Subwoofer repair… Ouch!
- Thread starter Botch
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I second this suggestion.
Picked up my burned-up subwoofer (Monitor Audio Silver, 5.1 speaker set) from the repair shop. Many powered subwoofers have what's called a "plate amplifier" driving them, and it's a common part available from places like Parts Express and Dayton Audio; I asked him about that and he claimed it had to be a 1:1 swap (I think "bullsh*t"). I've found a suitable 250W amplifier, on sale for $230, its only ten screws and two wires, but I tend to really screw up the simple things (I'm called Botch for a reason). The best alternative I saw today is a $499 subwoofer from RSL, 400W and 22Hz @ -3dB, pretty much the same size, but much better performance. I'm a music guy, not a movie guy so much, so that bottom 1/3 octave or so isn't that critical.
Does anyone have any pref of Parts Express vs. Dayton Audio? Experience with RSL subs? And, from reading some reviews, it sounds like the Dayton plate amp is a stereo amp, and if you use it for a single sub (me), you lose half the power; is there a way to combine the channels to get the full 250W?
The other issue is that I don't have a dedicated home theater, this is a living room system, and the Monitors are in a beautiful "rosenut" veneer. I'd love to keep the MA subwoofer in place, although the RSL sub is in matte black and won't mismatch too badly (mebbe then I'll give @Wardsweb a call)...
Gonna have to sleep on this one.
Does anyone have any pref of Parts Express vs. Dayton Audio? Experience with RSL subs? And, from reading some reviews, it sounds like the Dayton plate amp is a stereo amp, and if you use it for a single sub (me), you lose half the power; is there a way to combine the channels to get the full 250W?
The other issue is that I don't have a dedicated home theater, this is a living room system, and the Monitors are in a beautiful "rosenut" veneer. I'd love to keep the MA subwoofer in place, although the RSL sub is in matte black and won't mismatch too badly (mebbe then I'll give @Wardsweb a call)...
Gonna have to sleep on this one.
- Dayton Audio is a sister company to Parts Express and Parts Express sells Dayton Audio components exclusively. They are not two different things.
- Many consumer subwoofers design their amplifier modules with built in EQ and protection circuits specifically for the woofer they will be mated with. This is why any competent repair shop will state you need a 1:1 match to replace the sub amp.
- You can still install an aftermarket plate amp and get results, the results could sound fine, especially if the original factor amp modules didn't have an aggressive EQ or very extensive protection circuitry for the woofer which might be quite delicate without the protection. If you want to experiment with a random 3rd party amp, go for it, but don't expect identical results. I recommend ensuring the power output is similar into the given load of the woofer - that means you need to know the impedance of the woofer and match the amp for that impedance.
- I have used most of the brands of plate amp Parts Express sells and they are all about as good as you'd expect from their prices. Pay more, get more quality. What is important is that the plate amp is 100% sealed when it is mounted. Otherwise, the enclosure will leak excessively, and the bass performance will be very limited and reduced.
I hope you find a solution and continue loving music and movies. Let me know if you have questions or want advice.
- Many consumer subwoofers design their amplifier modules with built in EQ and protection circuits specifically for the woofer they will be mated with. This is why any competent repair shop will state you need a 1:1 match to replace the sub amp.
- You can still install an aftermarket plate amp and get results, the results could sound fine, especially if the original factor amp modules didn't have an aggressive EQ or very extensive protection circuitry for the woofer which might be quite delicate without the protection. If you want to experiment with a random 3rd party amp, go for it, but don't expect identical results. I recommend ensuring the power output is similar into the given load of the woofer - that means you need to know the impedance of the woofer and match the amp for that impedance.
- I have used most of the brands of plate amp Parts Express sells and they are all about as good as you'd expect from their prices. Pay more, get more quality. What is important is that the plate amp is 100% sealed when it is mounted. Otherwise, the enclosure will leak excessively, and the bass performance will be very limited and reduced.
I hope you find a solution and continue loving music and movies. Let me know if you have questions or want advice.
Deacon
Humble Servant
The biggest problem may be 'fitting' the new plate amp into the same 'cutout' as the old amp. You might have to do some woodwork to get it to fit right. Old as that amp is I assume it still has those heat sink fins to dissipate heat???
Actually the woodworking part is the only thing where I'm halfway competent. Right now I have a tech question sent in to Parts Express. They have a 250W plate amp that also includes a programmable, 5-band parametric EQ (which is complete overkill for a damn sub) and two outputs, and it sounds like it outputs 125W per channel, and I'm wondering if I can bridge them, or would be better served with a 300W mono plate amp. It doesn't have the DSP but my Yamaha has YPAO built-in and should take care of the cutoff points/balancing (it's also less expensive).
My sub does have heat sink fins; I assume that means it's a Class A/B type amp, and not Class D?
My sub does have heat sink fins; I assume that means it's a Class A/B type amp, and not Class D?
Is this the amp?
Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSP
Dayton Audio SPA250DSP 250W Subwoofer Plate Amplifier with DSPDayton Audio SPA250DSP Subwoofer Plate AmplifierElite Control with DSPDayton Audio's SPA250DSP true 250 watt digital switching plate amplifier features advanced signal processing control that every audio enthusiast wants. With Class D...
www.parts-express.com
It is a mono sub amp capable of up to 250W into a 4 ohm load. It is not a two channel amp.
The DSP section is capable of also processing a stereo output in addition to the internal subwoofer output. So, the DSP is a "2.1" processor with the .1 going to the internal amp that powers the subwoofer.
This allows you to use the plate amp as a very advanced bass management process for a stereo signal, feeding it a stereo signal then processing a stereo output to the amp(s) for the main stereo speakers that can be highly tuned for the perfect sound. If connected directly to the LFE output from a surround receiver or preamp/processor, the stereo outputs will not be necessary nor used. But, the PEQ can be very useful for tuning the subwoofer's performance in the room - they can be used to reduce the effects of a standing wave or to extend the bass a little, or to provide a subsonic roll off below the driver's capabilities to increase peak output and reduce distortion.
Wardsweb
Renaissance man
First off, thank you for the kind words. Second, I will add that you get to decide how good is good enough. Here is a Gallo sub that I put a no name TPA3255 plate amp I got from Walmart (also available on Amazon). I filled in the original hole and cut that to fit the new amp. Is it 100% a match for the original...No. Does it work? yes and is good enough for me.
Thanks, @Wardsweb. The fine folks at Parts Express answered my question within two hours, kudos to them.
When I looked at the block diagram for the first plate amp it sure looked like it was a stereo output, but then I looked at the block diagram for the second, "mono" amp and it too has stereo RCA inputs, as does your Gallo/Walmart sub. My Yamaha has a single Sub Out, and as indicated in the response I got Parts Express has a Y-connector to allow hookup to both inputs. Not sure why they're designed that way.
So, unless someone convinces me that a Class A/B amp at 250W would be superior, in a subwoofer, to a cheaper 300W Class D with less parts to go bad, I'll probably be going with the 300-watter. And, oh crap, I just thought to check the power of my sub's broken amp, it's 500W!! Back to the web....
Finally, earlier I asked:
Thanks for the help, guys.
When I looked at the block diagram for the first plate amp it sure looked like it was a stereo output, but then I looked at the block diagram for the second, "mono" amp and it too has stereo RCA inputs, as does your Gallo/Walmart sub. My Yamaha has a single Sub Out, and as indicated in the response I got Parts Express has a Y-connector to allow hookup to both inputs. Not sure why they're designed that way.
So, unless someone convinces me that a Class A/B amp at 250W would be superior, in a subwoofer, to a cheaper 300W Class D with less parts to go bad, I'll probably be going with the 300-watter. And, oh crap, I just thought to check the power of my sub's broken amp, it's 500W!! Back to the web....
Finally, earlier I asked:
From the email it looks like they're one in the same.
Thanks for the help, guys.
Note that I did this with a relatively inexpensive 8" Boston Acoustics subwoofer with a bad amplifier that I had originally planned to toss. In other words, I had nothing to lose by trying.
I removed the amp and used the plate as a template for cutting a new plate from some MDF with a rabbit to hold it in place. I then took the speaker wire from the driven and ran it directly to a pair of terminals in the plate before gluing it in place. Now I had a passive subwoofer.
I bought an inexpensive 3 channel FOSI amplifier. The sub channel had crossover and gain controls. I connected the sub, dialed it in, and it worked great. I am using it in my bedroom with the Overnight Sensation kit speakers I built and am quite pleased with how it sounds.
I don't know if that is a good idea or not. You'd have to ask Flint or someone else who actually knows what they are doing.
I removed the amp and used the plate as a template for cutting a new plate from some MDF with a rabbit to hold it in place. I then took the speaker wire from the driven and ran it directly to a pair of terminals in the plate before gluing it in place. Now I had a passive subwoofer.
I bought an inexpensive 3 channel FOSI amplifier. The sub channel had crossover and gain controls. I connected the sub, dialed it in, and it worked great. I am using it in my bedroom with the Overnight Sensation kit speakers I built and am quite pleased with how it sounds.
I don't know if that is a good idea or not. You'd have to ask Flint or someone else who actually knows what they are doing.
I just checked, my old amp was set at 50% output the whole time, and no I don't listen at high volumes. The 300W Class D amp they sell is the only one on backorder (of course, BotchLuck™) but they're supposed to have them by the end of the month.