subwoofer amplifier

A

akanarya

Audiophyte
Hi,

I have a Klipsch SW 450 home theatre subwoofer.
Its plate ampli is malfunctioning. Upto now my technician couldnt repair it.
Woofer is in good state. I need an amplifier suggestion.

I listed the specs of the sub below.
I only use sub (LFE) output from my Denon receiver, therefore crossover circuitry is not needed.
I contacted several amplifier sellers from ebay and aliexpress. But they said their products are not suitable for my sub.
I dont know why.
Here some examples i talked with sellers:

my sub specs:
FREQUENCY RESPONSE: 28-120Hz +/-3dB
AMPLIFIER POWER: FTC Rated Power: 200 watts continuous @ 1% THD, Dynamic Power: 450 watts
MAXIMUM ACOUSTIC OUTPUT 115dB @ 30Hz 1/8 space, 1m
DRIVE COMPONENTS 10” (25.4cm) high excursion, fiber-composite cone,down-firing woofer
AMPLIFIER Class D
PHASE: Switchable 0-180 degrees

its pdf datasheet:

Can you suggest me an amplifier to drive my woofer speaker?
note: I am aware of third party plate amplifiers but i am looking for a cheaper solution.

Thank you very much for your considerations.
sw-450-back_635042236795930000_medium.jpg
 
haraldo

haraldo

Audioholic Spartan
I heard tons of people haveing issues with plate amps and Gene was talking lots about plate amps failing over and over again.... I have the same issue, I got 4 subwoofers and multiple subs failing.

I am ripping out the plate amps and rewiring for external pro amps

Some alternatives, depending on budget

IMG Stageline STA-300D Stereo Class-D PA Amplifier $256.00
Class D but I am not sure which technology
Peak Output Power: 350W
RMS Power Rating: 300W
At 4 Ohms: 2 x 150W
At 8 Ohms: 2 x 100W
8 Ohm Bridged: 1 x 300W

IMG Stageline STA-400D Stereo Class-D PA Amplifier $337.50
Class-D concept with power amplifier modules from HYPEX
Peak Output Power: 700W
RMS Power Rating: 540W
At 4 Ohms: 2 x 270W
At 8 Ohms: 2 x 180W

IMG Stageline STA-800D Digital Stereo PA Amplifier $415.00
Class D concept with power amplifier modules from HYPEX
Power Rating: 800W
Power Rating At 4 Ohms: 2 x 400W
Power Rating At 8 Ohms: 2 x 210W
Peak Music Power Output: 1000W

Lab Gruppen PDX3000 Power Amplifier with DSP $641.00
Peak Output:
Wattage of All Channels Driven: 3000W
Max Output Power: (All channels driven)
2 Ohms per Channel: 1000W
4 Ohms per Channel: 1500W
8 Ohms per Channel: 800W

Wharfedale DP-4035 Power Amplifier
Stereo Power Output:
4 x 350W at 8 Ohms
4 x 595W at 4 Ohms
Bridged Mono Power Output:
2 x 700W at 16 Ohms
2 x 1190W at 8 Ohms
 
A

akanarya

Audiophyte
thanks haroldo,
I have a singel sub an I am looking for a cheaper solution, say not more the $60-70.
 
haraldo

haraldo

Audioholic Spartan
thanks haroldo,
I have a singel sub an I am looking for a cheaper solution, say not more the $60-70.
Yeah ... I thought it would be a bit on the pricey side for you...Did you consider some of the lower priced class-d amps made for car usage?, I have never looked into that for this kind of setup, but maybe that would work for you?
 
ryanosaur

ryanosaur

Audioholic Warlord
It is worth noting that many plate amps contain some DSP programming. I do not know if the model in question does. However, this programming is usually done in a way to include protections limiting voltage and perhaps an HPF; both preventing overexcursion and damage to the driver.
In most cases, drop in replacements are not possible, and even removing the amp and wiring for an external unit will likely yield poor, if not disastrous results.

I would urge caution in doing this.

you are likely much better off buying a good quality Sub from SVS, Hsu, or even the new Stark Sound. Monoprice Monolith subs are also highly regarded and on sale right now, iirc.
Any of these, even lower models, will far anc away outstrip the capabilities of your Klipsch.
 
Pogre

Pogre

Audioholic Overlord
Yup. I agree with Ryan. Cut your losses now and invest in a new sub. Then you can spend the next couple of weeks being blown away at the difference a well built, linear sub makes with just about everything. My experience was cleaned up sound from top to bottom.
 
A

akanarya

Audiophyte
Are we getting closer here?
This one can be bdridged

Power Acoustik VA2-1400D Vertigo Series 1,400-Watt Max 2-Channel Class D Amp $59.36

But you need a 12V power supply here
I looked a bit to car amplis. They require lower voltage because of car energy system (ie 12v dc battery capable of sourcing high current), that can be good.
However, because of that, car is occupied with low resistance speakers, 2-4 ohm. In that way speaker power is elavated. Otherwise using 8 ohm spaker will give lower gain.
I am not sure but with high probability home theatre subs have 6-8 ohm woofers.
Using math, if i use high power car ampli(which is easy to find ), i can get approx 200w (orginal rate of my sub) for my woofer. That is also good.
But car amplis specs are given for only 2-4 ohm. Therefore probably internal design is not optimised for higher
loads.
Even if it works, there may be high distortion etc. I dont know. Just considerations.
 
Pogre

Pogre

Audioholic Overlord
Even if it works, there may be high distortion etc. I dont know. Just considerations.
This is going to be a possible problem with any amp you try to match to the system. As Ryan mentioned a lot of the amps that come with a powered sub have proprietary dsp to protect the driver or help with linearity. You're very unlikely to find something aftermarket that will work as intended.
 
Eppie

Eppie

Audioholic Field Marshall
Partsexpress also has plate amps in various sizes and power ratings. As mentioned above, this is a cheap fix that is not guaranteed to work properly as most plate amps are designed to work with a specific style of woofer and cabinet. If you're desparate for a cheap fix, you can experiment with one of those but don't push the woofer to hard or you'll be back at square one. I saved up for an SVS after my Klipsch started acting up. Best investment I made this year.
 
Verdinut

Verdinut

Audioholic Ninja
and even removing the amp and wiring for an external unit will likely yield poor, if not disastrous results.

I would urge caution in doing this.
Wiring for an external amp but leaving the defective onboard amp in the cabinet could be fine. The reason being that the same internal volume should be kept to have the driver performance and frequency response remaining as originally designed.
 
A

akanarya

Audiophyte
Dear Ryan and other friends,
Thanks all your comments. I completely aware of the audiholic site.
Sound systems are all optimised within its design.
For example a subwoofer is tigthly coupled with its woofer, amplifier, cabinet and port by designers.
Any change will effect the performance. I am on your site.
However, how can i waste this woofer :(, i like its sound.
IMG_20211127_000656.jpg
And I have to wait more time to grab a good one.
Plus, i mostly use it for movies, therefore superior performance is not needed, just boom effects.
Because of that i am asking your thoughts and experience.
I am searching for a mid solution until SVS.

For example, take a look at this:
What do you think?
 
A

akanarya

Audiophyte
Wiring for an external amp but leaving the defective onboard amp in the cabinet could be fine. The reason being that the same internal volume should be kept to have the driver performance and frequency response remaining as originally designed.
got it thanks
 
Eppie

Eppie

Audioholic Field Marshall
Dear Ryan and other friends,
Thanks all your comments. I completely aware of the audiholic site.
Sound systems are all optimised within its design.
For example a subwoofer is tigthly coupled with its woofer, amplifier, cabinet and port by designers.
Any change will effect the performance. I am on your site.
However, how can i waste this woofer :(, i like its sound.
View attachment 51815
And I have to wait more time to grab a good one.
Plus, i mostly use it for movies, therefore superior performance is not needed, just boom effects.
Because of that i am asking your thoughts and experience.
I am searching for a mid solution until SVS.

For example, take a look at this:
What do you think?
I don't think that one is going to work for you. Note that he uses an external DC power supply. Easiest replacement will be one with a built in power supply just like your Klipsch, so all you need is an AC power cord and connect the speaker wires to the plate amp. The tough part is finding one the same size to cover the opening properly.

The board from AliExpress in your original post also requires a DC power supply, which needs to be factored into your costs.

Using an external amp and bypassing the plate amp is an option but then all of the adjustments (crossover points, phase and levels) has to be done at the receiver. Your Denon should be able to handle that.

The plate amps on PartsExpress are fully featured and are about as 'plug and play' as you're going to get. The problem is that many are the same price as a new cheap sub from BestBuy. Anything in the price range you mentioned will have less power than the defective amp. If you go the AliExpress route, price out a power supply that matches the specs that the amp calls for and think about how in the heck you're going to mount all that and wire it inside the old cabinet. What about the controls?

Most of those Youtube videos just show parts on a bench. They rarely show how you would actually mount all of this stuff into a cabinet, and they are typically intended for a DIY build where you can design the cabinet to fit the components. You are restricted by what you have, so replacing the amp is not that straight forward unless you can find a replacement plate amp the same size as the old one.
 
lovinthehd

lovinthehd

Audioholic Jedi
Is the impedance of the driver even known? I'd guess its likely 4 ohm, but I'd still look at amps capable of a significant 4 ohm load. One of these board amps might do the job with a sufficient power supply. Another thought is to buy a used amp to keep costs down.
 
haraldo

haraldo

Audioholic Spartan
Is it not possible to get a replacement amp from Klipsch?
Or find an even better ”repair guy” ro fix the amp
I think that would be best option

if not …. Agree with you guys that I am sure then the better option in this case could be to to ”take the loss” and go with another sub from svs or Monoprice. Looking at what Monoprice does at the moment, I am completely dumbfounded on how they can sell the products at the prices they do. Right now, their lowest priced sub starts at $118. It will not blow your socks off and ther is limited LF extension bur I believe what it does, it will do pretty well.

i have 2 blown amplifiers in my 4 Audio Physic Rhea II subs now and looking at what to do… these are much more capable subs and I will most likely be taking the risk and go with an external pro amp with inbuilt dsp
 
Last edited:
Eppie

Eppie

Audioholic Field Marshall
Is it not possible to get a replacement amp from Klipsch?
Or find an even better ”repair guy” ro fix the amp
I think that would be best option

if not …. Agree with you guys that I am sure then the better option in this case could be to to ”take the loss” and go with another sub from svs or Monoprice. Looking at what Monoprice does at the moment, I am completely dumbfounded on how they can sell the products at the prices they do. Right now, their lowest priced sub starts at $118. It will not blow your socks off and there is limited LF extension bur I believe what it does, it will do pretty well.

i have 2 blown amplifiers in my 4 Audio Physic Rhea II subs now and looking at what to do… these are much more capable subs and I will most likely be taking the risk and go with an external pro amp with inbuilt dsp
I tried gettig a replacement plate amp from Klipsch and none were available. If they stock any, it's only for a short time or it's for the expensive models. The cheaper subs do not get supported for very long. As to hiring a repair tech, that's probably too expensive. The amps are covered in goop to prevent vibration and very difficult to work on. I'm going to try and repair mine, but the problem is intermittent which makes it that much more difficult to diagnose. If the switching power supply is gone or a power transistor blew, that's much easier to determine.
 
A

akanarya

Audiophyte
let me sum up your valuable ideas

for additional power supply:
i am lucky, power board of my defective ampli is working, only amplifier section is gone.
I have to measure the voltages to be ensure that they are applicable to external amplifier board.
If so, it will be straight forward to collect all; just remove the ampli board from the plate, place new one
on the plate and mount orginal plate to the box. If everything went well :) this is good day plan.

prices of replacement plate are not so meaninfull. However if i encounter an opportunity, definitely i will consider.

I measured the woofer resistance as 4.6 ohm. I surely will take it into account if i go with an ampli board.

Infact my repair guy is good but there was a problem to find some parts here. Today i retalked with him, and he said that he found some. I am waiting good news now. I hope he could manage.That would be best option.
 
lovinthehd

lovinthehd

Audioholic Jedi
Is it not possible to get a replacement amp from Klipsch?
Or find an even better ”repair guy” ro fix the amp
I think that would be best option

if not …. Agree with you guys that I am sure then the better option in this case could be to to ”take the loss” and go with another sub from svs or Monoprice. Looking at what Monoprice does at the moment, I am completely dumbfounded on how they can sell the products at the prices they do. Right now, their lowest priced sub starts at $118. It will not blow your socks off and ther is limited LF extension bur I believe what it does, it will do pretty well.

i have 2 blown amplifiers in my 4 Audio Physic Rhea II subs now and looking at what to do… these are much more capable subs and I will most likely be taking the risk and go with an external pro amp with inbuilt dsp
Never hurts to ask Klipsch but that's an older model and suspect it's just simply too old for them to still have replacements hanging around.

FWIW Monolith subs are quite good from Monoprice, but the lower priced subs under the Monoprice brand is a different range of quality and capability. A couple of the Monoprice subs got decent reviews, but mostly it's the Monolith subs that are the exciting/desireable subs from them.....
 
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