Insignia CUSTOM 50 User manual

INSIGNIA HiFi
USER MANUAL
CUSTOM 50 Tube Amplifier

INTRODUCTION
This amp head is made by taking inspiration from vintage hand-crafted amplifiers made
by Dave Reeves. A look inside the amplifier will immediately bring your attention to
the hand-wired assembly & point-to-point wiring philosophy used. Needless to say this
gives unmatched robustness to the amplifier. The Power transformer used in the
amplifier is unconventional to the Guitar amps, as it is a Toroidal transformer custom
made by one of the best transformer manufacturers in India. These transformers are
common in HiFi as they are inherently noiseless & there is no leakage field outside. The
components are carefully chosen and hand selected with 2-3 time overrating to further
enhance the robustness. The chassis is made out of Aluminium sheet to ensure rust-free
life and excellent shield to noise due to external electromagnetic interference. The entire
amplifier is made with ultimate care and by a single person and we trust it will give you
ultimate sonic pleasure and glitch-less operation for many decades.
You are requested to go through this document well to ensure you adhere to safety
instructions and maintenance of the amplifier.

BEFORE OPERATING THIS EQUIPMENT
SAFETY IS MOST IMPORTANT ASPECT AND IN NO CIRCUMSTANCES IT SHOULD BE
OVERLOOKED. THIS IS A VALVE AMPLIFIER AND BY DESIGN IT CONTAINS VERY
HIGH VOLTAGES EVEN AFTER IT IS UNPLUGGED. IN NO CIRCUMSTANCES IT
SHOULD BE OPERATED BY THE USER WITH THE BASEPLATE REMOVED. THE
TRANSFORMERS AND VALVES SHOULD NOT BE TOUCHED WHILE THE AMPLIFIER IS
POWERED.
1. This amplifier is designed to operate at 220-230V, 50Hz ac, ensure the voltage
levels and frequency before turning it on.
2. Ensure that the power supply has proper ground. You can test the supply outlet
with fault tester to ensure the same.
3. Make sure you connect the speaker system of correct impedance (4 or 8ohms) in
the designated outputs.
4. There are 2 fuse sockets installed, one for Mains & one for HT. Boith are rated
at 1 A Slow Blow type, make sure you do not used fast blow type fuse.
5. Before turning on the amplifier make sure the standby switch is OFF. Turn it on
only after the tubes warm up, typically 30 secs at least.

DOs and DON’Ts
DO
Always keep the standby in OFF position while powering on
Always keep the standby in OFF position while amplifier is not in use for a
short time and you want to resume playing shortly and you intend to keep the
valves warm.
Always check the input voltages
Always check the correct speaker impedance
Always keep a track & monitor the health of output valves (EL34s).
oIf the tubes show red-plating or they have become too old (2 years) or
they have turned microphonic then replace with matched pair of EL34s
Time-to-time (Typically weekly) monitor the bias voltage at the back (Red
terminals), they should be less than 35-40mV.
Do have the amplifier serviced quarterly by a qualified technician
DON’TS
Never attempt to modify or repair the amplifier in any manner
Never allow a third person to change anything on the back panel
Never touch the valves/transformers or open the baseplate while the amplifier
is in ON state or valves are hot
oIn case you need to inspect the amplifier keep the power cable plugged,
power switch OFF & Standby switch ON
DO NOT attempt to clean the amplifier while it is ON

TECHNICAL SPECIFICATIONS
Design: PUSH-PULL
Power Tubes: El34
Preamp Tubes: 3 x ECC83 (12AX7)
Phase-Splitter Tube: ECC81 (12AT7)
Controls:
oNormal Volume
oBrilliant Volume
oBass
oTreble
oMid
oPresence
oMaster Volume
oMains Toggle Switch
oStandby Toggle Switch (HT)
oBias Adjustment Trimpot
Fuse Rating
oMains: 1A Slow Blow
oStandby: 1A Slow Blow
Output Impedance
oDefault: 8 OHMS
oOptional: Selector switch with 4/6/8/16 OHMS
Input Power: 160VA
Output Power: 50W (max @ 50 mA Cathode Current)