Letters

Listening on the go: a much better solution

April 18, 2015

Marc,

Here’s my dilemma: When I travel on vacation don’t laugh now I usually lug along my spare NAD CD player, my Creek headphone amp, and, of course, a bunch of CDs -- and headphones. Plus interconnects. It all works, but as you can imagine it’s a PITA.

I’m thinking of purchasing some sort of portable USB DAC to plug into my Mac. Presumably it would have a headphone amp built in. I would then download some tracks to the Mac. Am I going about this correctly? What exactly do I need to do this?

Sheldon Simon

You are a committed audiophile, lugging all of that stuff with you, or perhaps it's that you should be committed! What you propose, a USB DAC/headphone amp to use with your Mac (presumably a laptop), is the ideal option.

The best such product for you is the AudioQuest Dragonfly -- a DAC and headphone amp in one. It will replace your CD player and headphone amp with something the size of a USB thumb drive. You can literally put it in your pocket. As for music, you can rip CDs to your computer's hard drive or download recordings. The Dragonfly can handle up to 24-bit/96kHz data. You'll be surprised how much music even a mid-sized hard drive can hold. -Marc Mickelson

Atma-Sphere/Lamm hum

April 15, 2015

Editor,

A customer recently commented to us on the Lamm review by Tim Aucremann, found here. The customer wanted to know what we thought of this passage:

I planned to use the M1.2s with an all-tube Atma-Sphere MP-1 Mk 3.1 preamp, a unit known for delivering agile, high-resolution harmonic sophistication with low distortion and benchmark levels of transparency. Unfortunately, this combination resulted in a lower-band hum in both channels from the Wilson Audio Sasha speakers' midrange drivers. Try as we may, the hum issue was never resolved; final speculation (and I emphasize this as speculation only) had it resulting from an XLR wiring incongruity between the two units.

Tim is correct; the reason this happens is because the Lamm has an XLR input connector, but does not process the balanced signal internally, as pin 3 is ignored -- it's not hooked up. The MP-1, which supports the balanced standard, has its output occurring between pin 2 and pin 3 of the XLR; so when one of those pins is not connected naturally, there will be hum and buzz as the connection is incomplete!

The problem is that balanced line and single-ended connections are not considered compatible, so you have to jump through some hoops to make them play well together.

There are many high-end audio preamps that do not support the balanced standard yet have balanced outputs with XLR connections. In this way they would seem to get around this problem. One set of examples is the Audio Research preamps. These preamps employ two separate single-ended outputs that are out of phase with each other, both tied to the same XLR connector. Each output is dependent on the ground connection. Since the Lamm is really a single-ended connection on its XLR, this works fine with it, but it should be noted that only one of the two outputs of the Audio Research is actually in use.

In the balanced line standard, ground is ignored and is only used for shielding; the actual output (pins 2 and 3) floats with respect to ground. This not only eliminates noise (allows for a high CMRR value for those with a technical bent) but also dramatically reduces cable artifacts. When the ground becomes essential to the signal connection, these advantages are lost. This is why we support the balanced line standard.

A simple method of solving the hum problem with our preamp is to tie pin 3 of the output of the MP-1 to pin 1 (ground), thus causing it to become a single-ended source. We offer optional RCA outputs on the MP-1 with a switch that takes care of this issue.

Ralph Karsten, CEO
Atma-Sphere Music Systems, Inc.

Painting Aptitlig?

April 11, 2015

Roy,

Many thanks for your article regarding the IKEA Aptitlig chopping boards as supports for components.

Would you think the benefits of the boards would be negated/altered if I were to have the boards painted? I'm thinking of buying some and having them painted to match my living-room interior. Will help greatly with the wife-acceptance factor. I will have them properly sprayed by a mate who is a panel beater.

Jeremy Ryan

Interesting question! Before we even get to the sonic issue there's the small matter of the oil with which IKEA seal the surface of the boards. I'm not sure how undercoats or paint finishes would adhere to this, although your friend could probably advise. It may be a case of sanding the surfaces to remove a complete layer before painting, with the additional concern that if the oil has penetrated to varying depths, it might cause blemishes or differences in the finished surface. I guess the only way to find out is to try it, but I'd love to know the outcome. I guess you could always run an experiment with the smaller boards if you felt the need.

Sonically, I'd always opt for direct contact; a painted surface will be at least some form of barrier. However, especially if you are using couplers of any kind (wood blocks, Sort Kones or similar) if you establish their positions in advance then it should be easy to mask those areas and leave them bare -- with the added advantage that it will become immediately apparent if your mechanical grounds have wandered from their carefully optimized locations. Likewise, it seems an area ripe for experimentation, and although my gut feeling would seek the direct-path solution, I suspect that the sonic differences between that and a painted interface would be subtle, especially when compared to the overall improvement generated by the adoption of the bamboo shelves in the first place.

Perhaps the easiest and most versatile option would be to paint the edges of the boards and a "picture frame" on the top surface, leaving the bulk of the area beneath the units bare for positioning the couplers. That should give you the best of both worlds -- a painted appearance that extends under the edges of each of your components, with a direct connection between coupler and shelf. -Roy Gregory

Using IKEA's Aptitlig

April 6, 2015

Roy,

I read the article on the smart and useful equipment support system using Ikea's Aptitlig. Very nice! Thank you for that.

I have two questions regarding my system, and I need your advice. I own the same Soundstyle rack as you. First, can I use the bamboo base under my turntable, a Rega Planar 3? The Rega is sitting on the top of the rack. Second, under the Rega on the second shelf is the integrated amplifier, a Musical Fidelity A220. After running for half an hour, it is very hot! I am wondering if the heat of A220 will damage the Aptitlig. I have read that the Aptitlig has oil on it.

Christos Anesti

I’m glad that you (and so many others) are discovering the unintended, cost-effective musical joys of IKEA’s kitchenware!

The Aptitlig chopping boards will work brilliantly under both your Rega turntable and Musical Fidelity amp. In addition, it will be well worth experimenting with simple couplers to bypass the feet on the amp (and possibly the Rega). These could be cut from a close-grain hardwood or another block of bamboo. There are commercially available options, but initially at least, experimentation is both the name of the game and half the fun.

As to the issue of heat generated by the A220, as long as you can give it an inch or so (30mm) between the top of the amp and the shelf above it, you shouldn’t have any problems. I’ve used the Icon Audio A80 with its nine tubes, including four 6550 output tubes, in similar circumstances without any issues at all. -Roy Gregory

Woman to woman

April 1, 2015

Sue,

I would like to congratulate you on your first article with The Audio Beat! Starting your writing with the Bowers & Wilkins CM10 Series 2 is an impressive introduction.

What gravitated me was your knowledge and experience -- as a woman! There are zero to none in this industry, as you are already aware. I feel I am no longer alone (LOL).

Keep up the great work, and may this be the beginning of many wondrous written works of your art and wild rides.

Giselle Yetikyel

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