Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the Crown XLS 1002 rack mounted pro amplifier. It was kindly purchased new by a member and drop shipped to me. The 1002 costs US $339 including Prime shipping from Amazon.

Note: our company, Madrona Digital, is a dealer for Harman and hence Crown products. We use fair bit of Crown amps in custom installs usually to power in-ceiling speakers and such. Member wanted to buy it through us but the margin on it was no more than a cup of coffee (relative to online sites) so I suggested he buy it elsewhere which he did.

Not sure what to say about the look other than it is made to have some style while being rugged:



The LCD with bluish backlight reminds me of displays on electronics back in 1980s. I guess at this price they had to cut every penny.

I was relieved to see binding posts besides speakon connectors:



Now don't laugh but I could not figure out how to pull out the...

This is a review and detailed measurements of the Diapason Emera 2-way speaker. It is on kind loan from a member. It is an older design dating back to 2002 from the bit of research I have done. I can't find the pricing.

The fit and finish is very good:



The grill is screwed in. I took that as a signal to use the speaker that way so I tested it with it. Just the same, the speaker is titled back good but and that is how I measured and listened to it.

The back panel is simple but further shows the elegance in the design:



I believe the claim to fame on the design of this speaker is that the woofer is directly driven with no crossover. Reminds me of the same approach by Totem Acoustics. If so, this should present an interesting set of measurements.

Measurements that you are about to see were performed using the Klippel Near-field...

This is a review and detailed measurements of the brand new SMSL SU-9 Balanced USB DAC. It was kindly sent to me by one of their distributors, Shenzhenaudio. The SU-9 will be released September 30th and will cost US $439.99.

The SU-9 has a simpler but in my opinion more elegant look than previous SMSL DACs:



The display is now larger and courtesy of its fine resolution, nice to look at. The rotary control lets you navigate the menus by pressing and rotating. Alas, I could not figure out how to get out of the menus and had to wait for it to time out. Perhaps there is a way but not having read the manual, I did not know how. There is a remote of course which would make this simpler.

Back panel is what you expect in this class DAC plus addition of Bluetooth:



Power supply is included of course eliminating the external bricks that come with lower cost DACs. And of course balanced XLR output which I highly encourage...

This is a teardown of the Monoprice 150 watt Class D Amplifier which I just reviewed. The owner gave me kind permission to open it up.

Here is the overview shot of the entire unit:



The heart of the unit is an integrated switching power supply and stereo class D amplification.

I was surprised to see an angled bottom mounted fan in a rack mounted device! Usually there is equipment stacked on top of each other, not leaving any air in there to suck in. Granted, this fan is tilted a bit but still. Even if intake air is available, it is just blown randomly against the top of the case. It will surely provide more cooling than without but most certainly not optimized. Good news is that it is a larger fan so you can get quiet versions or even temperature controlled ones. It is nicely socketed as marked so replacement should be...

This is a review and detailed measurements of the Edifier R1280T Powered Bookshelf (computer) Speakers. I purchased a few weeks ago at a cost of US $99 for a pair including Prime shipping. Yes, a pair of powered speakers for just $99. Incredible value if the performance is there.

I must say I expected a larger speaker than what I saw in person:


The retro look makes one think the speaker is multiple times the size it is. That said, I definitely appreciate the form factor as it is the largest I like to have for computer desktop use. I find the grill very attractive but to be a purist, I measured the R1280 without it and listened to it the same.

Back side shows what you expect in this price range and type of speaker:



The pair of binding posts carry the speaker level signal to the other channel. This of course mandates a passive crossover. Company advertises 20 watts of amplification.

Surprisingly you get a remote and...

This is a review and detailed measurements of the Monoprice 150 watt "605030" rack mountable "pro" stereo amplifier. It was kindly purchased new and drop shipped to me for testing. The 605030 costs just US $119 from Amazon including Prime shipping which is remarkably low.

From a distance the unit looks like any other pro, R1U amplifier:



It looks rather cheap an unattractive to me but hard to imagine any pro amp getting some kind of design award for their looks.

Two gain controls are provided in the front which I appreciated. For testing I aspire for gain of 29 dB and I almost got there at max level as shown. That is how I tested the unit. There overload indicators which was nice

What I did not like one bit was the rather loud fan which runs continuously. Monoprice, please take another $5 from me and make the fan temperature dependent please!

Seeing balanced input in any amplifier at $115 price range is incredible but that is what we have...

I just reviewed the Niles SI-2150 amplifier. This is a quick teardown of the same.

Here is the main entire amplifier in one shot:



General construction seems fine.

The heart of the system are the two UC250LP-M OEM amplifier modules from Hypex. An input stage allows variable gain (board in blue) and speaker protection relays.

As best as I can tell, that complicated switching power supply is by Niles as it matches the color scheme of the buffer board. Looking at the capacitors, we see that they are the chinese brand, Jianghai:



I can't get good information on them. They certainly are not a tier capacitor company but seems like a very big company producing capacitors. May be hard to replace them with other parts given the compact size required for the thin amplifier enclosure.

The Hypex modules use...

This is a review and detailed measurements of the Magnepan LRS (Little Ribbon Speaker). It was kindly sent to me by a member and costs US $650.

NOTE: as you will see later, this is a special review with far more detail than I usually show in a speaker test. I thought it would be "fun" to see much more extensive treatment of these speakers. Result was three full days of measuring, processing, processing again and again, generating slides, generating those again, and again. I hope you appreciate the extra work that has gone into this review and no, I won't be doing this with future reviews.

Given the detail level, this is not for a casual reader of these reviews. As such, feel free to skip to subjective listening results and conclusions.

I was thankful for the thin and relative light weight of the LRS when I went to measure it and carry it to my listening room:



As you can sort of tell from above picture, there are two panels side-by-side...

This is a review and detailed measurements of the Niles SI-2150 Class D amplifier. It is on kind loan from a member. He purchased it refurbished and I see it for sale at $367. Original cost seems to be US $850.

By using efficient Hypex UcD250LP class D amplifier modules, the SI-2150 manages to fit in a small, 1U rack chassis:



Niles is targeting this amp as Custom Integration (CI) channel so has good control as far as trigger and such:



In use, the unit stayed cool and calm. When pushed into clipping it will go into protection. Sadly it stays in that mode until it is power cycled rather than recovering on its own.

Nice set of gain controls are provided which lets you get precise channel matching -- something that is rarely the case in many amplifiers. I set them to 29 dB for my testing.

Amplifier Audio Measurements
As usual we start with our 1 kHz tone dashboard into 4 ohm load:

...

This is a review and detailed measurements of the Yulong Aquila II USB DAC and headphone amplifier. It was kindly purchased by a member and drop shipped to me for testing. It costs US $640.

The Auila II breaks the mold of rectangular boxes for desktop DACs with compound angles:



The volume control also navigates the menus by first pushing it in multiple times until you land on the on screen item to modify and then turning the dial. The display is IPS and has very fine resolution which I appreciated.

The back panel has the usual connectivity:



The unit was plug and play with Windows over USB connection. Operationally it ran somewhat warm but no worse than other high performance DAC and amps.

Balanced DAC Audio Measurements
For the DAC portion I focused on performance of the XLR output only. Here is our dashboard:



Two years ago I would jump with joy at such low distortion and noise...

This is a review and detailed measurements of the Audiophonics EVO-Sabre Balanced DAC. It was requested by a member and the company was kind enough to send me one. It costs 239,00€ including tax and 199,17 € without (US $235).

The EVO is an unusual DAC in that it both works stand-alone due to use of an on-board microcomputer and display, and also as a slave to Raspberry Pi single board computer:



I tested it in stand-alone mode but you can plug in the RPI on the right and it will feed it power and I think its USB port becomes a peripheral to RPI.

The unit requires 9 volt input and is not self-powered with USB. I used my bench power supply to provide that as no power supply comes with it.

I was impressed with the quality of the OLED display with sharp, clear graphics. A remote control is also provided which is nice.

DAC Audio Measurements
As usual we start with our dashboard driven by the USB input:



Not bad...

I recently reviewed the NAD M28 multichannel amplifier based on Purifi modules. As promised, this is a tear down of the unit with kind permission of the owner.

The amp was a delight to open with beautiful screws holding the attractive top down. Once removed, we are greeted to a nice and modular layout:



The right side is a unified power supply for all 7 channels. I searched quickly but could not find a matching Hypex power supply. The only markings on it are:



As you will see later, NAD marks their boards with their name so I suspect this was custom designed by someone and not NAD.

There was a question about the fuse size. The fuse is rated at 15 amps and 250 volts. Total volt-amps available then is 1800 assuming 120 volt mains in US. Assuming there is power factor correction, this translates...

This is a review and detailed measurements of the Dynaudio LYD 5 powered studio/professional monitor (speaker). It is on kind loan from a member and costs US $499 each.

There is not much bothersome or unique about the look of the LYD 5:



The backside is perhaps more unique with slot port:



As you see, there are a few settings. I used the following for testing and listening:



Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors...

This is a review and detailed measurements of the NAD M28 Multichannel amplifier based on Purifi Eigentakt technology. It was kindly purchased by a member from a local dealer (Gig Harbor Audio) and sent to me for testing. The M28 costs US $4999 through its dealers.

As with the M27 amplifier I reviewed, the M28 comes in the same gorgeous industrial design:



At nearly 50 pounds, this is a heavy amplifier likely due to the weight of the enclosure as the class D amplifiers and it switching power supply are light.

The one thing I am not a fan of is the touch on/off button on top. It is not responsive. I wish the NAD logo was a hard switch.

The back panel shows how you do a first class job of termination...

This is a review and detailed measurements of the Minidsp DDRC-88A balanced 8 channel in, 8 channel out, Dirac and manual EQ DSP system. It is on kind loan from a member and costs US $999. The connectivity as you see is with phoenix connectors and if you order a set of cables to XLR for that, it would add another $60. A remote is included as I think a Dirac 3.0 license plus manual configuration software.

The front is business like and doesn't give you much control over the unit other than changing configs and volume:


Back panel shows the rich connectivity of both unbalanced (RCA) and aforementioned balanced:


Due to some mix up, I did not get the external adapter and had to use my lab power supply. It drew 750 milliamps at 12 volts.

To be clear, the DDRC-88A digitizes all the inputs, processes them using a DSP and then converts them back to analog. Stated sample rate is said to be 48 kHz at 24 bits.

The USB connection...

This is a review and detailed measurements of the Parasound Zphono phono stage. It is on kind loan from a member and costs US $200. There are also versions with USB and ADC (for ripping Vinyl) and higher-end version with more control.

The look is unmistakably Parasound which is to say somewhat industrial and plain:



The back panel shows the included, voltage selectable AC mains which I appreciate:



As you see the input gain can be changed from moving magnet (MM) to moving coil (MC).

Interesting to see an AC mains polarity switch. Not sure of the safety of that but I guess if you have a hum, it is worth having a switch like this to at least troubleshoot the problem.

Overall, the Zphono is a business-line phono amplifier with solid construction.

Phono Stage Audio Measurements
Let's start with our usual 1 kHz dashboard view with moving magnet setting:



As with all good phono stages...

This is a review and detailed measurements of the audio performance of the JBL SDP-55 AVP home theater processor. It was kindly purchased by a member and drop shipped to me for testing first. It arrived about two months ago. The SDP-55 costs US $6000.

Note: our company Madrona Digital is a Harman (and hence JBL) dealer. Our business though is almost entirely custom installation in commercial and high-end real estate. So we don't do much business with them for typical products I review here (and the company is totally separate from this website). That said, we can source Harman gear and the member indeed purchased this through us. So assign as much bias as you like to this review.

The SDP-55 has a very elegant, modern and serious look:


The menus and graphics are super responsive which is great. The large rotary volume control is nice but a bit too light for my taste. Then again it allows you to rotate it quick and watch the display...

This is a review and detailed measurements of the Swan Hivi 3.1A DIY Speaker kit with modified crossover by Sehlin Sound Solutions. It was kindly sent to me by @Mudjock as tested. The kit by itself goes for US $300 including Prime shipping. Unusual for a speaker kit, it comes with everything you need including the speaker box. As built the response is too hot in the tweeter (I think) and hence the mod: https://sites.google.com/view/sehlin-sound-solutions/hivi-diy-3-1-modifications

I must say I like the white finish on a DIY speaker better than black:



Please don't mind the little nicks. The crossover had come loose in shipping and I had to take the speaker apart to affix it.

The mid-range throw me off as I first thought those two little wires are debris so I proceed to try to grab then with my needle nose pliers! Fortunately I realized in time and didn't try to pull them off. So if you have grabby hands around your...

This is a review of Motu M4 4x4 audio interface (DAC and ADC). It is on kind loan from a member and costs US $220.

The enclosure is heavy gauge metal and sturdy:



The front inputs are for microphones with higher gain. For my testing I used the Line in (and out) in the back:



For testing I installed the ASIO drivers which came with a nice little control panel that lets you set the sample rate and buffer depth. I had no difficulty operating the unit during my testing.

And oh, there is a headphone amplifier in there also which I tested as well.

DAC Audio Measurements
I started my testing with the M4 acting as a normal DAC using its balanced TRS jacks:



I don't know why but I expected the performance to be worse so was pleasantly surprised by the sum (ratio) of the noise and distortion in the form of SINAD. This places the M4 firmly in the top bracket of all DACs tested regardless of...

This is a review and detailed measurements of a (built) Bottlehead Crack Tube headphone amplifier. It was sold from one member to another and kindly sent to me in between for testing. The version I have has the "speed ball" current source which brings its cost up to US $430.

The original owner did a beautiful job of building this kit:



And here are the internals:



Can't ask more in a DIY build.

I looked thorough the manual and it seems exceptionally well written and annotated.

I liked the feel of the volume control although as you will see later there is significant channel imbalance.

The tubes in the test unit are USA made 6080WC (output) and 12AU7 (driver).

Tube Headphone Amp Measurements
As usual we start with our dashboard:



It is a shock to the system coming from testing many solid state amplifiers to see SINAD (sum of distortion and noise) to be so low. That said, we have...