LA3 Line Level Pre-Amplifier
Shown here without the supplied attractive cover.
A versatile smooth sounding line Pre Amplifier hand built
Designed to partner almost any quality power amplifier including vintage or
modern, valve or transistor and transistor. The LA3 is designed bring your music to life.
The LA3 uses a very high quality power supply incorporating the classic ‘Pi’ HT filter with
a valve rectifier and choke for that sought after ‘Inky black silence’.
Class ‘A’ Sound
We use half a 12AU7 and a 12AX7 per channel, both double triode valves. The LA3 has an
extended frequency response with a smooth warm sound, and the enormous overload margin
means that it will handle the dynamics and transients of the most demanding input source.
Our philosophy is to keep things simple, that way the delicate audio signal has the shortest
path and less chance of degradation. Circuits like tone controls, filters, balance etc can affect
the sound even when not in use, so we don’t incorporate them. Internal wiring is silver audio
cable for the best sonic performance.
Why should I buy a valve amplifier?
Valves make ideal amplifiers in contrast to transistors, their simplicity means that they have
a smoother, open sound that is more involving and musical.
Will it work with my equipment?
Yes the input requirements are no different from any other amplifier. You will need a phono stage
if you are using a turntable.
What kind of sound does it have?
The LA3 offers a very open transparent detailed sound, which is warmer, and more involving
than solid-state counterparts. The sweeter treble makes for very easy listening, whether jazz,
classical or dance music. You can expect to hear a more detailed three-dimensional
soundstage with less confusion in complex passages. But above all a total absence of ‘Listening
Fatigue’, we guarantee you will not get tired of listening to our amp!
The LA3 is all ‘analogue’ and sounds great with LP’s, FM radio and tape, but it will also help
‘calm’ digital sources such as CD, MP3, NICAM TV, DVD sound.
How is the LA3 constructed?
The chassis is polished stainless steel, chosen for its nonmagnetic neutral sonic qualities.
The front & rear plate is
10/6mm solid anodised alloy plate. The steel transformer housing has an enamel crackle finish. The two
transformers and choke are encased in resin to minimise noise. Inside the chassis is a painted steel sub chassis.
The knobs are gold plated alloy. It is supplied with a very attractive valve cover, (see photo).
The chassis structure is resistant to unwanted vibration. Unlike amplifiers with printed circuit boards, all major
components are secured to the chassis. Note the use of ‘Hard Wiring’ ‘Point to Point’ and not
printed circuit boards or even tag boards that some of our more expensive competitors use.
This method of high quality construction ensures the shortest signal paths, with low impedance, low capacitance
&, low inductance signal paths. This helps to give a clean sound quality with low hum & noise.
Nothing gets hot under
the chassis and therefore component life is prolonged.
This gives you an amplifier with excellent performance that has superb build quality, is easily
upgraded and should last a lifetime.
Input and output terminals are gold plated. We use the famous ‘Alps Blue’ volume control
Electrolytic capacitors are only used in the power supply.
High quality polypropylene caps are used in the signal path. Resistors are oversized 2w metal oxide and wire
wound chosen to suit their application. The volume control is the famous blue ‘Alps’ potentiometer,
chosen for its superior sound quality. The unique attractive cover made from stainless steel and
high density Perspex gives added protection for more vulnerable situations whilst retaining good looks.
Please note that the reflective surface of the stainless steel chassis and cover appear to take on the colour of their
surroundings in the photos, but are in fact neutral in colour.
Is it easy to get replacement valves?
The valves we use are still in production and available from many sources including us. Cost is approx £40 for a set.
How often do they need replacing?
With an approximate life of up to 6,000 hours, that would give 3 hrs a day for 5 years.
The Design
We have kept the design relatively simple using popular easily available valves. Valve technology has been around
for a long time now, with excellent designs produced from the early 1950’s notably by the likes of Mullard & GEC
(who developed most of our modern valves). And whilst there are many excellent valve amplifiers available at
premium prices, our aim is to market a quality amplifier that is excellent value.
Our amplifiers like many of our expensive competitors are assembled in the far east, to our specification by an
experienced company, using high quality components from all over the world. The final testing and set up is done in Leicester U.K.
The standard rectifier shown left is the indirectly heated GZ34. Also available is the older 5Z3 directly heated
rectifier (above left) as an alternative. No modification is required. Please note that the height of the 5Z3 is to tall for the valve cover.
What is so special about Valve Amplifiers?
Transistors are a great current switching device used in TV’s, computers and digital equipment. They are small,
easy to mass-produce and very cheap. So it is not surprising that most hi fi amplifiers use transistors, (or microchips).
But many people believe that hi fi amplifiers using valves are better, for all sorts of reasons,
Although transistor amplifiers specifications look good on paper, but many people find that they have a ‘dry’ ‘clinical’
sound that is uninvolving and gives rise to ‘listening fatigue’ which takes some of the joy out of listening to music.
Therefore in more enlightened times when people are listening to more subtle qualities in audio possibly with
better recordings and speakers, many people are discovering that valve amplifiers are a better solution.
Transistor Switching
The output stage of many transistor amps involves ‘two transistors switching on and off, many people think that
they can hear this as an unpleasant ‘harshness’. None of the valves in the LA3 ever ‘switch off’
this contributes to the smooth musical, yet accurate sound.
Greater Headroom
Music is incredibly transient with a huge dynamic range of very quiet sounds to very loud. Transistor amps get very
distorted very quickly when they run out of power, this is one of the reasons why transistor amps need to be so
powerful. Transistor distortion is very unpleasant. On the other hand valve amps have lots of ‘headroom’ by which
they run into distortion gradually and valve distortion is more benign and gentle on the ear. Therefore valve amps
only need to be half the power of transistor designs, yet sound just as loud!
Can I use a turntable?
Yes but you will need a phono pre-amp. We have not included a phono-pre amp in the design
as not every one uses vinyl and you may prefer to choose your own.
Total price of LA3 Pre-amp £599.95
Specifications and Features
• No printed circuit board or tag board
• Japanese Blue ALPS volume pot.
• All Triode front end
• Valve rectifier, 5AR4 (GZ34) or 5Z3
• Choke power supply
• 2x 12AX7 (ECC83) Double triode
• 1x 12AU7 (ECC82) Double triode
• Signal to noise level -90db
• Freq response 7hz-150khz + or -0db (we mean it!)
• Total harmonic distortion 0.02%
• Transformers custom wound with Japanese high grade long grain steel with low oxygen copper
• Attractive cover included in the price
• High quality 2w metal film, & wire-wound resistors
• Blue LED mains indicator
• High grade polypropylene audio capacitors
• Internal audio wiring using audio grade silver cable
• Ceramic valve holders for minimum leakage
• Centre tapped heater circuit for minimum hum
• Pre-amp 6.3v heater circuit floated at 60v to minimise heater-cathode leakage
• Polished stainless steel chassis
• 10mm solid aluminium front plate
• Crackle finish enamel painted transformer cover
• Transformers & choke fixed in resin for low noise.
• Gold plated Input & output terminals
• Inputs for CD, Tuner, Aux, Phono pre-amp
• Tape monitor circuit
• 200mv input sensitivity
• Designed to match power amps with input sensitivity between 200mv to 2.5v. (High & low level outputs)
• Maximum output 30v (Output 1), 6v (Output 2)
• Output Impedance 100k
• 230/240volts, 35watts 1A anti-surge fuse
• C E certified
• 220W(280), 180H(210) 360D(430) 8.5kg with 5Z3 180H(210) (figures in brackets allow for rear connections & ventilation)
(Specifications subject to change, errors & omissions excepted 09/04/05)
