C.E.C. HD53N, Owner'S Manual

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HD53N’s design also allows the easy variation of the amplifi er gain. Consequently 

used an intelligent gain management (IGM) replaces a traditional volume control 

with a lot of advantages:

 - It uses the full signal level of the source and thus avoids dynamic losses and 

improves S/N-ratio.

 - The amplifi er noise level is signifi cantly reduced and reaches the usual noise 

level just on maximum volume.

 - The amplifi er’s sound quality improves when using lower gains. Generally the 

maximum gain is rarely needed, while traditional amplifi er designs always use the 

maximum gain.

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A headphone amplifi er has a very wide range of usage requirements. From low 

impedance (16 Ohm) headphones with high sensitivity up to high impedance types 

(300 Ohm) which require much higher voltage levels. At last the speaker operation 

is a different requirement. HD53N offers two different basic gain settings which 

allow the matching of a specifi c headphone. It also automatically changes the gain 

for leveling XLR and RCA inputs. This makes HD53N a very versatile headphone 

amplifi er.

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HD53N’s headphone output (LOW) is guiding the headphone’s movement by 

having a very low output impedance. Most (high grade) headphone will benefit 

from a strong amplifier control, but some headphones lack of low frequency 

substance when driven with a very low impedance source. For this purpose 

HD53N offers a second unbalanced output (HI) with 120 Ohm impedance.

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For a truly balanced amplifi er of course there is one balanced XLR input which is 

recommended to use. This matches perfectly to sources like DA53N D/A converter 

or other balanced sources. For those who don’t have a balanced source HD53N 

also has a standard RCA input. For preserving most of the balanced advantages 

this RCA input is handled differentially by HD53N without fi xed ground connecting. 

This is a quasi-balanced operation which shows much better measurement 

specifi cation than the traditional RCA connection. Both inputs can be connected at 

the same time and the input selector is located at the front panel.