in the characteristics of low powered valve amplifier tone and gives a very playable
‘feel’ to the S1-45 at reduced power settings.
We would recommend experimenting with the channel Gain and Volume, Master
Volume and DPR Control to achieve various combinations of preamplifier and power
amplifier distortion / compression.
Note:
Generally speaking the more DPR is applied (i.e. power is reduced) the more
dynamic compression and power amp clipping will be experienced at any given
volume.
Clean DPR Operation
The DPR control is extremely powerful in fine-tuning the exact dynamic compression
characteristics of the power amplifier.
Overdrive DPR Operation
The DPR control allows you to pin-point exactly how much valve overdrive you want
to come from the preamplifier section and how much is coming from the EL34s in
the power amplifier section.
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16. Treble
The Treble control allows exact adjustment of the treble frequencies within the sound.
At low settings (counter clockwise) the sound will be warm and darker in character.
As the Treble control is increased (clockwise) the sound will become brighter. At the
maximum settings the sound will be aggressive and cutting.
17. ISF (Infinite Shape Feature)
The ISF control works in conjunction with the Bass,
Middle and Treble controls. It allows you to choose the
exact tonal signature you prefer. Fully counter
clockwise has a more American characteristic with a
tight bottom-end and more aggressive middle, and
fully clockwise has a British characteristic which is
more ‘woody’ and less aggressive.
Unlike conventional ‘contour’ controls and parametric equalisation systems, the
Bass, Middle and Treble controls remain interactive with each other just like in a
traditional guitar amplifier tone stack. This leads to a very familiar, musical response.
Master
18. Resonance
The Resonance control sets the overall bass response of the S1-45. At lower settings
the cleans will be tight and funky and overdrives will be focussed in their bass
response. At increased settings the clean sounds will be become full and warm,
whilst the crunch and overdrive tones will be more bass heavy and resonant.
19. Presence
The Presence control sets the overall treble response of the S1-45. Percussive high-
end can be accentuated on clean sounds and the amount of aggressive treble
controlled with crunch and overdrive settings.
20. Volume
This controls the overall volume of your amplifier. Turning it clockwise increases the
volume.
21. DPR (Dynamic Power Reduction)
The DPR control allows the output power of the S1-45 to be
reduced anywhere from 45W (100%) down to 4.5W (10%) of the
rated power.
DPR works by controlling the power supply voltages to the EL34
output valves and also the level of drive signal into the power
amplifier stage. Importantly, there are no components placed in
between the output valves, the output transformer and the
loudspeaker – a relationship which is essential in the delivery of
valve tone.
In addition to reducing the output power of the S1-45, the DPR
system actually controls the amount of power amplifier
compression too. Power amplifier compression is a key ingredient
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USA
UK
Channel
Channel Channel
Master
DPR
Description/
Gain
Volume
Volume
Sound Character
Clean
Low
Mid
Mid
High
Maximum pre and power amplifier
headroom yields extremely dynamic
clean sounds.
Clean
Low
High
High
Low
Increasing drive to the power amplifier
and reducing output power gives a
compressed clean sound rich in power
amplifier induced harmonics.
Clean
High
High
High
Low
Higher channel gain further increases
the power amplifier drive producing a
‘full stack’ crunch tone at only 4.5W
output power.
Channel
Channel Channel
Master
DPR
Description/
Gain
Volume
Volume
Sound Character
Crunch
Low/Mid
Mid
Mid
High
Lower gain settings provide a dynamic
crunch utilising the full 45W of
available headroom.
Crunch
Mid
High
High
Mid
At these settings there is a blend of the
distortion and compression generated
in the preamplifier and power amplifier
valves. We recommend that you
experiment to find your ‘sweet-spot’.
Crunch
High
Mid
Mid
Low
Here maximum preamplifier gain is
combined with the lowest power
amplifier output for maximum valve
saturation.
