Exactly
when you need as many outputs and as many different inputs as possible, but in
the smallest possible size and at the lowest possible price... A normal
combination, right? In general, I have another Hellion "processing"
in my lab - this time a 12-channel one with a 12-channel processor. The
amplification channels are unequal - 8 channels work in class AB, and 4 in
class D. In general, a lot of useful things are stated, so I studied how it
actually works.
FIRST IMPRESSIONS, DESIGN FEATURES
The
amplifier is compact, measuring only 23.2 x 21.7 x 4.2 cm. All connectors are
on both sides. On one side - the whole linear part and the sources:
On the
other side are the high level inputs, outputs and power.
Let me draw
your attention right away - the processor channels not only go to the built-in
amplifier, there are also linear outputs. This is for when you need more power.
In general, the 12-channel has the same feature as the previously reviewed
6/8-channel "process" Hellion HAM6.80DSP - you can use the built-in
amp and line inputs simultaneously and build a dual
"everyday/variety" system. I'll say more about this later.
In terms of
inputs, the HAM12.80DSP seems to have everything you can think of without going
into the exotic. Let us flex our fingers and count:
Analog high
level, 10 channels
Analog line
(AUX)
Optics
Coaxial
(independent of optical)
Integrated
Bluetooth Audio with aptX HD
USB Audio
Sure, you
have to buy a tricky cable with two USB-A connectors to work in USB audio mode.
Plus an OTG adapter if you use a smartphone as a source.
The control
panel is also sold separately - the 12-channel one is the same as the
6/8-channel Hellion.
Of all the
cables and wires, the only one included is a USB cable for configuring the
processor.
And of
course "tails" to connect to the output jacks.
Oh, and
gloves, as if to indicate that this is a high-tech device. This is how it is
done these days, yes.
Well, okay,
this is the outside. Now for the inside.
First, the power supply. It is stabilized and can withstand significant drops in supply voltage - the processor lasts up to 5 volts, the amplifier part up to 9 volts.
Channels
1-8 are powered by a pair of 4-channel TDA7851L microcontrollers. By the way, these
are one of the few 12-volt power supplies that will normally operate with a 2
ohm load, so keep that in mind.
Channels
9-12 are powered by the D-class TPA3116 power chips in the bridge (i.e. these 4
channels are physically formed from 8 channels combined in pairs). They are
already powered by a higher voltage, so the output power is slightly higher.
The chips are hidden under an aluminum clip.
It was not
possible to see how the "math" of the signal processing works, but
the description talks about Cirris Logic, so the platform is essentially the
same as in the 6/8 channel Hellion HAM6.80DSP mentioned above.
HOW IT IS SET UP AND WHAT IT CAN DO
Our own
12-channel software. It also runs without installation and immediately connects
to the processor.
The initial
setup comes down to choosing the types of output channels - work on tweeters,
midranges, midbasses, subs, etc. It's a good idea to start there so you don't
get confused later, the filters return to their initial values, and the system
can be turned on safely without the risk of burning tweeters or delicate
midrange drivers.
The channel
routing is a traditional "matrix" with level controls. For each
source, as usual, you can set your own "routes" - what goes from
which input channel to which output.
Two
important points have been "inherited" from the 6-channel model. The
first is a software shutdown of the built-in amplifiers (real, where they
"sleep" and not just remove the signal). And the second is to save
the entire state of the amplifier in the preset, including the selected source
and the activity of the built-in amplifier.
Using these
two features makes it possible to build a dual system. The first can be built
entirely with a built-in amplifier (for example, for daily trips). And the
second - with external amplifiers (for example, a loud stage). We create our
own preset for each system and then simply switch between them.
CHECKING STANDARD DSP FUNCTIONS
The
12-channel Hellion was in many ways close to the previously tested 6-channel
HAM6.80DSP, but the measurements showed minor differences. This came as a
surprise as they share the same computing platform. However, the differences
are not very noticeable and sometimes not even obvious at first glance. I
assume that with a different number of channels, the "math" is
implemented differently.
The signal
processing time by the processor (with zero delays set in the program) is about
3.2 ms. As with the 6-channel, there is a residual attenuation on the pulse -
similar to the peculiarities of the DAC.
Check the function of the delays. The maximum delays are up to 15 ms (corresponding to a distance of about 5 meters). The real ones coincide with the set ones, but I was alarmed that the pulse shape fluctuates a little at different delays. And this is not the result of the operation of the amplifier, since the signal during this measurement was taken from the linear outputs.
Checking
the operation of the filters. I simulated a typical three-stripe and tried
different types of filters. The result is that the real frequency response
fully matches the declared one. Just for fun, I tried the maximum slope of 48
dB/octave: many DSPs start to have problems at their maximum values, but here
the processor seemed to cope.
Check the
equalizer operation. If the 6-channel had problems with the equalizer with wide
control bands (low Q values), the 12-channel had problems with this as well.
For example, here is an equalization curve at frequencies of 250 and 4000 Hz
(the volume is reduced to 30 units out of 40 in order not to limit the signal
amplitude).
CHECKING
THE OPERATION OF THE AMPLIFIER SECTION, CHANNELS 1-8 (AV CLASS)
First, I
looked at the spectra at the AB class outputs. With a small signal there is
little noise, but as the level of the useful signal increases, the noise rises
slightly - a familiar picture for an amplifier on microcircuits. However, this
is only noticeable instrumentally, so there is no reason to worry. The
harmonics are slightly dominated by the even ones.
The
intermodulation distortions are not quantitatively the lowest, but the spectra
do not turn into a continuous "comb", everything looks acceptable for
the microcircuit. In general, the capabilities of the TDA7851L are very
decently implemented in this particular amplifier.
I decided
to check the performance with an oscilloscope. As always, at the generally
accepted frequency for such cases, 1 kHz. Here's what you get with a 4 ohm
load:
And this -
at a 2 ohm load (at exactly the same input signal levels and volume settings):
At 4 ohms,
signal clipping begins at about 14 V amplitude (that's just under 10 V RMS). At
2 ohms, the amplifier also works well, but it is a little heavier, and the
signal clips at about 12 V (about 8.5 V RMS). Let us recall the formulas and
count:
Performance
parameters of the Hellion HAM12.80DSP, channels 1-8, class AB (measured at 1
kHz):
Operating
at 4 ohms, undistorted output power - 25 W
Operating
at 4 ohms, undistorted output power - 49 W
Operating
at 2 ohms, undistorted output power - 36 W
Operating
at 2 ohms, output power - 72 W
VERIFYING THE OPERATION OF THE AMPLIFIER SECTION, CHANNELS 9-12 (D-CLASS)
These
channels are slightly more powerful because they operate at a higher supply
voltage. Oscillograms at 4 Ohm:...and at 2 ohms:
At 4 ohms,
the limit occurs when the signal amplitude is about 18 volts (about 12.7 V
RMS), and at 2 ohms, at an amplitude slightly higher than 14 V (about 10 V
RMS). The performance parameters are as follows:
Power
parameters of the Hellion HAM12.80DSP, channels 9-12, D-class (measured at 1
kHz):
Operating
at 4 ohms, undistorted output power - 40 W
Operating
at 4 ohms, undistorted output power - 81 W
Operating
at 2 ohms, undistorted output power - 50 W
Operating
at 2 ohms, output power - 98 W
HOW DOES IT SOUND?
The
channels clearly have their own specialization, so listening to everything in a
wide range would not be very accurate. To solve this problem I used the
possibility to bi-wire my PSB Synchrony One B bookshelf speakers (separate
channels for HF and MF/LF). I tried different combinations and here are the
results.
It is
better to use channels 1-8 (AV class) on the sub-voice channels (rear, center,
etc.) or on the mid/high frequency section. Removing the output stages of
microcircuits from high currents (and the bass component basically
"loads" them) noticeably improves the detail and microdynamics in the
mid/high frequency range.
If we were
to describe the nature of the sound, it would be warm, without cold causticity
or unnatural sharpness, but with a healthy transfer of attack. However, as for
the attack and the speed of the system in general, a lot depends on the
convergence of the bands, so everything here is in the hands of the installer
and customizer. The main thing is that the TDA itself, "unloaded"
from high currents, can sound quite tolerable.
I would
describe channels 9-12 (D-class) as more universal. The control in the low
frequencies is noticeably better than in channels 1-8, although I wouldn't give
them to heavy woofers. However, with sensitive drivers that do not move too
much, you can get an elastic, clear and intelligible sound without the
characteristic buzzing.
If it is
possible to use separate amplifiers for the low frequencies, it is better to
use channels 9-12 for the mid/high frequencies: they sound a bit drier and
sharper than channels 1-8, but the brass of the drums, the acoustic guitar and
all kinds of cymbals-bells are transmitted as something more transparent, more
airy. Vocals are also interesting - light, with plenty of detail.
ABOUT THE CASE
Today it is
one of the most affordable multichannel processors in the lab and deserves
attention. In terms of price/feature ratio, the Hellion looks very attractive
in general.
First of
all, it works with a variety of sources: it has separate high-level and line
inputs, Bluetooth with aptX support, separate optical and coaxial, USB audio -
and all of this is independent of each other and, most importantly, out of the
box, i.e. no additional modules need to be purchased.
Second, the HAM12.80DSP is very flexible in terms of configuration. You can even build two independent systems and switch between them by simply changing the presets.
Thirdly,
the sound is not that simple. The main thing is to use the channels for their
intended purpose: it is better not to load 1-8 with low frequencies, and 9-12
with not too "heavy" acoustics. If this does not suit you, you can
optionally use separate amplifiers for the desired channels, and then you will
certainly not be deprived of anything.