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Hi John, the best option would be to make a so called 'star ground'. This means that all ground connections are bundled and attached to the chassis at one point. This prevents ground loops. In between the two filter caps, one could solder a lead. This lead can be routed to the star ground. The ground connection from the IEC-plug can be routed to this same point. This article is very interesting and explains it in more detail: sound-au.com/earthing.htm

Hi James I can tell you how my prebuilt version sounds. It has the same circuit board as in this video. The overall presentation is what I would call transparent, detailed and clear. There seems to be a little extra energy at around 2khz which enforces that detailed sound. Mine isnt a warm sounding amp and I could say it is a little forward but it isnt really harsh either.

Thanks! I found them on a local ham radio flee market a few years ago. Unfortunately I do not have a part number. But I do think that on AE and eBay similar items could be found.

Thanks! First I clean thoroughly with a degreasing agent and water (St. Marc works really well!), next I polish the plate with silver polish (for example Brasso). A last clean with water completes the job :-)

Thanks Priyo! Better than I expected. But in all honesty I have to say that the internal DAC of the BT-module is not superb. The best results are therefore achieved by connecting directly via the RCA's through a good DAC. The difference is clearly audible as the amplifier exceeds the BT-module in sonic capabilities. But... despite the BT-module has some shortcomings, I have to say that, considering it only costs a few dollars, the BT-module is quite an achievement that is real value for money ;-) Definitely a nice and cheap addition/feature to implement into a DIY gainclone!

@@PA4MW Well the BT surely add some convenience by sacrificing some audio quality. I liked the enclosure. It is pretty neat !

Thanks Bogdan! I bought it via AE, I am not allowed to put a link, but you can find it via BRZHIFI BZ2205R :-)

@@PA4MW Thanks.... The cost of shipping is 3x the purchase cost :( if you are thinking about a more refined & resolving amplifier, I can confirm that Rod Elliots 200W mosfet may well be the last amplifier to build sound-au.com/project101.htm

The board was unpopulated when I bought it. I find it a bit tricky to buy a populated version as the transistors could be counterfeit. And soldering is fun 😉

That is a speaker protection board which senses DC and adds a smal delay at startup. I added it mainly for protection, but the original NAP-200 also causes a small ‘pop’ towards the speakers when the amp is powered on (or off). It is based on the UPC1237 IC. Works like a charm 😃

@@PA4MW thanks !! Nice builds by the way

Phew, that is a difficult question to answer. If you ask me price is not always an indicator for quality; some amplifiers are value for money while for others one pays merely for branding and dissapointing quality. It is definetely possible to make high class audio with limited budget. Sure, it asks for creativity and a bit of luck when buying parts, but nothing is impossible :-)

you coud be able to build a amp that could cpmpete with a 3000 dollar amplifier. But you should keep in mind that the more perfomence you want, the more the price to performance ration will increase. I would say that you could build a amplifier that could compete with amplifier that cost 1500 dollar quite cheap. But upwards from there the price to performance ratio will increase quite alot. But if you want to accieved Super high end amplifier, then it exist alot of copies of amplifiers on aliexpress that are a fraction of the original amp cost. But any way, i assume you want to not pay more than 200 dollar. Then the performande per dollar ratio will highly depend on you doing your reseach before buying, and really try to shave down the cost on everything. The beyerdynamic a1 design are absoloutly the best price to performance design to use. I think it exist 4-5 different design base on the A1 design on Aliexpress, all differ abit in performance. The amp in the video are probaly the cheapest one, and all parts used in the video (not counting the cost off the case) are probaly around 40 dollar. 20 dollar for a finished board of the amp, and 20 dollar for the transformer.

Thanks David! I am planning of making a video with music soon. However, YT has a tendency to remove videos because of claims concerning author music rights. Did not want to risk that ;)

@@PA4MW I understand there is a site to go on that you can hear music that is free to play on YT, or at least one You Tuber said on one of his videos: Don't ask me were and what the music is like though Lol

@@PA4MW I understand there is a site to go on were you can hear music that is free to play on YT: I asked since I had been planning on buying an pre built ICE amp, but there could be a concern over input sensitivity since I wanted to use a passive pre and thought one of these 'Naim' amps could be the solution: There really are too many amps too choose from now: May I ask what the sound quality is like since I did read a feedback comment regarding the quality of the components inside, not the actual build quality, I would be buying pre built, thanks for posting and your reply of course

@@PA4MW let us know how it sound? compared to the real one

Thanks Martoon! The PCB I got from eBay, but last time I checked these are not available anymore. I am currently constructing a new version based on another bord. Will make a video soon :-)

Jims Audio (eBay)

Hi Roman, yes I did :-). The VU meter is not influencing the signal path. However, what is very important is that the circuit is DC fed via a separate PSU (or DC/DC-converter with galvanic separation). Otherwise there is a reasonable chance of a ground loop. This could culminate in buzz/hum (of 50/100Hz).

@@PA4MW cool! Thanks for your answer ! Is it relevant also in case I’ll use as mains toroidal transformer with two secondaries and 2 separate rectifiers pcb? I don’t want to put 2 trafos also it takes place inside, but probably 300VA toroidal with 2x24v and 1x12v will solve the issue?

@@inception-hifi No problem, glad to help 😃 That is perfect indeed; one toroidal transformer with 2x24 and 1x12 would solve the issue. You could also tap from the 2x24, rectify it and put it through a regulator to get a stabilised voltage. However, I would advise to then galvanically separate the 12V (to prevent ground loops). You can do that for example with a B1212S-1W DC-DC module (very cheap on Aliexpress). The 12V is in general very usefull because you could also power the DC protection circuit with it or a Bluetooth module.

@@PA4MW Thank you for the answer and your advise Michael! I think I will implement the Sony TA-212 VU meter schematics because I will use their VU meter for my amp. Also I have all the parts for this schema. And for the backlight I'm going to use 2 LEDs because I already have a dedicated line from rectifier board for the LED. I don't have your e-mail, so I can't send you mentioned schema unfortunately to have your opinion...

I have the same issue, does anyone know where we could find VU meters like this for sale? Or is the only way to find and old amp and tear it down???