Explorations in Audio

Explorations in Audio

Are you ready to Explore?

In 'Explorations in Audio' I aim to share some practical insights on setting up and optimising an affordable HiFi system. Although one would think that, really, all has been said about HiFi, some surprisingly simple questions still remain, e.g.: 'Is digital superior to analogue?' 'Do cables matter?' 'Can digital cables pick up interference?' 'Should speakers be placed on spikes?' 'Has evolution in HiFi made older gear obsolete?' 'Where should I place my sub?' 'Which room correction works best?' - On the other hand: 'Are these really the right questions?' - We shall see.

What’s new in eiaudio?

While the entries in this blog are divided into the three distinct categories above, you will find a mixed listing of the most recent postings below. The most recent article is shown first. If this is not your first time visiting, the listing below is a good place to quickly check if anything is new.

Your input is more than welcome, as long as you follow the basic audiophile rule of ‘ear over mind’. This means that you do not comment based on what you think you know, but only on the basis of your own listening experience. Please feel free to suggest gear for testing as well as leave comments on the descriptions provided here.

  • Sandra MacBeth ‘Conjugal Scene’

    Sandra MacBeth ‘Conjugal Scene’

    7/9/2020

    Author: Karsten Hein

    Category: Audiophile Music

    Tag: Jazz

    I first came across the singer and songwriter Sandra Mac Beth listening to her song ‘8 Ball’ on the ‘Uncompressed World Vol. II - Audiophile female voices’ sampler. The song immediately stuck a cord with me, because of the high quality of its recording, its warm and insistent piano tones, and because of Sandra’s voice that startled me in its rawness, clarity, and warmth. The song did not appear to have have any of the smothering effects so common to modern recordings and, as such, was very pleasing to my ears.

    I set out to find out more about the artist, because I was hoping to listen to more of her songs. Yet, for some reason, none of my usual sources of music purchasing and streaming produced the desired result. I also watched some YouTube clips of Sandra’s, but since these were lacking the desired quality and even material, I decided to write her an e-mail and ask her to send me a copy of the album that ‘8 Ball’ was originally on.

    Sandra wrote back to inform me that her album ‘Conjugal Scene’ included ‘8-Ball’ and was available on Apple Music—which I have not subscribed to—and that she could send me a copy of the album and a more recent long player on CD from Scotland, to which I happily consented. The little envelope holding the CD and long player arrived just a few days later, and I was happy to find that about half of the tracks are of similar quality and attraction as the song that had led me to my search.

    There is a marked difference between the earlier tracks, which are of average recording quality and the tracks around ‘8 Ball’ which sonically really open up into the room and manage to carve out that purity in the voice that is so hard to come by. This has lead me to the idea that I would ask her for an interview with me on Music & Talk. Quite audacious at this point in time. Obviously, much more needs to be done, before I am ready and able to provide the setting online, but…I have already started ‘exploring’ the possibility. And that is the motto of this page.


  • Hafler XL-280

    Hafler XL-280

    7/9/2020

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Power Amplifiers

    The XL-280 stereo power amplifier is arguably one of the best devices the Hafler has ever made. Offering 145 watts RMS into 8 ohms, it runs stable down to just 1 ohm and is thereby capable of driving even the most challenging speaker loads without having to fear instability, overheating, or the amplifier going into circuit protect mode and shutting itself down. The XL-280 was therefore predestined as a work horse to power the magneplanar and electrostatic speakers of the 90s, but also served more demanding conventional designs, such as some Infinity models. 145 RMS may not seem like a lot of power at first glance, however, this perception might change, if we consider that the watts nearly double as the ohms are cut in half, if the architecture and power supply permit. Thus, at 2 Ohms the XL-280 delivers 360 watts per channel, whereas many more conventional amps will simply throw in the towel.

    The XL stands for Excelinear, which—according to Hafler—means that it excels in linearity. The aim was to build an amplifier that would have the linear properties of a single straight wire. The benefit of such an amplifier would be that it neither adds or takes away from the signal it receives from the audio source. Hafler writes that “In phase, amplitude, transfer characteristic and other distortions, the XL-280 sets new standards for accuracy. It is so close to perfection that for the first time you can make a meaningful comparison of this amplifier with the classic zero distortion: a straight wire. (...) An Exclinear amplifier enables the ‘golden ear’ who demands the absolute in system linearity to move one step closer to perfection.” The operating manual goes on to describe that with the addition of the XL-10 switch box, A/B comparisons in distortion differences to a straight wire are possible, and that the XL-280 offers built in controls for load adjustment to accommodate specific speaker loads. To allow for this adjustment while the amp is closed, the top panel has two small holes that are sealed by rubber plugs through which a screwdriver can be inserted.

    Halfer, like Harman Kardon, believed that musical bandwidth should not be restricted for the sake of music integrity. The XL-280’s exceptionally wide bandwidth is demonstrated by the specified 1 watt output performance of ± 3dB from 0.1Hz to 500kHz. Impressively, phase shift within the conventional audio band (20Hz to 20kHz) is specified at less than 0.5°. In terms of build quality, the XL-280 is very similar to its predecessor, the DH-220, although it is actually 25mm wider. The black case consists of four construction units: 2 pressed steel sections which form the chassis and lid and 2 large anodized heat sinks—one on each side—to which the amplifier modules are attached and the 6 output transistors are screwed for passive cooling.

    In their review of the Hafler XL-280, stereo-amplifier.net writes: “Set up for Quad ESL-63 loudspeakers the Hafler XL-280 gave a truly exemplary performance. The bass was absolutely firm and seemingly more extended than I am used to hearing, despite the fact that my preamplifier has a built-in LF roll-off. The treble was crystal clear and wide open sounding, with no trace of sibilant 'splash' and the overall stereo sound stage rock-solid regardless of the dynamic activity of the music used. Some of the more subtle subjective differences one hears in top-end hi-fi equipment are terribly difficult to quantify, sometimes even to express, but my overriding impression of the Haller XL-280 is that it neither adds to nor subtracts from the source material fed to it. The word that kept coming to mind as I listened over a period of weeks was 'authority' and I can't think of a power amplifier that I've used, or for that matter heard, which demonstrates that quality more convincingly.”

    In my own listening so far, I can well relate to the relative authority which the amp attributes to the music. There is no halo, no trace of uncertainty in the representation of voices or piano notes. The amp rather seems to have an ultra-tight grip on the music that is truly fascinating. I cannot yet confirm the bass extension that we have come to know and enjoy from the DH-220, however, a fact that could mean that the capacitors in our unit have dried up over the years. While this would not be surprising for a unit that has been playing music since the 80s, it does mean that there is still some work ahead of us to reveal the XL-280’s full potential. Considering its fresh-from-the-shop condition, I would assume that this particular Hafler has been stowed away in the basement or attic for a long period of time, which is generally bad news for capacitors. Since we have already fallen in love with this amp, restoring it to mint condition will be well worth it.

    Specifications

    • Power output (RMS, 8 ohms): 2 x 145 watts
    • Transistor Type: Hitachi Mosfet
    • Frequency response (1 watt, -3 dB): 1 - 500,000 Hz
    • Total harmonic distortion: 0,007%
    • Signal to noise ratio: >100 dB
    • Damping factor: 300:1
    • Rise time: 0,7 uS
    • Weight: 12,25 Kg
    • Year: 1987 - 1990
    Hafler XL-280
    Hafler XL-280
    Hafler XL-280

  • Hafler DH-220

    Hafler DH-220

    6/26/2020

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Power Amplifiers

    There was a time when my good friend Luigi was bringing HiFi gear by our house for testing on a regular basis. And although there were lots of interesting discoveries to be made, somehow the devices did not strike a chord with us to the extent that we actually wanted to own them. One day, as I was climbing up the staircase from an evening teaching classes, I could hear music playing in the living room that sounded very realistic, even from a distance. Whatever this is, I was thinking to myself taking the last few steps, this is going stay. The system Luigi had set up for us was a Hafler combo consisting of the DH-110 preamplifier and the 60 watts DH-120 power amplifier. And its musicality was beyond anything we had heard at the time. When I later asked my wife at which point she knew that this would stay, she said that she had already heard it was very special from the kitchen - which is about thirty feet down the hall.

    There are not many amplifiers capable of winning over our hearts from 30 feet away with such unanimous vote and certainly not at a price tag that most people are able to afford. Because of the obvious qualities of the Halfer, Luigi decided to purchase the 115 watts DH-220 and had it readjusted and fitted with new caps. The class-A portion of the amplifier was increased in the process, which has a positive impact on sound and leads to greater heat dispersion. I think you can literally fry an egg on this unit. At twelve kilos, the little amp feels like a solid piece of metal. The heat sinks are massive, and with this much class A-power that is probably good as it is. For an amplifier of this caliber, distortion figures are very low at any frequency. The below specs show THD at 1 kHz.

    From my own experience I know that the DH-220 can be quite a princess, in the sense that it does not play with everybody. Some time ago we had borrowed it from Luigi to test it on our smaller system. In this scenario it had to play with some mediocre preamp and mid-fi speakers. The result was less than pleasing, and we soon returned the amp to look for something more appropriate. I was therefore surprised when Luigi insisted that I give this amp a second chance, now that all our other components had gradually been upgraded. In the current scenario the DH-220 was to replace the Citation Twelve Deluxe, a power amp that we have come to enjoy. And the playing partners were a Lenco L75 turntable, the Restek V1 pre, and Tannoy DC6t speakers at 8 ohms.

    We gave the Citation a final listen and then hooked up the DH-220 for comparison. The improvement in this scenario was immediately audible even though the amp was still warming up. The slight dreaminess of the Citation was gone, music now had a more intense and realistic dimension to it which became especially striking when playing live recordings. Whereas the Citation had caressed the listener, the Hafler had a straightness and insistence to it that was familiar to me from some Quad amplifiers. The DH-220’s midrange is tonally very accurate and at that pleasingly broad. Its bass lines are powerful and controlled which develops into a pleasing fullness of sound. Spatial representation is highly accurate and piano notes are flung deep into the room. The Halfer played so well that we were able to remove the weights that I had placed on top of each speaker for better imaging and could pull the speakers further into the room without losing foundation. We will certainly keep this amp around for a while to enjoy the new dimension in sound. The Hafler DH-220 is well worth exploring. Wherever this amplifier fits in, it is going to be very hard to beat.

    Specifications

    • Power output (RMS, 8 ohms): 2 x 115 watts
    • Transistor Type: Hitachi Mosfet
    • Frequency response (15 watts, +/-0.5 dB): 6 - 60,000 Hz
    • Frequency response (1 watt, -3 dB): 2 - 160,000 Hz
    • Total harmonic distortion: 0,0025%
    • Signal to noise ratio: >100 dB
    • Damping factor: 300:1
    • Crosstalk: 85 dB
    • Rise time: 2,5 uS
    • Weight: 12 Kg
    • Year: 1984 - 1990
    Hafler DH-120
    Hafler DH-120
    Hafler DH-120

  • LAPP Ölflex Classic CY 110 (3G 2,5mm)

    LAPP Ölflex Classic CY 110 (3G 2,5mm)

    6/18/2020

    Author: Karsten Hein

    Category: Gear & Review

    Tag: Accessories

    Probably the cheapest way of upgrading your existing power cords is through use of the now famous Lapp Ölflex Classic cable for industrial usage. Its specially shielded design provides a good foundation for power integrity, and the inner diameter of 3 times 2.5 millimeters should be more than sufficient for most HiFi applications, even if you are running a very powerful amplifier. This is not to say that it will not be an asset to our far less power hungry components as well.

    The hand confectioned cable shown above is based on Lapp’s affordable Ölflex CY 110 power cord and was fitted with a pretty looking Viablue sleeve to lessen the glossy effect of the visible shielding. The plugs are of the high quality made-for-audio kind and were manufactured in Japan. Viablue shrink tube was used to hold the sleeves in position and a ferrite IMF shield of the same brand was added for extra protection.

    I was a little disappointed with Viablue’s approach to the ferrite clamp, for two reasons: first, it is a slide-on design which is difficult to place over a just-fit cable. Second, it consists of a thin inner ferrite liner as well as an outer aluminum tube. While the outer tube may look impressive, all the work is done by the inner ferrite core which appears to be rather thin. I have not yet compared this cable with one that is fitted with a proper Würth Elektronik 74271151, 15mm ferrite ring, but I would not be surprised if it cannot compete. If I were to choose again, I would probably go with the more expensive Würth.


  • Martin Sasse Trio, Studio-B Konzert

    Martin Sasse Trio, Studio-B Konzert

    6/16/2020

    Author: Karsten Hein

    Category: Audiophile Music

    Tag: Jazz

    A treat for vinyl Jazz fans: Martin Sasse Trio, in genuine AAA recording. Brought a big smile on my face throughout the session.

    “Große Emotionen sind bei den Direkt-Mitschnitten aus den Bauer Studios garantiert, besonders wenn Musiker des Kalibers auf der Bühne stehen, wie sie das Martin Sasse Trio zu bieten hat. Der Namensgeber der Formation, der an einem Steinway Flügel Platz nehmen durfte, hat schon gemeinsam mit Bobby Mc-Ferrin, Billy Cobham, Till Brönner und Sting musiziert, um hier nur einige zu nennen. Akustisch perfekt eingefangene Jazzsession, die glücklich macht.” - Ralf Henke, hifitest.de