First of all, greetings everyone, first time posting to this forum, so don't beat up on me too much... 🙂
I've been looking for the "perfect" subwoofer amplifier to fit a specific need, i.e.
1. ~100W into 8 ohms (0.1% or less THD), 1 channel
2. Class D
3. ~US$100
4. 110~220V operation
5. Standalone box (not a "plate amplifier")
Nice to haves would be:
1. Variable LP filter
2. Variable HP (rumble) filter
This one looks interesting. It doesn't deliver on the nice-to-haves, but it does look like it delivers on the basics, at least at first. On further investigation, some things stick out.
Amazon.com: Subwoofer Amplifier TDA7498E Mini Sub Bass Amp Digital Class D Integrated Subwoofer Amplifier 220Watt x 1 Fosi Audio TP-02: Electronics
1. The quoted ratings are at 10% THD, driving 3 ohm loads
2. The PSU provided with that amp only seems capable of providing 90W
3. The feedback on that page seems to be for a totally different amp (the pictures show an amp with L/R RCA input, but the feedback suggests an amp with a mono mini phone jack.
Do you think that device would deliver what I need, or should I be looking at something else? If the latter, any suggestions?
I've been looking for the "perfect" subwoofer amplifier to fit a specific need, i.e.
1. ~100W into 8 ohms (0.1% or less THD), 1 channel
2. Class D
3. ~US$100
4. 110~220V operation
5. Standalone box (not a "plate amplifier")
Nice to haves would be:
1. Variable LP filter
2. Variable HP (rumble) filter
This one looks interesting. It doesn't deliver on the nice-to-haves, but it does look like it delivers on the basics, at least at first. On further investigation, some things stick out.
Amazon.com: Subwoofer Amplifier TDA7498E Mini Sub Bass Amp Digital Class D Integrated Subwoofer Amplifier 220Watt x 1 Fosi Audio TP-02: Electronics
1. The quoted ratings are at 10% THD, driving 3 ohm loads
2. The PSU provided with that amp only seems capable of providing 90W
3. The feedback on that page seems to be for a totally different amp (the pictures show an amp with L/R RCA input, but the feedback suggests an amp with a mono mini phone jack.
Do you think that device would deliver what I need, or should I be looking at something else? If the latter, any suggestions?
No, you won't be happy with that amp. If you really use 100W the amp can't dissipate the heat because air exchange is impossible, it will either trigger the protection or the amp will poop out.
The flexible crossover frequency is a must IMO. The amp doesn't have to have the feature though, you can use an external crossover. There are a lot of active subwoofer crossover boards on ebay for ~5-9 bucks. That means, you can also use a non-subwoofer amp, wich increases the range of possible candidates by a lot.
The flexible crossover frequency is a must IMO. The amp doesn't have to have the feature though, you can use an external crossover. There are a lot of active subwoofer crossover boards on ebay for ~5-9 bucks. That means, you can also use a non-subwoofer amp, wich increases the range of possible candidates by a lot.
Just throwing this out there, but how important is class d and can you stretch your budget by $45? If those are deal breakers, never mind this post.
Dayton Audio APA150 150W Power Amplifier
Mike
Dayton Audio APA150 150W Power Amplifier
Mike
I've had bad luck with those iNukes. I've got two 3000DSPs in storage at the moment, both of which failed (two different failure modes) just after a year or so of pretty easy operation.
I did come across tho APA150 in my search. It is on my list of possible options.
I had a look at that one, and the specs start to "fall apart" when I took a them. Output is only 60W per channel into 8 ohms, and that's at 10% THD. While the chip used in that amp supports bridging, it's not clear from that amp's documentation if bridging is provided as an option.
This one gets pretty close to what I'm looking for. There's no x-over adjustment, but everything else is there, and more. This amp is going to be located in a bar, and the less opportunity there is for someone behind the counter to fiddle with the settings, the better. This particular amp only has a power switch at the front, so that should cut down the potential for fiddling by quite a bit.
The quoted power ratings for the amp are 50Wpc into 8 ohms and 120W bridged into 8 ohms, but those are at 0.1% THD (according to the manual), so a bit better than the 10% THD output levels quoted for a lot of the other class D amp contenders.
Monoprice Unity 100-Watt Bridgeable Power Amp - Monoprice.com
The quoted power ratings for the amp are 50Wpc into 8 ohms and 120W bridged into 8 ohms, but those are at 0.1% THD (according to the manual), so a bit better than the 10% THD output levels quoted for a lot of the other class D amp contenders.
Monoprice Unity 100-Watt Bridgeable Power Amp - Monoprice.com
Hello Brian the Fosi BT20 is a great little amplifier I am using it to power a pair of Klipsch R-41M as desktop setup they sound great! It also comes with a power brick which is 110~220V operation as your requirement, the only setback from your list is that the amp is 0.5% THD.
I assume that you're referring to the BT20A, not the BT20C?
The BT20A is rated at 100Wpc, but into 4 ohms at 0.4%. This suggests that it's capable of doing 100W into 8 ohms bridged, if it does support bridging. Unfortunately, there's no mention of support for bridging on the Amazon site. The 24.5V 4.5A PSU can only deliver about 110W, which will limit its output capability a little, but if it actually IS bridgeable, it might be good fit for my needs.
""This amp was originally designed for the Overature 1 speaker system.
$60.00
Now included with your purchase is the origional OVTR Crossover at no extra charge!""
- Output of 100 watts at 8 ohms
- Adjustable gain control
- Fixed crossover frequency of 200 Hz
- 115VAC (220V also available)
- Built in switching power supply -- needs no power transformer
- Dimensions are 11 1/2" x 5 1/4" x 3 3/8"
- Mono
- Speaker level inputs
$60.00
Now included with your purchase is the origional OVTR Crossover at no extra charge!""
That may be okay for speakers witht in-build subs, for the vast majority of subwoofer uses, 200Hz is way too high crossed over. You'll have to add a different active crossover to it or it will be next to unusable. That in mind, 60$ seems to be too expensive. I's not a class D amp btw and does not have a low level input either.
DIY?
I know question was box with filters so maybe audio forum better? but then this is DIY, ...you can purchase board and put in box or prototype on breadboard then use solderable protoboard or etch your own circuit board (easy as developing old photos (old days)) toner transfer easier now! although I still develope mine
1) Build your own to your specs example
2) Quick overview of class D notice the feedback loop
3) Assembled unit (use 350 watt supply min.)
4) Assembled unit with case
5) Perfboard
6) Case
7) Protoboard
I know question was box with filters so maybe audio forum better? but then this is DIY, ...you can purchase board and put in box or prototype on breadboard then use solderable protoboard or etch your own circuit board (easy as developing old photos (old days)) toner transfer easier now! although I still develope mine
1) Build your own to your specs example
2) Quick overview of class D notice the feedback loop
3) Assembled unit (use 350 watt supply min.)
4) Assembled unit with case
5) Perfboard
6) Case
7) Protoboard
Last edited:
- Status
- Not open for further replies.