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The Acoustic Club
- Thread starter The Owl
- Start date
Oops...talking about heads. I already have the B410 and B115..and need an amp...I was going to get an Ampeg amp but I am just going to stay with acoustic since I dig the cabs so much.
The TONE out of the cabs is really great...really enjoying them...they just don't handle my low B well at all...not as tight.
correct me if I am missing something, but I don't think your math is quite right. The B450 runs at 450W at 4ohms. Adding the B810 to it gives you 4ohms + another 4 ohms in parallel, which is a total of 2 ohms. Adding the addition B410 (a 8 ohm cab) puts you under the minimal rating at 1.6 ohms.
A B450 + a B410 is going to give you that 2.67 ohm scenario and around the 575W mark. The only scenario where you'd be losing wattage on the B450 is if you disconnected the internal speaker and in turn were running the head at an impedance higher than 4 ohms.
Three 8Ω = 2.67Ω
The internal driver on the B-450 isn't wired the same as the B-200H nor the B-200 Combo. There's differences in Series vs Parallel wiring and the output jacks are in different circuits to assure that happenstance.
That it (B-450) is capable of 2Ω is documented if not by Acoustic, then the lettering on the back of the B-450 and the fact that I have over 30 hours running it that low.
That 2Ω rating is what got me all excited when I was looking at GK, Orange and Ampegs at GC. Well - there was the money too.
The only time I had a thermal situation was when the studio A/C pooped out and we had to complete a bass track in a Live situation at over 100ºF for three hours.
FWIW: the drummer was slinging sweat off his sticks into the cage around him so bad it was running down the Plexiglas.
The B-450 at that time besides driving it's own 8Ω load of 210s was also driving 2 Peavey 15" 8Ω monster cabs of unknown vintage and the B-450 cooling fan got to 3rd gear and started to whistle pretty loudly so I cranked down the LOWs a bit and it quickly slowed back down to 2nd gear on the cooling fan.
Up to that point I never knew the cooling fan had three speeds, and I haven't even seen/heard 2nd gear in it again after that musical sauna.
The B-600H however, is rated at 4Ω in the reference material and what I see on the back of the chassis, litho'd on by Acoustic.
So with no internal driver(s) of it's own, I can only surmise that 4Ω is where it bottoms out with two 8Ω cabs on it, although I find that somewhat strange.
The actual Wattage was brain computed by me and an audio engineer and we both arrived at the about same guesstimated values.
If the B-450 is rated to as low as 2Ω, and three 8Ω drivers only go to 2.67Ω, then there's a tiny bit of Wattage that's not making it to the drivers.
We [DEL]figured[/DEL] comp00ted that 575 Watts @ 2.67Ω or so was pretty close, allowing for some fudge zoning. See what I mean?
FYI, Their new website and updated owner's manual show the B600H rated at 2 ohms minimum!
http://acousticamplification.com/products/index.cfm?catid=3&&modid=13&product=B600H
http://acousticamplification.com/prodImages/acousticAdmin/products/gallery/B600H-Manual.pdf
And the B450 IS documented as rated down to 2 ohms here:
http://acousticamplification.com/products/index.cfm?catid=2&&modid=13&product=B450
[Invalid or Expired Link Removed]
Rock on!
FYI, Their new website and updated owner's manual show the B600H rated at 2 ohms minimum!
http://acousticamplification.com/products/index.cfm?catid=3&&modid=13&product=B600H
http://acousticamplification.com/prodImages/acousticAdmin/products/gallery/B600H-Manual.pdf
And the B450 IS documented as rated down to 2 ohms here:
http://acousticamplification.com/products/index.cfm?catid=2&&modid=13&product=B450
[Invalid or Expired Link Removed]
Thanks - I've resisted the urge to fire up more cabs on the B-600H - so that's a relief now. Makes sense though too - they are supposed to be the same guts anyway.
My B-600H is litho'd at 4Ω minimum, whereas the B-450 said 2Ω, so I thought it was in concrete.
Lessee --- two 410s plus an 810 = 16 x 10-inchers.
I can conceivably see a single B-600H running three B-810s.
YW. I always wondered about the oddballness of it.
I've been working on Kashmir for most of the day - got it pretty nailed I think. Interesting meter and rhythm.
So some diversion is called for.
Hmmm. Now I think I need another B-810 for this new season's BBQ and Corral gigs. The B-450 in between two 810s might be interesting.
I've been working on Kashmir for most of the day - got it pretty nailed I think. Interesting meter and rhythm.
So some diversion is called for.
Hmmm. Now I think I need another B-810 for this new season's BBQ and Corral gigs. The B-450 in between two 810s might be interesting.
I understand this. The B810 is a 4 ohm cabinet according to the documentation as is the internal speakers on the B450. The only 8 ohm cabinet you're using is the B410.
According to the documentation the B450 external speaker jack is wired in parallel. The specs on the B450 and the B600H are identical, that is, 450W @ 4 ohm and 600W @ 2 ohms.
I follow the math, but you're using the wrong specs. Either the documentation is incorrect or what's litho'd is wrong. I'm looking at the B600H and B450 manuals right now and they're both spec'd as follows:
600W @ 2 ohms
450W @ 4 ohms
I'm not sure why your B600H is litho'd at 4 ohms. In the documentation it is spec'd at 2 ohms on both the list and the picture of the back of the head. This is also noted on the MF website.
How are you seeing a B600H powering three B810s? The B810s are spec'd at 4 ohms each. Three 4 ohm cabinets gives you a 1.3333 ohm load. This would be below the 2 ohm limit of the B600H.
Now, given that the internal speakers of the B450 is actually 4 ohms (as it appears in the specs) the situation with the two Peavey cabs makes perfect sense. The Peavey cabs are 8 ohms each, which in parallel make for 4 ohms. This, combined with the 4 ohm internal speakers calculate to a perfect 2 ohm scenario.
Now, all this being said, the B450/B600H may be perfectly capable of running below the 2 ohm mark as long as you aren't really cranking them hard. Either scenario (1.6 or 1.333 ohms) isn't so far below 2 ohms to necessarily be a big problem. I know some SS amps are perfectly happy running without any load when they're being used as a direct connection for recording.
This is where it's all very confusing.
Acoustic - or what's considered Acoustic in the US is just a warehouse and they know nutthin' of what's in their cabs and the printed materials is all over the place for specs.
I believe I have one of the earliest owner's mags here somewhere and I can scan it for references, but as I remember it, it said the B-600H was rated at 4Ω minimum.
Also according to them - the B-450 has an external rating of 2Ω, saying nothing of the value of the drivers inside of the cab itself. As you can see, the only rating of concern is this litho'd label right here because that's the only one you can adjust:::
OK - so the B-450 has it's own 210 drivers inside it - and I haven't checked the rating of them yet, although I should have when I had that soldered lug problem, but coupled to two B-810 at 4Ω each - they would be 2Ω in parallel and still be driving the 210s in the combo.
If the internal drivers add up to 8Ω or if they run in parallel are 4Ω or 2Ω - well, I dunnow. That's not something that seems to be figured into the litho'd label since you can't do anything about their Ohm rating anyway.
Next was the statement from others here (but not clear to me so far) is that the B-600H can handle 2Ω too, so by extension, since the B-450 is handling 1 set of 210s (?Ω
, and 2 sets of 810s (4Ω each), logically then the B-600H should do the same even though all of it's drivers are external - right?
Seeing that (^) written makes me cringe a little, but the B-450 has successfully run at 2Ω with parallel 4Ω 810 cabs and it's own internal 210 drivers.
I need medication now.
Acoustic - or what's considered Acoustic in the US is just a warehouse and they know nutthin' of what's in their cabs and the printed materials is all over the place for specs.
I believe I have one of the earliest owner's mags here somewhere and I can scan it for references, but as I remember it, it said the B-600H was rated at 4Ω minimum.
Also according to them - the B-450 has an external rating of 2Ω, saying nothing of the value of the drivers inside of the cab itself. As you can see, the only rating of concern is this litho'd label right here because that's the only one you can adjust:::
OK - so the B-450 has it's own 210 drivers inside it - and I haven't checked the rating of them yet, although I should have when I had that soldered lug problem, but coupled to two B-810 at 4Ω each - they would be 2Ω in parallel and still be driving the 210s in the combo.
If the internal drivers add up to 8Ω or if they run in parallel are 4Ω or 2Ω - well, I dunnow. That's not something that seems to be figured into the litho'd label since you can't do anything about their Ohm rating anyway.
Next was the statement from others here (but not clear to me so far) is that the B-600H can handle 2Ω too, so by extension, since the B-450 is handling 1 set of 210s (?Ω
, and 2 sets of 810s (4Ω each), logically then the B-600H should do the same even though all of it's drivers are external - right? Seeing that (^) written makes me cringe a little, but the B-450 has successfully run at 2Ω with parallel 4Ω 810 cabs and it's own internal 210 drivers.
I need medication now.
Totally understand this. Their stuff is manufactured overseas and the folks over here seem pretty hands off about it. If Patrick was still with Acoustic I'm sure he can set it all straight.
I know they had some other issues with other first prints. Because of this, I wouldn't be surprised if the prints you were wrong and the current website info is correct. That being said, my understanding is that the B450 has a total rating of 2 ohm, not an external rating. That is to say, internal speakers + external = total load of 2 ohms.I believe I have one of the earliest owner's mags here somewhere and I can scan it for references, but as I remember it, it said the B-600H was rated at 4Ω minimum.
Also according to them - the B-450 has an external rating of 2Ω, saying nothing of the value of the drivers inside of the cab itself. As you can see, the only rating of concern is this litho'd label right here because that's the only one you can adjust:::
I have a question about your picture. I tried to find a picture of the back of a B450 online to no success. Are the internal speakers wired directly to the amp, or is one of the jacks connected via cable to the internal speakers? The latter seems to make more sense in terms of how the descriptions read, however I haven't seen anything clear on it.
The reason I suspect that the internal speakers run at 4 ohms is because the product manual states that the amp operates at 450W with only the internal speakers and the amp is spec'd for 450W @ 4 ohms. If the speakers were a different impedance, I would expect the amp to run at a different wattage with just the internal speakers.
Yep. Have you run the B450 with a pair of B810s? In the recording scenario you described you mentioned running with 8 ohm Peaveys (though I guess those were 15s).Next was the statement from others here (but not clear to me so far) is that the B-600H can handle 2Ω too, so by extension, since the B-450 is handling 1 set of 210s (?Ω
Like I mentioned before, it's completely reasonable that the amp is just fine operating below 2 ohms.
All I can say is what I took a pix of whilst inside the B-450 as a 'look-see' in April last year::
That's showing the PC connex to the internal drivers only.
The Parallel outputs are on a separate board and away from this pix.
HOWEVER - the owner isn't enlightened to the values of the internal drivers as it's not posted anywhere, just the 2Ω minimum admonishment in that area set aside for the external 1/4" output jacks - so what's one to assume?
After that studio set with the B-450 running the two Peaveys, I did try two B-810s and of course it was also running the legacy drivers at the same time.
Being outdoors this time, there was no overheating potential like that studio gig and I had no signs of overheating via the cooling fan revving up.
Currently I run 2xB-410 or alternately 1xB-410 and 1xB-115 with the B-450.
For the best all-around tone at medium Wattage, I run the B-450 on top of the B-115 or on a B-410.
That's showing the PC connex to the internal drivers only.
The Parallel outputs are on a separate board and away from this pix.
HOWEVER - the owner isn't enlightened to the values of the internal drivers as it's not posted anywhere, just the 2Ω minimum admonishment in that area set aside for the external 1/4" output jacks - so what's one to assume?
After that studio set with the B-450 running the two Peaveys, I did try two B-810s and of course it was also running the legacy drivers at the same time.
Being outdoors this time, there was no overheating potential like that studio gig and I had no signs of overheating via the cooling fan revving up.
Currently I run 2xB-410 or alternately 1xB-410 and 1xB-115 with the B-450.
For the best all-around tone at medium Wattage, I run the B-450 on top of the B-115 or on a B-410.
Maybe I'm just reading too much into the manual. I figure when the manual says the amp puts outs 450W with just the internal drivers and the amp is rated for 450W @ 4 ohms, it means that the internal drivers are 4 ohms. Also in the manual it states that the minimum external speaker impedance should be 4 ohms. Thus 4 ohms (internal) + 4 ohms (external), running in parallel, gives us 2 ohms.
That being said, the labeling on the amp certainly doesn't help. Of course, I've found that to be unfortunately very common with combo amps.
That being said, the labeling on the amp certainly doesn't help. Of course, I've found that to be unfortunately very common with combo amps.
That makes sense - the last part anyway.
Acoustic hasn't been very forthcoming with questions and GC/MF certainly won't know either as it's out of their realm of knowledge. If Acoustic can't get the specs right, then how is anyone supposed to know.
Maybe it's a case of Chinese-English translation where it falls apart.
Fortunately I've had no troubles with the B-450 in all the situations I've run mine, but the extended Pro-Coverage warranty runs almost another two years so we'll see.
I've got another big Spring and Summer of barnyard/BBQ gigs lined up when the weather clears and I'll need every Watt I can get for a few of the 120-acre ones.
Not that there'll be 120 solid acres of people - just open fields all around us - but I've been told that we can be heard in town, 4.5 miles away.
Welcome!
Where in FL?
Anywhere near Gainesville? I'll probably be selling my B200 combo soon (interested?)
This was my understanding as well... assumed 2 internal drivers @ 8 ohms each (in parallel, given the wiring diagram) producing the stated 4 ohms and 450 watts. Then add an external cab(s) (min combined 4 ohm rating) to bring the TOTAL ohms load no lower than the 2 ohm minimum to get you the total 600 watts @ 2 ohms.
Here's the text from the website description:
thesteve said:
AMEN!!! Also the manuals are very inconsistent/wrong!
This is a scan directly from my Owner's Manual, not the one that has all the different gear, but specifically for the B-450 - notice that it says BOTH things in two separate sentences: {I tinted it orange for clarity}
In sentence #2 - it says that the two parallel jacks are 2Ωs minimum. That's simple.
Then it makes an about-face and says that the additional speaker(s) should equal 4Ω minimum.
It can't be both ways!!!!!
What I'm saying is that the instructions never tell you the impedance of the internal drivers and if you don't know, you'd go by what the owner's manual or the litho'd statement on the back of the head says.
Nowhere is the Ohm rating of the internal drivers printed nor posted on the cab. There's is NO WAY to compute what you need to know, should consider or CAN do.
Assuming (this could be dangerous) that the internal drivers come to 8Ω, then adding various external drivers at the loads shown below will be:
8Ω external + the legacy set equals 4.00Ω
4Ω external + the legacy set equals 2.40Ω
2Ω external + the legacy set equals 1.70Ω
If the legacy drivers are 2 x 8Ω and they are parallel at 4Ω then we get some different numbers:
8Ω external + the legacy set equals 2.40Ω
4Ω external + the legacy set equals 2.00Ω
2Ω external + the legacy set equals 1.33Ω
Again, like I say if Acoustic doesn't give some good numbers and the correct info, then what's to be expected?
I haven't had any troubles - and perhaps there's a caveat here too.
What's the tolerances of drivers anyway? Is it 2%? 5%? 10%? More?
In sentence #2 - it says that the two parallel jacks are 2Ωs minimum. That's simple.
Then it makes an about-face and says that the additional speaker(s) should equal 4Ω minimum.
It can't be both ways!!!!!
What I'm saying is that the instructions never tell you the impedance of the internal drivers and if you don't know, you'd go by what the owner's manual or the litho'd statement on the back of the head says.
Nowhere is the Ohm rating of the internal drivers printed nor posted on the cab. There's is NO WAY to compute what you need to know, should consider or CAN do.
Assuming (this could be dangerous) that the internal drivers come to 8Ω, then adding various external drivers at the loads shown below will be:
8Ω external + the legacy set equals 4.00Ω
4Ω external + the legacy set equals 2.40Ω
2Ω external + the legacy set equals 1.70Ω
If the legacy drivers are 2 x 8Ω and they are parallel at 4Ω then we get some different numbers:
8Ω external + the legacy set equals 2.40Ω
4Ω external + the legacy set equals 2.00Ω
2Ω external + the legacy set equals 1.33Ω
Again, like I say if Acoustic doesn't give some good numbers and the correct info, then what's to be expected?
I haven't had any troubles - and perhaps there's a caveat here too.
What's the tolerances of drivers anyway? Is it 2%? 5%? 10%? More?
Like I've said before, the fact that the owners manual states that the B450 is rated at 450W @ 4 ohms and the portion you posted says that the amp runs at 450W with the internal speakers leads me to believe that the internal speakers = 4 ohms total.
I understand it's poorly worded, but I believe the 2 ohm minimum refers to the overall load on the amp. This seems to be the most consistent interpretation of all of the statements made in the manual.
I understand it's poorly worded, but I believe the 2 ohm minimum refers to the overall load on the amp. This seems to be the most consistent interpretation of all of the statements made in the manual.
That's prolly a safe assumption - but the one thing I remember whilst in the cab is that the drivers are wired in parallel - I just didn't bother looking for any ratings on them nor did I test them either.
