Stereo Amplifier and Ohms question.

[wag123]

Originally Posted by DuckRyder
Originally Posted by wag123
krismoriah72, I just looked-up the amplifier that you are using. It is NOT 2 ohm stable running in bridged (mono) mode. Most amplifiers that operate in bridged output mode will not be 2 ohm stable. You should run it in stereo mode and run the two 8" subs (modified to 8 ohms each like I mentioned above) connected in parallel off of one channel and the 10" sub (also modified to 8 ohms like I mentioned above) off of the other channel then connect the inputs together in parallel with a Y adaptor making it a 2 channel mono amp. Doing it this way you wouldn't need the 4 ohm resistor in series with the 10" sub and you can reduce it's volume independently with the input level adjustment on that channel's input.


I think there is more than one "ds18 - 1200w" amp.

Since he said monoblock, maybe this one:

https://ds18.com/collections/amplifiers/products/exl-class-d-monoblock-amplifier-1200-watts-rms

Claims to be able to drive a 1 ohm load. Color me skeptical of a ~250.00 "1200W" one ohm capable amp, but hey...
It is a Class D (PWM digital) amp. Yes, Class D amps can be 1 ohm stable. Drivehard already mentioned using this kind of amp.
Actually, using a stereo amp wired the way that I mentioned would be a more elegant solution to his problem.

 

[DuckRyder]

Originally Posted by wag123
It is a Class D (PWM digital) amp. Yes, Class D amps can be 1 ohm stable.


Oh I know... I didn't say it wasn't possible, I said I was skeptical of a ~250.00 amp that claimed that. Seems since it has blown up (twice?) I'm right to be skeptical

Originally Posted by wag123
...Actually, using a stereo amp wired the way that I mentioned would be a more elegant solution to his problem.


Agree...

The system seems oddly put together to me...

 

[krismoriah72]

Ok sorry about the confusion. Ive had more bad luck somewhere...

The first amp that blew was a 2 channel Powerbass amp (marine) installed by the installer..

He installed a DS18 amp https://ds18.com/collections/marine...al-marine-monoblock-amplifier-1200-watts

After that he rewired it, had the two 8s on 4ohm, and the one 10 on 2 ohm and tied them all in together on the one channel. That lasted about 12 weekends.

I ordered the same amp on ebay and its still not here after almost 9 days.. (he is going to credit me for the amp).


In the mean time i bought a 2 channel amp from walmart https://www.walmart.com/ip/Dual-XPR52-2-Channel-Bridgeable-Amplifier/46270883 just to get me thru memorial weekend. (this amp has great reviews on youtube)..so i figured $60 was worth the enjoyment


I bought one amp and wired it as the old one was wired... and all the subs sounded like they were on mute. I ran all new power/ground/and inputs and also used 2 sources of signal... no help.

So i took the amp back to walmart thinking it was defective.

I installed the new one and same thing. I ran new power wire, new ground, 2 sets of inputs, and 2 sources of signal.

I even put the amp on the seat and hooked it to each of my batteries (I have two).

Same result.. i have even individualized each sub.. no matter what i do everything is on mute like barely thumping.

I have turned every knob and nothing fixes it.

So i am taking a small break from it.. i may just drop it off at his shop and have him figure it out.. he is an installer and he builds the boxes.

Nothing makes sense at this point.. and perhaps my original amp isnt even blown.

I even have a spare sub... and its on mute as well.. everyone i have asked or talked to says its impossible.

 

[krismoriah72]

Originally Posted by The_Nuke
Sounds like you have too many subs. Keep the 10 or the two eights and put the other(s) in a vehicle?


My buddy has a RZR with 2 10s and 2 8s.. with a 9 speaker overhead..it sounds amazing. I cant put the extra 10 in mine because mine is a Turbo.

 

[The_Nuke]

Verify the signal you are feeding the sub amp(s) is good. That's about the only thing I can think makes sense based upon your description of the situation - you have a bad signal coming in, so the amp isn't going to do anything to improve that, it will have to be fixed upstream where ever the problem 1st occurs

 

[krismoriah72]

Originally Posted by The_Nuke
Verify the signal you are feeding the sub amp(s) is good. That's about the only thing I can think makes sense based upon your description of the situation - you have a bad signal coming in, so the amp isn't going to do anything to improve that, it will have to be fixed upstream where ever the problem 1st occurs


I have two verified signals- My overhead system uses a marine head unit and has its own amp. The overhead signal is fine, it has its own line out to the Sub Amp. I plugged a portable speaker into this and it works fine.

I also have my phone/mp3 player with a jack and an RCA splitter.. good signal to my overhead and portable speaker.


I have tested redundantly the input, the power and ground.. the failure so far is with the output.

Everytime i write or tell someone it becomes more impossible.. as this is a pretty simple job. My new amp will be here in a day or so, i will know then whether to start over with wiring.

 

[The_Nuke]

Originally Posted by krismoriah72
Originally Posted by The_Nuke
Verify the signal you are feeding the sub amp(s) is good. That's about the only thing I can think makes sense based upon your description of the situation - you have a bad signal coming in, so the amp isn't going to do anything to improve that, it will have to be fixed upstream where ever the problem 1st occurs


I have two verified signals- My overhead system uses a marine head unit and has its own amp. The overhead signal is fine, it has its own line out to the Sub Amp. I plugged a portable speaker into this and it works fine.

I also have my phone/mp3 player with a jack and an RCA splitter.. good signal to my overhead and portable speaker.


I have tested redundantly the input, the power and ground.. the failure so far is with the output.

Everytime i write or tell someone it becomes more impossible.. as this is a pretty simple job. My new amp will be here in a day or so, i will know then whether to start over with wiring.



Then you are out of possibilities, literally. It has to be something you've overlooked or missed somehow.

Given the sheer number of subs and sub amps you tried but got identical (poor) results from, I'm still thinking there is something wrong with the signal going into the sub amps or coming out of them. No other way to explain those results.

Are you certain the signal you feed the sub amp contains the lower frequencies you are expecting to play from the sub?

What do you have the LPF frequency set to on the sub amp? Can you verify the amp is getting those frequencies?

Remove any Y-cables or other non-linear adapters upstream of the sub amp that could be filtering out the low frequencies. Once you verify they aren't filtering out desirable low notes, you can always replace the removed

Can you get an A/C voltage measurement at the speaker terminals on the sub amp without sub hooked up? If so, does it change in proportion to the head-unit volume?

Do you have a phase issue going on?

 

[krismoriah72]

Originally Posted by The_Nuke
Originally Posted by krismoriah72
Originally Posted by The_Nuke
Verify the signal you are feeding the sub amp(s) is good. That's about the only thing I can think makes sense based upon your description of the situation - you have a bad signal coming in, so the amp isn't going to do anything to improve that, it will have to be fixed upstream where ever the problem 1st occurs


I have two verified signals- My overhead system uses a marine head unit and has its own amp. The overhead signal is fine, it has its own line out to the Sub Amp. I plugged a portable speaker into this and it works fine.

I also have my phone/mp3 player with a jack and an RCA splitter.. good signal to my overhead and portable speaker.


I have tested redundantly the input, the power and ground.. the failure so far is with the output.

Everytime i write or tell someone it becomes more impossible.. as this is a pretty simple job. My new amp will be here in a day or so, i will know then whether to start over with wiring.



Then you are out of possibilities, literally. It has to be something you've overlooked or missed somehow. I agree

Given the sheer number of subs and sub amps you tried but got identical (poor) results from, I'm still thinking there is something wrong with the signal going into the sub amps or coming out of them. No other way to explain those results. I am tending to agree with you The head unit, my phone and an mp3 player all give same results]

Are you certain the signal you feed the sub amp contains the lower frequencies you are expecting to play from the sub? Yes

What do you have the LPF frequency set to on the sub amp? Can you verify the amp is getting those frequencies? I have tried every setting on the two new amps on LPF i can get only the lows and on on the HPF i can get the mids and some highs but its like they are on a mute setting very low volume

Remove any Y-cables or other non-linear adapters upstream of the sub amp that could be filtering out the low frequencies. Once you verify they aren't filtering out desirable low notes, you can always replace the removed The aux out is hooked to my overhead sound system and those cables are deep inside i would agree with you but i get the exact same result if i hook my phone or an mp3 player to the sub amp and bypass that

Can you get an A/C voltage measurement at the speaker terminals on the sub amp without sub hooked up? If so, does it change in proportion to the head-unit volume? Not yet i havent tried that due to the two brand new amps

Do you have a phase issue going on?
unknown

My 3rd new amp will arrive tomorrow.. i will hook it up and then if it doesnt work im taking it to the installer.. he wants to know what is wrong with it as much as me..