Amplifiers for keyboard use

[frajag]

At the start, I would like to make clear that this is written for :
1.   Those who have PSR series keyboards
2.   Users who are not professional performing musicians
3.   Keyboards that only need to be heard in a small  room (e.g. home use)
4.   And most importantly, those of us on severely limited budgets.
If you own a Genos/Tyros with the MS01 you probably do not need this and thank you for understanding.  I recently acquired a Lepai 2020A amplifer (sometimes listed as Lepay 2020A).  This is an extremely small  "made in China" amp. The rated output is RMS 20 watts  per channel  but this depends on the speaker impedance. There are multiple reviews on the internet (from audiophiles, techies and modders). Overall the experience is positive considering the price of just over $20!
CNET review  https://www.cnet.com/reviews/lepai-lp-2020a-plus-review/
Read more about small digital amp ICs here :
https://www.radioworld.com/news-and-business/the-mighty-tamp-youll-be-blown-away
Also popular is the TPA3116 based amp (since the Tripath based chip is no longer produced)
The Lepy 2020A is listed on Amazon but there are other models and there are other manufacturers of sub-$100 amps using a variety of digital circuitry . There are numerous mods for the Lepai, but the most popular are to replace the 13.5V 2 watt power supply with 4-5 watts and upgrade the capacitors.  I will try to do this in the future. Today I had some time and put my Tyros 5 output through this little unit and 6 ohm speakers  and it sounded quite good (I did also hook up a subwoofer). There is a push button switch to disable the tone controls (not needed with a keyboard). I have had two PSR-S units and was not impressed with the built in amplifier. I would be interested in knowing the experience of Keyboard users with these small amps and please remember the disclaimers at the start before you tell me to get two Bose Compacts. If you insist and post, you will need to send me a cheque.   

[mikf]

There many, many options around the 100 - 150 mark that work well. The final choice is personal. A pair of small powered monitors work well because you have stereo.
I have a pair of small MAudio and a pair of similarly sized Fluid audio. Both are very good, I think the Fluid were a slightly better buy, better and more powerful sound. I used the Fluid in a small gig once and they were great. I doubt the MAudio would have coped, but they are fine for home use. But as I say, sound quality is really a personal choice. Mackie which I tried in a store when I bought the MAudio are also decent.
Mike

[DerekA]

You say you are not impressed with the built-in amplifier. Do you mean built-in speakers?

I don't quite understand why you need an amplifier for home use.

Don't you just plug the L/R outputs on the back of the PSR into external powered speakers?

[mikf]

It's just terminology Derek. All sound reinforcement is a combination of an amplifier and speakers. Amplifiers used to be the complicated part of the combination with valves, transformers, whatever, but modern solid state amps are so small and cheap that building them into small stereo speakers became simple and the term powered speaker emerged. But some people especially guitar players still refer to the combination as an amp.
Mike

[frajag]

Thank you MikF for the clear explanation. I was just probing for the experience of users. The integrated circuit manufacturers have been producing many amplifier chips and these are being used to make very small and powerful amps. I am sure every powered speaker (including subs) use them as well as bluetooth and other wireless speakers. The prices are amazing. I think it is taking a bit of time for the music world to catch up to the techies.

[BogdanH]

hmmm.. Power supply is 12V 2A... thus, total power consumption of amplifier can be max 12Vx2A=24W. So, if there would be zero loss in circuit (impossible) and zero heat dissipation (impossible), we would get max 12W/channel.
But.. audio amplifier is not a toaster where only power matters. By making quick check on web, I couldn't find any official specifications from manufacturer (C'net and similar are a joke). I've found a page where it's said "Frequency response: 20Hz-20kHz". And? Where's the rest of very important data? I.e. Linearity curve in 20Hz-20kHz range? There's also "Total harmonic distortion: 0,5%".. Again, at what power? At what frequency range? In short, only useless numbers are given which serve the purpose to impress.
$20 is very cheap indeed.. but we should keep in mind, there's a reason why's that. It always is.
Just my 2c

[mikf]

The prices are not that amazing because you still need a pair of speakers in cabinets. Add in a decent pair and you will be getting up around the Powered speakers cost. The powered speakers probably use amps that are even cheaper, because there is no need for a separate box.
Mike

[casiokid]

Don't forget looking at the Korg KONNECT and the subwoofer Yamaha  KS-SW100

[Yamahaman]

For a good sound you can consider a second hand Bose 321 series.
Good sound and volume, simpel installation and reasonal prices.