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Posted 20 hours ago

Nobsound Mini Bluetooth Power Amplifier Stereo Hi-Fi Digital Amp 2.0 Channel 50W×2 with AUX/USB/Bluetooth Input Wireless Audio Receiver PC Sound Card with Power Supply (Black)

£9.9£99Clearance
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ZTS2023
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About this deal

There is only one power transformer under the box, which delivers 17V to output transistors, 7V to microchips and 6. This is interesting as I used a signal generator with my standard HD650 XLR-4 cable and looked at the phase on my Rigol DS1054 oscilocope and pin for pin the input and output are in phase. Reddit and its partners use cookies and similar technologies to provide you with a better experience.

Looks like they keep putting out newer/revised models and actually do a great job of fixing/adding features each year. Read more My first unit had a problem with the AUX section and the seller sent a new one immediately. Given the fact that the connectors aren't hand wired and are soldered onto the PCB correctly this leaves a few conclusions. In other words you are likely to damage the speaker voice coil by driving a speaker with such a signal. First of all, every speaker handles high-frequency signals differently since a speaker is designed to be driven with signals at frequencies below 25 kHz.The amp and speaker combination works really well with jazz/folk/accoustic music but can get a bit muddled with complex music like rock or orchestral music. I applied the variable signal 2B to the input of the amplifier and looked where it comes to when the 6n1p and 6p15p lamps were removed. We have over 30 years' experience with using and listening to high end audio amplifiers and over 25 years in improving the valves. A circuit diagram is very difficult to draw, because the circuit is on both sides of the board and the details are too small.

Rubbish Chinese amps like this one are getting rarer - the majority of them now have excellent build quality and aspire to be a hi-end product. Just check out Audio Space, Cayin, Prima Luna, Consonance, Mingda, Doge and Line Magnetic are all excellent.

Normally tyhere is an output lowpass filter which removes those switching components and only leave the audio signal. When manufacturers measure amplifier dirtortion they usually measure distortion by adding a low-pass filter after the Class-D amplifier. Finance is provided by PayPal Credit (a trading name of PayPal UK Ltd, Whittaker House, Whittaker Avenue, Richmond-Upon-Thames, Surrey, United Kingdom, TW9 1EH). Update: I just read Veri's and others' earlier comments in this forum re the poor performance of this amp. There is general consensus in the audio world which of the pins are assigned to a signal as used by HIFIMAN for instance.

Where does the signal on the cathode 6n1p and on the cathode and anode 6p15p comes from, if the signal comes on the 6n1p grid only when tubes are removed? C: An early production unit may have been designed with a swap and a (siltently) revised PCB has been used after the manufacturer found out.

On topic, I've also heard some excellent sounding Chinese gear like Ming-Da and Line Magnetic (have an LM dac myself) and have built gear using affordable (not cheap) Chinese line transformers, plate chokes etc. It all started with those counterfeit semiconductors which appeared at around the same time as Chinese made valves (around 25 years ago). The cheapest amplifier with just analogue inputs that I would be willing to risk my money with is probably the 2x100 watt Sony STR130. The second picture shows the measured output signal with no speaker load attached while streaming silence. I can safely say, 100% goods sold are fake (not cheap) and they do it openly, and authority don't care.

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