LFD AUDIO: DIY tweaking of their products

Occasionally I get a phone call or email about tweaking of a piece of LFD Audio electronics. Howard …. how about changing internal wiring, removing filters, adding better ones, inserting very expensive fuses making tweaks that seem obvious? I have two thoughts on this: first, there isn’t a product in the world that cannot be […]

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PETER COMEAU: Director of Acoustic Design @ International Audio Group IAG interviewed by Howard Popeck

All images shown here have been selected by the HFA editorial team. HFA: How did you first become interested in music speaker design and/or hi-fi? PC: In my youth reel-to-reel tape recorders were all the rage and, as a singer in our church choir, I started making choral recordings. It fairly soon dawned on me […]

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LFD AUDIO: Q/A with Dr Bews – Does a low output impedance usually results in better defined bass sound?

Dr. Bews writes: Low output impedance for line level products (provided impedance is less than 500ohms) I believe has little or no influence on subjective balance of a product. PSU design, parts selection, wiring, circuit layout,  etc have much more influence on sound. Lowest global prices GUARANTEED  

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EMMINENT TECHNOLOGY: Howard Popeck speaks at length to people with interesting things to say: Bruce Thigpen – Eminent Technology

Hello Bruce. You are I believe not only the conceptualiser but the senior engineer, team leader and public face of the company. Have I got that right? Yes that’s right, I wear a lot of hats and frequently have reservations about my qualifications. Are you by training and/or an electronic expert, mechanical engineer, acoustician or […]

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BENCHMARK: Audio application notes – Feed-Forward Error Correction

John Siau writes: The Benchmark AHB2 power amplifier and HPA4 headphone amplifier both feature feed-forward error correction. This correction system is an important subset of the patented THX-AAA™ (Achromatic Audio Amplifier) technology. It is one of the systems that keeps these Benchmark amplifiers virtually distortion free when driving heavy loads. It is also the reason […]

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BENCHMARK: Audio application notes – Balanced vs. Unbalanced Analog Interfaces

John Siau writes: If you look at the back of any Benchmark product, you will find balanced XLR analog-audio connectors. As a convenience, we also provide unbalanced RCA connectors on many of our products. In all cases, the balanced interfaces will provide better performance. We build our unbalanced interfaces to the same high standards as […]

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BENCHMARK: Audio application notes – Relay-Controlled Volume – The Ultimate Solution for Analog Audio

John Siau writes: Benchmark has introduced the new HPA4 headphone/line amplifier with four 256-step relay-controlled attenuators and four 16-step relay-controlled boost amplifiers. Together these form two fully-independent, fully-balanced stereo volume controls. One volume control is dedicated to the line output and one is dedicated to the headphone output. Each has a +15 dB to -122 […]

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BENCHMARK: Audio application notes – Laboratory Use of the Benchmark AHB2 Power Amplifier

John Siau writes: SEAS driver test system uses Benchmark AHB2 SEAS, a well-known manufacturer of high-quality loudspeakers, selected the Benchmark AHB2 as a key component for use in testing loudspeakers. They created an innovative test system that measures loudspeaker motor strength and moving mass with higher accuracy than previous methods. This new measurement system was […]

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BENCHMARK: Audio application notes – Laboratory Use of the Benchmark AHB2 Power Amplifier

John Siau writes: SEAS driver test system uses Benchmark AHB2 SEAS, a well-known manufacturer of high-quality loudspeakers, selected the Benchmark AHB2 as a key component for use in testing loudspeakers. They created an innovative test system that measures loudspeaker motor strength and moving mass with higher accuracy than previous methods. This new measurement system was […]

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BENCHMARK: Audio application notes – Interpreting THD Measurements – Think dB not Percent!

John Siau writes: Distortion measurements (THD, THD+N and IMD) are traditionally expressed in terms of percent. But what do 1%, 0.1%, 0.01% or 0.001% mean in terms of loudness or audibility? If you are like most people you just know that 0.001% is the best of the three numbers listed above. If you are a well-trained […]

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BENCHMARK: Audio application notes – Speaker Sensitivity and Amplifier Power

John Siau writes: Speaker sensitivity is a measure of how loud a speaker will play at a given input power or at a given input voltage. Sensitivity is normally measured with a 1 watt power input or a 2.83 Vrms voltage input. The acoustic output is normally measured in an anechoic space at a distance […]

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BENCHMARK: Audio application notes – Intersample Overs in CD Recordings

John Siau writes: We have frequently used Steely Dan’s Gaslighting Abbie from Two Against Nature in our listening tests. This is a spectacular CD recording with lots of dynamics and a low noise floor. Nevertheless, in a little over 5 minutes, this track has 559 intersample overs on the left track and 570 on the right track for a total […]

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SPICA: John Bau interview – Interstellar Overdrive

John Atkinson (Stereophile) writes ….. Elsewhere in this issue, I review the new Spica Angelus loudspeaker, only the fourth product to appear from this Santa Fe-based manufacturer since it started operations at the end of the 1970s. You will have to read the review to learn what I thought of the speaker, a distinctively styled […]

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Passive preamps, the downside.

Hello Colin. I’m sure you’re aware of passive preamps such as Music First. I don’t think you’ll sort person to comment negatively on a particular brand but I do wonder what your views are on such devices? Not wishing to anticipate your answer, I’ve listened to the MF device and been very impressed by the […]

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ELSDON WONFOR AUDIO: LS-XXV (LS-25) speaker cable test review

Alan Brown writes ….. Obscenity My problem with high-end cables is that it’s possible to spend truly obscene amounts on them. Obscene, because it seems to me many offerings to the audiophile market are overpriced hype with no real merit. Well it does seem like that doesn’t it? I mean ….. that’s the easy stance; […]

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TRILOGY AUDIO: Colin Wonfor involvement?

Hi Colin. Is it true you were involved with Trilogy audio? I have not had any significant input into Trilogy. Nic and I are old friends. We’ve known each other for 30+ years from when he first started. He and I bat ideas of each other and have worked together on other projects, including airfield […]

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BENCHMARK AUDIO: Application notes – Rules of Thumb for Music and Audio

John Siau writes: As an engineer I like to use “rules of thumb” to make quick estimates that help explain what can be expected from the physical world around me. These rules of thumb are easy-to-remember approximations that eliminate the need for complicated and needlessly precise calculations. If you learn a few key rules of […]

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HARBETH: Alan Shaw on amplifiers…

From the archives, but still relevant I believe. Neil —//— The latest on this ongoing ‘amps are all the same’ thing on the Harbeth User Group forum – ‘The last word on audio amplifiers – Jan 2015’ http://www.harbeth.co.uk/usergroup/showthread.php?2505-The-last-words-on-audio-amplifiers-Jan-2015[/URL] The comments are getting quite heated on this one but Shaw will not be moved stating that […]

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BENCHMARK MEDIA: Howard Popeck speaks at length to people with interesting things to say: John Siau – Benchmark Media DACs

Originally published 2014 John … in the audiophile world Benchmark Media have entered quickly and built a terrific reputation from scratch. Very impressive. However from your perspective, how do you see the differences between studio buyers and audiophile end users? The short answer is that audiophiles talk more. Audiophiles are passionate about their love for […]

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AUDIOPHILE FUSES: Nonsense or what?

Hello experts. I have used audiophile fuses for years in various equipment without problem, generally appreciative of sound quality improvement. Recently, I’ve encountered problems with audiophile fuses blowing in my Coincident Turbo 845SE amplifier. At this point I’ve had two failures of Synergistic Red Quantum 6.3a 250v sloblo fuses in this amp. Recently I discovered […]

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