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Front Panel
1. Input
Plug your guitar in here. Always use a good quality screened guitar lead.
With no jack applied to the Input the amplifier will automatically be switched to a
safe, low power consumption, silent mode.
2. Volume I
This controls the volume of Channel I. Turning it clockwise increases the volume.
At extreme clockwise settings the preamplifier will start to overdrive slightly. It has
a natural, variable ‘bright’ response designed in. At lower settings the tone is
‘brighter’ with comparatively more high frequencies passed though. As the control
is increased the perceived brightness is effectively reduced due to the increase in
all other frequencies.
3. CH. II Select
This switch selects between the two preamp channels, as well as adjusting the
response of the valve power amp. With the LED off it is set to Channel I which is the
cleaner, ‘mid ’60s American’ preamp and a tight, linear response from the power
amp. Switching to CH. II will turn the LED on and activate Channel II.
Channel II on ‘EL34’ models use an early ’60s British style valve preamp gain structure
and sets the power amp to be loose and resonant.
Channel II on the ‘6L6’ models use a ‘modern’ cascaded valve preamp gain structure.
The power amp response is dependent on the Voice setting (see below).
When the footswitch is connected this switch is bypassed but the LED will still indicate
the channel status.
4. Gain II
This controls the gain of Channel II and the amount of overdrive or distortion. Lower
settings will clean up and respond well to the player’s dynamics and guitar volume
setting. Higher Gain II settings will push the valves harder into progressively more
overdrive and distortion.
5. Voice / Boost Switch
This switch selects between the two voices of Channel II.
On ‘EL34’ models this switches in a clean 10dB boost at the input stage which pushes
the valve preamp into overdrive, although the basic tonality remains recognisable.
On these models the power stage remains ‘open loop’ in both settings, therefore
loose and resonant.
On ‘6L6’ models this increases the gain into the valve overdrive section pushing the
saturation available from the Gain II control even further. This is great for fluid ‘legato’
lines and sweep-picking techniques, as well as aggressive alternate picking.
On these models the power stage is tight with Voice off and reconfigures to a more
resonant response with Voice on, to provide the low end ‘chug’ of modern high gain
amps.
When the footswitch is connected this switch is bypassed, but the LED will still
indicate the Voice / Boost status.
6. Volume II
This control adjusts the overall volume of Channel II. Turning it clockwise increases
the volume. This is useful for setting the required balance between the two channels.
7. Bass
This adjusts the amount of low-end frequencies in your tone. High settings will be
fat, warm and resonant. Low settings will be thinner, but sometimes less muddy. This
is a dual ‘potentiometer’ with each part working separately and differently on each
channel. More on this below.
8. Middle
This adjusts the amount of mid frequencies in your tone. The middle frequencies are
particularly important in setting the amount of ‘body’ your tone has. As with the Bass
control, this is a dual ‘potentiometer’ with each part working separately and differently
on each channel. More on this below.
9. Treble
This adjusts the amount of high frequencies in your tone. At low settings the sound
will be warm and darker in character. As it is increased the sound will become
brighter, eventually to the point of being aggressive and cutting. Again, this is a dual
‘potentiometer’ with each part working separately and differently on each channel.
Differences in EQ ‘tone stacks’ on each channel and each model:
At Blackstar we are always trying to get the best versions of a specific tone and spend
hours (days!) analysing circuits; both electronically and sonically. We felt that despite
having one set of EQ controls, a ‘one size fits all’ approach for all the channels was not
good enough. Therefore, we have used dual pots for each of the Bass, Middle and
Treble controls and kept the rest of the EQ components electrically independent. This
means we did not need to compromise on the control frequencies and level ranges of
any of them. Instead, we have tuned the EQ to be different for each channel type and
have used what is most appropriate for the specific channel.
Channel I on all models uses the same EQ topology as expected for a mid ’60s
American clean tone. Bright treble, restrained middle and solid bass.
On the ‘EL34’ models with the ‘classic’ type preamp, Channel II uses a highly
interactive Bass and Treble arrangement, appropriate for the ‘chimey’ clean and
crunch tones it produces.
For the MIDDLE control we have configured it as an active mid cut and boost. In the
middle / centre position it is not altering the tone at all, but turning up or down allows
a very useful way to shape the mid-range without affecting the expected operation of
the classic Bass and Treble circuit.
On the ‘6L6’ models with the ‘modern’ type preamp, the Channel II tone stack is
configured similar to a British style lead amp for authentic rock tones and the response
will be familiar for that application.
