Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the Pro-Ject Phono Box DC MM/MC Phono stage. It is on kind loan from a member and costs US $129.


The box is non-descript but it is made out of heavy gauge steel. There are no controls as you see. Here is the back panel:

Nice to see support for both moving magnet and moving coil as the latter is sometimes left out in budget phono preamplifiers. Let's test it and see how it performs.

Pro-Ject Phono Box DC MM/MC Phono Preamp Measurements
Let's start with moving magnet mode:

With highest distortion at -100 dB, that is not an issue for the format. Performance is dominated by mains noise which is typical for the class. Gain is right on at 40 dB.

Moving coil mode naturally brings high penalty in noise department due to much higher gain:


I was totally impressed by the implementation of...

This is a review and detailed measurements of the Onkyo TX-NR7100 8K 9.2 Channel THX certified Audio/Video Receiver (AVR). It is on kind loan from a member and costs US $1,099.

Not much departure from the classic look of AVRs in the last 30 years. The on screen interface has been enhanced to be high resolution and is responsive. While some parts of it are intuitive, others are not. Options are grayed out at times with no indication as to why. For example I wanted to turn on Zone 2 audio but the option was gray. Reading the manual revealed that you have to first enable Multizone option to get access to that. I updated the firmware over the air and that went well. But when finished, it just told me on the AVR that the update was completed but then sat there locked up requiring a power cycle.

Back panel shows the puzzling inclusion of analog composite and component video:


I guess it is for folks who still...

This is a review and detailed measurements of the NAD C 316BEE V2 integrated amplifier with phono stage and headphone jack. It is on kind loan from a member and costs US $399.

The unit feels just heavy enough to not feel cheap. Controls have a nice feel and can be managed with a remote control. The rounded front is a bonus touch in this budget oriented category. Bakc panel shows nice speaker binding posts and a hard power switch:

It is basically the modernized version of amplifiers we used to buy 20 to 30 years ago with that captive power cord and such. No, I don't miss those units with the cardboard back panels and cheap RCAs.

NAD C 316BEE V2 Amplifier Measurements
I adjusted the volume control to get nominal 25 dB of gain and ran our...

I just picked up one of the Parks Audio Waxwing "digital" phono stages. The new model that replaces the Puffin that @amirm already measured.

There are threads about this product already, so I won't go into a lengthy introduction.

My use case is to use the ADC part only, to then run optical into my AMP (NAD C3050). The amp has it's own mm only digital phono stage, but not the flexibility the Waxwing should offer.

I measured it using my RME ADI-2 PRO and @pkane 's wondeful Multitone software. Toslink out of the Waxwing using 96kHz sample rate.

In it's natural environment:


THD IN MM (40dB gain) MODE

similar to Amir's measurement of the Puffin...

This is a review and detailed measurements of the AIYIMA T1 Pro tube preamplifier with tone controls and Bluetooth support. It was sent to me by the company and costs US $75.



Build quality is a step above budget products in its class. Case feels sturdy and controls have good feel. Nice to see a tone control defeat (how I tested it). Volume setting in the picture is "unity gain." (again, how I tested it). Back panel shows what you expect:



Nice to see trigger output. Power is provided by a small switching adapter (a bit larger than the size of a phone charger).

FYI I told the company in advance of sending the amplifier that I expect it to not measure well. Company to their credit, still wanted it tested/reviewed so here we go.

AIYIMA T1 Pro Preamplifier Measurements
Let's start with our usual dashboard with 2 volts in/out:


Large amount of harmonic...

This is a review, listening tests and detailed measurements of the Dell CN-03GVVD USB-C to 3.5 mm headphone adapter/dongle. It is on kind loan from a member and sells for $12.45 on Amazon for a pair.

As they say, you have seen one dongle, you have seen them all. There is no marking on the thing so best not throw it in a drawer with other dongles like it.

FYI Windows allowed me to adjust the volume in 1% increments. I don't recall other adapters doing this.

Dell CN-03GVVD Measurements:
Let's start with our dashboard:

We have good news and bad news. Good news is SINAD of 97 dB which is about average for all dongles regardless of cost:


Bad news is the 0.49 volt output. This will...

This is a review, listening tests, EQ and detailed measurements of the Yamaha flagship YH-5000SE open back headphone. It was kindly drop shipped by a member and costs US $5,000.

Unlike many high-end headphone, the YH-5000SE is quite light. It is sturdy though as parts are made out of metal. I really like the adjustable suspension band as once to your liking, it almost feels like you are not wearing a headphone! Very nicely done on this front.

The drivers are mounted quite deep in the cup with a very transparent fabric protecting them. It doesn't show well in this picture but here it is anyway:



Two sets of pads are provided. I opted to measure with the default leather ones you see here. There is another set that is made out of velour. It is similar...

This is a review and detailed measurements of the IOM 500 Hypex NCx500 class D based stereo amplifier. It was sent to me by the company and costs €1,099.00 ex VAT (US $1,199).

We have a more premium case for the class with good bit of weight. The amplifier comes with both fixed or variable gain. The latter is what I have for testing:

I like the hefty weight and solid feel of the gain selector but it is squeezed tight between binding posts, making it hard to turn. It has a wide range of 11 dB to 34 which is very convenient as far as matching to the source output voltage. I tested it at 11 and 16 dB as you see below.

IOM 500 Stereo Amplifier Measurements
I started with the lowest gain which matches the Hypex NCx500 reference design:


While performance...

This is a review and detailed measurements of the D-Sonic M3a-600M Class-D monoblock amplifier. It is on kind loan from a member and costs US $1,175.

Packaging is a step above "DIY"/budget class D amplifier with heavy gauge steel all around. It also weighs more than amplifiers in those classes. Back panel shows balanced input and trigger which is appreciated:



Company doesn't state the origin of its class D design but a review says it is based on Pascal X-Pro series. Many OEMs uses these modules for their reliability and high power capabilities. To wit, the spec for M3a-600M calls for 800 watts into 8 ohm despite the name indicating otherwise.

D-Sonic M3a-600M Measurements
Let's start with our dashboard of 5 watts into 4 ohm load using XLR input:

I was disappointed to see such high level of 3rd harmonic in this day and age. That dominates SINAD, delegating the...

This is a review and detailed measurements of the Theory Audio SB25 on-wall speaker with its companion 8-channel ALC-1809 amplifier and DSP. It is on kind loan from a member. Speaker costs US $1,095 each and amplifier, US $4,950. Sorry for stock pictures:



As you see, this is a very sleek speaker designed to be hung on the wall and comes with nice bracket. Built quality is excellent with the speaker feeling like a rock. Weighs as much too for its size! Unexpectedly for a system speaker, it is driven passively with the crossover being inside the speaker rather than DSP module. On the other hand, this halves the number of amplification channels needed which is a lot in a home theater/surround system:
[ATTACH type="full" alt="Theory Audio SB25...