Melbourne Audio Club

General Meeting Reports for 2025

May 2025

Hugh Dean's Aspen Titan monoblocks

At our May General Meeting, Hugh Dean presented the latest iteration of his ASPEN Titan monoblocks. These are rated at 120W each and both monoblocks use a 300W power supply. They were fed from a laptop using MediaMonkey software, and on the night used high resolution audio files via USB to the state of an art SMSL D6S. This DAC uses the latest audiophile ESS DAC chip and includes an analogue preamp. The speakers were Adelaide Speakers Ascension model, upgraded by our very own speaker guru, Ron Newbound. They now sport a SB acoustic Satori mid-range and tweeter, with custom made cross-overs to suit.

In my 35+ years MAC experience few presenters have ever provided handouts detailing the equipment for the presentation. Yes, on occasions, there has been some generic marketing material available near the gear for those interested. But, NO-ONE ever provides a running playlist with additional explanations of the gear and music choices. Every member received this playlist at entry to the Willis Room. In one thoughtful master stroke Hugh made them all look amateurs.

He supplied a single A4 print out with a concise technical explanation of the audio system on one page, and the full playlist, including track, artist, date, bitrate and a brief comment, on the other. The playlist ensured all members could see what was coming next and what to listen for. So simple, so easy to follow and it kept the audience engaged.

In between the fifteen tracks Hugh gave us a brief description of each stage of his amp design and how each was implemented. His in-depth technical explanation of the inner workings of the amplifier was progressively revealed.

The ASPEN Titan uses a singleton input topology, unlike 99% of solid state amplifiers that use a long tail pair. The singleton has the advantage of producing dominant 2nd harmonic distortion, phased at negative 90 degrees which Nelson Pass confers depth of image. This is in contrast to most solid state amplifiers which are dominant 3rd harmonic distortion.

The next voltage amplification stage uses a very high quality fast transistor bootstrap loaded with meticulous compensation to ensure stability. The final stage, the output section, comprises two pairs of bipolar transistors in Emitter Follower Type II configuration, designed for 4 ohm loads, dipping to 3 ohms. Hugh spent weeks to identify the best operating points for this critical stage. For driving even more difficult speakers he suggests the preferred 200W MAYA.

Both designs deliver very high stability margin and utilise a modified differential nested feedback first proposed by Professor Ed Cherry from Monash University in the seventies. In essence, this power amplifier bristles with modern innovation which works very well with the inevitable harmonic distortion in all amplifiers so that it can be manipulated to offer a musical sound.

And what of the equipment and its sound in the notoriously "sound killing" Willis Room? Very, very good. As you might expect the ASPEN Titan monoblocks delivered the goods to his substantially modified Adelaide Speakers. This system filled the room with a very engaging sound.

Hugh's music choices were mainly Jazz and Classical. However, he started the evening with a very high resolution Fleetwood Mac track, "You Make Loving Fun" showing depth of image and great dynamics. Hugh commented "Titan's global feedback is limited to 30dB as beyond that level we tend to lose the depth of image." Being a bit of a Pop/Rock guy I would've liked one more of this genre but overall it was an excellent selection as each track had been meticulously chosen to illustrate specific characteristics of the system.

The Jazz at the Pawnshop album track was "How High the Moon", and featured Arne Domnerus playing Saxophone and Clarinet providing wonderful ambience. The presentation starkly revealed a myriad of little details such as the cutlery being used by the audience.

After the break Hugh introduced the audience to Alan Walker's "Time", an electronic variation of the Hans Zimmer's "Time" composed for the movie Inception. With the electronic synthesiser at work this track demonstrated amazing dynamics with powerful deep bass.

Hugh ended the evening with Mussorgsky's "Pictures of an Exhibition" delivering an amazing sound stage with large scale and height. Research and development is still ongoing at ASPEN Amplifiers with a new amplifier utilising error correction topology currently in the skunk works.

All in all, an absolute delight of an evening. Beautifully crafted, brilliantly presented and an absolute delight to experience. Thank you Hugh.

Matt Jelicich with additions from Damian Ware.

Apr 2025

An epic rock MAC gig

On the April Meeting MAC members were treated to an epic rock presentation at the Willis Room. It was 'The Winter of Discontent', the opus magnus of our esteemed Matt Jelicich and the leader of a rock band, Danny Lopez. We also enjoyed an accomplished choir comprised of four ladies and four gentlemen. All presenters were professional and very talented, but more on that later...

As you may know, Matt was raised an only child in the difficult period immediately after WWII. Life was tough and driven by survival, and most people of that time preferred a salaried, business pathway. Raising and supporting his family took centre stage and his "scribbling" (his term, not mine) became a background indulgence. During Covid, Matt quickly realised that much of his earlier 'scribbling' related to the "new" Covid world. He was motivated to complete a dark epic, conveying his alarm of our world as it slipped into pandemic, distorting our institutions, changing our governance, stripping our freedom and mental health. As a wordsmith Matt has a great love of Leonard Cohen, and an awareness of the dark aspects of the human condition. Our resourceful Programme Co-ordinator, Dave Polanske, encouraged him to present his work to the Club.

The evening started with Matt introducing us to his work, its origins, and a hint of its meaning... he warmed up the audience very well, but we did not glimpse the deep intent in his lyrics and Danny's music. The performance began with the full ensemble of musicians and singers, a rock ballad which warmed up the audience to the "Winter of Discontent". It was followed by a beautiful rendition of 'Duke of Earl', a wellknown 50s piece sung by an acapella with four male members of the eight-member choir. The third piece was with all the singers gently backed by the band but lightly amplified, and the sound was wonderfully harmonising. It was very pleasing music, harking back to a brighter era of the US. The rendition showed the range and skill of the four part Acapella and set the scene for an abrupt mood change.

Next Danny, accomplished front man and composer of the music, performed a short but impressive guitar solo leading into "Winter of Discontent". This broke the stillness with Kane Skinner, the outstanding percussionist, Jon Lambousis, the bass guitarist and the eight-part choir. All instruments were amplified, and the 'Winter of Discontent' was very, very loud! The sound was redolent of Jimi Hendrix; Danny is a wonderful rock guitarist and vocalist. Matt's words were displayed overhead via slide projector, so the audience could see dramatic images and read off the lyrics.

We might describe the 'Winter of Discontent' as Rock. But with musical accompanist from Danny, his musicians with some recorded backing and words from Matt the situation transformed to a hybrid of rock music, protest song, and classical requiem. This most unusual work reminded me of Pink Floyd's 1979 'The Wall', Barry McGuire's 1965 'Eve of Destruction', and Benjamin Britten's 1962 War Requiem (words from Wilfred Owen). If that was Matt's intent, he certainly had our full attention!

Knowing Matt, I was not surprised by the darkness, energy and breadth of 'Winter of Discontent'. It was shocking, dystopic, highenergy and thought-provoking. In any conversation with Matt, we are always impressed with his sociable pessimism and his insightful cynicism, and these traits were in full song in 'Winter of Discontent'. I came away somewhat dispirited by his dystopian future where truth, freedom and democracy are corrupted; musically 'Winter of Discontent' was fast-moving; a magisterial, dramatic sound, a little discordant. It was charged with startling lyrics, suited well for a young generation, all the clearer for the lyrics and captions projected on the screen at the meeting's end. But philosophically the work reminded me of Richard Strauss' 'Four Last Songs' written in 1947-8, a year before he died. Strauss paints a picture of a dying civilisation and the effect is profound emotionally. Matt's piece left me with similar feelings; profound sadness and the loss of great future.

Any piece of great art in any form should leave us with a sense of wonder, and sometimes with a sense of unease and even a dark awareness of despair. Matt's words and Danny's music achieved these emotions in spades. We should be very grateful for Matt and Danny and offer admiration that Matt had the courage to create, produce and commit his work to our Club; very few of us would ever have the self-belief to present our own artistic work. The 'Winter of Discontent' was one of the presentations over almost thirty years in the Club I will never forget.

For those who did not attend and/or those who did but would like to revisit the finished work at a volume level better suited to their preference, here is the YouTube link:

https://www.youtube.com/watch?v=6piuSYuTso0

Hugh Dean
19th Apr 2025

March 2025

JayVee Technologies and HeyNow! HiFi

Our March GM was presented by Toby Taylor of JayVee Technologies and Geoff Haynes of Hey Now Hi Fi. Toby brought along of electronics from the Sound Performance Lab range driving a pair of Revival Audio speakers. In the first half he demonstrated a modestly priced streamer, around $600, paired with one of their mid-priced integrated amplifiers.

The demonstration, together with a varied and interesting music selection courtesy of Dave Polanske, gave a hint of what the system could do but when the streamer was substituted for a Mark Levinson turntable and one of SPL's monoblocks the sound became richer, possibly more valve like and definitely more engaging.

During the second half Geoff showed off the Kirmuss record cleaning system and was busy cleaning and drying a dirty record several times to demonstrate its effectiveness. Geoff played the record for us, then completed 3 cycles of the cleaning process, taking approximately 15 minutes. He then played it again.

To me the sonic improvement of the before and after cleaning process was quite noticeable, and most members agreed it was very apparent. I think a lot of them were surprised how effective this cleaning process is. It showed the Kirmuss RCM is worth considering as a means to get the most SQ from your vinyl collection as well as reducing the intrusion of clicks and pops during playback.

My sincere thanks to Toby and Geoff for their time and effort spent on their presentation and for providing us a great evening's entertainment.

Laurie Nicholson

February 2025

Tim Robbins and Ric Clarke from HRSA

Tim and Ric brought along an array of vintage Williamson amplifiers (valve, of course) to showcase the very great leap in practical amplifier design that Theo Williamson, a Scotsman, achieved in 1947. Tim and Ric's exceptionally entertaining talk was peppered with juicy morsels, including the cover of an electronic magazine of the time nominating the Williamson as "the amplifier to end amplifiers" (how often have we heard that claim made?) and a personal description of the dubious joys of adjusting the bias of an old valve amplifier when the adjustment potentiometer was un-insulated and carried 400 VDC. The two amplifiers on demonstration were fed by a very modern Technics SL-G700M2 streamer provided by the program co-ordinator, Dave Polanske. Dave also provided the Leak sandwich speakers, more of which anon.

In the days just before the meeting I had a couple of colleagues ask me what I thought about the impending demonstration. I explained in broad terms the historical significance of the Williamson amplifier and the novel design of the Leak sandwich speakers, and concluded by suggesting it could be a very interesting session but that I was afraid the system would struggle to fill the Willis Room. After all, the Williamson amplifier was rated at only something like 13-15 watts (on a good day, with a tailwind and a downhill slope) and the Leak speakers, despite being floor-standers, were likely quite inefficient and probably themselves rated at only 15- 20 watts. Having seem modern transistor and Class D amplifiers with power outputs that would rival those of a small nuclear reactor struggle in the cavernous Willis Room, I thought I had good reasons for some trepidation as to how the system would cope.

How wrong I was! The system made GLORIOUS music. (Note that I say 'music', not 'sound'.) Person after person I spoke to during the evening and afterwards, on the weekend, remarked on how magnificent the system portrayed music. One member, who I would describe as an ardent audiophile, said "They aren't hi-fi but they make fabulous music". Another, this time of more antiquated audio and musical interests, reported the set-up had among the best instrumental timbre he had ever heard (and he owns a pair of QUAD 57s, so that's quite some praise). He thought the rendition of the Dean Martin track was remarkable. I was won-over by the Elvis track played just after the coffee break: had "Can't help falling in love" (recorded in 1961 for Elvis' 1962 film Blue Hawaii - and in the film sung not to his lover but to his grandmother!) ever sounded so heart-felt, so emotive, so moving, so musically correct?

So, what was the equipment responsible for such unbridled pleasure? I'll start with the speakers, as I have a long-standing personal connection to the Leak sandwiches. The Leak sandwich speaker saw the light of day in 1961. It was called a 'sandwich' because the speaker cone was a thin (2 mm?) layer of expanded polystyrene foam sandwiched between two very thin layers of aluminium foil. The chassis was made of cast aluminium and the surround was made from cambric fibre. The bass driver was big at 13" and the cabinets themselves were also substantial (60 L) and - of course - finished in period-correct real walnut or teak veneer with a thick cloth grille. The tweeter was also a sandwich design, of 3" diameter, and it crossed over to the woofer at 900 Hz. Since the speakers were designed to be used with a valve amplifier, they had an impedance of 15 ohms. I believe this initial, large, floor-standing version was called the Model 2060.

I was seriously mistaken when I hazarded to guess that the system would be inadequate for the Willis Room. The speakers must have been far more efficient than I had guessed, as they had no problem at all in filling the room. I tried to find what their efficiency was via an online search, but came up with nothing. I now believe it must have been somewhere in the mid-to-high 90s (i.e. dB/watt at 1 m; and remember they were 15 ohm speakers). A very harsh critic might say the top-end was rolled off too - but what can you expect from a 3" cone tweeter with what would now be considered an impossibly heavy cone (i.e. it wasn't built from no beryllium or titanium or diamond wunder-material). In any case, it's likely that few of our members can hear beyond 10-12 kHz, so our hearing and not the drive units is probably the limiting factor. And, yes, the bass driver didn't plumb the depths down to stygian, sub-sonic frequencies: who cares? What the system did do magnificently was portray voices, and particularly male voices. Bravo. Was this because they were being reproduced by a huge (13") woofer that operated solo up to 900 Hz? Maybe.

The sight of these lovely floor-standing, realwood- veneered creatures brought back a flood of memories. About 25 years ago I owned a near-mint pair of their smaller and younger brothers, the Sandwich Model 200. They had a smaller (8") sandwich-cone bass driver and two purple (yes, purple!) 60 mm Mylar drive units, one for the midrange and the other acting as the tweeter. I drove them via a 1960s Japanese amplifier that went by the name of 'Star' which, if recollection serves me correctly, used four EL34 values in push-pull operation. It made a lovely, warm, comfortable sound, perfect for my office. Not a lot of deep bass, not a lot of extreme treble, but a magnificent mid-range and more than satisfactory dynamics. Once you get the mid-range right, who but lovers of heavy metal and other types of doof-doof needs ultra-extended bass or treble?

I say my Leaks were 'near-mint' because the cambric roll surrounds had hardened with age over the then 40+ years of their existence. I took them a speaker repair fellow, based in Northcote I think, and he recommended replacing the original sandwich bass drivers with some hideous, cheap, Chinese rubbish that had bright yellow cones (but obviously were not real B&W kevlar units, "copy-cat yellow" being then the choice of colour for the cones of nearly all drive units). I recoiled in horror at the thought, mentally equating it to the travesty of replacing the 4.2 L straight-six DOHC XK engine in an E-type Jaguar with a pushrod Chevy V8 on the grounds that the latter was more reliable. Barbarian. Instead, in what can be subsequently described only as a fit of madness, I sold the amplifier and speakers. And sold them for a pittance, such stuff being almost unwanted at the time by audiophiles who prided themselves on being totally up to date with all the most modern equipment. Three words describe that action too: Regret. Regret. Regret.

Now onto the Williamson amplifier. It has been described in innumerable reports, of which I have the published paper by Lankshear (1990), the magnificent unpublished paper by Stinson (2020), and the three-part series of books on valve amplifiers by Popovich (2016). Scott Frankland wrote a detailed three-piece analysis in 1996 and 1997 for Stereophile on the history of push-pull amplifiers and their relation to earlier, single-ended, typologies. The first of Frankland's articles (December 1996) described the historical precedents of the Williamson design, its dependence upon the earlier (1934) amplifier design by W.T. Cocking, and how in turn the Williamson became the basis for much further development by other audio designers. The invention of ultralinear operation by David Hafler and Herbert Kereos in 1951-52 was one such development.

The Williamson design first appeared in the April (Part 1) and May (Part 2) editions of Wireless World in 1947, and was updated in the August, October and November 1949 editions. Revisions suggested in the updates included a change from the original four L63 single triodes to the use of two 6SN7 dual triodes in the preamp stage. Interestingly, 6SN7 valves are still used today (my Cary uses them as phase splitters). Popovich (2016, p. 190) argued that "The Williamson's design was not novel even in its day. There is nothing in it that hadn't been seen before, except, perhaps, the triode connection of the [tetrode] output tubes. However, it combined a few clever design choices, resulting in a relatively simple yet (for the time) well performing package." Frankland (1996, p. 115) was slightly kinder, concluding that "Williamson's amplifier enjoyed unprecedented momentum in the marketplace" and "has become the prototype for feedback amplifiers the world over." Lankshear (1990, p. 153) was kinder still, concluding that "The real importance of Williamson's work was that he demonstrated that extremely low distortion was achievable by using plenty of negative feedback, combined with carefully designed output transformers. His design set a standard of performance that is still acceptable today."

Figure 1 shows the circuit diagram for the early version. You will see the use of L63 triodes in the pre-amplifier stage and two KT66 valves in the output stage. (The KT in the valve's name stands for "kinkless tetrode", the kinkless bit being a reference to the shape of the value's performance curve, representing an effective way to circumvent the similar improvement in response recently patented for pentode valves.) 'The rectifier valve was a U52. In summary, it is a four-stage, Class A triode design using deep global negative feedback (20 dB) and a push-pull typology for the output tubes. The fact it was a four-stage design is important because an additional amplification stage was required to recover the input sensitivity lost due to the use of the global feedback. A push-pull typology using triode valves was considered in the 1940s to be the optimal basis for the design of a high-quality audio amplifier (notwithstanding the triode's chief drawback, high input capacitance).

The Williamson amplifier is significant in audio design, and this is because it eliminated the multiple inter-stage transformers that had been widely used in earlier designs and it DCcoupled the first two stages, both innovations being critical in minimising phase shifts. Williamson recognised it was vital to keep phase shifts to a minimum with a push-pull, negative-feedback design, given that the output transformers were integral to the global negative-feedback loop. The transformers therefore had to be of exceptional quality, otherwise they would be responsible for introducing large shifts in phase at frequency extremes. Were these to develop, what was intended to be a global negative feedback loop would quickly morph into a global positive feedback loop. The amplifier would then become a massive oscillator - with disastrous results for your speakers.

The well-known and respected English transformer maker Partridge Transformers Ltd was responsible for building the output transformers. The primary required 4,400 turns, the windings divided into ten primary and eight secondary sections and as by Lankshear (1990) noted "all interleaved into two balanced halves." They must have cost a fortune to make, and the highlight the deep skill-base of the English audio industry immediately after WW2. Negative feedback was optimised at 20 dB, and levels greater than that, Williamson concluded, served little or no useful purpose.

By demonstrating an Australian-made amplifier of the time that used slightly smaller transformers than those developed by Partridge, Tim and Ric showed just how essential high-quality transformers were to the Williamson design. The single most critical component in any valve amplifier is the output transformer, and as Tim and Ric noted, these are the single biggest cost in a valve amplifier, commonly accounting for at least a third of the total. In this situation there will always be a financial incentive to use cheaper transformers, i.e. ones that are smaller, lighter, less complex, or use lower quality wiring or non-grain-orientated steel in the transformer core. Tim and Ric showed plots of output power and phase shift of the Australian model to show how the amplifier with the smaller transformers had a markedly poorer performance than one with the big, expensive Partridges. It was still a good amp, just not as good as the original design would allow had better (i.e. dearer) transformers been used.

The Williamson amplifier is astonishingly significant in audio history because through it Williamson proposed - and then implemented - a set of design specifications that still hold today. Slightly later than its 1947 debut,

Williamson collaborated with Peter Walker (of QUAD fame) on an article published in a 1952 issue of Wireless World that expanded upon these requirements: Total non-linear distortion (i.e. harmonic and intermodulation) should be less than 0.1% at all power outputs (1-2 % was typical for the time) Linear frequency response within the audible spectrum of 10 Hz to 20 kHz Frequency response should be better than -3 dB at 3 Hz and 60 kHz, in order to minimise phase shifts through the audio bandwidth (40 Hz to 10 kHz + 1 dB was typical at the time) Phase shifts within the entire audio bandwidth should be less than 20o, in order to prevent the amplifier becoming an electronic oscillator Good transient response, with a power supply sufficient to accommodate large dynamic peaks in the music Output impedances as low as possible, and always "much less" than the speaker impedance, in order to provide adequate electric damping and limit undesirable peaks in the bass response of the speaker Hum and noise at least 80 dB below the maximum output. They concluded (p. 357) that this was "a formidable specification, and by no means every amplifier styled as "high quality" will meet it."

Nevertheless, specifications as tight as these were required because of the very great advances in recording quality that had been made in the late 1940s. An example is the introduction in June 1948 by Columbia Records of the 33 1/3 rpm microgroove LP record; until then, far looser specifications for frequency range etc were acceptable as they were sufficient for the shellac 78s and (AM) radio broadcasts that then made up all the program material. Greg Milner, in his 2009 book Perfecting sound forever: the story of recorded music, showed the degree to which recording processes had been improved after WW2 (e.g. as seen in Decca's FFRR records), microphones and speakers had become much better as a result of wartime technical developments in sonar etc, FM radio broadcasts (invented in 1933 but first provided in 1948 in New Jersey), and tape recorders using high-frequency bias (a wartime invention in Nazi Germany by AEG) were just coming onto the market (e.g. the Americanmade Ampex Model 200 in 1948). What an exciting period it must have been for those interested in music reproduction in the late 1940s and early 1950s!

To conclude - we heard last month an amplifier that was designed in 1947, teamed with speakers that first saw the light of day in 1961. In other words, an amplifier from eight decades ago and speakers from six decades ago. What glorious music they made, and made on track after track after track, regardless of genre or period of recording. What perfect, unbridled pleasure they provided. And the track that stood out for me - Elvis' "Can't help falling in love" - was recorded back in 1961 too. In other words, at the same time the Leak speakers were introduced and thus also over six decades ago, recorded using valve microphones and mono valve tape recorders and valve mixing desks etc, etc, etc. Yet we are told relentlessly by audiophile manufacturers that "new is best", that the most recent amplifier and speaker designs are light years ahead of what was claimed as first-class only a few months ago, that only modern 196 kHz 24-bit recordings will do as sources, that we need at least 24, preferably 36, speakers in our living/music/ theatre room to obtain the best sound, and this must include at least six sub-woofers.

Rubbish to all that self-serving baloney. The Williamson amplifier/Leak speaker combination is a superb corrective to the debilitating audiophile disease of upgradism. It makes beautiful music and what our hobby is about is music, not which amplifier has 0.000000001% total harmonic distortion at 2 Hz at a rated output of 3 kW per channel. It provides a remarkable antidote to the Cult of the New. Thus my new credo: "Long live audio 'anachronisms'!"