Sugden A48 amplifier (1973)

The A48 integrated stereo amplifier is a "Luxury" development of the A21 amplifier. It is in many ways similar , almost identical in size and appearance , except for the 10 buttonn push button banl instead of 6. briefly the facilities are varied as follows:

Power Output

Doubled to 40 W RMS per channel ( 80 W from both channels simultaneous operation)

Filter Facilities

L.F. filter - switchable and operating on all inputs with a terminal slope of 18 dB/octave

H.F. filter - single turnover point and slope replaced by three turnover points of 4 kHz, 7 kHz and 10 kHz with a choice of two slopes -6 dB or 18 dB/octave

Disc Input Sensitivity

A further sensitivity position of 10 mV is available in addition to the 2,5 mV position to cater for such high output cartridges as the ortofon with transformer. The overload factor also increases by the same scale of four.

Quiet Facility

A switch position providing a quiet listening facility with an attenuation at mid frequencies of 16 dB only 8 dB low frequencies with the response contoured to the difference in the equal loudness curves of the ear. This facility, where normal volume is set and then 'quiet" selected is to be preferred to the so called :loudness" compensation of a volume control which has no relevance to the incoming signal level.

Specifications

Power Output: 40 watts RMS per channel(both channel driven at clipping  level into 8 Ω)

Total Harmonic Distortion:  less than 0,1% mainly 2nd and 3rd harmonic, negligible proportion of high order harmonics and reducing in proportion with reducing power

Frequency Response:  30 Hz - 20 kHz ±1 dB

Output to Tape Recorder:  Direct connection from radio and aux, input, 200 mV from disc amplifier when correctly loaded at average modulation

Input Sensitivity (25W level 8 Ω):

Radio, Tape, Aux :  100 mV into 200 k Ω flat response

Phono Magnetic Cartridge:  2,5 mV into 47 k Ω equalized RIAA standard

Overload Capabilities:  100 mV on magnetic disc input; infinite on radio, aux, tape

Signal-to-Noise Raatio (30 phon weighting): 

Radio, Tape, Aux :  80 dB

Phono :  70 dB

Interchannel Crosstalk:  typically 40 dB 20 Hz - 10 kHz, dependent upon input load impedance

Rumble Filter:  Buil in on disc input, 12 dB/ovctave below 30 Hz

Control Knobs:

Bass : ±14 dB at 40 Hz

Treble :  ±14 dB at 10 kHz

Volume :  logarithmic (Channel balance ±1 dB maintained to 40 dB attenuation)

Balance :  ±6 dB for 180° rotation, either channel eliminated at limits of rotation

Push Buttons to select

Inputs :  Disc, Radio, Aux, Tape

L.F. Filter :  18 dB/octave below 70 Hz

H.F. Filter :  turnover 4, 7 or 10 k Hz, slope 6 or 18 dB / octave

Function :  Mono, Stereo, Input Right, Input Left

Power Consumption:  140 watts max

Dimensions (W x H x D):  400 x 130 x 230 mm (15-1/2" x 5" x 9")

Weight:  11 kg (24 lbs)

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