DBX MPA 150 Split Spectrum Amplifiers: Good deal or new boat anchors?

[pilotputz]

Just picked this pair of DBX MPA 150 amps up today. I didn't pay much and figured they'd be fun to clean up and run; maybe even flip for a little extra cash...

Anyway, I got them home and cleaned up. I plugged them into my preamp, ran speakers to the amp and proceeded to get no sound out of either amp!!

I am new to the bi-amping concept and was hoping like heck that I'm not hooking the speakers up correctly. It strikes me as a little odd that both amps would not put out sound. I could certainly see one being bad; but both just strikes me as a little odd. When plugged in they both light up at the power switch and the VU meters both move like they're doing their correctly.

So I'm hoping there's somebody out there in AKland that could maybe give me a pointer or two as to how I should be wiring these up for playback. I uploaded a couple of photos that the flash kind of flubbed. Over the right speaker posts it reads, "Inputs". Over the left posts it reads, "Output to right and left sub-woofer".

Any ideas?
Thanks.
Pilot

 

[Chazb11]

Looks like the wiring is pretty self explanatory, nothing tricky.

Have you taken the covers off to look for any obvious problems. There may be internal fuses that are blown or something else easy to spot and fix. that would be step one.

 

[pilotputz]

Yup. It was pretty self explanatory.
In the photo on the right you can plainly see that it states for single speaker to hook up at these posts.

I did that and you get mono sound. So, obviously this is why the fella I bought them from had two: They're mono blocks if wired like that!!

I believe that they can also be a stand alone stereo amp if you wire it up differently. I believe that if you use the in-amp crossover, it splits the highs into left and right. But if you use the single speaker only option from the posts that run the subs you get mono sound because bass is mixed mono. I BELIEVE all this to be true but I have not seen any literature to back any of that up.

I'll certainly have to try and track down a manual. The entire speaker binding post in the middle photo is a mystery to me. It seems as though it wants you to run TWO pairs of speaker wires to each speaker and attach them in the top and bottom posts for each channel. Curious.

 

[jhoyt]

Hope this helps...

This type of amp gets it input signal from speaker level signals. You basically "pass through" your main speaker cables from your amp/receiver/whatever to the speakers. The DBX amp reads the speaker level signal, much like a voltmeter, and amplifies it for the subwoofer output. So, I don't think you can run this by itself (without another amp). In fact, it probably has an internal low-pass filter. Therefore, it would not even work for full-range amplification.

Edit: I see the low-pass filter is switched on the front...but it still won't work by itself.

 

[baco99]

this amp also has a line input, so why wouldn't it work via the line input and speaker out?

 

[Nightingales]

Not so bad amps

The dbx subwoofer amps are getting a bit of a bum rap here. While I don't own the MPA 150 yet, I have two of the XB140's and they are solid good amps. You use them if you have a passive subwoofer setup and want to upgrade the sub to an active one. As such, here is what the 150 is supposed to do:

The MPA 150 is made to accomodate two different setups, that's why the in- and outputs might seem a bit confusing at first:

1) If your preamp, receiver, amp, etc. has a dedicated line-level subwoofer output, you hook this up to the 150's line input. (see pic 1).

2) Now, if your receiver, amp, etc. does NOT have an dedicated line-level subwoofer output, you hook your amp's speaker outputs up to the 150's terminals labelled "Speakers Input". Then you take speaker cables from the 150's DIRECT OUT SPEAKERS terminals to your existing speakers - the MPA 150 should act as a passive crossover filtering out the lower frequencies to those speakers. (My 140 does).

1) + 2) In BOTH setup cases, you connect your subwoofer to the Subwoofer left output (assuming you have one subwoofer. In some rare cases, passive subwoofers might contain two separate speakers then you connect left and right. But that's a really rare setup). See pic 2. At this point you are done. You can adjust the subwoofers volume with the levels of the 150.

I hope this helped people getting the MPA 150 hooked up correctly. While the XB140 manual is on the net, the MPA 150's seems elusive. But the hookup is basically identical.

 

[gary7]

The dbx subwoofer amps are getting a bit of a bum rap here. While I don't own the MPA 150 yet, I have two of the XB140's and they are solid good amps. You use them if you have a passive subwoofer setup and want to upgrade the sub to an active one. As such, here is what the 150 is supposed to do:

The MPA 150 is made to accomodate two different setups, that's why the in- and outputs might seem a bit confusing at first:

1) If your preamp, receiver, amp, etc. has a dedicated line-level subwoofer output, you hook this up to the 150's line input. (see pic 1).

2) Now, if your receiver, amp, etc. does NOT have an dedicated line-level subwoofer output, you hook your amp's speaker outputs up to the 150's terminals labelled "Speakers Input". Then you take speaker cables from the 150's DIRECT OUT SPEAKERS terminals to your existing speakers - the MPA 150 should act as a passive crossover filtering out the lower frequencies to those speakers. (My 140 does).

1) + 2) In BOTH setup cases, you connect your subwoofer to the Subwoofer left output (assuming you have one subwoofer. In some rare cases, passive subwoofers might contain two separate speakers then you connect left and right. But that's a really rare setup). See pic 2. At this point you are done. You can adjust the subwoofers volume with the levels of the 150.

I hope this helped people getting the MPA 150 hooked up correctly. While the XB140 manual is on the net, the MPA 150's seems elusive. But the hookup is basically identical.

I just picked up a MPA-150. You can use it as a straight stereo amp also through line level input from a preamp and do not engage the low pass switch.

 

[toddalin]

I had one. It/they was/were actually made by BSR for DAK back in the day. Mine eventually died, and even new filter caps didn't save it.

 

[sol7]

Bringing to life an old thread. Just to make it clear, this is not a stereo amp. This is a mono sub amp. Sure you can hook up two speakers to it, but it will be mono output and not true stereo. I'm not talking about the speaker line level input/outputs. I'm talking about the sub speaker output. If you want to run two speakers in stereo, you need two mpa 150's.

 

[SpeakerDavid]

Looks like the wiring is pretty self explanatory, nothing tricky.

Have you taken the covers off to look for any obvious problems. There may be internal fuses that are blown or something else easy to spot and fix. that would be step one.

I know it’s late never knew about this site but I gotta say one thing and I’ve been in the stereos and speakers and power amplifiers since I was 12 and I’m 56 now and considering these amps are being monobloc and you could use them either a for a Stereo that doesn’t have a subwoofer output or if you just want to add more speakers without making the 1 inch struggle tastings are great. I have four of them. They work perfect for exactly what I want and I also used one McIntosh champ two Yamaha and 80s two Accio with the big meters to 506 models and four Kenwood power me power amp with the power meters to end 28 because I run a lot of speakers and stuff because I’m addicted to it, but I’ll tell you what that work perfect I’ve won 415 off of them and they just whoever says ain’t no good. Don’t know what they’re talking about definitely worth the money and especially if you know how to hook them up which it’s really easy to hook them up. It’s just like 10 people that try to say the radio shack, realistic, and Optimus Mack speakers I run a pair of Mack Two an a pair of the Mack threes on my Yamaha M 80 if if anyone knows about that it’s a 250 W RMS per channel for more than 2530 years now never had a problem never blew out a speaker. Nothing ever happened to them. They still sound like New and work like New and then I also have two pair. Of klipsch with my other Yamaha m80 and if I had to sell anything I would get rid of klipsch 15” woofers in a horn mid range and a horn tweeter just like Mack 3 before I got rid of anything else and my McIntosh can’t I like it and love the way it looks, but I don’t even use it. I just got it to prove to people that the Yamaha and the Oteo are just as good as that amp, but I know the DBX amp works great for what they did. I wish they would’ve made more than but with more power but just like them the mono block and they need a bigger power meter on it then they were the pin awesome which they still are. They just need a bigger power meter to analog one like how the Accio do big ones like that then it would’ve been really really nice but anyways, thanks for reading what I had to say and it does sometimes gets me so mad when I see people put down good products just because they have a one tracked mind if they don’t cost a lot of money to them it ain’t no good

 

[SpeakerDavid]

I know it’s late never knew about this site but I gotta say one thing and I’ve been in the stereos and speakers and power amplifiers since I was 12 and I’m 56 now and considering these amps are being monobloc and you could use them either a for a Stereo that doesn’t have a subwoofer output or if you just want to add more speakers without making the 1 inch struggle tastings are great. I have four of them. They work perfect for exactly what I want and I also used one McIntosh champ two Yamaha and 80s two Accio with the big meters to 506 models and four Kenwood power me power amp with the power meters to end 28 because I run a lot of speakers and stuff because I’m addicted to it, but I’ll tell you what that work perfect I’ve won 415 off of them and they just whoever says ain’t no good. Don’t know what they’re talking about definitely worth the money and especially if you know how to hook them up which it’s really easy to hook them up. It’s just like 10 people that try to say the radio shack, realistic, and Optimus Mack speakers I run a pair of Mack Two an a pair of the Mack threes on my Yamaha M 80 if if anyone knows about that it’s a 250 W RMS per channel for more than 2530 years now never had a problem never blew out a speaker. Nothing ever happened to them. They still sound like New and work like New and then I also have two pair. Of klipsch with my other Yamaha m80 and if I had to sell anything I would get rid of klipsch 15” woofers in a horn mid range and a horn tweeter just like Mack 3 before I got rid of anything else and my McIntosh can’t I like it and love the way it looks, but I don’t even use it. I just got it to prove to people that the Yamaha and the Oteo are just as good as that amp, but I know the DBX amp works great for what they did. I wish they would’ve made more than but with more power but just like them the mono block and they need a bigger power meter on it then they were the pin awesome which they still are. They just need a bigger power meter to analog one like how the Accio do big ones like that then it would’ve been really really nice but anyways, thanks for reading what I had to say and it does sometimes gets me so mad when I see people put down good products just because they have a one tracked mind if they don’t cost a lot of money to them it ain’t no good

Sorry for some of the misspelled words and sometimes it looks like it didn’t come out right but a few years back I had a bad accident and had head trauma so I don’t know how to read and write. I talking to the phone and it supposed to say what I say but sometime it doesn’t so I apologize if it doesn’t come out right or if it changed things around, did I say, but if you have any questions about what I wrote, please feel free to reply back so I could fix my mistake. Thanks

 

[SpeakerDavid]

When I had my iPhone, read me back what I wrote the first time wow I’m sorry everyone it definitely didn’t say what I wanted it to say like when I tried to say onkyo 506 power amplifier ..it said I accio.. I apologize that my phone changed words around to names. I don’t even know what but I hope you use that to know about power engine and all the good brand like Yamaha McIntosh. Onkyo Ken wood power amps