Your MCP 1 Head Amplifier is designed to operate to its performance limits for many years. If you have any questions, please contact:
CUSTOMER SERVICE
Mcintosh Laboratory Inc.
2 Chambers Street
Binghamton, New York 13903-2699
Phone: 607-723-3512
Take Advantage of 3 years of
Contract Service...
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CONTENTS
SERVICE CONTRACT INFORMATION |
1 |
INTRODUCTION |
2 |
HOW TO CONNECT |
2,3 |
PERFORMANCE LIMITS |
3 |
HOW TO DESIGN A HEAD AMP |
4 |
MCP-1 SCHEMATIC DIAGRAM |
5 |
McINTOSH THREE YEAR SERVICE CONTRACT
An application for A THREE YEAR SERVICE CONTRACT is included with this manual.
The terms of the contract are:
1.Mcintosh will provide all parts, materials and labor needed to return the measured performance of the instrument to the original performance limits. The SERVICE CONTRACT does not cover any shipping costs to and from the authorized service agency or the factory.
2.Any Mcintosh authorized service agency will repair Mcintosh instruments at normal service rates. To receive service under the terms of the SERVICE CONTRACT, the SERVICE CONTRACT CERTIFICATE must be presented when the instrument is taken to the service agency.
3.Always have service done by a Mcintosh authorized service agency. If the instrument is modified or damaged as a result of unauthorized repair, the SERVICE CONTRACT will be cancelled. Damage by improper use or mishandling is not covered by the SERVICE CONTRACT.
4.The SERVICE CONTRACT is issued to you as the original purchaser. To protect you from misrepresentation, this con-
tract cannot be transferred to a second owner.
5.To receive the SERVICE CONTRACT, your purchase must be made from a Mcintosh franchised dealer.
6.Your completely filled in application for the SERVICE CONTRACT must be postmarked within 30 days of the date of purchase of the instrument.
7.To receive the SERVICE CONTRACT, all information on the application must be filled in. The SERVICE CONTRACT will be issued when the completely filled in application is received by Mcintosh Laboratory Incorporated in Binghamton. New York.
8.Units in operation outside the United States and Canada are not covered by the Mcintosh Factory Service Contract, irrespective of the place of purchase. Nor are units acquired outside the U.S.A. and Canada, the purchasers of which should consult with their dealer to ascertain what, if any, service contract or warranty may be available locally.
Copyright 1983 © by Mcintosh Laboratory Inc. |
1 |
Introduction
WHY A HEAD AMP?
It is in the very nature of a moving coil cartridge, the way in which it must be made with the limitations imposed by today's materials, that it requires a head amp. A moving coil cartridge is really an electrical generator. Just like the generators at an electrical generating plant that convert the energy from falling water, the moving coil cartridge must have a source of mechanical energy which it can convert to electrical energy. For the moving coil cartridge the mechanical energy is supplied by the motion of the stylus as it follows the music signal impressed on the record groove walls. The movement of the stylus corresponding to the musical information is very small, being measured in only thousandths of an inch or tens of microns. Such a small mechanical motion converts into a correspondingly small electrical energy. The output of a moving coil cartridge is measured in only millionths of a volt. A typical moving coil cartridge will deliver only two or three hundred millionths of a volt which is equivalent to an energy output of only a billionth of a watt. The head amp must amplify this energy and increase its voltage level to a few thousandths of a volt in order to protect the musical content from loss of information and contamination by interfering electrical fields
which surround everything and everyone of us. Such contaminating fields would add noise and hum to the musical signal and decrease its meaning for us.
AN ALTERNATIVE DESIGN
There is another possible means of increasing the voltage level of the head amp and that is by using an input transformer. While the transformer can increase the voltage output of the moving coil cartridge it can not amplify the energy content of the musical signal from the moving coil. Hence as the voltage of the moving coil is increased its corresponding current is decreased. The source impedance, the ratio of the moving coil voltage to its current is increased by the square of the voltage gain. Thus a voltage gain of say one hundred times is accompanied by an impedance increase of ten thousand. The higher the impedance of the output circuit the more susceptible it is to interfering hum and noise fields. The head amp can solve this problem by being designed to have an output impedance of only a few ohms. . .
But there is another problem with transformers operating at extremely low voltage levels. The ease with which the magnetic core concentrates lines of magnetic force varies with voltage level at extremely small levels. This variation adds distortion to the music signal at low frequencies. The MCP 1 head amp solves this problem too. The musical definition of the MCP 1 is far superior to input transformers that are many times the weight and size of the MCP 1.
For the highest quality music recovery from your recordings it is best to locate the head amp close to the base of the turntable arm. The extremely low energy levels developed by moving coil cartridges must be protected from exposure to loss of quality from long cables to the preamplifier. When the low voltage signals of the cartridge are amplified by the head amp, they can then leave for the preamplifier in robust form, able to survive the passage without loss of content and be uncontaminated by added noise or distortion components.
The MCP 1 is powered directly from your 117 volt line. But an ingenious new development from the Mcintosh engineering group completely isolates the MCP 1 from any noise components in the power line.
How To Connect
Connect the leads from your turntable to the proper impedance for your cartridge on the MCP 1 input.
Connect the output of the MCP 1 head amplifier to the moving magnet phono input on the preamplifier.
Connect the turntable ground to the
MCP 1 ground terminal.
Then, connect a ground wire between the MCP 1 ground terminal and the ground terminal on the preamplifier.
It is imperative that there be no ground loops (multiple grounding paths) on the input and output cables connecting the MCP 1. Each channel of the MCP 1 has independent ground circuits. The input cables from the tonearm must have separate grounds for each channel and these grounds must not connect to the turntable frame ground. The output cables from the MCP 1 should have independent ground paths to the preamplifier. If you would like to, you can test the grounding system using an ohm meter. When testing the MCP 1 without any connections to other equipment, the ohm meter should measure 200 ohms between the left and right channel grounds and 100 ohms from each channel ground to the MCP 1 ground terminal.
2
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