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Subwoofer amp help please

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jmaloney

New Member
Hello I am new to the sight an am having a problem with a subwoofer amplifier. I have a klipsch RSW 12 sub and Klipsch can not give me schematics due to the item still being in production. I had a problem with the amp cutting at a loud base levels and coming back on after. After hours of reading electronics books and tracing signals the problem turned out to be a prefab cable that send the signal from the pre amp to the amp had a poor connection. Repaired this connection and Sub works now except it now has about 60 percent of the punch it used to have. I replace
d one lm324 quad op amp in the pre amp early on. I used another lm324 but I used a socket should this matter. and also what else can I look for and how can I know if my pre amp gain is correct without schematics thanks.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
jmaloney said:
Hello I am new to the sight an am having a problem with a subwoofer amplifier. I have a klipsch RSW 12 sub and Klipsch can not give me schematics due to the item still being in production. I had a problem with the amp cutting at a loud base levels and coming back on after. After hours of reading electronics books and tracing signals the problem turned out to be a prefab cable that send the signal from the pre amp to the amp had a poor connection. Repaired this connection and Sub works now except it now has about 60 percent of the punch it used to have. I replace
d one lm324 quad op amp in the pre amp early on. I used another lm324 but I used a socket should this matter. and also what else can I look for and how can I know if my pre amp gain is correct without schematics thanks.

I wouldn't have thought an lm324 would have failed, they are reliable devices and probably not under any strain in the circuit.

As the chances of two different faults occuring at the same time are slight, I would suggest it's either something you've accidently done, or you've not repaired the faulty connection properly.
 

jmaloney

New Member
you are correct the lm324 did not fail it was a guess that was wrong as for the wire repair it is simply a crimp on wire and it ohms at zero i was wondering if by putting in a chip socket if this could be causing my problem thanks
 

Nigel Goodwin

Super Moderator
Most Helpful Member
jmaloney said:
you are correct the lm324 did not fail it was a guess that was wrong as for the wire repair it is simply a crimp on wire and it ohms at zero i was wondering if by putting in a chip socket if this could be causing my problem thanks

No, a socket is fine - I generally fit a socket for any IC I have to change.
 

chandima283

New Member
I need some help

I have a subwoofer consisting TIP2955 and TIP3055 transistors.
the problem I have is, the sound coming out from the woofer is not smooth like other subwoofers. I replaced the transistors also, but the problem is still there.
 

tcmtech

Banned
Most Helpful Member
LM324's, TIP2955's and TIP3055's!:eek:
I hope this was a high quality amp that was built back in the 1980's! ;)
By todays standards its crap and a half! :(

Who is Klipsch associated with? Rockford Fosgate, Bose, Pyramid, China Joes Discount Audio? :confused::p:D

Klipsch is really just a foreigners misspelling of 'clips sh!t' !:D

Unless your an audiophile of course! Then this is some high end gear worth dollars on the cents!;)

Yea I am an ass because for poking some rough humor at you. Sorry if it doesn't go over well.:(

I used to fix audio gear and got a very good look at some "high end" audio systems and was shocked and disapointed by how many have the customer paying for the name and not the quality of construction or design.:mad:
 

crutschow

Well-Known Member
Most Helpful Member
I have a subwoofer consisting TIP2955 and TIP3055 transistors.
the problem I have is, the sound coming out from the woofer is not smooth like other subwoofers. I replaced the transistors also, but the problem is still there.
Did it just suddenly go bad? What does it sound like? Is there any damage to the speaker cone?
 

Speakerguy

Active Member
TIP2955 and 3055 are OK. Still very common O/P transistors. The LM324 has no place in audio equipment, though. I'm amazed anyone still uses that POS.
 
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tcmtech

Banned
Most Helpful Member
My bad. :eek:
I dont usually look at the original post dates on threads with only a few post replies total.
If a thread pops up I have not seen before but has a full page or two or more of replies I look at the start dates.

Maybe electro tech should have the header background color change if a thread is dormant for more than a month.

It would help clarify the time line relevancy for us less observant folks. :p
I know I am not the only one that has done this though!:D
 

chandima283

New Member
Did it just suddenly go bad? What does it sound like? Is there any damage to the speaker cone?
crutschow,, the sound is somewhat distorted (a sound like "grrrrr..")
The woofer is ok. cone is not damaged.
What should I do to make it normal and to work like other subwoofers.
 

crutschow

Well-Known Member
Most Helpful Member
crutschow,, the sound is somewhat distorted (a sound like "grrrrr..")
The woofer is ok. cone is not damaged.
What should I do to make it normal and to work like other subwoofers.
If the cone is ok then something apparently has failed in the electronics but, without a schematic, it would be difficult to determine what is wrong. Do you have a schematic?

You might see if you can measure the DC power voltages. There may be two equal magnitude plus and minus voltages.

The easiest may be just to buy a new amplifier. Parts Express, for example, has some inexpensive amps **broken link removed**, if you don't require a lot of power.
 

Chippie

Member
Can you please tell me, what are the IC's and transistors used in new types of subwoofer circuits.:confused:

Mosfets are common place nowadays in new designs....they dont suffer the thermal runaway problems of earlier bipolar designs...

Best to use a search engine for designs...or have a look here:300/500W Subwoofer Power Amplifier

The design presented as an example, is based bipolar devices.

Then, this one: https://sound.westhost.com/project101.htm

is mosfet based.....
 
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tarquinkrikery

New Member
Hi,

I know this is an old thread, but I thought this might be a good place to put a query I have. I'm hoping one of you lot may know where I should start with my problem.

I have an Eltax Active subwoofer I bought a few years ago (since it was cheap). Recently it cuts out after 10-15 minutes, or following a loss of LFE signal from the soundtrack (so when it goes into standby mode). The only way to get it to work again is by either turning it on and off - or by switching the phase from 0-180 degrees or vica versa (or putting from 0-180 then back again).

I'm assuming there's a problem with the amplifier itself given the symptons. I have emailed Eltax for a schematic, but have had no luck. Any chance that any of you experts may have an idea what where to start?

My electronics knowledge is limited, but I'm confident given some pointers I may be able to work things out!

Any help would be really appreciated as this is really frustrating! lol

Thanks
 
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