Thermionic Culture The ULTRA Vulture User manual

Thermionic Culture Ltd. 2021 1
WARNING
For your personal safety, please read this operating manual and
this warning thoroughly before using the equipment.
This unit must be installed in such a manner that operator access
to the mains plug is maintained. Where the product is to be rack
mounted, this may be achieved by having access to the
disconnection device for the whole rack.
To reduce the risk of electric shock, it is essential that the unit is
disconnected from the mains supply before removing the cover.
Please also note that the power supply capacitors within this unit
can remain charged even after the mains supply has been
disconnected. It is essential that these capacitors are discharged
after the mains supply has been disconnected and the covers
have been removed.
In the event that this unit has been dropped or has suffered an
impact, an electrical safety test must be carried out before
reconnection to the mains supply.
This equipment is not intended for use in explosion hazard
environments. It must be used and stored in studio conditions,
such that the ambient relative humidity does not exceed 80%, nor
is the temperature to be allowed to drop to a level, which would
cause dew point to be reached.
The Ultra Vulture, though valve based, does not run exceptionally
hot. Other equipment can be mounted in the rack directly above
and below it, as long as the rack is well ventilated and the
ventilation slots are not obstructed.
It is not advisable to operate this equipment unless all valves,
especially the Output valve in the centre, are in place.

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CONTENTS
Section Page
1 Introduction 3
2 Controls & Meters 4
2.1 Drive 4
2.2 Output Level 4
2.3 Bias (and meter use) 4
2.4 Function Switch 5
2.5 Filter 5
2.6 Presence 5
2.7 Bypass 5
3 General Operational Hints 6
4 Inputs and Outputs 8
5 Servicing and Maintenance 9
5.1 Valves 9
5.2 Operating voltage / Fuse 10
6 Specification 11

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1 Introduction
The Culture Vulture is universally renowned as the first and only
all valve unit, dedicated to producing the best harmonic
distortion money can buy.
THE ULTRA VULTURE takes the Culture Vulture to a new level
making it more suitable for accurate stereo uses, including
mastering, where extended frequency response, low noise and
re-callability are of prime importance. Transformer balanced
line ins and outs are standard, on XLR connectors.
Although the unit can be "clean” (less than 0.2% THD), added
valve saturation may be quite desirable, improving naturality
and smoothing off unwanted digital spikes. But The Culture
Vulture can be used for distortion effects! Push it and try it!
The user has total control over the type and amount of
distortion, which can be changed from even to odd harmonics or
a combination of both. Starved, the sound from The Vulture
becomes thin and loses its body, overfed, it becomes fatter.
. The Function switch now has 2 "effects” positions, ‘P2’ & ‘P3’.
The extra ‘+10dB’ drive position gives some of the bite of
'Overdrive’ but with far less noise. When ‘+10dB’ is selected
(only) the ‘Presence’ switch is available. The ‘-10db’ output
switch allows the unit to be driven into extreme distortion but still
have an easily achieved stereo balance. However, the ‘P2’ and
‘P3’ positions will become so extreme that true stereo won’t
always be applicable.
All pots, except ‘Bias’, are indented for easy recall. Use meter
readings to accurately recall ‘Bias’ settings.
A test report comes with each unit indicating best settings for
mastering.

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2 Controls & Meters
2.1 Drive
This control is really in 2 parts, a switch and a rotary pot.
The switch gives a coarse control and the pot a fine control
of the signal input level. At the first position 'Normal’ (for
line level signals) the frequency response is flat. The ‘+10’
position increases the gain by 10dB and adds some top
end for extra bite. 'Overdrive’ is 30dB above 'Normal’ and
can be used for extreme distortion effects at line level, also
guitars and other low-level sources.
The ‘Drive’ pot controls the amount of signal you are
feeding to the 2nd valve, so the higher it’s set the more
effect. It should be used in conjunction with the ‘Output
Level’ control to keep overall levels where they are desired.
2.2 Output Level
Again, this control is in 2 parts, a switch (-10dB) and a
rotary control. This controls the signal going to the output
valve. Usually, it’s advisable to set the rotary control at 8-12
(check test report) with the ‘-10dB’ switch down for low
distortion at line level. Set the switch to ‘-10dB’ and reduce
the rotary control when pushing the distortion valve at other
than P3, which always requires maximum ‘Output level’.
2.3 Bias (and meter use)
This control varies the current through V2 by changing the
positive voltage on its cathode. The actual current is shown
on the milliammeter. When the Vulture is starved of current
the sound is thinner and when over-fed it becomes fatter,
but current above 0.6 mA will shorten valve life. The best
setting for low distortion is usually 0.25 - 0.3 mA (see test
report for exact figures with valves supplied).

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When the Vulture is being pushed into heavy distortion the
meters will twitch.
N.B. The ‘Bias’ pot is naturally noisy in operation as all of
the valve ’s current is flowing through it, but it should be
silent when set
2.4 Function Switch
'T’ and 'P1’ positions mean that V2 is configured as a triode
(even harmonics) or a pentode (odd harmonics).
'P2’ is an exciting new discovery. It will sound quite clean
until overload is close when lots of harmonics are suddenly
added, and at higher levels over-compression will occur
and dynamics are inverted
'P3’ is a very distorted sort of pentode. Rectifying effects
can be obtained when lowering the ‘Bias’ and this can
result in what sounds like the pitch changing up an octave
to the ear.
2.5 Filter
This is a low pass filter cutting frequencies above 5 kHz by
up to 6 dB, reducing “harshness”.
2.6 Presence
This switch operates only on ‘+10dB’ gain. It broadly boosts
mid to high frequencies by up to 4 dB.
2.7 Bypass
This switch links the Line input to Line output directly,
cutting out the electronics of the ULTRA Vulture. It does not
function when using DI input or Output Lo jacks.

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3 General Operational Hints
When just "warming” the sound use 'T’ or ‘P1’ settings with
output level control at 8-10. Turn down the control as you
increase input level and/or increase V2 current settings. Turn to
max for 'P3’ applications.
The "cleanest” setting for the ‘‘Bias is usually 0.22 to 0.32mA
and 'T’ function, this should be used to give sounds just a bit
more 'naturality’. Check test report.
A good setting to simulate analogue tape distortion is 'T’, normal
drive, meter set to 0.3-0.4 mA.
A generally popular setting is 'P’ 0.4mA with ‘Output’ level
reduced accordingly.
When used with low amounts of drive these settings can appear
to enhance the warmth and size of the audio and can be used to
reduce unwanted transient peaks, much like a limiter, resulting
in a louder sounding output.
On the 'P2’ & ‘P3’ settings, a characteristic of the type of valve
used is that a frequency doubling effect can occur when
distortion sets in, due to waveform rectification. This can be
quite interesting and is most likely to occur with high ‘Bias’
(around 0.1-0.2 mA current).
Use the ‘+10’ setting of the ‘Drive’ switch if you want a little more
'bite’ or brightness. There may be sufficient gain to use this
setting for some electric guitars when DI’d, if a low ‘Bias’ (high
current thru V2) is used. Otherwise, use the ‘Overdrive’ setting
when DI-ing guitars. Of course, you can chain the 2 channels
together, using ‘Overdrive’ on the first for extreme effects.
Use the 'Filter’ switch to reduce unpleasant upper harmonics,
especially useful when using 'P2’ & ‘P3’ effects.

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If using the unit across a stereo mix or group, then ensure that
you set it up with both meters reading the same rather than
relying on knob positions. You can only expect an unchanged
stereo picture when the ‘Function’ switch is set to 'T’ or 'P1’
positions. Little chance on 'P2’ & ‘P3’ position but that may not
necessarily be undesirable.
N.B., You may find that to obtain a perfect stereo balance in
both T and P1 settings, you may need to set Drive levels so that
the 2 sides read slightly differently. This is quite normal and is
due to component tolerances.

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4 Inputs & Outputs
Inputs and outputs are connected as follows:
Line ins and outs are on XLRs with signal pins 2 & 3. Pin 1
ground.
Low level outs are also TRS jacks with Tip as output. Ring and
Sleeve are grounded so can be used with “balanced” cables.
The DI inputs on the front are mono (TS jacks). NB. The DI
input overrides the Line input.
All jacks are gold plated for best connectivity.
Always use twin screened “balanced” cable when connecting
line inputs and outputs. There should be no problem
whatsoever when connecting line inputs and outputs into
balanced or unbalanced systems.
The ULTRA Vulture is designed to work into equipment with
an input impedance of at least 4kΩ. Nearly all equipment
currently sold meets this requirement, though certain units still
have 600 Ohm line inputs. If you plug into one of these there
will be a loss of both level and low bass frequencies.

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5 Servicing & Maintenance
5.1 Valves
The unit comes with a 12 month warranty covering all
parts, including valves, and it is essential that it is returned
to our factory or to the dealer from which it was purchased
for repairs to be carried out otherwise the warranty is
invalidated. There is, however, one important exception to
this rule:
Valves are quite delicate items and the most common
cause of failure, despite our choice of highest quality ones.
If a fault occurs on one channel, a valve is quite likely to be
the cause, so if you feel confident and willing to do the
following, here’s the procedure:
Unplug the power and remove the top by undoing screws
which attach it. Note: 1 screw is silver and must be
replaced in the same place. The unit can be powered up
safely without the top on provided that the screening plate
above the circuit board is not removed and reasonable care
is taken not to touch exposed connections, but don’t
change valves with the power on! Change over the 2 input
valves. These are the ones with metal screening cans
nearest the left & right sides. If you press down a little and
twist the can anti-clockwise it will come off, then gently pull
out the valve. Be careful when replacing valves that the
pins line up. Do not bend them! Plug back in and see if the
fault has changed sides, if not try changing the next pair
inwards (the “distortion” valve). Be sure not to mix up the
valves as they are different types and have different pin
connections!
The valve in the centre is the output valve and is a double
triode common to both channels. This is very robust – the
type 5963 has top marks for reliability. If you want to be
sure, you can replace it with the common ECC82 (12AU7)

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with very slightly degraded results. Spares can be obtained
from Thermionic Culture Ltd.
Input valves can be replaced individually but “distortion”
valves should be replaced in matched pairs if you use the
unit for stereo. (otherwise it can be quite fun to have
different sounds from each side – some of our old
customers prefer it!)
Valve complement: (equivalents in brackets, nearest 1st)
Input 2 x 5654 (M8100, CV 4010, EF95)
Distortion 2 x 5725 (6AS6W, CV 4011, 6AS6)
Output - 1 x 5963 (ECC802S, 6189, ECC82, 12AU7)
5.2 Operating voltage / Fuse
The ULTRA Vulture is switch selectable to operate from
either 230V or 115V 50/60Hz AC mains supply.
NOTE: Mains fuses may be replaced in accordance with
the following table:
Operating Voltage Fuse Rating
115V T500mA 20mm type
230V T250mA 20mm type

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6 Specification
A) Figures obtained with 1kHz signal, 0.25mA ‘Bias’ current,
Function at T, feeding a 10kΩload.
Distortion (THD): 0.2%
Frequency response: 20 Hz to 25 kHz, +/-1dB
Max Output Level (MOL) +19 dBm, 2% distortion
Gain available: 46dB line, 52dB DI input
Noise: 90 dB below MOL (2%)
B) Maximum Figures
Distortion (THD): 98%
MOL: +24 dBm, 20%+ distortion
Gain: 70dB (approx), P1, min. ‘Bias’.
C) Impedances:
Line Input: 20kΩ
DI Input: 50kΩ
Line Output 1kΩ
Lo Output 4kΩ
D) Power Consumption: 20W
E) Net Weight: 6 kg

Thermionic Culture Ltd., Harlow, Essex, UK
Tel: [phone] email: [e-mail]
Thermionic Culture Ltd. 2021. Printed in UK.