit louder. You will never KILL the room with a very small cab no matter what power. We had Voice of the theaters for a PA, and you could burn the place down with a 30 watt CD player driving them. Speaker enclosure / speakers are important.
    BasturdBlaster likes this.
  12. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    That's exactly what I ended up doing when I got my B-15 restored and it worked out great for me, although I actually ended up needing 50w on most of my gigs. Some gigs I could totally get away with the B-15's 25w and some required a little more. Can't recall doing a gig that required more than that since I was a kid.
    Raw N Low likes this.
  13. I think when you get into that place for the gig you are going to quickly realize that you do not have enough amp at least not without FOH support..putting it up on a stand and using it for a monitor would probably be fine but with a DI going to the board..or mic. I tried to use a 100 watt peavey max combo once and it struggled to keep up and I had the volume up to like 3 oclock..not good..So I went out and bought a 500 watt mini max head and a 15" cab to use instead..

    Do I need 500 watts..nope not even close, I keep the volume on about 9 clock on it and the gain about the same. Like Bboobbennie said, its about the headroom. I also DI out to the board..I don't want to push an amp hard to hear myself..I don't think that amps last very long when you are pushing it too hard over a long period of time..my amp after a gig is cool to the touch..not even the slightest bit warm..thats the way I like it..every room you gig in is going to be different and then there is outside..better to have more amp than you will ever need than to have one that is going to struggle or not be enough to do the job...Thats just my opinion..others have their own theory...thats fine..

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