KAHAYAN Proaudio 12K72 Series User manual

12K72
STEREO AND MONO MICROPHONE PREAMPLIFIER
OPERATOR'S MANUAL
Version 1.0
Avd. de la Estación 4, local bajo
Zarzalejo, Madrid 28293
Spain
[email protected]
www.kahayan.es

2
TABLE OF CONTENTS
IMPORTANT SAFETY INSTRUCTIONS…………………………………3
INTRODUCTION…………………………….……………………………..4
USE AS A MICROPHONE PREAMPLIFIER……………………………..5
RECORDING ELECTRIC INSTRUMENTS ..……………………….……5
USE AS LINE AMPLIFIER INSERTED IN THE STEREO MIX……….…6
POWER SUPPLY…………………………………………………………..6
SPECIFICATIONS & WARRANTY.……………………………...………..8
RECALL SHEET…………………………………………………………….9
CREDITS…………………………………………………………...………10

3
IMPORTANT SAFETY INSTRUCTIONS
1. Read these instructions
2. Keep these instructions
3. Heed all warnings
4. Follow all instructions
5. Do not use this apparatus near water
6. Clean only with dry cloth
7. Install in accordance with the manufacturer's instructions
8. Do not install near any heat sources such as radiators, heat registers,
stoves, or other apparatus (including amplifiers) that produce heat
9. Protect the power cord from being walked on or pinched particularly at
plugs and the point where they exit from the apparatus
10. Only use attachments/accessories specified by the manufacturer
11. Unplug this apparatus during lightning storms or when unused for long
periods of time
12. Refer all servicing to qualified service personnel. Servicing is required when
the apparatus has been damaged in any way, such as power-supply cord or
plug is dam- aged, liquid has been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to rain or moisture, does not
operate normally, or has been dropped

4
INTRODUCTION
The 12k72 is a high class preamplifier which contains a ‘module’ per channel.
The main feature of these ‘modules’ is a sound completely clear and
transparent, with deep bass and an extremely natural treble.
The components used in manufacturing come essentially from the same
manufacturers that supplied the ones used originally, reproducing and
expanding the benefits of these. Everything inside this preamplifier is high
quality: the wires, rotary switches, capacitors, resistors and connectors.
STAGES
The 12K72 is formed by two stages, the first gain stage is set with a Gain
control, while the second stage remains fixed.
The Output control regulates the amount of signal passing from the first stage
to the second stage (as a typical fader function).
HEATING AND WARM-UP
It is advisable to wait a minute after turning it on, to modify the gain and output
levels, this way avoiding any noise generated by the lack of capacitor charging.
An effect that may damage the reference speakers.

5
USE AS A MICROPHONE PREAMPLIFIER
Set the input switch in the Mic position. For proper calibration input gain
should be placed to gain control at -20db and the control Output in the
position indicated by a small arrow where distortion remains below 0.1%. Then
turn up the gain control until the signal has a maximum level, but without
audible distortion (which is very evident in your ear when present). Once the
Gain is set, if it´s necessary, the Output control can be varied to modify the
output signal.
RECORDING ELECTRIC INSTRUMENTS (electric guitars, electro-
acoustic, basses, ...)
Connect the instrument to the female jacks on the front panel, place the switch
in the Mic position (not the Line), set the output key in the position indicated by
a small arrow, and adjust the necessary gain. It is important to have the switch
in the mic position because in this manner the output will give us a good level
without raising too much Gain.
The +48V Phantom Power is not present in the front jacks in any possible
combination of switches, to prevent damage to the instruments.
In the case of connecting electric keyboards or sound modules, it is advisable
to place the switch in the Line position due to their high level output.

6
USE AS LINE AMPLIFIER INSERTED IN THE STEREO MIX
Set the input switch in the Line position. At this time the useful scale becomes
that shown in orange and around the Gain and Output control.
In this position the phantom power off automatically.
The unbalanced output on the rear (OUT N.B.) is taken before the output
transformer which gives a subtly different colour from the balanced output.
Jack connectors-female format found on the front panel, allow us to have
balanced inputs stereo jack format. When you insert a jack into the front
connector it automatically disconnects the corresponding rear canon
connector. This system also makes the movement of phantom power to the
input jack impossible.

7
POWER SUPPLY
The 12K72 has a power supply that must be connected to the 5 pin XLR
founded on the rear of the preamp.
NOTE: Don´t forget that the external power supply has an on/off switch.
See Safety Instructions on page 3
SPECIFICATIONS
•Iron rack format of 1 unit
•Two mic / line independent preamp working in pure class A
•Using discrete technology (no IC`s)
•Gain control in steps of 5dB
•Output level control by steps of 1dB
•48v phantom power with pilot light
•Phase-change switch
•Mic / Line Selection Switch
•Balanced and unbalanced Input Output (XLR y jack)
•Inputs: Mic Input: 1200Ω, 3 pin XLR bal.
Instrument Input: 10KΩ, stereo jack bal.
•Outputs:
Balanced: 3 pin XLR

8
•Unbalanced: Jack Mono. The signal is taken before the output transformer
giving another colour to the balanced output
•Max. Gain: XLR input: 65 db
•Output control: Key steps of 12 positions adjustable in 1dB steps (the typical
fader function)
•Distorsion: To 22 dbu of output, 40hz less than 0.1%,1Khz less than 0.03%
10 Khz less than 0.05%
•POWER SUPPLY: 220v. 50hz. 110v. 60hz
The manufacturer reserves the right to change the technical specification of the
product without prior notice.
WARRANTY
These products are guaranteed for a period of two years from the date of
shipment to the end user for countries of the European Union. For other
countries, please refer to the law in effect.
During the warranty period Kahayan Pro-Audio will, at their discretion, either
repair or replace products which prove to be defective, provided that the
product is returned to an authorised Kahayan service facility.
Defects caused by unauthorised modifications, accident, negligence or any
misuse are not covered by this warranty. For further information please contact
your dealer or the distributor in your country.

9

10
NOTICE OF COPYRIGHT AND OWNERSHIP
All designs, circuit board artwork, front panel artwork, text contained herein
and therein, and all other intellectual material is the sole property of Pablo
Kahayan from Kahayan Audio. Unauthorized use, distribution, reproduction,
etc. is strictly prohibited. Kahayan intellectual property is protected by
international copyright laws. Violators will be prosecuted to the fullest extent of
all applicable laws.
Transfer of ownership of this unit neither confers nor implies any transfer of
ownership of the intellectual property, proprietary design, etc. contained
herein.
CREDITS
Concept: Pablo Kahayan
Written by: Pablo Kahayan and Luis del Toro
Edited by: Luis del Toro and Pablo Kahayan
Additional editing: José Ángel
Photos and Recall sheet: José Ángel