Articles, Reviews and Measurements of Audio Products

Six Acoustics York Review (phono pre-amp)

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This is a review and detailed measurements of the Six Acoustics York moving magnet/moving coil stereo phono stage. It is on kind loan from a member and costs US $437.
Six Acoustics York Review MM MC Phono Preamplifier Stage Stereo.jpg

I like the form factor and clean look of the unit. Nice to see a variable gain control as well. Back panel shows the usual connections:
Six Acoustics York Review Back Panel MM MC Phono Preamplifier Stage Stereo.jpg


There are loading selection from resistance to capacitance underneath (dip switches).

Six Acoustics York Measurements
Let's start with our MM mode using the default center gain level:

Six Acoustics York Measurement MM Phono Preamplifier Stage Stereo.png


Like the absence of distortion spikes but noise level is high enough to place the unit below average compared to its rivals:
Best desktop phono stage preamplifier review.png


For MC, I lowered the gain to 60 dB:
Six Acoustics York Measurement MC Phono Preamplifier Stage Stereo.png


I was impressed with the in-band flatness of the RIAA equalization:

Six Acoustics York Measurement Frequency Response MC Phono Preamplifier Stage Stereo.png


Sadly there is no rumble filter so that extra...

Technics SB-F1 Review (Vintage Speaker)

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This is a review and detailed measurements of the Technics SB-F1 mini vintage bookshelf speaker. It is on kind loan from a member:
Technics SB-F1 Review mini bookshelf vintage speaker.jpg

SB-F1 was produced in Japan around 1978. It has a stout, diecast aluminum frame. I understand it was quite expensive for its time despite its diminutive size. I got a kick out of the circuit breaker in the back. Had forgotten about these back in the day:

Technics SB-F1 Review back panel mini bookshelf vintage speaker.jpg


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 enable...

Graham Slee Gram Amp 2 Communicator Review (Phono Preamp)

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This is a review and detailed measurements of the Graham Slee Gram Amp 2 Communicator phono stage. It costs US $299.
Graham SLEE Communicator Gram Amp 2 Review.jpg


The company gets the fonts right which look kind of classy. Otherwise, the case is ultra light which causes the unit to fall back under the weight of the cables. The edges of the front panel are also rather sharp. Back side shows this is as bare bones as a phono stage gets:
Graham SLEE Communicator Gram Amp 2 Back Panel Review.jpg

Naturally the unit is for Moving Magnet (MM) cartridges only.

Graham Slee Gram Amp 2 Communicator Measurements
As usual we start with our dashboard:
Graham SLEE Communicator Gram Amp 2.png


I was pleased with absence of distortion spikes and mains leakage. Not so impressive was the noise figure which sets SINAD below average:
[ATTACH type="full" alt="best...

Tripp Lite IS250 Isolation Transformer Review for Audio (Video)

Tripp Lite IS250 Review (Isolation Transformer)

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This is a review and detailed measurements of the Tripp Lite IS250 Isolation Transformer in the context of audio performance. I purchased it for US $140 with kind donation from a member.
Tripp Lite IS250 Isolation Transformer Audio Review Filter.jpg


The case is utilitarian but is not meant to be something you look at. Despite the low power rating of 250 Volt-Amp, the little box is quite heavy courtesy of the transformer inside. Back panel provides two outlets which is appreciated:

Tripp Lite IS250 Isolation Transformer Back Panel Stere Audio Review Filter.jpg


Notice the UL hologram/safety certification which is quite often lacking in audio tweak products.

Despite the name, please note that the safety earth ground is NOT isolated. Let me repeat: the safety ground pin in your outlet goes right through the device and comes out the same pin in the rear outlets. This is required for...

Moondrop Blessing 2 Review (IEM)

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This is a review and detailed measurements of the Moondrop Blessing 2 IEM. It was sent to me by Shenzhenaudio and costs US $320.
Moondrop Blessing 2 Review IEM BA Driver.jpg

Blessing 2 feels substantial in hand without being overly large. The tips included are silicone and rather thin. This made it harder to mount on my headphone fixture but worked very well for my ears.

Note: The measurements you are about to see are made using a standardized Gras 45C. Headphone/IEM 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 end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I...

JBL SCL-7 Review (In-wall Speaker)

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This is a review and detailed measurements of the JBL SCL-7 in-wall "custom" home theater speakers. It was purchased new by a member and kindly sent to me for testing. It costs US $1,100 each.
JBL SCL-7 Review Home Theater Custom In-wall speaker.jpg

It is an interesting design with two mid-woofers and asymmetrical waveguide/horn. There is a near/far boundary setting. I tested it in far mode.

Measurements were performed using special mode of Klippel Near-Field Scanner which ignores everything outside of a radius in front of the speaker. As such it simulates speaker being mounted on infinitely large wall. Edge diffractions are also removed as are reflections.

Note: our company, Madrona Digital, is a dealer for Harman products including JBL line. While there is little subjective opinion in this write-up, feel free to read what level of bias you like.

JBL SCL-7 Measurements
As usual we start with our frequency response...

FiiO FD5 Review (IEM)

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This is a review and detailed measurements of the FiiO FD5 IEM. It is on kind loan from a member and costs US $299.
Fiio FD5 Review IEM.jpg


The FD5 is very elegant looking and feeling. It is solid weight wise yet has those fine features. It is not too big so fit my ear easily.

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 end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass...

64 Audio U12t Review (IEM)

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This is a review and detailed measurements of the 64 Audio U12t IEM. It is on kind loan from a member and costs US $1,999.
64 Audio U12t Review high-end IEM.jpg


Typical of these IEMs, the U12t is a chunky unit. While comfort was fine, it made it challenging at first to measure. Included cord was a bit too short for my taste but I think this is typical of IEMs. And alternate set of "silver" pipes come with the unit. I did not test that and stuck with the gray one you see in the picture.

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 end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I...

Audio-Technica ATH-R70x Review (Headphone)

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This is a review and detailed measurements of the Audio-Technica ATH-R70x open-back headphone. It was kindly sent to me by a member and costs US $349.
Audio-Technica ATH-R70x Review Open Back Headphone.jpg

As you see the design is unusual with those support paddles. Even though the headphone is feather-light at just 205 grams, I found them uncomfortable to wear. The left cup was not quite large enough and bothered the edges of my ear. And the paddle above it felt like it was digging a hole in my head! Most headphones fit me well so this is one of the infrequent exceptions.

The connection to the headphones are locking 2.5mm connectors with long and thin cable which worked fine.

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...
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