Review and Measurements of PS Audio Sprout100

[Patrick1958]

Strictly from a French point of wiew, the Sprout has a terrible name, marketing-wise:
"Prout" being the infantile word for... "fart"...

Sprout is a little cabbage, winter vegetable = brussels sprouts
IMO they are referring with their device to something small

 

[Veri]

Sprout is a little cabbage, winter vegetable = brussels sprouts
IMO they are referring with their device to something small

Or something that gives you gas ...

 

[graz_lag]

 

[patient_ot]

I'm surprised it measured this poorly but have long been suspicious of this product. It seems to be a go-to product for people that claim they don't have room for a regular 2-ch. integrated amp because they can't figure out how to orient their equipment vertically on a rack. I also suspect that anyone that buys it is counting on decent DAC performance...maybe people can stop recommending this thing now.

 

[anmpr1]

The whole subjectivist thing is either a) entertaining or b) boring. I think it starts out entertaining, and then becomes boring. In audio it's ridiculous, to the point of people arguing that a bit of special wire here, and a certain wonderful capacitor there, will make a huge difference in soundstage, front to back depth, and pace (whatever that is).

I don't know of any other hobby that this sort of idiocy is allowed. Except possibly in the world of electric guitars. Electric guitar fans have the same sort of thing... how a thinly sprayed coat of nitrocellulose allows a solid body electric to 'breath,' making the tone airy, while a coat of poly binds the wood, making the tone darker. But hey, if you run it all through a distortion pedal, turn up the gain on your Marshall stack, and then start to shred, I'm sure the arena crowd will notice the 'difference.' LOL

 

[jhaider]

At least it no longer has the fixed the bass boost the first Sprout did. If you want compact and better-sounding for similar money and can live without vinyl input, ELAC EA101 and MartinLogan Forte present as better alternatives. Both have thoughtful room correction: a proprietary system overseen by Andrew Jones in ELAC and ARC in MartinLogan. No comment on electrical measurements. ARC performance is well documented. I measured ELAC's room correction and found it to work well. I think ELAC has the sharpest industrial design in the class. MartinLogan looks and feels cheap but adds AirPlay streaming, albeit not AirPlay 2.

 

[Wyllio]

The new NAD D 3045 also falls in the same category, but at $100 more than the Sprout100. Based on previous reviews, I would assume that the amplifier section measures better than the Sprout. However, their DAC section in the compacted product line isn't great for what you pay for. NAD doesn't like to give out details of how they built their products and which components they used.

 

[Fone]

Disappointing.

 

[MZKM]

I wonder how the SMSL AD18 stacks up, similar feature set save for phono and less wattage, but at $150, I wonder if anything beats it. This is one of the products I really wanna see measured, and no way in hell Stereophile would ever touch such a cheap product.

 

[gr-e]

I wonder how the SMSL AD18 stacks up, similar feature set save for phono and less wattage

There's also the SMSL A8 which is a direct competitor to sprout with $600 price tag and same 125asx2 amp module

 

[MZKM]

There's also the SMSL A8 which is a direct competitor to sprout with $600 price tag and same 125asx2 amp module

Wow, didn’t know that existed (I thought their only integrated was the AD18). Now I wanna see both measured .

EDIT: Oh, and the Sabaj A4 vs AD18; and might as well add the Sabaj D4. Sorry for the wishlist @amirm.

 

[GGroch]

Thanks for these measurements Amir. The Sprout 100 has been widely reviewed, nearly always positively, but so far as I can tell this is the 1st review to include measurement of any kind. Measurement is particularly important when the manufacturer's specifications are so general as to be nearly meaningless.
When trying to determine if a particular amp would be a good match for my medium/low efficiency 8 Ohm speakers I need more than "50 WPC both channels driven". At what distortion level? What frequency bandwidth? Continuous or Peak?

To be fair, the Sprout's vague specifications are not unique. The vast majority of mini digital amps have vague or inflated specs. For a $100 Chinese eBay purchase I do not really have a problem with that. Its a lifestyle purchase. But in the case of the Sprout, there are quite a few high performance alternatives in the $500-$800 range.

.......Fortunately, Herb Reichert at Stereophile didn't lavish praise on it, nor was it put on the bench for testing. (JA responded in the comments "No measurements planned, sorry." I wonder if he knew something?)
:

I had not seen the Stereophile Sprout Review, but it is very unusual for Stereophile amp reviews to have no measurements. I think you are right, Stereophile must have had an agreement prior to publishing to review the Sprout as a lifestyle product rather than a piece of serious performance audio.

On the other hand, perhaps if Amir had tested the Sprout using a high resolution PS Audio AC cord, things would have turned out very differently

 

[restorer-john]

It reminds me of these cute little marvels from Aiwa in the early 1980s.

 

[restorer-john]

You have to admit, these are cute huh? Fully separate components, multivoltage and decent performance. Lots were sold in the 'duty-free' days to travellers- hence the cool set in a flight-case.

The power amplifier is actually a miniature beast:

It's all transformer and guts flanked with diecast heatsink sides all in a tiny box. I've got several sets of mini Aiwas and Akais in storage- they are fun little things.

This Akai mini component setup was a work of art. The casework on the preamp, power amp and tuner is all diecast one piece with no screws visible, everything is inserted from the bottom and the base screwed on. The power amp uses an SMPS and dishes out around 35watts per channel.

I have the above setup minus the remote control receiver unit. The preamp uses potted reed relays and logic for switching and has MM/MC stage.

All gold plated RCAs- very deluxe in the early 1980s...

I think the Sprout is extremely cute and I can see why it appeals to people.

 

[VintageFlanker]

How do you deal with Anglophones named "Peter"?

The name "Peter" is not pronounced the same than the verb "péter".

 

[restorer-john]

I have a few comments/questions on the review.

The output was variable so I adjusted it to 2 volt.

So the line out was variable, what was the maximum output, and was 2.0V near the upper end or lower end of the preamplifier section's capability? Did S/N improve or get worse at higher output levels?

Per my review notes above, the power amplifier was on and was whaling away into the dummy load at the same time.

It is fair to test the unit as a standalone D/A converter while at the same time driving the power amplifiers hard enough to cause it to frequently shutdown during your test? There would be considerable noise from the loaded and struggling Class D amplifier inside the unit which may compromise the standalone D/A results. Why not disconnect the dummy loads when testing the D/A section as a standalone?

Same noise problem manifests itself hugely in linearity test:

That smooth, exponential rise indicates random noise polluting the voltage reading at each level.

Correct me if I am wrong here. I'm assuming this test is essentially a fade to noise test or a dithered 1Khz signal that stepped down in level to ~-120dBfS?

0dB is where a perfectly monotonic and completely noiseless D/A would theoretically track.

Random noise will cause a fluctuation above and below the 0dB as level gets lower in the fade to noise test. With a fixed frequency test, a smooth exponential positive rise such as this suggests to me a consistent and increasing offset of the lower bit levels, not random noise. I was under the impression everything (noise) is filtered out except the fundamental (1KHz) in such a test and the AP tracks that?

Thoughts?

 

[SIY]

Random noise will cause a fluctuation above and below the 0dB as level gets lower in the fade to noise test. With a fixed frequency test, a smooth exponential positive rise such as this suggests to me a consistent and increasing offset of the lower bit levels, not random noise. I was under the impression everything (noise) is filtered out except the fundamental (1KHz) in such a test and the AP tracks that?

Thoughts?

It's not 1kHz (I think it was 200 or 400 Hz), but essentially yes. The noise adds to the signal and that's why it slopes upward. Power averaging multiple sweeps separates the noise contribution from the linearity contribution and with a linear converter, the trace stays flatter. I showed some measurements of this a few months ago.

edit: although there's filtration around the test frequency, the 1/f causes the signal's envelope to vary at a low frequency- that's the noise I'm talking about.

 

[restorer-john]

I showed some measurements of this a few months ago.

Can you point me to your investigation/measurements?

 

[SIY]

Hmmm, my response to @restorer-john seems to have vanished.

And now it's back.

Anyway, here. And I know you read it before...

 

[restorer-john]

Hmmm, my response to @restorer-john seems to have vanished.

Thanks SIY, I read it before it disappeared.

Site gremlins maybe?

It's back: