alner hamblin electronics ltd. sp400 passive preamplifier

ALNER HAMBLIN ELECTRONICS LTD.
SP400 PASSIVE PREAMPLIFIER
Owners Instruction Manual
ALNER HAMBLIN ELECTRONICS LTD.
3 BOULTONS ROAD
KINGSWOOD
BRISTOL
ENGLAND
BS15 1RU
Tel/Fax
+44 (0) 117 9614239
E-mail
alner@globalnet.co.uk
1
Design Philosophy
The SP400 is not strictly a Pre-Amplifier in that it does not provide any
Amplification. It would be more accurately described as an Input selection unit with
adjustable attenuation.
The SP400 was designed to provide Source and Recording selection, together with
Level adjustment for the SA400 Semi Digital Amplifier. The design objective was to
provide Source selection and Level control that would introduce as low a distortion
and noise level as possible. To reduce distortion and noise to its lowest possible level,
it was necessary to eliminate any electronics or reactive components in the signal path
together with any power supplies that would be needed. By removing the mains
transformer there is also one less system component, which could contribute to Hum
Loops.
The SP400 uses just three basic Components: Input and Output Sockets.
Level Control.
Rotary Switches.
All of the above components are the highest quality available to ensure that no
additional noise or distortion is added to the Input Signal when applied to the SA400
Amplifier.
Equality of channel level is most Important for High Quality Audio Equipment, which
has to be better than +/- 1dB. The manufacturers of Level controls in general will only
guarantee this level of matching from approximately 30% to 70% or 10 o/c to 2 o/c.
The gain structure of the SP400/SA400 combination ensures that the Level Control
for normal listening will be in this range.
A disadvantage of the Passive design approach is that the Output Impedance is
somewhat higher than that of an Active (Electronically Powered) Unit. Consequently,
to avoid High Frequency attenuation, attention to Output cable Length and Capacity
must be observed. The Frequency Response Table in the specification shows various
cable capacities and lengths at the worst-case position of the Level Control. Ideally of
course, the SP400 would be mounted beneath the SA400, and, in this position; even
the highest cable capacities will still ensure a frequency response to over 70kHz.
High quality Screened cables must be used to interconnect the units.
As the unit has no powering of any kind, remote control is not possible. The SP400
has nevertheless, a Standby Switch that will put the SA400 into Standby Mode.
2
Specification
Gain (Maximum): -
1 (0dB)
Separation (2Hz – 20kHz): -
>50dB
Frequency Response. (-3dB): - (Length of Output cable versus capacity per metre)
Length of cable
Cable Capacity per metre
0.5m
1m
2m
4m
100pF
796kHz
398kHz
199kHz
99.5kHz
500pF
159kHz
79.6kHz
39.8kHz
15.9kHz
1nF
79.6kHz
39.8kHz
19.9kHz
9.9kHz
The above figures were measured with a load of 20k Ohms.
Output Impedance (Worst case): (Assuming a Source Impedance <150 Ohms)
5k Ohms
Channel matching (12o/c): -
+/- 0.2dB
Attenuation at 12o/c: (Assuming a Source Impedance <150 Ohms)
16dB (Open Circuit Load)
18dB (10k Ohms Load)
Inputs: -
5
Outputs (Main): -
2
Outputs (Record): -
2
Tape Loops: -
1
Dimensions (Including Knobs): -
D 340, H 95, W 445 mm
Weight: -
Net
Packed
6kg
8kg
E. & O.E. The policy of Alner Hamblin Electronics Ltd. is that of continuous design
and development. We reserve the right to change specifications without prior notice.
3
Cleaning
Use a soft damp cloth to clean the unit.
Do not use cleaners or solvents.
Do not use an abrasive cloth.
Guarantee Registration
Your Alner Hamblin SP400 Pre-Amplifier will be guaranteed free from defective
parts and Labour costs for two years from the date of purchase. Return carriage will
be chargeable.
Please complete the Guarantee Registration Form and return it to the address shown
for Inclusion on our database where we document the complete Service/Repair history
of your Pre-Amplifier. You will also be notified of any new products or upgrades that
may become available.
Should your Pre-Amplifier require repair or service, please return to the address
below in its original packaging. Pre-Amplifiers not returned in their original
packaging will have a new set of packaging substituted, which will be chargeable.
This Guarantee does not affect your statutory rights.
Your personal details will not be released under any circumstances to a third party.
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Alner Hamblin Electronics Ltd.
3 Boultons Road
Kingswood
Bristol
Tel. +44 (0) 1179 614239
England
Fax. +44 (0) 1179 614239
BS15 1RU
E-mail.
alner@globalnet.co.uk
Guarantee Registration For
Alner Hamblin Electronics Ltd.
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