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Holfi Pre MC1 Transformer
User Manual
 

 
 

The HOLFI Pre MC1 is driven by four 1.5V batteries, size R20 (Dia 33.5mm x 61mm). 1.25V nickel- cadmium cells can be used together with a 12V DC/200mA AC-adapter.

Assembling Batteries

Loosen the four screws placed on the underneath of the cover. Then dismount the cover and place the batteries in their clips. Be sure to polarize the batteries correctly as shown on the clips.

The batteries must always be in the same condition; that is, the same brand, and the same charging. Otherwise the amplifier won't function at optimum. This is very important when rechargeable cells are used.

Warm Up

The Pre MC1 needs a warm-up period of several hours before optimum sound quality is achieved. This means that the Pre MC1 should be kept ON permanently. By the use of rechargeable cells and suitable AC-adapter the Pre MC1 will always be kept ON, independent of the position of the power switch.

Alkaline batteries offer one month continuous use. Do not use low quality batteries, as they will result in a poor sound quality from the Pre MC1.

Employing Rechargeable Batteries

To minimize the consumption of batteries and thereby protect the environment, HOLFI recommends that the Pre MC1 be driven by rechargeable batteries. (Nickel-cadmium cells.....NiCd)

The Pre MC1 has a built-in charger, which enables the cells to remain in the Pre MC1 during charging.

The charger in the Pre MC1 may ONLY be used for Ni-Cd cells.

The Ni-Cd cells have a capacity in the range of 1Ah to 5Ah. We strongly recommend the Ni-Cd cells with the highest capacity as they offer the best sound quality for the Pre MC1.

An ordinary 12 Volt DC/ 200mA AC-adapter is connected to the minijack input. The batteries will be charged when the power switch is in the OFF position. At the same time the Pre MC1 is powered by the charger. Thereby the Pre MC1 is kept warm and always ready for use with the highest sound quality available.

The power switch should only be in the ON position when the Pre MC1 is used.  The batteries will always be charged.

 
Capacity of the batteries
1.5 Ah
3.0 Ah
4.0 Ah
Charging time
16 hours
32 hours
43 hours
Continuous
2 days
4 days
6 days
 

Polarity Of The Minijack
 

Polarity is as shown in the figure. Unless the minijack is connected with the correct polarity, the batteries will not be charged. Correct polarity can be checked when the adapter is connected and the power switch is in the OFF position.  With correct polarity the Pre MC1 will be operational.

To avoid hum, we recommend that the AC-adapter is disconnected during listening.

Lifetime On Ni-Cd Cells

The lifetime on Ni-Cd cells is very dependent on how they are used. The built-in charger in the Pre MC1 offers the maximum lifetime for you Ni-Cd cells. To extend the lifetime to its maximum, the Ni-Cd cells should be completely discharged once a month. To do this, leave the Pre MC1 in its ON position until it will not operate any longer.

It is important that used Ni-Cd cells should not be disposed through the usual removal of refuse, as they contain heavy metals. Please contact your dealer on this issue.

Gain Adjustment

The Pre MC1 is based on Current Amplification. The current amplification offers not only the best sound quality but also the best signal to noise ratio available with active electronics. By different gain settings it is possible to handle any kind of MC-cartridges with any kind of output level.

How Much Gain Do I Need?

In order to get the lowest distortion as well as a good signal to noise ratio, the best gain setting is as follows: When listening to the gramophone, the signal level should be a bit more than half the level of the CD-player (CD: 2Vrms output). The gain can be adjusted in four steps by different settings of the "G.A."-switch. The different gain settings are shown on the printed circuit board.

How To Avoid Hum

Do not place the Pre MC1 close to electromagnetic noisy sources such as television sets, computers, transformer etc.

If necessary, use an extra ground wire between the turntable and ground contact on the Pre MC1. If you have the possibility try also experimenting with a true ground connection.

Use pseudo-balanced cables between the turntable and the Pre MC1, and connect the shield to the Pre MC1 only.

Warranty

HOLFI supplies Pre MC1 with three years of manufacturer's warranty.

 
Specifications
Sensitivity 0.05mV / 10 Ohm Cartridge Impedance
Frequency range  0/-3dB 1 Hz - 0.8 MHz / 47 KOhm / 200pF
THD Power Consumption : 20 mA
Charging Current 130-150 mA
 
HOLFI: Vejenbrodvej 74, DK-2980 Kokkedal, Denmark
Phone (45) 49 18 18 39,  Fax  (45) 49 18 16 08


 


 
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