Hi All,
I have a set of the original (rev 1) Klipsch ProMedia 2.1 THX powered computer speakers. When I purchased these, I remember calling my wife over to listen to them because they sounded so amazing! Well, recently the subwoofer started to get quieter and quieter, and needed to be looked into. I opened it up to see if I could see anything like burnt components or leaky caps. I didn’t see anything except the sub board was slightly discolored. I leave it on all the time, and it does stay warm even when not in use, and I’ve had it for over 15 years, so I kind of expected it wouldn’t last forever. It looked like a huge job to test all the caps because you have to unsolder boards from each other just to get at them, and there is a lot of glue/potting that really inhibits disassembly.
A new ProMedia system (rev 3) is about $120, and is apparently not as well liked, so I decided to keep the speakers and just replace the amp and power supply. After a bit of research, I purchased a zk-tb21 50w + 50w + 100w 2.1 class D amplifier for $30 from amazon, and a 24v 5a 120w power supply for $21. You can look up the specs, but it looked like a good match for the speakers. I pulled the original plate amp off the sub and replaced it with a sheet of aluminum (I reused the original gasket). I mounted some banana jacks on it so I could disconnect the sub when needed. The sub was considerably lighter without its electronics, which amounted to more than half of its original weight. I also removed the control pod off the right satellite speaker since it was also no longer needed. I found that the original polarity on the sub was intentionally reversed (not sure why), so when I reconnected it to the new amp, I tested the phase alignment between the sub and the satellites. Sure enough, if you connect positive to positive, you get destructive interference, and if you reverse it, the phase of the satellites and the sub are aligned. I’m not sure how important that is with the sub under my desk, but hey, they’re aligned when they are sitting together.
The end result was quite successful. It sounds awesome again. The amp has way more power than the speakers can use, and way more than I usually use even when gaming. I over-specced it a bit because someday I might get a bigger sub or nicer satellites, and this allows room to grow. After a few days of use, I found the power supply is room temperature all the time. The amp cover plate gets a little warm after an hour of hard use (maybe 85 or 90 deg F, slightly cooler than body temp) and gets a little cooler, but still above ambient when the amp is on, but not amplifying anything. I haven't decided whether I will turn it off or leave it on all the time. I found I like a slight bit of bass on the satellites, but I caution against using too much bass on those unless you are keeping the main volume down. I doubt there is any low frequency (lots of power in the low end) protection inside the two ways. The picture of my amp settings go along with my typical pc volume slider usage of about 25% for casual listening, 100% for occasional really loud listening. I post them to show you that even at pc vol of 100% you probably won't need to go above ~40% on the amp if you use a 24v ps.
Pros of this mod are…
Cons of this mod are…
I just thought I would document this simple build here, because I see a lot of these great speakers dying off, and if you are a little handy, you can probably get yours back up and running for pretty cheap.
My Original Satellites and Sub
Removed Control Pod
Removed Original Plate Amp From Sub (Spotted Backwards Polarity)
Fashioned New Cover Plate
Spray Painted Plate Black, And Buttoned It Up
All Ready To Go
My Settings For Balanced Response At PC Output Levels
I have a set of the original (rev 1) Klipsch ProMedia 2.1 THX powered computer speakers. When I purchased these, I remember calling my wife over to listen to them because they sounded so amazing! Well, recently the subwoofer started to get quieter and quieter, and needed to be looked into. I opened it up to see if I could see anything like burnt components or leaky caps. I didn’t see anything except the sub board was slightly discolored. I leave it on all the time, and it does stay warm even when not in use, and I’ve had it for over 15 years, so I kind of expected it wouldn’t last forever. It looked like a huge job to test all the caps because you have to unsolder boards from each other just to get at them, and there is a lot of glue/potting that really inhibits disassembly.
A new ProMedia system (rev 3) is about $120, and is apparently not as well liked, so I decided to keep the speakers and just replace the amp and power supply. After a bit of research, I purchased a zk-tb21 50w + 50w + 100w 2.1 class D amplifier for $30 from amazon, and a 24v 5a 120w power supply for $21. You can look up the specs, but it looked like a good match for the speakers. I pulled the original plate amp off the sub and replaced it with a sheet of aluminum (I reused the original gasket). I mounted some banana jacks on it so I could disconnect the sub when needed. The sub was considerably lighter without its electronics, which amounted to more than half of its original weight. I also removed the control pod off the right satellite speaker since it was also no longer needed. I found that the original polarity on the sub was intentionally reversed (not sure why), so when I reconnected it to the new amp, I tested the phase alignment between the sub and the satellites. Sure enough, if you connect positive to positive, you get destructive interference, and if you reverse it, the phase of the satellites and the sub are aligned. I’m not sure how important that is with the sub under my desk, but hey, they’re aligned when they are sitting together.
The end result was quite successful. It sounds awesome again. The amp has way more power than the speakers can use, and way more than I usually use even when gaming. I over-specced it a bit because someday I might get a bigger sub or nicer satellites, and this allows room to grow. After a few days of use, I found the power supply is room temperature all the time. The amp cover plate gets a little warm after an hour of hard use (maybe 85 or 90 deg F, slightly cooler than body temp) and gets a little cooler, but still above ambient when the amp is on, but not amplifying anything. I haven't decided whether I will turn it off or leave it on all the time. I found I like a slight bit of bass on the satellites, but I caution against using too much bass on those unless you are keeping the main volume down. I doubt there is any low frequency (lots of power in the low end) protection inside the two ways. The picture of my amp settings go along with my typical pc volume slider usage of about 25% for casual listening, 100% for occasional really loud listening. I post them to show you that even at pc vol of 100% you probably won't need to go above ~40% on the amp if you use a 24v ps.
Pros of this mod are…
- sub restored to working condition (the whole thing sounds as good as the original to me)
- cost only a little over $50
- modular components. So if amp, ps, or speakers fail, they can now be replaced independently
- amp has volume and tone controls for satellites and sub individually (nice to tailor response)
- Bluetooth and hardline input connectivity included (no wireless on stock ProMedia)
- more power than needed (possible upgrade path)
- the amp and ps are now outside of the high pressure, high temp environment
Cons of this mod are…
- the input cap on the amp is huge, so I get a spark when hooking up to power
- I now have an additional power brick under the computer table
- the amp and wires takes up a bit of space on the top of the desk
- the control pod had a headphone jack, and an aux input, that are now gone
- not sure about longevity
I just thought I would document this simple build here, because I see a lot of these great speakers dying off, and if you are a little handy, you can probably get yours back up and running for pretty cheap.
My Original Satellites and Sub
Removed Control Pod
Removed Original Plate Amp From Sub (Spotted Backwards Polarity)
Fashioned New Cover Plate
Spray Painted Plate Black, And Buttoned It Up
All Ready To Go
My Settings For Balanced Response At PC Output Levels
Hello. I just ran across your post and working on restoring my Promedia 2.1 system. I have the same setup, but wanted to know were you able to replicate the original bass response with the original hardware? Mines is a bit less than the original deep rich sound it had. I reversed the polarity as you did, but it still seems the same even after playing with the amp settings. Are both sides on the opposite polarity (bass and amp)? Any reason I wouldn't get the same response with this type amp? I really love the original bass sound versus the muffled sound I hear now. This is my second set of these speakers I've had in over a decade and nothing really compares in my opinion when working properly. I appreciate your feedback. Thanks.
I have the Wuzhi Audio ZK-TB21 amp. I'm considering finding something with more quality. Any recommendations? I hear that the FOSI Audio mini amps are decent. I just want to reproduce that deep bass as the original. I know it won't be perfect, but it's not even close now. Thanks for your feedback.
Hi there,
Yes, I was very pleased by the bass response using the ZK-TB21. It was a little hard for me to tell if it is exactly like the original response, because the original sub amp died slowly over several months, making it hard to make a mental comparison. I will say with the new amp and the ability to control the sub cutoff frequency and gain separately, as well as tweak the bass going into the satellites, the amount of bass shaping capability is quite amazing. Yes, I would characterize it as deep and full, and not muffled at all. It does get a little muddy if I set the cutoff higher than the 12:00 knob position. And if I set it lower, the very low frequencies remain strong, but you can hear something is missing around 100 to 120 hz or so, but moving it back up to noon or so provides a nice even bass response. This was a cheap and easy project so I didn't go to the trouble of capturing the frequency response with my measurement mic and a sine sweep.
As Karlsonate says, it could be you just got a bad one. Also check that your power supply is adequate. If you don't have the current and voltage to drive the amp and sub, the bass response is what will suffer most.
As for your phase question, I used the correct polarity for both satellites, and just reversed the polarity to the sub. I judged this to be the correct phase alignment by selecting a frequency that both the sub and the satellites could produce and lining all three speakers up on a table all facing a sound pressure meter. When the phase is correct, all three will sum constructively and give a stronger db reading, when the sub has the incorrect phase it will interfere with the satellites, and you will get a weaker db reading. Again though, I'm not sure how important that is because nobody puts the sub on a table in between the satellites, it usually goes on the floor several feet away, so the phase alignments gets all wonky anyway.
Please add to this post if you find an amp you like better, or if you find your power supply was the issue. I, and future readers, will love to hear your experience.
Yes, I was very pleased by the bass response using the ZK-TB21. It was a little hard for me to tell if it is exactly like the original response, because the original sub amp died slowly over several months, making it hard to make a mental comparison. I will say with the new amp and the ability to control the sub cutoff frequency and gain separately, as well as tweak the bass going into the satellites, the amount of bass shaping capability is quite amazing. Yes, I would characterize it as deep and full, and not muffled at all. It does get a little muddy if I set the cutoff higher than the 12:00 knob position. And if I set it lower, the very low frequencies remain strong, but you can hear something is missing around 100 to 120 hz or so, but moving it back up to noon or so provides a nice even bass response. This was a cheap and easy project so I didn't go to the trouble of capturing the frequency response with my measurement mic and a sine sweep.
As Karlsonate says, it could be you just got a bad one. Also check that your power supply is adequate. If you don't have the current and voltage to drive the amp and sub, the bass response is what will suffer most.
As for your phase question, I used the correct polarity for both satellites, and just reversed the polarity to the sub. I judged this to be the correct phase alignment by selecting a frequency that both the sub and the satellites could produce and lining all three speakers up on a table all facing a sound pressure meter. When the phase is correct, all three will sum constructively and give a stronger db reading, when the sub has the incorrect phase it will interfere with the satellites, and you will get a weaker db reading. Again though, I'm not sure how important that is because nobody puts the sub on a table in between the satellites, it usually goes on the floor several feet away, so the phase alignments gets all wonky anyway.
Please add to this post if you find an amp you like better, or if you find your power supply was the issue. I, and future readers, will love to hear your experience.
Hey Sparky,
I was about to suggest Knight to go traditional - dedicated plate amp for subwoofer + 2.0 amp for the satellites if all else fails. Then I thought some more and wondered if the original amp can be fixed. What's wrong with it? I have seen full sets of these expensive computer speakers with dead amps/controllers.
P/s: another idea just came across. You said that the electronics inside the subwoofer are responsible for about half its weigh. Could it be that their removal upsets the OG design somehow and negatively affects the bass?
I was about to suggest Knight to go traditional - dedicated plate amp for subwoofer + 2.0 amp for the satellites if all else fails. Then I thought some more and wondered if the original amp can be fixed. What's wrong with it? I have seen full sets of these expensive computer speakers with dead amps/controllers.
P/s: another idea just came across. You said that the electronics inside the subwoofer are responsible for about half its weigh. Could it be that their removal upsets the OG design somehow and negatively affects the bass?
Hi Karlsonate,
There are several youtube videos that show the topography of the amp and how to disassemble it, but it's all encased in a hard polymer resin type material. I'm sure it protects the components and wiring from pressure oscillations and vibration, but it makes it really hard to repair. I suspected the failure may have been leaky electrolytic caps because of the gradual decay over time that I noticed, but I couldn't get to any of them to check them without a huge amount of effort.
The volume of the electronics I removed is probably about 5 cubic inches. Most of the weight was in the big iron core transformer. I was curious if that would make a difference too, but when I listened to the finished mod, it sounded really good, so I didn't do anything to try to reclaim that volume.
There are several youtube videos that show the topography of the amp and how to disassemble it, but it's all encased in a hard polymer resin type material. I'm sure it protects the components and wiring from pressure oscillations and vibration, but it makes it really hard to repair. I suspected the failure may have been leaky electrolytic caps because of the gradual decay over time that I noticed, but I couldn't get to any of them to check them without a huge amount of effort.
The volume of the electronics I removed is probably about 5 cubic inches. Most of the weight was in the big iron core transformer. I was curious if that would make a difference too, but when I listened to the finished mod, it sounded really good, so I didn't do anything to try to reclaim that volume.
Thank you Sparky Coldfire! I just want to confirm and recommend this mod to everyone with a nonworking Klipsch ProMedia 2.1. Not only is it simple and cheaper than buying a new one, but it sounds just as good if not better. Being able to adjust the satellites independently from the sub is so nice. The sub sounds the same and with some adjusting it does sound better than before. I went with the exact parts listed by Sparky, purchased off Amazon, used Legrand 2-Pack Plastic Banana Binding Post from Lowes, kept the original back plate and gasket and spray painted it all black.
Anyway, I thought I would give an update and thank you for saving me a bunch of money.
Anyway, I thought I would give an update and thank you for saving me a bunch of money.
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Hey, that's great Wonluv! Nice way to connect it. Love the pics, thanks for sharing them. I had mine go silent a few times during the summer on hot days when I would leave it on all day. I have since tried to remember to turn it off when I'm not on my PC (which I should probably do anyway), and the problem hasn't occurred since. I suspect the amp was hitting a thermal limit on those hot days. I agree with cvanc too, I continue to be amazed at their sound quality and can confirm they are plenty loud. Great immersion for gaming and movies.
Hey guys. It's been awhile since I replied. I tried the method as shown, but I am not getting the same output as the original setup. The sub bass is flat no matter how I tweak it. I've done reverse and straight wiring and still the same result with the sub. The satellite speakers sound great. It's just the sub. Since I started back working on it, I've noticed that the sound will go out every other second with a popping sound in the sub. Could that be the power adapter not pushing enough voltage? I really want to replicate the original sound like you all have. The only thing I didn't do was the banana clip option, but that shouldn't matter being that it's wired point to point. I may have to buy a different amp to try. Any thoughts?
With my sub I didn’t have to reverse wire my sub. In fact I didn’t touch the wires other than to connect them to those post. I just bought the banana jack connectors to try out as well. I got the power adapter sparky had listed 24v 5a 120w not sure if it’s the exact one could be from a different manufacturer but so far so good.
Also, how are you using the amp? AUX in or BT (Bluetooth)? I have mine setup through the BT on my PC. I know I had to switch some settings on my computer, I had to disable Mono Audio under Settings > Sound. You might have other 3rd party filters or EQ throwing your sound off. You might want to try using your phone just to test a different device or some other source to rule out your if its the sub or something else.
Thats about all I can think of to troubleshoot.
Thats about all I can think of to troubleshoot.
Well guys, If only I had followed Sparky Coldfire's instructions to the T, I would not be writing. Well, needless to say, my brain decided to go elsewhere and not pay attention to detail. So I ordered another mini amp with more output. The ZK-HT21, 160*2+220W to be exact, which requires a 36V adapter. Initially, I had the same problem of punchy bass. After tinkering for a bit, I decided to put the original cover up to the opening and BOOM, problem solved. I literally just leaned it up against the opening without screwing it down and you can hear the immediate change in tone of the bass. Therefore, I cut all the excess wiring off of that panel and screwed everything down accordingly. Needless to say I am very pleased with the sound now. Unlike Sparky, I just ran the speaker wire between the cover, but it does leave an air gap which slightly noticeable. I will most likely do what Sparky did with the banana clips to make moving it around easier, but for now, this works just fine. I appreciate all of the feedback and help!
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Ok guys, here's a somewhat cleaner update. Found a wall plate along with the binding posts at Home Depot and decided to make it work. I think it came out decent. Could I have found something different, maybe, but I'm satisfied with the sound overall. When I put my ear up to where the banana plugs are, I can hear a little bit of rattling, but I can't hear it from a distance. I'm not sure where it's coming from. The plate doesn't move and I sealed it with silicone. It could be the plugs, but once again everything is sealed tight and nothing rattles or moves when I shake the backplate. I actually had fun doing this and will forever keep these speakers because I love the sound.
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I got my Promedia 2.1 from Costco and paid a whopping $70 for the system. Probably the best $70 I've ever spent. There is just nothing that beats this for double (triple??) that little of an investment. Unfortunately, Klipsch really needs to put a couple more bucks into the amp. The amp board on this unit couldn't be much simpler, but they are failing left and right. So when my amp died, I looked at Parts Express and Amazon for a replacement. Clearly, kits with the TPA3116 chipset was the way to go.
I decided to spend a little more and get this external amp that included a 24V PSU: https://a.co/d/bDEv2uB. I wasn't loving the open sides to the amp kit others are using. As far as mods, I kept it super simple. I yanked the power cord out of the sub and put a 16awg speaker cable in its place. Yes, I could have wired this through the existing speaker terminals, but I wanted to dump the power cord and that was just as good a hole as any and even reused the existing strain relief. I did put some connectors on the inside so I could disconnect the cable from the driver if I needed to. That's it! It took me all of 30 minutes to do the mods. The new amp definitely sounds better than the old one and has a few more controls to tune the sound.
So if you are out there saying "Hey, that amp cost as much as the speakers did" while that's true, it still did save me $50 if I decided to get a new system. Better yet, it kept me from spending even more as it squelched my desire to upgrade even more to something bigger, badder, funnier.
I decided to spend a little more and get this external amp that included a 24V PSU: https://a.co/d/bDEv2uB. I wasn't loving the open sides to the amp kit others are using. As far as mods, I kept it super simple. I yanked the power cord out of the sub and put a 16awg speaker cable in its place. Yes, I could have wired this through the existing speaker terminals, but I wanted to dump the power cord and that was just as good a hole as any and even reused the existing strain relief. I did put some connectors on the inside so I could disconnect the cable from the driver if I needed to. That's it! It took me all of 30 minutes to do the mods. The new amp definitely sounds better than the old one and has a few more controls to tune the sound.
So if you are out there saying "Hey, that amp cost as much as the speakers did" while that's true, it still did save me $50 if I decided to get a new system. Better yet, it kept me from spending even more as it squelched my desire to upgrade even more to something bigger, badder, funnier.