NEWS

Tektron-Italia

A wonderful range of  hand-built, point-to-point wired amplifiers.

Objects of beauty both physically and sonically.

The elusive qualities of single-ended amplification done right.All news about Hi-Fi go here

The Genius of Glenn Croft

by
When Quad developed the Quad 303 they were one of the first to introduce a fully regulated power supply to control their Quad ESL-57 electrostatic speakers.
 
While it was highly unusual for consumer solid-state amplifiers of the late 1960s to feature regulation, Quad’s legendary founder, Peter Walker, deliberately designed a unique internal regulator board for a very specific engineering reason.
 

Why the Quad 303 Needed Regulation (and Glenn didn’t)

The Quad 303’s regulated power supply was explicitly engineered to protect and perfectly drive the original Quad ESL-57 electrostatic speakers.
 
  • Voltage Clamping for Safety: Electrostatic panels can literally arc, catch fire, or sustain permanent damage if they are fed too much voltage. By utilizing a fully regulated power supply clamped strictly at 67 Volts DC, Walker ensured that the amplifier could never accidentally swing a voltage high enough to destroy the delicate Quad 57 panels.
  • Combating Supply Ripple: Solid-state technology in 1967 was prone to hum, noise, and mains supply ripple. The regulated PSU actively ironed out this background noise, ensuring the 303 maintained a black, dead-silent background.
  • The Low-Impedance Penalty: While the regulation made the 303 incredibly stable, it introduced a major drawback for mainstream speakers. Because the regulator strictly limits current, the 303 delivers its peak 45 watts beautifully into an 8-ohm load but aggressively suffocates and drops its power when forced into modern 4-ohm speakers.

Was Regulation Common in Other Vintage Amps?

No, the Quad 303 was a rare exception. The vast majority of its mainstream contemporaries—such as vintage amplifiers from Pioneer, Sansui, Marantz, and Leak—opted for simpler, unregulated power supplies consisting merely of a transformer, rectifiers, and large smoothing capacitors.
 
Unregulated supplies were cheaper to build, ran much cooler, and allowed the amplifiers to naturally deliver massive “bursts” of peak dynamic power into traditional moving-coil speakers when a music track demanded it. Quad’s choice to prioritize strict voltage limits over raw dynamic output is exactly why the 303 remains legendary for electrostatics but is often considered a bit soft or polite on conventional dynamic speakers.
 

The Genius of Glenn Croft – “designing an amp without Regulation to control the Quad ESL-57’s.

 
The basic Croft Series 7 power amplifier controls the Quad ESL-57s perfectly without active regulation due to a unique blend of “over-engineered” current safety, specific transistor physics, and a minimalist, zero-feedback design.
 
Rather than using an electronic regulator to forcibly restrict the amplifier’s behavior (like the Quad 303), Glenn Croft designed the circuit so that its natural, unrestricted state aligns precisely with what an electrostatic speaker needs to remain stable and controlled.
The control is achieved through four distinct engineering approaches:
 

1. Naturally Stable “Current Drooping” (The Anti-Explosion Safety)

The biggest risk of driving a Quad 57 with an unregulated solid-state amplifier is that as the speaker’s impedance drops, the amplifier will try to pump out massive, destructive amounts of wattage.
Glenn Croft engineered the base Series 7’s power supply to naturally “droop” or flatten its power delivery when under extreme loads:

  • Into 8 ohms: 45 Watts
  • Into 4 ohms: 50 Watts
  • Into 2 ohms: 50 Watts 

Because the output power stays strictly capped at 50 watts no matter how low the impedance plunges, the amplifier cannot deliver a high-voltage surge that would arc the Quad 57 panels. It behaves with the safety of a regulated amp, but achieves it naturally through power transformer physics rather than aggressive clamping circuits.
 

2. High-Current Lateral MOSFETs

The Series 7 utilizes specialized Lateral MOSFET output transistors. Unlike traditional bipolar transistors found in most vintage amps, Lateral MOSFETs possess a physical trait called a negative temperature coefficient. 
If the Quad 57’s vicious, highly reactive load causes the amplifier to heat up, the MOSFETs naturally restrict their own current flow to prevent a thermal runaway. They possess massive current reserves, meaning they can effortlessly handle the Quad’s high-frequency dip down to 0.5 ohms without breaking a sweat, collapsing, or blowing a fuse.
 

3. An Oversized, Low-Impedance Power Reservoir

While the voltage supply isn’t electronically regulated, it is incredibly robust. The Series 7 features a massive 300VA toroidal power transformer paired with heavy-duty smoothing capacitors. 
For a modest 45-watt amplifier, a 300VA transformer is technically “overkill”. This means that when the Quad 57 rapidly demands current to push a transient or a sudden bass note, the power supply reservoir is so deep that the voltage doesn’t sag or ripple aggressively. It acts like a massive tank of water—even without a regulator pump, the pressure remains incredibly steady because the tank is so large.
 

4. Zero Global Negative Feedback (Open-Loop Design)

When a typical amplifier drives a Quad 57, the speaker’s capacitive load reflects a massive amount of electrical energy back into the amplifier. In an amplifier that uses “Global Negative Feedback” to correct distortion, this backward energy confuses the feedback loop, creating severe phase shifts, high-frequency oscillation, and harsh, unmusical sound. 
The Croft Series 7 operates as an open-loop, minimalist design with zero global negative feedback. Because the amplifier isn’t constantly trying to cross-examine and “correct” its own output signal, it is completely immune to the back-EMF energy thrown at it by the Quad panels. The amplifier simply delivers the signal and ignores the speaker’s erratic electrical misbehaviour. 
 
 
Glenn Croft was widely considered a genius within the British hi-fi industry because he rejected the “measurement wars” of the 1970s and 80s. Instead, he focused entirely on minimalist engineering, short signal paths, and real-world speaker interaction.
His philosophy boiled down to a simple rule: the best sounding component is no component at all.
 

The Genius Elements of the Croft Philosophy

  • Fewer Parts, Pure Tone: A typical modern amplifier uses dozens of resistors, capacitors, and complex protection circuits to handle difficult speakers. Croft cut all of that away. By using fewer high-quality parts, there were fewer components in the way to degrade, colour, or distort the fragile musical signal.
  • Hard-Wired by Hand: Croft notoriously despised printed circuit boards (PCBs) for audio signals. He hand-wired his amplifiers point-to-point using solid-core silver-plated copper wire. This meant electrons flowed directly through component leads rather than traveling across thin copper tracks on a fiberglass board, drastically reducing resistance and capacitance.
  • Hybrid Realism: He realized that valves (tubes) are unmatched at handling delicate, low-level voltage signals (like a musical source), while solid-state transistors excel at delivering raw, high-current delivery to physical speakers. By using a valve for the input stage and Lateral MOSFETs for the output, he captured the holographic, emotional midrange of tubes without the flabby bass or high maintenance costs of traditional tube power amps.
  • Affordable High-End: Because he didn’t spend money on thick, flashy aluminum faceplates, remote controls, or marketing, you were paying strictly for the internal engineering. His base Series 7 outperformed amplifiers costing three to four times its price.

When Glenn Croft sadly passed away in 2022, the audio world lost one of its last true artisan designers. His amplifiers were never built to look pretty on a shelf; they were built like industrial lab equipment designed solely to make music sound incredibly alive.
If you want to explore how this philosophy translates to your actual system, let me know:
 

Objectivists again…

by

It is amazing how many objectivists are confident in their ability to pin the tail on the donkey precisely on Neutral!

Counterproductive modifications.

by

I am working on what was a nice pre-amp which has been upgraded by a customer with:

  1. CNC sockets which seem to need a blow torch to solder to effectively.

2. A typical silver solder of a type which does not flow properly. (Some with many additives do better e.g. Cardas.)

3. Oil impregnated hook-up cable which needs to be cleaned scrupulously to get a good joint and were not.

Put the 3 things together and you can get terrible solder joints and a sound which is a significant downgrade… 😂

Nelson Pass amps.

by

This is going to sound bitchy but… I have heard a few of his amps at length and in shows and I really like them in all areas bar one.

(I have had a longer exposure to the Pass Aleph 3 and the Threshold S200 in particular.)

But, I find the timing in both quite ploddy and I place great importance on timing.

Sounds ridiculous?

I certainly believe some amps are more ‘on the beat’ than others.

And some companies cheat by rolling off early in the bass, mentioning no Names…

Usually, amps which are full bodied/overly full bodied will sound less on the beat particularly in the bass.

But these were rather ploddy sounding without being overly full bodied in my opinion.

A down side of Class A perhaps?

Any comments welcome?

Fake Blue Alps

by

Had a bit of a shock lately.

The strong suspicion that a fake Blue Alps outperforms the genuine article.

More musical and lively partly because it has a more Linear, incorrect, arc of movement.

Please report back anyone who has done the comparison…

Denafrips Ares 2

by

Was really surprised to hear some terrible lag from this popular dac into its USB port from a laptop.

Poor implementation of its USB port when used with a laptop with an effect like wow and flutter.

A rather disjointed flow of the music at times.

I recommended the customer buy a cheap USB to SP/DIF converter (RCA end going into dac) and problem was solved.

The Speaker Presentation Trap.

by

I have always argued that the voice is the sound we recognise the best because we are most attuned to it from our mother’s voice as a baby and onwards through life to wanting to hear the exact characteristics of a favourite singer’s voice.

Consequently, I have always been beyond fussy about voice and the midrange. E.g. Croft amps, classic BBC speakers and, of course the Quad ESL 57s.

Whether a bass guitar should sound tighter (very venue dependent) or a synthesiser more focussed in the original recording is neither here nor there if voices do not sound simply superb IMO.
For this reason, my speakers over the years have had to excel in this area. The V or U shaped frequency response curve seems absurd to me especially if you listen to vocal music…
Also, the prominent bass it requires will sound slower with more overhang than was intended. I prefer a fast, leading edge to the bass notes without the bloom.
And yet, I have been a little surprised lately by how some recent speaker designs in shows have seemingly clearer, better defined midrange instruments than my all-time favourite speakers while at the same time having inferior, more synthetic-sounding vocals!
Then it dawned on me, when I was studying some speaker crossovers, that often the tweeter is tipped-up to give ‘better definition’. One demonstrator pair had 3 ohms less resistance on the tweeter than the original crossover diagram to impress the gullible. This ‘improves’ midrange definition and attack but tends to make voices sound less real and more robotic! (Never mind the fact that many ears prefer a dip around 2 KHz over the flat response…)
A manufacturer’s trick which relies on impressiveness over naturalness in vocal tone.

RIP Glenn Croft

by

The man I have looked-up to the most in my life has suddenly died.

He had many rare qualities and what he stood for spoke volumes to me.

In some ways he combined those rare British strengths of being inventive, stoical, loyal, honest, shy, an animal lover, kind by nature, a man of his word.

But also strong, sensitive and quiet with a sharp wit that came out of the blue.

I stocked only the Croft brand of amplifiers he built by hand because they ‘spoke’ to me and to thousands of others.
Voices were real, the soundstage was 3 dimensional, timing spot on.

His genius lay in the intuitive minimalism of his designs. Sometimes, other designers would look at his beautiful hand-wired work and scratch their heads in disbelief at the apparent simplicity.

I have been thinking lately about how to view death; the cocktail of being unwell mixed with the illness of these times is heavy.
He became angry with the unbelievable, self-serving egotism of the Conservative party, the absurd bureaucracy around Brexit, Covid, Putin’s war. Most sensitive and observant people feel this burden.

I will never forget you Glenn. You understood the duality between objective and subjective better than any person I know. I just can’t believe you have left us!

Hi-Fi Shows

by

I went to the Milan Hi Fidelity show last weekend and the same 3 things struck me as happens in just about all the Hi-Fi shows I attend.

1) Some absolutely dreadful Muzak is played just because they are excellent recordings. This means that when I request a decently-recorded CD track I know well to be played, I am nearly always disappointed compared to my own system.

2) Some systems have impressive bass; more than I am used to. From experience, having owned some bass behemoths in the past, I know that – for me at least – it is just a novelty that soon wears thin. I much prefer a fast, transparent bass to room-shaking depth and the compromise in midrange clarity that comes with that. The unrealistic desire many have to recreate orchestral scale in their rooms detracts from the delicacy needed for World Music, Jazz or Folk.

3) And now for my most controversial point. I am used to what some would dismissively call ‘pipe and slipper’ speaker designs such as old Spendor BC1s, Harbeth HL Monitors and Rogers LS5/8s. As often happens, I heard a track I knew well at the show, a viola da gamba track played by Jordi Saval. The speakers were Brave New World designs built from what looked like solid aluminium billet. The natural resonances and reverberations I expected were, for the most part, bleached away! Many recordings seem to lose much of the natural resonance and 3 dimensionality of the music. The approach of most modern Hi-Fi systems is to be clean, focussed, tighter-than-reality and rather uninvolving. Valves add a global 3 dimensionality often lost.
There is an intuitive understanding that for music to sound real something more Yin and Yang than simple resonance control is required. It is not that subjectivists condone adding colouration, as many objectivists claim, but that they instinctively seek that extra connection and engagement you get with the original performance which the recording often lacks. Furthermore, valve amps generally sound more natural than transistor probably because the signal travels through a vacuum rather than silicone.

Cleaning records.

by

I have tried cleaning records in various ways over the years.

From tap water and washing-up liquid which can leave a calcium residue to wood glue which  can get stuck in the grooves where spread too thinly.

I recently tried Covid hand sanitiser rubbed gently into grooves with my finger tips and used warm water to rinse it off. This works very well and leaves no calcium deposits. By using finger tips one can feel how much attention each record needs before it becomes clean.

The objectivist/subjectivist battle rages on in audio forums

by

Denial that subjectivist types hear what they think they hear.

That the ear is not reliable in blind tests etc.

That natural body and resonance are coloration etc. 

That an explicit, hyper-detailed sound must be right.

When long-term realisation shows that it is just tiring. If you want to show your system picks up a vocal inflection, a click of the tongue ”more betterer” than your friend’s system that’s fair enough I suppose but you are probably cheating.

The fact that it is probably a manufacturer manipulated upturned frequency response to impress in a comparison audition… well never mind. When I look at Hi-Fi magazine reviews I am mainly looking out for the reviewer’s description of something as ‘musical’. That is what music is about not logic. Should not need to be said really…

Or equipment that you simply really enjoy that takes your mind off comparing – ”but this, but that”… that is always a good sign.

Or an album track suddenly ‘making sense’ that never quite gelled before – that is a good sign.

When it comes to music with vocals, I think we are too generous when we say people have different tastes. The voice is either as real as possible or it is not. Too many systems produce voices in a way that is slightly robotic and cold. (Speakers with baffles less than 8 inches wide tend to be poor in this area.) I don’t accept this trade-off !

I sometimes genuinely forget that I have loaned an item from my system such as a DC blocker and filter which would be hidden behind the equipment rack. I absent-mindedly wonder why the soundstage is relatively congested, where the life has gone. Then I remember I have loaned this or that.

Or when you audition something that should be better than what you had. You start by hearing what it does better. Then, maybe through tiredness, you just listen almost subconsciously, half-listening. Then you can really judge if overall it is more musical and enjoyable than what you had before. In other words, when you are not looking for a difference and you hear one that is what counts! Call it subconscious comparison. 

Damage to New Records

by

Record sleeves even with specialist pressings are often made of cardboard and put fine scuffs on the records every time they are removed. This can cause surface noise. E.g. Aldous Harding – ‘Party’ my most recent buy. I have had to buy plastic-lined paper inner sleeves which work well but the original cardboard one doesn’t fit alongside them.

 

Lavardin – Support Furniture Article

by

I LIKE THE HONESTY OF THIS ARTICLE SO I HAVE POSTED IT WITH PERMISSION FROM LAVARDIN.

What is the best rack to put under an amplifier?

A platform for audio components should firstly support the component stably and secondly be itself as neutral as possible.

For this reason, placing components on resonating materials seems like a really bad idea. Some materials which at first may not be suspected of resonating do in fact do so much more than expected: glass, marble, even granite and all minerals and metals have very poor self damping properties and allow vibrations to be stored, amplified and sent back to the component.

The ultimate material is wood. Wood is made of random fibres that conduct energy and reduce it when energy has to pass from one fibre to another. Moreover, plywood behaves much better than solid wood because of its thin crossed layers that allow a maximum dispersal of energy. Chipboard and “medite” powdered wood do not spread energy because they lose the fibrous structure of real wood.

For these reasons, avoid any stand made completely or partially with:

– Minerals, glass, marble, granite, ceramic: dry sound, too much treble, loss of nuances.

– Carbon fibre, compounds, polyester, etc: as above.

– Metal, steel, aluminium, …. loss of nuances, aggressive sound.

– Pressed wood and medite: loss of detail and nuances.

– Solid wood: expensive and not as good as plywood : simplified music, loss of nuances.

– Springs, rubbers, magnets, air chambers: loss of treble, detail and nuances.

From our point of view, combining minerals with metal, rubber and everything else, is not a demonstration of know-how…

As soon as the life of the music is killed by poor sounding audio racks, tonal balance remains the only thing to discuss, sadly…

If you have a solid, well-built, heavy piece of wood furniture supporting your equipment, it has a good chance of sounding far better than most of the Super High Tech Space or Formula One technology ( ! ) options available on the market.

Furthermore, you can add a thick board of plywood under each component for even better results….

4 ohm speakers and effect on power delivery.

by

I often get asked about this and some speaker manufacturers like to avoid stating average impedance when they quote speaker sensitivity…

In 2002, Paul Messenger described beautifully the paradox of 4 Ohm speakers.

‘Over the years, speaker makers have tended to evolve their designs to suit the typical transistor amplifier which is essentially a voltage source with a low source impedance.

Halve the speaker’s impedance from 8 to 4 Ohms and the speaker draws twice the current and power from the amplifier. This extra power gives an increase in apparent (though mythical) sensitivity. Once one manufacturer adopts the strategy, others feel obliged to follow.’

A 4 ohm speaker actually draws 2W when provided the voltage required to provide 1W into an 8 ohm speaker so a 93db 4 ohm speaker is no easier to drive than a 90db 8 ohm one!

‘SME’ RCA plugs.

by

Many years ago I used to curse the overly complex 4-5 piece RCA plugs which were often referred to as ‘SME’ plugs.

I don’t know if SME made them but they were dreadful.

Often attached to arm leads the wires would shear, come loose and cause all sorts of intermittent problems.

The screen wires were trapped by a threaded portion which would soon enough break off the filaments or develop a loose connection.

To my surprise, some Chord cables use a similar design of RCA plug with a plastic outer casing.

My Chord iChord lead has been very unreliable with the centre pins sometimes sticking in the socket and the plastic body sliding off the plug (hence the ugly glue fix) and the same issues with the screen- pinching piece needing tightening and the screen coming detached.

Now, the last straw, the earth has sheared causing a rare drive-unit to be blown…

 

Audioflair

by

There has been some confusion about our status. We never traded as Audioflair Ltd. We applied to be a Ltd Co to protect the Audioflair name but it remained dormant until it was voluntarily dissolved by us in 2016.  I have always been a sole trader and still am.

Vasari Gold Cartridge tested by TONE Audio

by

There’s a new little star in the constellation of our cartridges: the name is Vasari, the sound is…well, just read the review by Jeff Dorgay on this month’s issue of TONE Audio if you want to find out:

“With decent cartridges in the four-figure range, what’s the new audio enthusiast to do? Four words: Gold Note Vasari Gold. And you can get one for $385.”

read the article on the magazine

Gold Note DS-1000 Music Streamer is on 6moons

by

The brand new DS-1000 is our take on music streamers, we suggest to use it in pair with QNAP or Synology NAS and your favourite UPnP music server (like MinimServer) to achieve the best reproduction quality.

You can also use DS-1000 to enjoy TIDAL or Qobuz simply installing the MConnect Player app (see MConnect for iOS and MConnect for Android) on your smartphone and tablet.
Visit www.qobuz.com/goldnote to try the service for free with a 1 Month trial – please remember that Qobuz is not worldwide available yet.  

Now DS-1000 is also on 6moons:

“DS-1000 fears no competition. It is a very complete versatile machine with an unusually extensive upgrade path […] From a sonic standpoint, what else can be said than mission accomplished? Elegance, vividness, resolution, transparency and great dynamics honor the essence of music.”

read the complete review on 6moons.com

Fake Balanced Leads

by

Many balanced leads available in the HI-FI World are not – one earth pin is either not connected internally or bridged in a pseudo-balanced way. Glue-up plug barrel – Hey Presto!

Reflecting back on Stereophile’s Croft Integrated review

by

I have had many Croft Series 7 hybrids through my hands over the years and they do not run hot. They run warm as owners will attest. Yet, when being technically measured by Stereophile, they managed to make the Croft Integrated amplifier run ‘very hot’ and considered it a fair report.

My suspicion is that a music signal is less stressing to some amp topologies than the ‘steady-state one third power signal into a simulated load’ used by the technical reviewers.

So a topology of amp which tolerates this will have a technical advantage over one that does not. Of course, if you like to listen to a single note all the time….

This is one way in which you can achieve the contradictory situation where the reviewers rave about the amp, as occurred with the Croft Integrated, while the technician finds fault.
You can bet the Integrated did not run hot at the reviewer’s houses (before and after the measurements were taken) when sounding so musical.
As is often the case their testing is not what they think it is. If it ran hot on test bench they were overloading it in some way and inducing distortion.
The trouble with this kind of ‘science’ is that readers of such reviews tend to feel obliged to bow to the measurement facts unquestioningly.
Many years ago Glenn Croft said, ‘When you know what you’re measuring, measure it!’
It seems the measurements were taken from the Tape Out rather than the speaker outputs which would have loaded-down the amplifier’s output and induced the 6db roll-off.
Let’s not forget that Total Harmonic Distortion is also overstated as many Jap amps had vanishingly low figures such as 0.01% distortion and sounded rather thin and unengaging in reviews. In the meantime most speakers distort by about 33%…
If you prefer a more objective perspective regarding magazine technical measurements, Steve Elford of Vertex AQ cites that:
“Fourier transform theorem or FFT software is the wrong way to measure because it’s in the frequency domain and is an iterative process over time so you only see the presence of constant sine waves. By analysing the signal in the time domain, only then can you see the tracking error.”