Articles, Reviews and Measurements of Audio Products

This is a review and detailed measurements of the ISOTEK EVO3 Aquarius AC Power conditioner and filter. It is on kind loan from a member and costs US $1,999.

From the front, the unit looks fine but on the back, I was disappointed by the thin sheet metal that bent when I tried to insert and remove the included "Premier C19"
AC cable:



Likewise, the sockets feel plasticky and loose as evidenced by them not lining up. On positive front, I like the 20 amp rated socket.

The unit has won a number of accolades:

“In suppressing line noise, IsoTek unlocks low-level transparency in the same way that removing layers of old wax from a fine wood surface allows more of the inherent depth and beauty of the wood-grain patterns to shine...

This is a review and detailed measurements of the Vera Audio P400/1000 Hypex NC500 based amplifier. It was sent to me by the company and costs 26 000 NOK ex VAT (US $2934).

The case is milled from solid aluminum and has a nice quality and look to it. It is also quite heavy for a class D amp. Back panel shows some of the value add:


I like the nice switch selectors for gain. And 12 volt trigger. All the connectors look very high quality.

Company makes specific case for thermal management which you can see from the included, variable speed fan:



There is a hole on the other side. In use, I could not hear the fan come on despite stress testing amplifier. They even have heat sinking for the output coil which from past measurements, it gets quite hot.

Finally, there is a nice clipping indicator which I really appreciate. Recovery from overload was instantaneous as well...

I reviewed and measured the Starke Sound AD4.320 multichannel amplifier a few months ago. This is the measurements of a second sample kindly sent in by a member.


The first sample missed its power by a factor of two. Company disputed this and promised their own measurements that would show otherwise. This did not materialize. We did find out that the review sample received by Audioholics had similar power shortfall to my (new) sample. Explanation given through Audioholics was that a few samples had miswired power supplies rated for 240 instead of 120. This was puzzling as the unit has a switch for such selection internally. I have not heard of any new results by Audioholics but a member sent me his unit for measurement so let's see how it does.

Starke...

This is a review and detailed measurements of the KEF Reference 4C Center home theater speaker. It was kindly purchased new by a member and drop shipped to me. 4C costs US $7,500.



Apology for using stock picture. Speaker weighs 100 pounds and I got interrupted mid-review with our home flooding so still in measurement room. I had finished the measurements though and hence this write up. You can't tell from above picture but this speaker is deep, very deep. The finish is gorgeous but I found a tiny blemish which was disappointing. Back bindings are custom tool metal ones and the best I have seen and felt. No question KEF has targeted high level of execution with this speaker.

A coaxial driver handles midrange and tweeter responsibility. Woofers then bring the bass along (3-way total).

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

This is a review and detailed measurements of the Carver Crimson 275 tube stereo power amplifier. It was purchased new by member @paulbottlehead and given to me for testing. It costs US $2750.

I really like the way the amplifier looks. The burgundy color is attractive as is the handle. On the latter, the unit is very light though so the handle while handy, is not necessary to lift the thing. Back panel shows high quality connectors:


The tubes, four Tun-sol KT120, pair of 12AT7W and 12AX7 can in their original boxes for the owner installation. Went to open one of the small tube boxes but found nothing in it! Worried, I looked around and it had come out of its box and was just floating in the larger box that they all came in.

Prior to installation of tubes I had something to investigate: there was clearly something loose in there, rattling around. So I took the back panel off to find a...

Hello you all. You probably noticed I have been away from the forum a few days. Last Thursday the finished lower floor of our house which is below grade developed a leak. This quickly became a massive flood, overwhelming our efforts to keep it at bay. To make matters worse, near midnight, my wife slipped on the wet stairs and badly injured her back side and elbow. So we spent the next day at the hospital and thankfully, nothing was broken but she has been in serious pain (but getting better). We had two days of dry weather which gave us a chance to repack things of value but then the rain came and multiple flooding with it. We would spend 12 to 16 hours pumping and drying out the floor, only to get fully overwhelmed in a matter of hours.

I have bought every pump and gadget you can think of but none of them are effective with shallow flooding of quarter of an inch of water (seeping through the walls). Actually it has been so bad that in the time it takes me to go to the...

This is a review and detailed measurements of the Sennheiser HD560S. It is on kind loan from a member and costs US $170.

I was taken aback by how light these headphones are. You can see it in this table relative to most of the others I have tested:


This doesn't give them feeling of luxury but sure are comfortable to wear given the large cups that are 73mm x 45mm. Drivers are mounted at an angle and have a maximum depth of 28 mm.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in...

This is a review and detailed measurements of the KEF T101 slim/wall mountable home theater speaker. It is on kind loan from a member and costs US $650 for a pair.

This is a very solidly built thin speaker:


It is clear a lot of engineering has gone into it. KEF developed a very shallow conventional midrange for this 2-way speaker in order to get the case so thin. The series was introduced back in 2011.

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...

This week I received a TotalDAC USB cable/filter from a friend who was throwing it out. He was happy to let me have it to try out and take apart.
I tested the TotalDAC USB cable/filter with a Chord Mojo (data only), Schiit Fula (data + Power) and a Hidizs S8 (power+Data). I had my eldest son swap between the TotalDAC USB cable/filter and a plain cheap Rino USB cable from amazon. Sometimes he swapped the Rino out and the Rino back in and sometimes swapped in the TotalDAC USB cable/filter. All of this was blind to me. I could hear no difference and couldn't tell which cable was been used each time.

Getting in to the box was a pain due to the epoxy/resin on the screws. Once chipped out, it was easy with bench drill to drill out the screws.
The soldering looks pretty poorly done, with flux everywhere. Also the USB cable was damaged where it must have been crushed by the box.

More details of the USB cable/filter can be found at http://www.totaldac.com/cables-eng.htm cost is...