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Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). I have also enclosed a picture of the output waveform with a 4 Ohm load connected to one of the outputs when driving the amplifier with a sine signal.
Sadly unable to use currently and test performance, the item requires an external power source of a voltage I don't have, have to try source suitable power source,, disappointed item wasn't supplied with this important piece of the package to work, item seems robust and solid enough, good quality appearance and build, but until power adaptor sourced unable to judge performance,sad the adaptor not included. These kits have been put together after many hours of listening tests to confirm the valves performance in any given application. As such I would bet this amp does not meet the FCC Part rules section 15B which is a requirement by law and as such most likely is even illegal to distribute in the US. Another major problem with filterless Class-D designs such as this Nobsound Bluetooth amplifier is EMI which stands for electromagnetic interference. When connecting long speaker wires, there will be lots of unwanted EMI radiated since this receiver is outputting the high-frequency signal without any low-pass filtering (except for some small ferrite beads).
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? Given the fact that the connectors aren't hand wired and are soldered onto the PCB correctly this leaves a few conclusions. Most purchases from business sellers are protected by the Consumer Contract Regulations 2013 which give you the right to cancel the purchase within 14 days after the day you receive the item. 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. AUX mode has slightly better sound but I find myself connecting mostly with Bluetooth because it's so convenient.
There was reported that Russian tubes sound much better, and the tubes with golden grids make the best sound. If the item comes direct from a manufacturer, it may be delivered in non-retail packaging, such as a plain or unprinted box or plastic bag. Just check out Audio Space, Cayin, Prima Luna, Consonance, Mingda, Doge and Line Magnetic are all excellent. A circuit diagram is very difficult to draw, because the circuit is on both sides of the board and the details are too small.However, in this case it is safe to assume that the actual distortion that occurs inside the speaker will be magnitudes higher than the specs shown on the Nobsound data sheet since it is lacking the output filter. The audio is detailed and transparent and quite revealing that my Mordaunt Short MS15 speakers, although lacking a bit of bas. Class-D amplifiers work by switching the output between ground and the supply voltage at a high frequency.
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. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform.Vintage amplifiers usually have more “fun” in the sound, mainly due to far from flat frequency response and THD levels.
We have over 30 years' experience with using and listening to high end audio amplifiers and over 25 years in improving the valves. Update: I just read Veri's and others' earlier comments in this forum re the poor performance of this amp. It all started with those counterfeit semiconductors which appeared at around the same time as Chinese made valves (around 25 years ago).This results in a strange stereo image where bass is affected and voices and instruments cannot be placed properly, a fuzzier stereo image. They could have very easily been honest and up front with this product, and they would have been successful. Filterless Class-D amps for the above reasons are usually only used in amplifiers of less than 5 Watts and also designs where the amplifier is mounted directly onto the speaker to avoid EMI issues. After being lived in Shanghai for a year, my experiences just put me off that anything is made in china, especially Chinese brand. It's a Douk audio rebrand from Weiliang Audio E600 which from my experience cannot do proper SE>BAL or BAL>SE, as well as having an out of phase XLR-4 output.
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