I use it with a laptop charger and it has minimal noise. The sound and bass are the strongest, I connected them to 50 watt Sony speakers

The best mini amplifier on the market for the price. Made a box out of walnut with some mdf for the guts. Matted it to some 3.5 kicker drivers with tweeters and it sounds amazing. Used a 18v makita battery with a Amazon adapter and works wonders. 6ah battery should last hours. Bluetooth connects very quickly.

Amp sounds great but when using the 3.5 mm input jack I here crackling.Turns out the jack was flaky. Maybe I just got a bad one. Don't know.Should be OK using bluetooth, but I can't say. I didn't try it.

Utilizzato per muovere 2 casse satelliti Harman Kardon scopo casse da PC. Alimentato con un alimentatore da PC portatile di recupero da 19V 3,9 A. fa molto bene il suo lavoro e suona bene. Avevo provato con un 12v 2A e a bassi volumi OK ma alzando un pò distorceva. Comodissime le regolazioni Alti e Bassi, sopratutto nel mio caso in quanto le casse in oggetto sono mancanti di bassi (Dovrebbero lavorare con il Sub), quindi riesco a recuperare un pò. Collegamento audio fisso con il cavo mini Jack, ma ho provato anche il Bluetooth ed è funzionante e con buona qualità . Consigliato

Attenzione al collegamento dello spinotto di alimentazione che va' rinforzato o protetto meglio

Lo pruebé como amplificador directo detrás de una guitarra acústica con un mix microfono/pickup magnetico activo : funciona honorablemente a mi gran sorpresa (mis demás amplificadores no aguantan el cable no-balanceado).Con el microfono el sonido es bien definido; hay un pelín de ruido de fondo + larsen posiblem a muy alto volumen pero es normal. Con el pickup magnetico no hay ruido de fondo pero el sonido se queda más en los medium, nada sorprendente.Hasta con una pila cuidrada 9V el sonido es honorable.Quito una estrella por lo pobre que son las instruciones en inglés : podrían pagar un estudiante en idiomas para hace el trabajo mejor que un traductor automatico.

Inserito in una cassa autocostruita, con 2 altoparlanti ovali da 25W e un'alimentatore a 13V con una potenza di 40W circa. Abbiamo costruito una cassa attiva con bass reflex per basso elettrico, è venuto fuori un progetto fantastico con suono pulito e bassi potentissimi. Comodo anche il Bluetooth per ascoltare la musica dal cellulare, per il bass reflex abbiamo escogitato il modo semplice per trovare l'accordo giusto in frequenza.⭐⭐⭐⭐⭐ Meritatissime

I have the DAMGOO ZK-502T and the ZK-1002 digital amps. They are both great running on a 16V laptop supply. Both provide plenty of volume. I have bought class-D for the TV and for the garage, and I got great results. I needed replacements due to a house fire.** After a few weeks, mine failed. The BT "ready" signal continued to beep, interrupting music play on the wired input. BT has priority, and if it fails to connect, well, you are stuck with repeating beeps. Amazon Chat support quickly arranged for a warranty replacement with return of failed item. Replaced item works fine. **The directions for these talk about what size of speakers they will support, and that small speakers require less power. This isn't right. The truth is that larger speakers are generally more efficient. In fact, if you have very large, efficient speakers, you can probably drive them straight out of your computer's sound card. I've done it.Your speakers will make all the difference; get good ones. If you go to a thrift store, only get a name brand like Sony, Aiwa, Yamaha, KLH, Pioneer. Never a lesser brand like Sharp or RCA. I have good quality 8 Ohm Yamaha speakers.Now I'll focus on the differences between these two that I think are most important.ZK-502Tpro: bass and trebble controls! I like the flexibility.con: lame stick-on heat sink, probably should lay it flat. Better yet, mount with real thermal tape.ZK-1002pro: larger screw-mounted heat sink, suitable for mounting in any position. Good, because mine is outside and exposed to the summer heat.pro: neat looking inductor coils, but I can't hear the difference.ZK-502TCurrent test with 2x 18650 cells (8 Volts) at 50% physical volumeAverage values: 50mA idle/quiet BT 100mA 50% vol BT 200mA 75% vol BT (with 1 Amp peaks) 600mA 80% vol BT (with 2 Amp peaks)2500mA peak at 100% vol BTRecommended for long battery life: 2x 18650 cells with 2500mAh capacity, 12 to 24 hours runtime depending on volume. Better than some products off the shelf.Common A/C power supply recommendations:Minimum: 9V 1AmpAlso suitable: 12V 3Amp, 16V 4AmpFor 6dB greater distortion free volume: 19V 4.5 AmpThe biggest difference between power supplies is that the audio is 6dB louder at most at 16V plus. The power regulator stays cool at 9V and begins to heat up at 16V. The main chip stays cool at 9V, and at 16V heat begins to build up as it is slowly dissipated through the board and components. I used a thermal camera to check this, and max temp I ever saw was a moderate 100 degrees F. Loud volume with a weak 9V supply can cause it to fail and restart. So only use a weak 9V supply if you plan on listening at moderate levels.With my 16V supply, there is sufficient current available for very loud music with no interruptions. Higher voltage is required for more volume, but results in more heat. At 16V, temps reach 115 degrees F. Semiconductors can take much more heat, and the main TPA311 chip has thermal protection. So these measurements are only for your information.The supplied stick-on heat sink didn't heat up much -- it is for show. Heat is also dissipated from the main chip through the board, however. I scraped off the black adhesive and used thermal tape instead -- with better results. I recommend you do this if you use a 24V supply.The reason I tested current usage was to confirm what I suspected -- that these amps are very efficient and require little power. I also wanted to know my battery life. I recommend 2 18650 cells. More than that will offer more volume, but will shorten battery life, as more power will be wasted in the power regulator.My AUX audio source is a Sony walkman mp3 player. Your source and/or a higher voltage power supply could get you more output power. But I believe it would never be close to 25 Watts, and this is something we should all be aware of.Bluetooth devices with Aux capability usually have better performance on BT. This amp is no exception. Idle power use is lower and audio is clearer at low levels.- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -More testing with a 12V battery and a new setup.See photo of my weekend project: Li-Ion battery, solar power, handy carry handle. With the battery disconnected, and in direct sun, the panels power this at medium volume. With the battery connected it extends battery life. Estimated life of 20 hours. (No time limit while in direct sun.)Approximate current used:BT 22mA (OFF)idle 50 mAlow volume 75 mAmedium volume 200mAloud volume 600 mACurrent peaks at 2A before distortion sets in. Any supply with at least 2 Amps and a minimum of 9V should be good for a quiet location, 16V if a bit more volume is desired for a loud location. (edited)Good luck and have fun!-Chris

The amp is small and light, in my use it didn't get too hot, it has two impedance ratings its compatible with 4Ohms and 8Ohms, one channel I was running a woofer rated at 150-watt power at 4 Ohms even though this amp only pushes 50 watts at that impedance the sound quality wasn't too badly affected. I used the second channel to run two small 4Ohm speakers in series and they sound great, overall I think I've used this amp to its limits, up to this point a few weeks in everything seems great.If you are looking for something small and lightweight with a very quick Bluetooth connectivity this is a good buy for the price,Cons; The turn knobs are cheap and don't line up well even if you spend time trying to, but these amps are usually hidden away, the assembly is only shown in a picture, but still, it was really easy to figure out.

Es un pequeño amplificador que permite modular los tonos (Treble -Bass). Si se usa con un transformador de 24, realmente muestra toda su potencia. Llega desarmado, de ahí que le he dado 3 estrellas en su facilidad de uso, se que hay personas que al verlo desarmado se encontrarán con una sorpresa. Luego de armar y conectar los cables sin conectores especiales y conectarle un transformador que tengamos en casa o compremos a posta para su uso, no queda más que conectar por cable o Bluethooth, sí de sencillo. No se de su duración ya que recién hace unos días que lo tengo.

Sound quality was reasonably good. Pairing was simple and easy with my iPhone. Bass and treble controls are more than adequate to compensate for the speakers I will be connecting .Two minor drawbacks:First, there are no standard holes in the circuit board that would allow me to mount this internally to anything. The only holes are for the screws and standoffs for the upper and lower housing plates that it came with.Second, the only other drawback is that it makes a tone when you pair with it. At least I can control the volume of the tone, and it’s only one. I will probably use this amplifier again! Solid four stars across-the-board.

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