Gazember serviced and fully upgraded

DUAL MONO QUAD 303

Excellent cosmetic condition (minor scuffs)

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160 Watts RMS per channel into 4 Ohms

80 Watts RMS per channel into 8 Ohms

(Standard 303 is rated at 28 Watts RMS into 4 Ohms and 45 Watts RMS into 8 Ohms)

including all cables

photo quality copies of the handbook

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TWELVE MONTH PARTS AND LABOUR GUARANTEE

RETURN WITHIN 30 DAYS IF NOT DELIGHTED

FULL REFUND LESS EBAY AND POST COSTS

Very good Condition - minor scuffs

The Gazember design changes release the peak power available from a Quad 303 in order to play music with a wide dynamic range at realistic levels rather than to heat resistors by playing sine waves (the method used by Flat Earthers to assess amplifier quality - I recommend listening to music rather than the crackling of an overheated resistor).

The peak output power levels are true RMS power but unlike the standard Quad 303 which can be run at 45 Watts with the outputs shorted (max power allowed by the limiting circuits - see the graphs below)  - "Gazember" amps CANNOT be safely shorted at high power levels nor are Gazembers designed to be run flat out with sine waves feeding heating coils instead of speakers. 

Gazember power output is assessed exactly like the high power C Series NAD amps which quote the increased power delivered into lower loads as "IHF dynamic power".  Using NAD's terms - the Gazember can produce 160 Watts of IHF dynamic power into 4 Ohms.

Check a typical NAD spec at http://nadelectronics.com/products/hifi-amplifiers/C315BEE-Stereo-Integrated-Amplifier/specs

Dual mono power supply utilising a 9 amp bridge rectifier bypassed with Schottky diodes (per channel) giving a significant improvement in stereo presentation.

Supply voltage stabilisation limits an amplifier's ability to deliver peak transient current so the power supply voltage regulator board and transistor have been removed (Quad fit the regulator and limit the current to protect their Electrostatic speakers).

The highly rated Quad 50E and Quad 405 amps do not have power supply voltage stabilisation - neither does the Gazember 303.

A further weakness in the Quad power supply design is that all of the power dissipated by the four output transistors is supplied via the single supply transistor - removing the supply transistor reduces the power supply source impedance and halves the heat output from the amplifier at all output levels with the result that a Gazember runs cooler than a standard 303 and heat dissipation is well within Quad's original design limit.

The driver board earth loop resistance has been reduced and the amplifier output impedance has been halved - further reducing the heat output from the amp and giving the amplifier significantly better control over the speaker coils.

Each of the two 2200 µF power supply capacitors have been reconditioned and bypassed with one low ESR 2,200 µF electrolytic plus a metallised polypropylene capacitor to increase the peak current delivery at all frequencies.

Each of the two 2200 µF output capacitors have been  replaced with four low ESR 2200 µF capacitors plus a metallised polypropylene capacitor to improve the mid and high frequencies and to increase the peak current delivery at all frequencies.

The increase in output capacitance from 2200 µF per channel to 8400 µF per channel allows full power to be maintained down to below 20 Hz instead of the usual drop off starting at 70Hz - giving a deeper, tighter and more dynamic base.

Output transistors are replaced with high power modern equivalents to enable reliable delivery of 160 Watts RMS and entire Gazember comes with a 12 month parts and labour guarantee

The Gazember 303 amp is not designed to work safely with Quad electrostatics - the peak output voltage is too high - I can provide ESL Gazembers that can work safely with Quad electrostatics by reducing the amplifier line voltage.

The Bridged Gazember has a single power supply and larger output capacitors

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