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               NEW PRODUCT.
  
 Entry Level Stereo Mosfet Amplifier Kit.
    Constructed to a high specification and standard of finish QTA's entry level
mosamp provides the ideal solution to those wishing a hands on experience in amplifier construction without the worry of full electrical / mechanical involvement.
    The main amplifier boards are pre-assembled and tested prior to shipping and a low component count 420VA power supply completes the assembly.  For the more adventurous, blank unpopulated boards and circuit layouts are available for full DIY involvement. All components and boards are mounted on a separate pre-punched and folded internal chassis form, constructed from 2.4mm aluminium. The outer casing bolts to the inner chassis, the side panels being in 2.4 Aluminium whilst the top, bottom and rear panels are in 18SWG steel. The main casework is finished in Fine Black Texture  paint. The rear panel is yellow zinc passivate. Fitments include gold plated RCA (phono), input sockets,  four output terminal posts per channel to facilitate ease of bi-wiring and parallel wired Speakon sockets to complete the line-up.
         Front panels can be provided in 19" rack mount 3.2mm NS4 grade Aluminium or 17.1", 12mm veneered and hardwood lipped MDF. Standard supply is 19" rack mount. Printed circuit boards are on high grade 2.4mm, 3oz Copper FR4 board, single sided design with full, screen printed legend / component layout.
    Mirrored input circuitry is used for good distortion  performance with DC offset monitoring using CMOS logic. High grade caps used throughout.
    There is the option of one or two pairs of output devices per channel, two pairs  provides for better distortion performance,  damping factor and low impedance drive capability,  but one pair is sufficient. Note, two pairs do NOT give higher output power unless the transformer is uprated along with other circuit components.
    Heat Sinks are drilled and tapped to provide location for 3 * TO126 / TO220 devices and 4 * TO3-P Power output devices. Available for other projects, (60*160*40)mm, 0.8W/C approx.
    We assemble and test the main power amp boards, you do the rest; Build power supplies, mechanical assembly, interconnect wiring and final set-up etc.
    Most parts are available separately including pre-built boards, heat sinks, chassis components and electrical items.
        As mentioned all external panels to form a finished professional looking case are screwed / bolted to the inner tray. Of course, if you want to do your own thing on casework it's your choice but metal bending / punching / finishing  is expensive so.... Top & bottom panels feature vertical airflow arrangement for Output stage cooling. 

DATA:-  Stereo amplifier Class B.
                    Single power supply +/-42V @ 420VA total, unregulated.           
                        Power output 60Watts rms into 8 ohms Load, conservatively rated. 
                            Minimum Safe load speaker impedance,  4 Ohms nominal.
                                Distortion, THD Less than 0.05% over 20hZ TO 20Khz
                                   Power Band 15Hz to120Khz @ -3dB points.
                                        DC Offset. Less than 30mv after warm-up, Trimable to
                                         nominal zero.
                                            Speaker protection. DC trip, Load disconnect on fault
                                               condition.
                                               Resets to operate on fault removal. 
                                          Requires input Level Control (pre-amp, digital output level
                                        control etc.).

The Pictures show the basic layout. Please note, the illustration features a twin power supply and not the single version .Other features are similar.

         Note;- There are a limited number of development boards available for the main amp PCB which require a small amount of rework i.e. hole resizing for diodes and PCB pin insertion to accommodate changes in output devices etc. A bit of leg bending, (crossover) etc is also required. These are supplied with layout diagrams, circuit  and component listing. You forage for bits and do your own thing, you also get to find out which holes are undersize too. We can help out in this area for most parts but please not one resistor at a time eh!. They do not have on-board DC monitoring / offset protection like the production boards although a small circuit diagram which will do this job is included in the paperwork. You use it as an add-on Board etc. or indeed design your own. The PCB (singular) plus documentation costs £18 inc postage. Limited assistance is available to trouble shoot on this one, i.e. It's very nearly 'real' DIY but also good fun so.......

PRICES:- GBP inc VAT,  Carriage Extra, See below.

 

PART No.	QTA Entry Level Stereo Mosfet Amplifier  Components.	Price GBP
A000	Complete Kit, Built Amp Boards, PSY Parts, Casework with C006 front panel, Plugs, Sockets, Wire n Stuff, documentation.	591.00 ea
A000A	Main Amp PCB Board + Components + Single Set Output Devices + Documentation, No Heat Sink. Do your own thing. You need a sink around 0.8C/W and +/-35V DC Rail Voltage to get it going.	82.00 ea
A001A	Kit for Raw Power Supply, makes one PSY, unbuilt, includes Transformer, PCB, Budget Caps, 35A Bridge Rectifier, Snubber caps, Fuseholders, Fuses, Power Resistors, Inner assembly tray. Documentation.	108.00 ea
A002	Main Amp PCB's, Built and Tested, includes Heat sinks	135.00 ea
A002A	As per A002 But with 'Two' sets of output devices per channel.	148.00 ea
A003	Complete set of Casework, Includes all button head bolts and nuts for assembly. Fine Texture Black. Yellow passivated steel rear panel.	134.00 set
A004	Sundry Fittings: RCA Phono sockets,4 Pairs output terminals + Mouldings, Earth terminal + Mains Switch, Fused Input socket, Cable, Rubber boots, Nuts and Screws etc.	49.00 set

 

Issue 2:- Last Modified 15 June, 2007

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