Visaton BG20 Active Stereo Speaker Combo

I’ve been looking for a cost effective stereo combo amp for my new keyboard and I’ve not really found anything that’s suitable, size, price, features, so I was wondering about maybe making my own. I’d use this for practicing, jams and maybe small gigs.

I’ve seen the visaton BG20 drivers, and I think a pair of these would be sufficient for what I need, but I’m struggling to find suitable components for the amp side.

I’ve seen a few of these type amp boards on eBay eBay

suggesting they can deliver 2x150w which would be more than enough, however I have no idea what sort of power supply I would need to power one of these boards, or even if one of these boards would actually be powerful enough (as they look pretty unsubstantial)

What suggestions are there for either some form of plate amp or amp board and psu to make a little combo amp capable of comfortably hitting 60w.
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If you scroll down in the ad, you'll see that it calls out a power supply of 12-24VDC at 3 Amps
If you go to, say, Ebay GB and search by power supply 12V 3A you'll find a bunch of them.

It looks like those boards you linked to are plenty robust for what you want to do. Class D amps are efficient and don't need
a huge heat sink like analog power amps do.

I don't know what access you have to PartsExpress in the UK, but if you search for Class D amplifiers, they list several that ought to do the job for you.
Here's an example:
Ebay usually shows many similar amps for sale as well.
Good hunting!
Can't I just use the finished product?
I am using Aiyima A07.
The power adapter is 33V, 4.1A and it is loud enough.

Aiyima A07.jpg
Powered mixer was common solution for keyboard.
Since mixer has many inputs and effect sends.
Something cheap now days be PMP500MP3
or many others like it.

BG20 be fun for home studio.
For live something which handles more power.

otherwise some class D boards use dual supply.
More popular for simplicity is bridge topology using
single supply. And switch mode power module.
whatever wattage power amp is. use supply 2x rated
IMO, as these Visaton speakers are efficient (92dB!) theoretically you don't need 100+ W, 60W sounds about right. Besides these tiny boards won't put out too much power before the THD number skyrockets :oops:
The TPA3116 has been superseded by the TPA3221. And some members have had a great time with this dual 3221 setup, which comes with or without a case (only board): DUAL MONO TPA3221 Pictures Inside | Page 2 | diyAudio
P/s: I believe @nandappe reviewed a similar 8" driver that's better and (maybe) cheaper than the Visatons you suggested, can't quite remember the model number unfortunately.
Exactly sensitivity is high for BG20 home use/monitor.
Dont need much more the 30 to 40 watts.

If using for wideband with bass.
You really wont be putting much more than 7 to 12 watts.
Till you hit linear excursion/distortion.
Actual listening level 1 to 3 watts

Highpass for 3way. you can get closer to full power
or actually easily exceed thermal rating.
so feasible as a mid in pa application.
Visaton PA design actuall uses 2 BG20 for thermal rating
and on crossover

For home monitoring I always just used HiFi speakers.
Live performance is any numerous 2 or 3 ways
with 12" or 15" inch woofer.

I just used typical 100 watt home receiver and monitors
preamp was just a small Behringer mixer.
Mixer has numerous outputs.

so home was hifi amp and speakers.
live was pa speakers and pa power amp.

mixer allowed easy hookup to all of them.
easy solution is " powered mixer" since it is mixer
and amplifier. with many more channels, sends, effect loops
etc etc
Thanks for the suggestion. So I already have active 12” PA speakers and sub and a digital mixer, I also have a Laney keyboard combo with a 10” speaker and horn (which has that loud, unrealistic sound). So loud volume with lack of finesse I can already do. I know there’s various solutions on the market for monitoring (Yamaha ms101s), unfortunately most of these are mono. Hence the reason for this DIY project, i very specifically want something which is more hi fi than banging PA. But what I build needs to be more robust than active studio monitors for instance, as they usually don’t have any speaker cone, tweeter protection, in case it is used for rehearsals, chucked in the back of a car etc. What I’m trying to get away from is lugging around lots of separate kit, amps, mixer amps, separate speaker cabs and individual power cables. I think a stereo combo would be ideal.

Maybe the BG20’s are too modest for the sort of output I want?

In terms of the amp power supply, what sort of PSU would match the TPA3221?
Would something like this do it? Power supply

As a note I’m hoping to put something together for about £100.
So I’ve decided the best thing for me to do is to buy a rack mount power amp (I’ve purchased a Samson Servo 260, as it’s fan-less and fairly compact) and then build a compact enclosure for this and a pair of full range speakers. I’ve ordered some Beyma 10ag/n’s.

So I’m wondering how to calculate the enclosure size and whether I need to port it or not. I’m thinking of a slopping enclosure similar to a Roland Street Cube.

Any help with calculating the enclose size would be appreciated.
Thanks for this. What is aperiodic box and what about the specs suggest that type of design? I’ve had a quick look online and information seems a bit thin on the ground about aperiodic enclosures other than to suggest that maybe a ‘leaky box’ or stuffing cabinets with something to give the impression that the cab is bigger than it is.
Yes, aperiodic is leaky box, some of internal pressure is released thru resistive vent(s) so box can be around 1/3 smaller compared to closed box.
Recommendation is based on high Qts of the driver. Its unsuitable for bass-reflex and closed box has to be big compared to Vas.
Making aperiodic box is a bit of experimental work, so if you wish simple solution for this driver, make a closed box with Vb at least 3xVas (60 liters) and stuff it well with some suitable damping like poly-wadding or glassfibre.

Another cabinet that may work in this case (taking also into account Fs=100Hz) is open-back box, but again some experimenting/modeling will be necessary for best results.
Thanks for explanation. So I’ve been looking at resistance vents and come up with a little 3d printed design for an adjustable vent. I can rotate the vent to increase or decrease the airflow, to test.

This will need some kind of poly filler, but I’m wondering about trying this first.


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