Stereo Vacuum Tube Amplifiers

Hi-Fi Valve Amplifier

        The photograph below shows a 'one tuber' - a single ended, stereo, power amplifier utilizing just one 'spud' per channel.  Designed exclusively by a member of our audio engineering crew, this model, which is hand crafted in the U. K. & produced to order, is of the type in which just three components lie in series with the audio signal path to attain near optimum musical reproduction.  The output transformers * (also designed in-house) are of premium grade, British made, each with its windings elegantly interleaved in several sections to secure adequate magnetic coupling.  The amplifier can comfortably deliver an average power of 5W ** into a pair of 8 ohm loudspeakers & has an input sensitivity of 1Vrms.***  The design is such that the second harmonic component is promoted whilst all higher order harmonics are attenuated; the overall characteristic sound reproduced by the unit has been likened to that which was once ubiquitous during the era of vintage wireless...reminiscent of bygone times. 

        Note that the product described is a chassis assembly & as such will require an appropriate enclosure - see below for further details.  We have recently introduced an attractive, smokey grey, tinted glass plinth & cover in response to customer inquiries related to enclosures (See 'Photo Gallery'...17 to 24).

        We offer the options of anodized black chassis, & 4 ohm output impedances.  We also produce a 'Tetrode Tube Amp' version.

        The amplifier can be driven directly by a laptop computer, a disc player with integral volume adjustment, a solid-state micro dukebox or the audio outputs of a television set.  For vinyl record playback, a suitable pre-amplifier comprising RIAA equalization is required.  A high quality lead & connectors should be used to couple any chosen source to the amplifier.

        The electronic component parts of the assembly are connected by method of point-to-point & its physical shape is such that it could sit neatly on a bookshelf.  Solid carbon composition resistors are used with good reason.  Please visit the 'Photo Gallery' to view some examples of the product described.

        Liquid insulating tape is applied to the transformer terminals prior to dispatch (See 'Photo Gallery'...9 of 24).

        Power Bandwidth (DIN 45-500):  2.5Wav + 2.5Wav over 30Hz to 16KHz into 8 ohm loads with 3Vrms input signals. 

        Defined by the output transformers, the upper cut-off frequency quoted is adequate for low power, hi-fidelity amplifiers & allows for betterment in other areas of output transformer design.  We find no perceptible furtherance in having power bandwidths extending beyond the audible range.  Use of fine quality materials & good design techniques are the key to achieving best results.

        Zin:  > 150000 ohms.

        Feedback:  0dB  (decreasing distortion complexity).

        Tube Biasing Method:  Cathode. 

        Output Transformer Lp 24H @ 30Hz. 

        D. C. Fuse250mA, anti-surge.

        Power Consumption:  55 Watts.

        The power supply RC filter reduces ripple voltage to 1/30 of that across the reservoir capacitor.


                            NOTE THE FOLLOWING: HIGH VOLTAGE WARNING!

        The entire assembly is constructed on an aluminium chassis & delivered thus (as shown) within 21 days of purchase.  Under no circumstances should the unit be operated in this rudimentary form owing to exposed live parts measuring in excess of 300 Volts.  The product has been designed specifically to be set in a personalized enclosure as desired by the individual purchaser - so making the overall finished article unique in appearance & safe to operate.  We do not provide this service.  A qualified technician must undertake to complete the installation prior to operation of the amplifier in order to ensure users' safety, albeit we have no objection in giving some related guidance.  Adequate venting is important.

        Unit dimensions:  W 14 3/4" (375mm), D 4" (102mm),  H 4 3/4" (121mm).

        Input socket:  5-Pin/180 DIN (preferred over RCA for earthing considerations).

        Loudspeaker sockets:  2-Pin DIN.

        The amplifiers are sold without vacuum tubes (type EL84 & type 6V6GT).  We leave brand selection & other tube preferences to each individual purchaser, since they all have their personal favourites; however note that 'one tubers' are highly sensitive to vacuum tube performance - we have experienced vast, all 'round improvement in sound quality when utilizing premium grade n. o. s. tubes.

        Cosmetically, each subsequent assembly may vary somewhat from that pictured below; parts are sourced from different, selected U. K. suppliers/manufacturers depending on the delivery times quoted for any given order; quality however is never compromised. 

        A one year warranty is given, covering any production defects, & every unit is tested prior to being packed & dispatched.  Postage is recorded/tracked.  We sell this product to U. K. residents & export to limited, selected destinations - Spain, France, Italy & Greece.  The chassis come complete with a UK 3-pin, fused AC mains plug connected.  Export buyers are required to replace this with (or adapt it to) a Schuko (Type F) or for operation in France a Type E.  Good earthing is essential!

        Our objective is to contribute the principal constituent of what will become a uniquely personalized, fine sounding, high quality, audio component.

        If not completely satisfied, a customer may return his amplifier within fourteen days of shipping for a full refund.  The assembly must arrive back in pristine condition; & please note, we do not refund the return carriage.

       Whilst a high degree of care is taken during the crafting of each assembly, aluminium is highly susceptible to tarnishing & marking through surface contact; we take all possible steps to minimize these throughout the construction process.  

        To purchase one of our vacuum tube amplifier assemblies, please select 'Buy Now - Tube Amp.'.  The price of a single assembly is £490, which includes packing & postage charges.  The sum of £30 will be refunded to every U. K. buyer shortly after making their purchase, since £30 is the standard export shipping charge to continental Europe.  When making your purchase, please specify which model has been selected, ie. EL84 or 6V6GT. 

        Do 'Contact' us with any questions you may have.

    *  Select 'Output Transformers' for further details.

   **  Select 'Audio Power Output' for more information.

 ***  For (in our opinion) best tonal quality (as a result of additional, hysteresis generated harmonics) yielding            350mW.



                                                                                                                    Grippeaz-UK / Ilissus Audio