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")
