LFD AUDIO: Professor M. J Hawksford (joint founder of LFD): Audio Amplifier Systems, A Compilation

This document is a compilation of technical papers relevant to both analogue and digital audio amplifiers and related systems. Topics include error correction, voltage-controlled amplifiers, current drive, current-to-voltage conversion and PWM. Emphasis is given to circuit techniques that include novel forms of distortion reduction. Audio Amplifier Systems, A Compilation (PDF Download Available). Available from: https://www.researchgate.net/publication/312557447_Audio_Amplifier_Systems_A_Compilation […]

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LFD AUDIO: Bews views: The thoughts, opinions and observations of Dr. Richard Bews:

Dr. Bews – as I understand it, volume controls of all kinds affect sound quality in negative ways, some more than others. Is there one type of level control that’s better than all others and if so, why? Also, how do your findings impact on future LFD designs? A: All pots have different sounds, even […]

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LFD AUDIO: MCT phono stage and the very rare MCT ‘transformer coupled’ version – clarified by Dr. Richard Bews

What is the difference between the MCT phono stage and the very rare MCT ‘transformer coupled’ version? All MCT are transformer coupled (“T” in MCT). There is a (SE) version where the MAINS transformer is much larger (it retails for about £4k), also there is a slight change to a passive component. This gives more […]

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LFD AUDIO: Dr. Bews discusses the 2019 integrated LE(VI)

Hello Dr. Bews. What can you tell us about this new release? 20 years of evolution of the LE range of integrated amplifiers has resulted in the new LE(VI) which takes over from the LE(V). A complete revamp of the input stage in the power section where the following: carbon composite, carbon film resistors and […]

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LFD AUDIO: Q/A with Dr. Bews. Problem (and solution) re Audio Research driving PA2M

Q: I have an lfd pa2m amp and find there is a hum .any way of stopping this problem?am using audio research ref 2 pre/amp connected by balanced cable but balanced from pre– then balanced cable connects to single ended cable connecting to lfd amp.thank you A: Dr Bews replies: I guess it’s the balanced […]

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LFD AUDIO: The Practical Reality (Unpalatable Truth) About Resale Values Of Pre-Owned Audio Equipment. Part #2 Or …. What Price Will You Actually Get For Your Surplus Lfd Equipment?

Good question, right? Right! Since 2011 I have been monitoring the AVERAGE ACHIEVED prices for pre-owned LFD Audio equipment SOLD PRIVATELY. Here are some examples. If what you are looking for isn’t listed here please send me a private message and I’ll give it some thought. Linestage LS1 £244 Linestage LS2 £490 Any other LFD […]

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The Practical Reality (Unpalatable Truth) About Resale Values Of Pre-Owned Audio Equipment. PART #1

It’s not unusual for owners wishing to dispose of surplus equipment to expect the highest possible prices. Unfortunately they are, in the main, unrealistic in their expectations. The owner’s perception of value may well (a frequently does) differ significantly from the buying public’s perspective. There are as I see it the following facets contributing to […]

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LFD AUDIO: Q/A with Dr. Bews – development speakers

Q: Dr. Bews. What speakers do you use during development? I use a pair of modified Celestion SL600 loudspeakers, rewired and the crossovers outside the box. These modifications helped immensely, to relieve the rather laid back, and slightly congested sound. Really I don’t think the absolute quality of the loudspeakers is that important when developing […]

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LFD AUDIO: Dr. Bews discusses Integrated Mistral 2019 with and without phono stage

Hello Dr. Bews. What can you tell us about this new release? “The internal phonostage of the Mistral is based on a new circuit, which uses a dual op-amp, so is different to the phonostage LE and needs to be specified at manufacture since the back pcb needs to be modified to allow input “1” […]

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LFD AUDIO: Dr. Bews discusses LFD Integrated LPCD – the low powered class d

Hello Dr. Bews. What can you tell us about this new release? “The cost of the LPCD is for the standard line level version (NO remote control) is £7500, it can be configured to have internal phonostage or internal DAC (192khz/24bit SPDIF only), at a higher price (probably around 10% extra for phonostage and 15% […]

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LFD AUDIO: Q/A with Dr. Bews – The battery DiscStage; where does the cost go?

Q: Dr. Bews – your battery DiscStage is your most expensive product. Where does the cost go? A: I actually don’t get the usual manufacturer’s mark up with the Battery DiscStage, since it would become prohibitive in price. There are very expensive parts in the battery DiscStage, i.e. 26 off sealed lead acid batteries, 1W […]

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LFD AUDIO: Dr. Bews’ design philosophy

Hi Howard. You have ended up only selling LFD amps. What makes them so special and what is their design philosophy please. And no jargon please if you can. Thanks. Ralph. Dr. Bews reply: LFD Audio believe that audio Amplifiers can be most easily optimized if the basic amplifier topology is kept as simple as […]

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BI-WIRING: How important is the type of jumper? Dr Richard Bews responds

Recently I wrote: This started way back at Subjective Audio in the 1980s I played music for the staff on our reference system, then going around to the rear of the speaker, making a quick ‘mystery’ change they all noticed for the better. What I did was simple; I moved the speaker cables from the […]

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LFD AUDIO: Q&A … damping factor

Howard writes … A question of mine, to address my inquisitive nature.  My preference, for most types of music and most speakers is a high damping factor. I value speed, agility and articulation over heft, weight and so on.  To date, the PA2M(SE) is the most satisfying I have heard. Hypothetically, is it technically possible […]

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Professor M.J Hawksford (joint founder of LFD): Low-frequency sound source localization as a function of closed acoustic spaces

Further development of an emerging generalized theory of low-frequency sound localization in closed listening spaces is presented that aims to resolve the ambiguities inherent in previous research. The approach takes a robust set of equations based on source/listener location, reverberation time and room dimensions and tests them against a set of evaluation procedures to explore […]

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BENCHMARK DAC: LFD Audio LS3 linestage, an irritated wife, Joni Mitchell and … a lesson learned!

Originally published June 2006 Just like you I understand that our connection to music comes from multiple angles: emotional, analytical, as a student, as a teacher, as a critic or just casually. Moreover irrespective of how we are connecting we can easily tell when we like something or we don’t Neither you nor I need […]

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