Hill Audio LPA SERIES, User Manual

PAGE 7

Installation, Cooling and Wiring

Rack Mounting

Due to the weight of the unit, rack mounting shall only be expedited in racks with additional rear 
mounting profiles and internal front-to-rear support shelf rails, in order to avoid the complete unit 
weight to be only held by the units’ front rack ears. Mounting an amplifier into a rack without such 
support shelf rails may cause damage to both the rack and the amplifier.  

Fig. C: Cleaning the air filter

Fig. A: Internal air flow

Fig. B: Rack arrangement

Cooling

LPA amplifiers employ front-to-back cooling with 
fan-forced air flow (Fig. A). To achieve proper cool-
ing, it is thus important that the front-side air inlet 
is unobstructed, same as the rear-side air outlet. 
Further, sufficient air circulation on the rear side 
of the amplifier is essential to avoid hot air conges-
tion, which may lead to overheating. 

In contained spaces like flight cases and racks, 
this requires to include air ventilation panels  in 
the rack layout (Fig. B). Preferably, one 1U ventila-
tion panel is placed on top of every amplifier.  

From time to time, it is recommended to clean the 
front air filter. Unscrew the frame holder screw 
and remove the filter frame as shown in Fig C. 
Blow out dust from the filter and re-assemble in 
reverse sequence. 

Speaker Cabling

Aside of proper signal cabling for the input signals (see chapter Operation - Connections), the choice 
of suitable speaker cables is often a neglected but at the same time essential point of amplifier instal-
lation. Speaker cables, specifically long ones, can significantly contribute to the load impedance of the 
amplifier, thus reducing the power output and turning some of the output power into heat instead of 
delivering it to the speakers. The most important aspect is to keep cables as short as possible and to 
choose a sufficient copper cross-section, with maximum length values as per below: 

Cross-Section

AWG

2 Ohms

4 Ohms

6 Ohms

8 Ohms

0.75 mm

2

18

1.00 m

2.00 m

3.00 m

4.00 m

1.5 mm

2

15

2.00 m

4.00 m

6.00 m

8.00 m

2.5 mm

2

13

3.50 m

7.00 m

10.50 m

14.00 m

4.0 mm

2

11

5.00 m

10.00 m

15.00 m

20.00 m

Holder

Frame

Filter

Screw

USER MANUAL - LPA SERIES AMPLIFIERS