Amptastic Mini-1- PSU Question

[southall-1998]

Just acquired a Mini-1 (2020 chip) amp. Sounds very good....lovely clear sound!

The amp came with the ''PSU-1'' Power Supply.

I notice there's a noise coming from the PSU-1 unit itself... sounds high pitched. Others may call it a ''whine''

The PSU noise doesn't affect the sound performance, no noise coming from the speakers.....All is quiet, when I put my ear up close to the speakers.

I've had headphone amps in the past. Ones that come with those smaller ''plug in wall'' PSU's. They all make that same high pitched noise.

Just out of curiosity. Why do these particular PSU's make those high pitched noise?

S.

[RothwellAudio]

Just acquired a Mini-1 (2020 chip) amp. Sounds very good....lovely clear sound!

The amp came with the ''PSU-1'' Power Supply.

I notice there's a noise coming from the PSU-1 unit itself... sounds high pitched. Others may call it a ''whine''

The PSU noise doesn't affect the sound performance, no noise coming from the speakers.....All is quiet, when I put my ear up close to the speakers.

I've had headphone amps in the past. Ones that come with those smaller ''plug in wall'' PSU's. They all make that same high pitched noise.

Just out of curiosity. Why do these particular PSU's make those high pitched noise?

S.

There's an inductor or transformer in there running at a high frequency and the windings are vibrating at that frequency. It is possible to pot the windings in varnish or silicone or something but it would be a lot more work than it's worth really. Nothing to worry about in my opinion.

[southall-1998]

OK, Thanks Andrew.

S.

[bobvfr]

Glad you posted this, has any one tried any of the SMSL mini amps that are all over Amazon.

I have just set up my second system, it's basically my Surface Pro 4 with docking station, a full size AIWA amp and a pair of floorstanding Eltax speakers .flac files as the main source but has also tried Netflix, BBC iPlayer the PC's system sounds.

Sounds very good but the size of the amp is just too big and I am tempted by one of these mini amps and at £50 ish, if it's crap I haven't lost much.

Just had a look at the Amptastic website, I like the "Engineered in Cambridge" bit on the back, still made in China I bet, at least their website is in English though, some of the other ones really struggle with translation.

And they do say they will replace defective parts within 14 days.

[southall-1998]

Got this response from Chris this evening.

''Hi Shane, some switch mode power supplies emit a slight humm/noise when under load, the inductors oscillate at high frequency. If the unit is running cool then this is normal.
It’s a 100W PSU so quite powerful.
Hope this helps,
Chris @ Amptastic.com SALES''

S.

[Pigmy Pony]

I recently borrowed an Amptastic Mini-T from a fellow AOS'r, and was so impressed with it, I bought a Mini-1 from another member by placing a want ad on the forum.

It's unreal how much sound can come from such a small box. A used example probably wouldn't cost much more than these cheapo ones, and chances are it would keep doing good things long after the others have turned to landfill. Really you owe it to the environment!

Even the cost of a new Mini-1 would still be great vfm.

By the way, I can't hear high pitched noises coming from my psu, but then 40 years of rock concerts and raves will do that to your hearing

[southall-1998]

Enjoy it, Steve. It's a damn good amp for the money. Maybe your PSU is more quiet than mines.

Someday I'll treat myself to a pair of efficient speakers.

S.