Articles, Reviews and Measurements of Audio Products
Burson Soloist 3XP Review (Headphone Amp)
This is a review and detailed measurements of the Burson Soloist 3X Performance balanced headphone amplifier. It is on kind loan from a member and costs US $1,200.
The overall package feels heavy and solid but I am not a fan of lack alignment of all the connectors, holes, etc. Volume control is digital but controls a Muse IC volume control. The microprocessor managing it is very fast and responsive but alas, there is no acceleration. If the volume is too loud -- which can very well be with this powerful amp -- good luck in turning it down quickly! We are talking many turns to go from 99 to zero. Very strange how many companies miss implementing this useful feature.
Back to volume control, there is a glitch between volume level 35 and 36. It is a minor tick but otherwise it is silent as it adjusts its volume.
A switch on the right puts you in the...
The overall package feels heavy and solid but I am not a fan of lack alignment of all the connectors, holes, etc. Volume control is digital but controls a Muse IC volume control. The microprocessor managing it is very fast and responsive but alas, there is no acceleration. If the volume is too loud -- which can very well be with this powerful amp -- good luck in turning it down quickly! We are talking many turns to go from 99 to zero. Very strange how many companies miss implementing this useful feature.
Back to volume control, there is a glitch between volume level 35 and 36. It is a minor tick but otherwise it is silent as it adjusts its volume.
A switch on the right puts you in the...
SMSL HO100 Review (Headphone Amp)
This is a review and detailed measurements of the SMSL HO100 balanced (input) stereo headphone amplifier. It was sent to me by Aoshida Audio and costs US $149.
The HO100 matches its companion DO100 DAC. Switches feel nice and so does the volume control. While 4.4mm penticon connector is provided, its output is no more than 1/4 HP jack (so it is for convenience, not power).
What is unusual and welcome at this price point is inclusion of AC adapter and XLR inputs:
As with other SMSL products I have tested, it comes with regulator and safety certification:
SMSL HO100 Measurements
As usual we start with 4 volts in (for XLR input) and adjust the output to get 4 volts out. This meant using medium...
The HO100 matches its companion DO100 DAC. Switches feel nice and so does the volume control. While 4.4mm penticon connector is provided, its output is no more than 1/4 HP jack (so it is for convenience, not power).
What is unusual and welcome at this price point is inclusion of AC adapter and XLR inputs:
As with other SMSL products I have tested, it comes with regulator and safety certification:
SMSL HO100 Measurements
As usual we start with 4 volts in (for XLR input) and adjust the output to get 4 volts out. This meant using medium...
SMSL DO100 Review (Stereo DAC)
This is a review and detailed measurements of the SMSL DO100 stereo balanced DAC with Bluetooth. It was sent to me by Aoshida Audio and costs US 239.
Sorry about the fuzzy front panel picture. It looks better in person. The rotary control makes it nice to adjust volume. Back panel is the usual affair but with USB-C connector instead of the usual Type B:
Nice that AC adapter is built into the unit so you don't have to worry about a dongle. The usual SMSL remote control is provided.
SMSL DO100 Measurements
Let's start with our usual dashboard using XLR balanced out:
This is superb performance especially at this price, landing the DO100 nicely in our top 20 list of best DACs ever measured:
RCA output is just slightly worse:
...
Sorry about the fuzzy front panel picture. It looks better in person. The rotary control makes it nice to adjust volume. Back panel is the usual affair but with USB-C connector instead of the usual Type B:
Nice that AC adapter is built into the unit so you don't have to worry about a dongle. The usual SMSL remote control is provided.
SMSL DO100 Measurements
Let's start with our usual dashboard using XLR balanced out:
This is superb performance especially at this price, landing the DO100 nicely in our top 20 list of best DACs ever measured:
RCA output is just slightly worse:
UWAYKEY: Can an $18 Amplifier Be Any Good?
A member asked me a while ago to test the ultra cheap ($18) UWAYKEY Mini Bluetooth Amplifier on Amazon. To make the clickbait title work 
, I omitted the cost of the external power supply you need to bring yourself. What you get is a three board assembly:
It took less than 5 minutes to put the heatsink on the main class D amp chip and sandwich the main board with the top and bottom. The chip used must be for smart speakers as it has voice prompts when you change inputs. Speaking of that, it has Bluetooth (which I did not test), analog and USB in. The little heatsink has no air flow and in testing, it got quite hot to touch at times.
For testing, I used my lab power supply and set the output voltage to 24 volts (max spec). The supply has 3 Amps max current. Amplifier is rated for dual 50 watts at...
, I omitted the cost of the external power supply you need to bring yourself. What you get is a three board assembly:It took less than 5 minutes to put the heatsink on the main class D amp chip and sandwich the main board with the top and bottom. The chip used must be for smart speakers as it has voice prompts when you change inputs. Speaking of that, it has Bluetooth (which I did not test), analog and USB in. The little heatsink has no air flow and in testing, it got quite hot to touch at times.
For testing, I used my lab power supply and set the output voltage to 24 volts (max spec). The supply has 3 Amps max current. Amplifier is rated for dual 50 watts at...
Sabaj A1 2022 stereo integrated amplifier measurements
Let me share a few basic measurements of the Sabaj A1 (new 2022 version) stereo integrated amplifier. The amp is based on the popular Infineon MA12070 chip and I bought mine for $68.99 (total, shipped to EU).
A few pictures of the amp:
As you can see the power brick (Sabaj branded, 24V / 6,75A, FCC and CE markings) is bulky and the amp is quite tiny! Due to to small case all controls and ports are relatively difficult to operate as everything is cramped into a small space. The tone pots have a center indent (though not very precisely positioned - as you will see). There is unfortunately a relatively low-quality, imprecise feel to all of the pots, but apart from that build quality feels solid to me.
The tools used for measurements:
A few pictures of the amp:
As you can see the power brick (Sabaj branded, 24V / 6,75A, FCC and CE markings) is bulky and the amp is quite tiny! Due to to small case all controls and ports are relatively difficult to operate as everything is cramped into a small space. The tone pots have a center indent (though not very precisely positioned - as you will see). There is unfortunately a relatively low-quality, imprecise feel to all of the pots, but apart from that build quality feels solid to me.
The tools used for measurements:
- ...
CHORD Mojo 2 Review (Portable DAC & HP Amp)
This is a review and detailed measurements of the CHORD Mojo 2 portable, battery operated stereo DAC and headphone amplifier. It is on kind loan from a member and costs US $799.
The Mojo 2 is solidly built. While I am definitely not a fan of multi-color interface, the buttons feel better in this model and some of the lights kind of make sense (e.g. showing volume level).
Input interfaces are crammed into one side but it is workable and I appreciate having dual USB input jack options (USB-C and Micro-USB):
On the other side there are two headphone jacks:
I am unclear why in this day and age of personalized music consumption, one would want to share the device with another person listening to the same content.
I charged the unit and tested it with USB input and the left headphone jack out.
Chord Mojo 2 DAC Measurements
Let's treat the unit as a DAC by adjusting...
The Mojo 2 is solidly built. While I am definitely not a fan of multi-color interface, the buttons feel better in this model and some of the lights kind of make sense (e.g. showing volume level).
Input interfaces are crammed into one side but it is workable and I appreciate having dual USB input jack options (USB-C and Micro-USB):
On the other side there are two headphone jacks:
I am unclear why in this day and age of personalized music consumption, one would want to share the device with another person listening to the same content.
I charged the unit and tested it with USB input and the left headphone jack out.
Chord Mojo 2 DAC Measurements
Let's treat the unit as a DAC by adjusting...
PAC LC-1 Passive Volume Control Review
This is the review and detailed measurements of the PAC LC-1 passive attenuator. It was kindly purchased new by a member and costs just $9.50 including shipping from Amazon.
I must say for such a cheap device, the RCA cables feely nice and supple. And volume control itself is smooth. Inside there is a tiny PCB where all the cross connections are made. From documentation it seems that it is for car stereos but obviously you can also use it for home audio as long as all you want is attenuation.
PAC LC-1 Measurements
I used the LC-1 between my Audio Precision APx555 unbalanced input and output across two 6 foot sections of cabling. Here is the dashboard:
So at this volume level, performance is completely transparent. Let's see how good channel separation is:
So there is a distinct hit but it is still more than good enough for most things.
The issue with passive...
I must say for such a cheap device, the RCA cables feely nice and supple. And volume control itself is smooth. Inside there is a tiny PCB where all the cross connections are made. From documentation it seems that it is for car stereos but obviously you can also use it for home audio as long as all you want is attenuation.
PAC LC-1 Measurements
I used the LC-1 between my Audio Precision APx555 unbalanced input and output across two 6 foot sections of cabling. Here is the dashboard:
So at this volume level, performance is completely transparent. Let's see how good channel separation is:
So there is a distinct hit but it is still more than good enough for most things.
The issue with passive...
Musetec Audio (LKS Audio) MH-DA005 Review (DAC)
This is a review and detailed measurements of the Musetec Audio (LKS Audio) MH-DA005 ES9038 based stereo DAC. It was kindly purchased new and drop shipped to me. It costs US $3,299.
At 12 Kg/26 pounds, this is one of the heaviest DACs I have tested. Fit and finish is excellent as you can see in the above picture. That carries to the chunky metal remote:
When I plugged the unit in, Windows did not load the class driver for it which means it is not class compliant. I could not find a driver online but a flash drive as shown above comes with an ASIO driver. The internal USB interface is the common but old Amanero. Driver installed but the ASIO driver would not function. The remote was not functional either. I saw a...
At 12 Kg/26 pounds, this is one of the heaviest DACs I have tested. Fit and finish is excellent as you can see in the above picture. That carries to the chunky metal remote:
When I plugged the unit in, Windows did not load the class driver for it which means it is not class compliant. I could not find a driver online but a flash drive as shown above comes with an ASIO driver. The internal USB interface is the common but old Amanero. Driver installed but the ASIO driver would not function. The remote was not functional either. I saw a...
Rek O Kut Ultra Phono Preamplifier Review
This is a review and detailed measurements of the Rek-O-Kut - Ultra Phono Preamplifier. It costs US $159.
As "DIY looking" audio gear goes, this is one of the better implementation. The case is metal and weighs reasonable amount to stay put and not get tugged by the RCA cables. Differentiating on the functionality side is support for dual turntables, and four different EQ settings to account for lack of standardization in early years of LP production.
Back panel is as you expect with power provided by a 24 volt switching power supply:
For a budget product, I think this is excellent look and functionality.
Rek-O-Kut Ultra Phono Measurements
Since the only support is for moving magnet cartridges, testing is much simplified. So let's start with our dashboard using RIAA equalization:
I substantially reduced ground loop in the red channel but I was powerless on...
As "DIY looking" audio gear goes, this is one of the better implementation. The case is metal and weighs reasonable amount to stay put and not get tugged by the RCA cables. Differentiating on the functionality side is support for dual turntables, and four different EQ settings to account for lack of standardization in early years of LP production.
Back panel is as you expect with power provided by a 24 volt switching power supply:
For a budget product, I think this is excellent look and functionality.
Rek-O-Kut Ultra Phono Measurements
Since the only support is for moving magnet cartridges, testing is much simplified. So let's start with our dashboard using RIAA equalization:
I substantially reduced ground loop in the red channel but I was powerless on...
Bowers & Wilkins Formation Flex Review (Speaker)
This is a review and detailed measurements of the Bowers & Wilkins Formation Flex lifestyle speaker. It is on kind loan from a member and costs US $499.
The form factor is what we expect these days but the B&W unit is heavier than others I have tested. And that metal ring with their name gives it some style. There is some kind of grid pattern behind the thin fabric as you can barely tell from the photo.
Main connectivity is through Wifi although Ethernet is also provided:
The interface is typical of these speakers with touch sensitive "buttons" on top for power/status, play and volume up and down.
Bringing the speaker to life was a nightmare as it always seems to be the case with these speakers. Manual says to down the app but doesn't give the exact name -- again a common mistake. I found it in the app store and installed it. I then went to look for it in my Android app folder but could not see...
The form factor is what we expect these days but the B&W unit is heavier than others I have tested. And that metal ring with their name gives it some style. There is some kind of grid pattern behind the thin fabric as you can barely tell from the photo.
Main connectivity is through Wifi although Ethernet is also provided:
The interface is typical of these speakers with touch sensitive "buttons" on top for power/status, play and volume up and down.
Bringing the speaker to life was a nightmare as it always seems to be the case with these speakers. Manual says to down the app but doesn't give the exact name -- again a common mistake. I found it in the app store and installed it. I then went to look for it in my Android app folder but could not see...