Convert Acoustic B200 to B200h

[sabre79]

Hello,

I have an Acoustic B200 combo amp that I bought salvaged. The head was torn away from the speaker cab section. I built a new cabinet to match the old combo cabinet and all was fine. Now, I want to seperate the head and the speaker again and turn the amp into a B200h and make a cab for the 15. I've looked at the signal flow diagrams for the B200 and the B200h and they appear to be the same except that in the B200 the internal 15" speaker is wired in series with the external jack while the B200h has two external jacks which are wired parallel.

The switch to turn on the tweeter is located on the back panel of the B200 amp so that will have to be moved to the 15 cab. I'll need to add a speaker jack too.

My question is should I wire the speaker jacks in series or should I run the two jacks in parallel like the B200h. I will be making a 2x10 cab to plug into the other jack.

Thanks

[WingKL]

I think it depends on the minimum impedance the amp in the B200 can handle and the impedances of the cabs you want to connect to it.

[SurferJoe46]

I bought a semi-crushed (fell off the truck) B-450 with the B-600 head in it for $20.00.

The head was untouched, but the cab was a mess. I am also in the process of duplicating a head-cab for it at a friend's house and doing what you are doing to your B-200.

I think the head would have trouble with changing out the Horn driver though.

That circuit for the horn is figured into the overall of the amp's output, but it looks to me that (even on my other B-450 combo), it has to remain divided from the rest of the drivers, with the switch to turn it on and off on a separate line from the amp.

On the flow chart I have for the B-600H and the B-450 amp (it's the same amp, by the way), that horn circuit is a separate entity from the other driver wires, since the unit originally had two-pair of wires leaving the underside of the amp through a chassis punch-out that runs into the top of the cab.

Now - having said that - I also have a 410 and a 115 that have horns in them with switches on the back of the cabs, near the jack-IN connex, so I don't think adding the horn switch to the back of your almost new -210 cab would be a problem, but I don't see using the original horn circuit from the amp since it would require two wires/jacks/etc to make it active like original.

FYI- the B200H can handle both a 410 and a 115 at the same time, or even 2/ 410s:

From the Acoustic Site:

The two speaker output jacks allow you to directly connect to each enclosure (such as the B115 and/or B410) to maximize your tone and power.

I think driving a 115 and a 210 would be what I would do to a 200 Watt amp though, and a single 15 and 2 10s would sound just about perfect.

[sabre79]

Originally Posted by WingKL

I think it depends on the minimum impedance the amp in the B200 can handle and the impedances of the cabs you want to connect to it.

The 15" is 4 ohms. The 2x10 can be 4 or 8 ohms and I'm not sure about the B200. The manual says that the B200h needs 4 ohms minimum load.

[SurferJoe46]

This is confusing since you are taking the B200 out of the cab which HAD a 115 in it and then you COULD have run another cab.

Here's the Acoustic specs on the B200 Combo:

The series extension speaker jack provides an output for an additional cabinet such as the Acoustic B115 or B410.

Once you convert it to a B200H, you remove the original load from the 115 and now you need to compute what you have running.

So you could have run the original 115 and another 115 - or the original 115 and another 8 Ohm cab like a 410.

I've always kinda scratched my head when I see on the back of the B-450 that I can run down to 2 Ohms. It's just not clear if you should or should not factor in the drivers IN the cab itself, but I just went ahead and run down to 2.7 Ohms with outside cabs and have no troubles at all, so it must NOT include the legacy drivers in the combo-box itself.

[sabre79]

"That circuit for the horn is figured into the overall of the amp's output, but it looks to me that (even on my other B-450 combo), it has to remain divided from the rest of the drivers, with the switch to turn it on and off on a separate line from the amp."

I believe there are two pair of wires running from the head to the 15" below. What I want to do is leave the horn with the 15" and add a switch to it's jack plate. Then build a seperate 2x10 cab without the horn.

[WingKL]

If you plan on using the 4 ohm 15 with another cab and the minimum impedance for the head is 4 ohm then the answer is simple. You have to run the other cab in series just like it was wired in the combo so your impedance won't go below 4 ohms.

[SurferJoe46]

OK - one pair of wires DEFINITELY run to the HORN and then the other pair go to the drivers. That's the way it is on m y B450.

Here's inside my B450/600 amp:



Look at the three prong connex right next to the toroidal transformer and see that naked white male plug on the vertical PC board. That's the location where the two pair of wires leave the amp circuit and go through a hole that you can see right below it.

Two pairs of wires go out through there and one set is like I said - directly to the horn and the other is to (in my case here) the 210 drivers in the cab.

The only way to control the horn from the back of the amp is by having different wires from the amp, since the switch is on the back of the amp and not on the cabinet itself. That would be silly in a combo unit.

[sabre79]

"The only way to control the horn from the back of the amp is by having different wires from the amp, since the switch is on the back of the amp and not on the cabinet itself. That would be silly in a combo unit."

I'm not sure if I understand you, will it be possible for me to leave the horn with the 15 and put a switch for the horn in the jack plate on the 15 cab?

Thanks for your help, BTW. You stole that B450. I paid $60.00 for mine.

[SurferJoe46]

OK

I see it like this:
The B200H is designed to run a pair of cabs with horns and they surely don't have dual pairs of wires running to them for the horns + the drivers.

You can certainly run a switch on the back of the cab to turn ON/OFF the horns and those can be run off the same single pair of wires from the amp itself.

IF you want to run a little more balanced, I'd run the original 115 driver and a pair of 10s - both with horns.

But somehow you stated you want to run a 410 can and the 115 from the original setup. That's OK - not optimal - but OK.

Just fer kicks, I'd run a pair of 15s though. That would give a lot air-in-motion and I have no thoughts of farting out TWO 15s!

You just will NOT be able to use that other horn circuit on the back of the 200 head since you will be running only one pair of parallel outputs for the cabs you will be driving.

FYI: The Horn circuit shares a ground with the driver circuit, (that's why the PC driver + Horn output male receptacle is only three prongs) and the positive Horn lead is interrupted by the slide switch on the back of the cabinet. There appears to be no problem running the horn circuit open-ended, as is the usual case with a solid state circuits anyway.

[BassmanPaul]

My take on this is that if the extension jack is series connected then the internal speaker is the lowest that the amp can take. Probably it's a 4Ω amp. Whatever you connect to the amp should add up to 4Ω or higher. If you plan to use the internal speaker you should use it alone.

Paul

[SurferJoe46]

Originally Posted by BassmanPaul

My take on this is that if the extension jack is series connected then the internal speaker is the lowest that the amp can take. Probably it's a 4Ω amp. Whatever you connect to the amp should add up to 4Ω or higher. If you plan to use the internal speaker you should use it alone.

Paul

I don't totally follow that if the original design allowed additional speakers posted down to 4 Ohms on the output jacks with the combo speaker still running at whatever Ohm-age rating it had.

[RickenBoogie]

Because the ext spkr output was wired in series, that's why.

[SurferJoe46]

Parallel, not series.



I also found an interesting pix too from Acoustic Amps:



That's a B-200H, and a B-115 on top of a B-410 - and that should be about 5-feet tall.

[RickenBoogie]

Ok then, all the other new Acoustic combo amp models are wired in series, this one would be the one exception. Good to go.

[Old Joe]

Originally Posted by SurferJoe46

I bought a semi-crushed (fell off the truck) B-450 with the B-600 head in it for $20.00.

The head was untouched, but the cab was a mess. I am also in the process of duplicating a head-cab for it at a friend's house and doing what you are doing to your B-200.
...

And here I was all happy thinking I made a good deal on a crushed B450. You only paid $20 for it?

I know this thread is really old but this is pretty much my situation right now.

BTW, did you ever got to fix it? I am in the process of fixing mine. Building a new cab and a separate case for the head.

[SurferJoe46]

Originally Posted by Old Joe

And here I was all happy thinking I made a good deal on a crushed B450. You only paid $20 for it?

I know this thread is really old but this is pretty much my situation right now.

BTW, did you ever got to fix it? I am in the process of fixing mine. Building a new cab and a separate case for the head.

Actually I did!

I/we got it all back together as an amp-alone and a separate cab with the 210+ horn in a new-built cab for them that we measured all the dimensions from the destructo'd cab and tried to reproduce the internal dimensions.

I had a wood working buddy who took the challenge to do it all and he covered everything in crimson Tolex and put on the corner guards and we sold it for a nice profit.

Sadly, no pix and that's a shame as it was really unique and very well done, if I say so myself.