Niles SI-275 power amplifier

[SEKLEM]

Would any of you folks be interested in seeing how this amplifier would measure? I've had this amp for a few years and it seems overbuilt, but appearances can be deceiving. For all I know it could be an absolute dog on the bench. I did some A/B comparisons, level matched, with a B&K 125.2 and I wasn't able to discern any audible differences. The Niles typically sells for $100-150 used and appears to be well made to say the least. The B&K looks nicer and appears to be better made, but costs considerably more to purchase used.

https://imgur.com/a/toCmjLe

I can take some pictures of mine when I get home, the ones above are just ones I pulled off the web.

 

[SEKLEM]

Doesn’t seem to be much interest here. I’ll probably forgo popping the top of mine if there’s no call for it.

 

[RayDunzl]

Give your posts at least 24-48 hours to ferment.

I'm just seeing it now.

If you can measure it, post.

 

[Ron Texas]

Give your posts at least 24-48 hours to ferment.

Ferment, great choice of a word.

 

[SEKLEM]

Give your posts at least 24-48 hours to ferment.

I'm just seeing it now.

If you can measure it, post.

I don’t have the means to measure it. I messaged Amir about reviewing it. He suggested I put out a feeler on the forum to gauge interest. I’m curious to see how it would do and if it’s a worthwhile endevour for other folks to buy one if they’re on a tight budget.

 

[SIY]

What's the vintage?

 

[SEKLEM]

What's the vintage?

Less than 10 years old. Many are available on eBay.

 

[SEKLEM]

The manufacturer rates the power output at 75 watts per channel into 8 ohms and rated as low as 2.66ohms (no power ratings at 2.66ohms are provided). The amp weighs about 20 lbs.

I took a couple shots of the inside.

 

[SIY]

I'll be interested to see how that measures. Looks superficially like a very straightforward Lin-type design.

 

[GGroch]

Niles is one of an interesting group of manufacturer's that focuses on the custom home rather than audiophile market. I would be surprised if its measurements were exceptional since that is not a priority for these guys. Triggers, excellent cooling, trouble-free operation, and performance per $ spent are what matters most to trunk slammers, who tend to be as objective as you can get.

 

[SEKLEM]

I'll be interested to see how that measures. Looks superficially like a very straightforward Lin-type design.

Lin-type meaning “linear”?

 

[SIY]

Lin-type meaning “linear”?

No, it's a topology named after a guy name Lin, usually a diff amp in a transconductance mode feeding a voltage amp (Vas) which provides most of the voltage gain, and then to an emitter follower output.

 

[SEKLEM]

usually a diff amp in a transconductance mode feeding a voltage amp (Vas) which provides most of the voltage gain, and then to an emitter follower output.

I wish I understood what this meant.

I see the tag next to your name that says “technical expert”. Mine should say 99% technically illiterate.

 

[SIY]

I wish I understood what this meant.

LOL! Sorry, I'm a geek.

It's a very, very standard and common solid state amp topology, very much in the mode of an opamp. Here's Doug Self's exposition on it.

 

[rickhoutx]

Would any of you folks be interested in seeing how this amplifier would measure? I've had this amp for a few years and it seems overbuilt, but appearances can be deceiving. For all I know it could be an absolute dog on the bench.

I just picked up one of these off of the auction site and am very pleasantly surprised by the clean power output. Thus, I second your motion to have Amir conduct his usual excellent measurements. Does the motion pass?

 

[SEKLEM]

I just picked up one of these off of the auction site and am very pleasantly surprised by the clean power output. Thus, I second your motion to have Amir conduct his usual excellent measurements. Does the motion pass?

I doubt it. The only viable option to get one of these is to find them secondhand, and while they are plentiful, I just don’t know that many of the base of this forum are interested in this type of amplifier. This forum is enthusiastic for class D stuff, which isn’t a bad thing.

That said I’m glad you are enjoying yours.

 

[Niles300z]

Thanks for the review. I grabbed one of these and a russound and a sonance just to see how bad these ci/ pro audio models sound only they didnt.
Even the little si-245 sounded decent even with the low snr ratio due to im guessing the 1.75 inch height. The others speced better.
I have an inclination these may be made in the same factory. I think ATI was my guess at one point but i could be all wet.
Sound is subjective but i have taken pause since i have heard so many amps and these dont sound any different which is enough to give a wannabe audiophile fits because of the price point. Many can be had for well under 100 bucks. I guess i wont sweat it.

 

[NTomokawa]

An American product with a CSA mark!? Now that's something I don't see every day...

 

[SEKLEM]

An American product with a CSA mark!? Now that's something I don't see every day...

I’m gathering this is sarcasm? I’m not sure what the CSA mark is or what it means. Haha.

 

[dgkula]

I have two of these driving two sets of outdoor speakers by the pool and at the patio. Long cable runs. They sound good to me but with outdoor speakers my expectations are low! I also have an SI-245 driving a pair of in wall speakers in an indoor fitness room. All bought on ebay and functioning fine.