Getting more power

Pip1969 · #1 03-18-2010, 11:22 PM

Yo guys I'm running my AMpeg B-25(B) into an 8ohm acoustic 1x15. Is there any way to get a little more volume out of it? Maybe with a power amp or something, i don't know.
Also any ideas on a good e.q. pedal?

rodl2005 · #2 03-18-2010, 11:36 PM

Another 8 ohm cab will give U lots more volume & a heaps bigger sound - more than adding more amp/power/watts.....

will33 · #3 03-18-2010, 11:38 PM

Plenty of ampeg guru's here will catch this tomorrow. In short, the best way to get louder with your B15/B25 is to play it through more speakers. Adding speakers gets you louder than adding watts does. That would mean disconnecting the internal speaker and running it through a 412, 810 or 215 instead, just make sure the impedance complies with what the amp is made to run. If the tone you're getting now is to die for (and it should be if that thing's up to snuff) keep the internal speaker running and add an extension cab made of the same box, same tuning, same speaker etc. as the original. Again, watch the impedance. Those old ampeg "B" bass amps have some of the best tone around, they just do it lower volumes. For now, check out www.fliptops.net for more info.....or just wait. Change your post title to ampeg B25 and watch how many ampeg guru's chime in tomorrow or monday while they're screwing off on talkbass while they're supposed to be working their day jobs.

Pip1969 · #4 03-19-2010, 02:21 PM

It doesn't have an internal speaker and I dont think I can run two 8ohm cabs, so if I had two 16ohm cabs would that seem louder than a single 8ohm?

Disclaimer: im a bit of a noob when it comes to these things

JimmyM · #5 03-19-2010, 03:06 PM

Quote:

Originally Posted by Pip1969

It doesn't have an internal speaker and I dont think I can run two 8ohm cabs, so if I had two 16ohm cabs would that seem louder than a single 8ohm

all depends on the cab. like two small 16 ohm cabs will be quieter than a big 8 ohm cab with lots of speakers. but since 16 ohm cabs are pretty much a thing of the past, maybe you could take two 8 ohms, hook them together in series, and wire them up to one speaker input.

billfitzmaurice · #6 03-19-2010, 04:17 PM

Quote:

Originally Posted by JimmyM

all depends on the cab. like two small 16 ohm cabs will be quieter than a big 8 ohm cab with lots of speakers. but since 16 ohm cabs are pretty much a thing of the past, maybe you could take two 8 ohms, hook them together in series, and wire them up to one speaker input.

Is it tube or SS? SS has a minimum load impedance, tube is maximum. Two cabs in series give the exact same sensitivity as one, so there's no gain there unless the amp has enough power to drive one speaker beyond its displacement limit, and if the 25 stands for watts that's not going to be the case.

JimmyM · #7 03-19-2010, 05:52 PM

Quote:

Originally Posted by billfitzmaurice

Is it tube or SS? SS has a minimum load impedance, tube is maximum. Two cabs in series give the exact same sensitivity as one, so there's no gain there unless the amp has enough power to drive one speaker beyond its displacement limit, and if the 25 stands for watts that's not going to be the case.

well it's tube, and it's an oddball because the transformer does 16 + 16 ohms, 55w if i'm not mistaken, and i believe it was originally sold with a 16 ohm 215 cab. not sure how that would work out with two 8 ohmers in series on a tube amp, but i imagine the same way, eh?

RickenBoogie · #8 03-19-2010, 06:03 PM

It is a bit of an oddball, but a great sounding amp nonetheless. The best solution would be to find the original 215 cab for it, or a pair of them. Either that, or an 8 ohm 4x10. The thing is, with that amp, you're not only limited by the speakers, but also the 55 watts. If you really *need* loud, maybe get a bigger amp?

johnk_10 · #9 03-19-2010, 06:26 PM

a B25 can be pretty loud if you run the right (or enough) cabs with it. IME, they sound like they put out alot more than a 50 watt bassman, and believe it or not, i've gigged with 66 bassman head thru a large cab containing two JBL D130F's and it was louder than you might think. of course its not going to be as loud as a V4 thru the same cab.

lobey · #10 03-19-2010, 06:55 PM

Quote:

Originally Posted by JimmyM

well it's tube, and it's an oddball because the transformer does 16 + 16 ohms, 55w if i'm not mistaken, and i believe it was originally sold with a 16 ohm 215 cab. not sure how that would work out with two 8 ohmers in series on a tube amp, but i imagine the same way, eh?

+1

Mine has 2 output jacks and the back, and from the vast knowledge of the TB crew, it has been confirmed that two 8 ohm cabs can be connected to the jacks (one 8 ohm cab per jack).

There's a ton of threads on this amp, and when I get some free time, I'm going to try to put together a knowledge base of this info.

Calaverasgrande · #11 03-19-2010, 07:42 PM

Careful. I am not familiar with this particular amp. But I have blown an output transformer on a Traynor YBA1 running 4 ohm loads because other folks told me it was cool. Output transformers arent cheap! I would get something definitive (like an ampeg manual) before you play at volume through a 4 ohm load.

craig.p · #12 03-19-2010, 08:14 PM

Well, I admit it's been a while, but if memory serves me right, the B25 played games with the output jacks where connecting one speaker to the main jack gave you the transformer's 16Ω tap and connecting a second speaker to the "external" jack gave you the transformer's 8Ω tap. (Used fancy speaker jacks that did winding selection, too, based on whether something was plugged into them.) So, I'm with Jimmy. But if TB'ers are running 2x8Ω setups in the field and nothing pops or smells funny, then I guess that's the acid test. Can't argue with "it works."

billfitzmaurice · #13 03-19-2010, 08:28 PM

Quote:

Originally Posted by Calaverasgrande

Careful. I am not familiar with this particular amp. But I have blown an output transformer on a Traynor YBA1 running 4 ohm loads because other folks told me it was cool. Output transformers arent cheap! I would get something definitive (like an ampeg manual) before you play at volume through a 4 ohm load.

Running a low impedance load usually won't bother an output transformer, not even if it's a dead short. Most have switched jacks that will short the output if there's no speaker plugged in, to protect them against what will kill them is short order, which is no load. I'd chalk up your experience to things sometimes blow.

lobey · #14 03-19-2010, 11:03 PM

Quote:

Originally Posted by craig.p

Well, I admit it's been a while, but if memory serves me right, the B25 played games with the output jacks where connecting one speaker to the main jack gave you the transformer's 16Ω tap and connecting a second speaker to the "external" jack gave you the transformer's 8Ω tap. (Used fancy speaker jacks that did winding selection, too, based on whether something was plugged into them.) So, I'm with Jimmy. But if TB'ers are running 2x8Ω setups in the field and nothing pops or smells funny, then I guess that's the acid test. Can't argue with "it works."

+1

Exactly what needed to be said.

Pip1969 · #15 03-22-2010, 10:23 AM

So no go on two 8 ohms?

Rick Auricchio · #16 03-22-2010, 10:39 AM

The answers so far sound too vague to gamble the amp's future on it. At least for me.

Calaverasgrande · #17 03-23-2010, 02:32 AM

Quote:

Originally Posted by billfitzmaurice

Running a low impedance load usually won't bother an output transformer, not even if it's a dead short. Most have switched jacks that will short the output if there's no speaker plugged in, to protect them against what will kill them is short order, which is no load. I'd chalk up your experience to things sometimes blow.

Well thats what the amp tech told me. Besides YBA1a's run those EL34's very hard. At the time I was playing very loudly (it was the 90's everything was EXTREME) All I know is that after I did that once I learned my (costly) lesson. dont run your tube amp into the ground on low ohms!
The OP should be able to find some info on what the min ohms are somewhere online I would think.

JimmyM · #18 03-23-2010, 02:37 AM

Quote:

Originally Posted by Calaverasgrande

Well thats what the amp tech told me. Besides YBA1a's run those EL34's very hard. At the time I was playing very loudly (it was the 90's everything was EXTREME) All I know is that after I did that once I learned my (costly) lesson. dont run your tube amp into the ground on low ohms!
The OP should be able to find some info on what the min ohms are somewhere online I would think.

you mean like in the post i made above where i said the transformer runs at 16 + 16 ohms? yes, that would be online, i suppose.