A deceptively simple high quality single stage design followed by an output buffer. But what makes the LA4 III special is the power supply and our “finely tuned” design. A high end pre amplifier must have the best power supply. The LA4 MK III has two chokes in double Pi configuration for well conditioned power giving superb smoothing for velvety inky black silence. The rectifier valve, which makes a surprising difference, is the excellent GZ34. This outstanding Western Electric design is probably the best sounding power valve available.
The three audio valves we use are the 6SN7 double triodes. This 1940 vintage valve has all the best characteristics for the job, and its larger size means long life and good stability. Also the sound is more musical as we feel these have a more fluid sound. You can experiment with both vintage and modern types.
Built to last
Like all our equipment the LA4 III is very solidly made. It has a heavy alloy and steel chassis. The internal wiring is all “point to point”, “hand wired”, this is essential for valve amplifiers, and allows for upgrading to larger capacitors, and makes future servicing very simple.
Very simple high quality line pre-amp. Ideal for virtually any kind of power amplifier.
Specifications and Features
Comprehensive manual supplied
All hand wired point to point without PCBs
ALPs motorised volume pot.
All Triode design
3x 6SN7 valves (CV181)
Adaptors available for 12AU7/ECC82
GZ34 Valve rectifier (also 5AR4/274B)
Double Choke HT supply
DC heater supply
Signal to noise level -90db
Freq response 20hz-20khz +0 – 0.1db
Total harmonic distortion typically less than 0.1%
Gain x4, 12db
Max input level 5v for 20v output#
Very low output impedance of 100Ω
Suitable for power amps 100mv-5v sensitivity
Attractive valve cover available (£50 extra).
High quality 2w metal film, & wire-wound resistors
Solen/SCR audio capacitors (Jensen upgrade option)
Silver PTFE audio cable
Gold plated Input terminals
Four line inputs
Tape monitor circuit and record output
Optional plexiglass valve cover available
C E compliant
25cmW, 37D, 23H (with 274B and cover), or 17H with GZ34 (no cover) 12kg packed#
(Specifications subject to change, errors & omissions excepted 06/07/18)
Various valve and capacitor upgrades are available