Phaedrus Audio Groove Sleuth Micro User manual

User Manual for
GROOVE SLEUTH MICRO
NON-EQUALISING
PHONO PREAMPLIFIER
(including PHLUX-Bridge version &
Groove Sleuth TRANSFORMER)
Version 2.3 (September 2020 –Groove Sleuth MICRO)

Chapter 1 - Introduction
Phædrus Audio's Groove Sleuth MICRO preamplifier has
two roles. It may be used in conjunction with the Pspatial
Audio’s Stereo Lab Software App’ which runs under OS X
on the Apple Mac. Or it may be used as a base-station for
the Phӕdrus Audio PHLUX active phono cartridges. And
it can act as both.
With Stereo Lab
Stereo Lab has a wide feature set but it devotes a large
part of its functionality to software digital signal
processing analogue records. See
http://pspatialaudio.com/index.htm
For Stereo Lab to process needle-drops
1
, it needs
recorded files of the "raw" signal, direct from the
pickup, unfettered by analogue equalisation. And that is
where the Groove Sleuth MICRO preamplifier comes in.
It is a high-quality phono preamplifier but without
equalisation, so that the signal fed to the computer is
the closest version of the signal direct from the phono
cartridge itself, but at a suitable amplitude for
digitisation. See Chapter 4.
The Groove Sleuth MICRO preamplifier may be used
with Phӕdrus Audio’s PHLUX-II active cartridge range.
This is a time of order option (SKU: GS-MICRO-PHLUX
OPT).
PHLUX-Bridge version
The second role for Groove Sleuth MICRO is as a base
station for the PHLUX-II active phono cartridge. The
Groove Sleuth MICRO PHLUX-Bridge version allows the
PHLUX-II active phono cartridge to be used in all standard
hi-fi applications.
The Groove Sleuth MICRO PHLUX-Bridge version is a
low-cost version of the Groove Sleuth MICRO and has no
line level output. See Chapter 5.
Chapter 2 –Safety
General
Before using any piece of equipment manufactured by
Phӕdrus Audio, be sure carefully to read the applicable
items of these operating instructions and the safety
suggestions. Keep them for future reference. Follow the
warnings indicated in these operating instructions.
1
A needle-drop means a version of a music album that
has been transferred from a vinyl record to a digital
audio medium.
THE USER SHOULD NOT ATTEMPT TO SERVICE THE UNIT.
ALL SERVICING SHOULD BE REFERRED TO QUALIFIED
SERVICE PERSONNEL OR FACTORY ONLY. See Chapter 10
for battery replacement.
Phӕdrus Audio products should NEVER be connected to
the external power supply or in any other way energised
when the case is opened and/or the circuit boards are
accessible.
General Safety Instructions
Do not operate this equipment near any source
of water or in excessively moist environments.
Keep this equipment away from babies,
children and pets.
Do not let objects do not fall, or liquids be
spilled, onto the enclosure.
Situate this equipment away from heat sources
or other equipment that produce heat.
Ensure this equipment has adequate
ventilation. Improper ventilation will cause
overheating, and can damage the equipment.
When cleaning this equipment, remove all
connections to the unit; including power and
gently wipe with a clean lint-free cloth; if
necessary, gently moistened with lukewarm or
distilled water. Use a dry lint-free cloth to
remove any remaining moisture. NEVER use
aerosol sprays, solvents, or abrasives on this
equipment.
This equipment should be serviced by qualified service
personnel or returned to Phӕdrus Audio when: an
object (or objects) have fallen into the enclosure; or
liquid has fallen into, or been spilled into the unit; or the
unit has been exposed to rain or high humidity; or the
unit does not operate normally or exhibits a marked
change in performance; or the unit has been dropped,
or the enclosure has been damaged

Chapter 3 –Groove Sleuth
MICRO preamplifier
The signal from a phonograph pickup is too small to apply
to the line input of most sound-cards or audio interfaces.
What is required is a dedicated phono preamplifier to
bring the small signal from the cartridge up to a healthy
level for input to the computer sound-card.
The Groove Sleuth MICRO preamplifier is suitable for
high-output moving-coil and moving-magnet cartridges.
It is also suitable for Phaedrus Audio PHLUX (PHLUX II)
active phono cartridges. See Chapter 5 for more
information about PHLUX active cartridges.)
For support for low-output moving-coil cartridges, use
the Phӕdrus Audio TRANSFORMER, see Chapter 6 and
Appendix 4
The Groove Sleuth MICRO presents the cartridge with the
correct impedance at the “TURNTABLE” RCA phonos and
amplifies the signal. The output is presented on the
3.5mm stereo mini-jack on the rear of the Groove Sleuth
MICRO unit.
All Groove Sleuth preamplifiers feature the iLOOP - a
wide-bandwidth, low-noise, buffered signal loop-
through.
The amplification in the Groove Sleuth MICRO is
accomplished with wideband, low-noise, class-A, discrete
circuitry and circuit noise, distortion and frequency-
response are exemplary. This level of performance is
required to complement dual and quad-rate, high-
resolution needle-drop recordings and for needle-drops
of quadraphonic CD-4 (Quadradisc) carrier recordings
which may be decoded in Stereo Lab.
Power supply
The Groove Sleuth MICRO unit is supplied with a
universal, external mains power-supply with detachable
mains-plug heads and connects to the Groove Sleuth
MICRO via a high-quality screw-lock connector.
The Groove Sleuth MICRO preamplifier incorporates the
very low-noise, internal battery supply. This means the
preamplifier can be charged from a conventional,
international-style
power supply but be
switched to battery
supply during needle-
drops to ensure the
very best possible
noise and aliasing
performance. This
delivers first-rate
quality at a very
reasonable price.
The selection of the battery supply may be accomplished
using the front panel CHARGE/PLAY switch.
Alternatively, for the “ultimate” isolation from the mains
electricity, the PSU may simply be unplugged, in which
case the battery supply automatically engages (but this is
NOT shown on the front panel indicator lights which will
extinguish to keep battery life to a maximum). A remote-
controlled mains socket makes for a slick solution.
The Groove Sleuth MICRO has well over 100 hours’
operational charge, but we recommend battery play be
limited to approximately 12 hours. A full charge cycle is
about 4 hours (from fully discharged cell). The unit may
be kept in charge mode when listening with only a minute
loss of quality.
Power consumption is very low (less than 0.2W), so
leaving the unit powered is not profligate and is
compatible with European Eco-Consumption directives

Chapter 4 - Connecting the Groove Sleuth MICRO to your turntable
and sound card
The Groove Sleuth Micro is connected to your turntable
and the line-level inputs of your sound-card as illustrated.
Levels should be set on the interface in the normal way
and you will find that the Groove Sleuth Micro delivers
audio at a sufficiently high level for all commercial sound-
cards, both internal and external.
Some turntables have a thin “ground” wire which
connects to the metal components of the tonearm and to
the plate which carries the main turntable bearing. If this
wire is not earthed, the record-deck signal will often be
noisy and “buzzy”. Appendix 2 offers suggestions as to
how best to connect the turntable earth wire (if present).
The best choice depends on the complexity and choice of
the related equipment.
Chapter 5 –Groove Sleuth MICRO PHLUX-Bridge
The alternate role for Groove Sleuth MICRO is as a base-station to the PHLUX-II active phono cartridge. Called the Groove
Sleuth MICRO PHLUX-Bridge, the unit allows the PHLUX-II active phono cartridge to be used in all standard hi-fi applications.
Connections are made as illustrated above.
The Groove Sleuth MICRO PHLUX-Bridge version retains
all the advantages of the MICRO (rechargeable battery
PSU etc.) but it has no line-level output. It may not be
used with computer sound-cards for needle-drop
recordings.
Some turntables have a thin “ground” wire which
connects to the metal components of the tonearm and to
the plate which carries the main turntable bearing. If this
wire is not earthed, the record-deck signal will often be
noisy and “buzzy”. Appendix 2 offers suggestions as to
how best to connect the turntable earth wire (if present).
The best choice depends on the complexity and choice of
the related equipment.

Chapter 6 –Groove Sleuth TRANSFORMER
Housed in the same diminutive chassis as the Groove Sleuth MICRO
preamplifier, the Groove Sleuth TRANSFORMER includes a pair of step-up
transformers to extend the range of the Groove Sleuth MICRO, (or any
other standard MM preamplifier) to include all moving-coil and moving-
iron cartridges.
By incorporating a range of transformers (fitted as a time-of-order option),
the Groove Sleuth TRANSFORMER can adapt even the fussiest cartridges,
including very low output devices and "outlier" high-output moving-coils,
like the Denon DL-110 which rather "under-load" standard MM input stages without a transformer. See table below.
All the very high-quality transformers in the Groove
Sleuth TRANSFORMER have cores of a high
permeability, nickel-iron alloy and incorporate a Faraday
shield between primary and secondary to keep out
radio-frequency garbage. The transformers are fitted in
tight-fitting mu-metal cans and are thus magnetically
screened. The large primary inductance of the
transformers ensures an extended low-frequency
response (-3dB at <3Hz with a 10Ω source).
TRANSFORMER 1 has a step-up ratio sufficient for the
lowest output, moving-coil cartridges.
TRANSFORMER 2 covers mid-output MC and MI
cartridges which prefer a slightly higher load.
TRANSFORMER 3 is mostly intended for "high-output"
moving-coil cartridges which could do with a little more
level into a standard MM phono input.
See Appendix 4 for a (near complete) range of contemporary cartridges and the best choice of Groove Sleuth
TRANSFORMER.
Groove Sleuth TRANSFORMER (1)
Size: 80 x 64 x 32mm (aluminium chassis)
Power: Passive, no PSU required
Sensitivity: 400µV RMS (-66dBu) nominal @ 5cm/s
Gain (to computer output with G.S. MICRO): 52dB (× 400)
Gain (to iLOOP output): 22dB
Frequency response: <10Hz to 22kHz (-1dB, Bessel response at HF)
Distortion: 0.1% THD nominal output level
Equivalent input noise (EIN): 50nV (-144dBu), A-weighted in 20kHz. 10Ω source
Phædrus Audio reserves the right to change specification without notice.

Chapter 7 –PHLUX with Stereo Lab
The PHLUX-II cartridge has a very level frequency response. Variation is confined to ±1dB. It is, nevertheless possible to
correct this very slight response anomaly in Stereo Lab software. The combination of PHLUX-II, Groove Sleuth MICRO and
Stereo Lab offers a solution with which to extract the information captured on the original record with forensic accuracy.
Chapter 8 - Specifications
Size: 80 x 64 x 32mm (aluminium chassis)
Power: 12V DC, Universal plug top PSU included with detachable mains connection heads
Power consumption: <0.2W; compatible with European Eco-Consumption directives. The unit is intended to remain
energised all the time.
Sensitivity: 5mV RMS (-44dBu) nominal @ 5cm/s: or PHLUX-II active cartridge
Gain (to computer output): 30dB [not available in PHLUX-Bridge version]
Gain (to iLOOP output): 0dB
Frequency response: 2Hz to 300kHz (-3dB)
Distortion: 0.01% THD nominal output level
Equivalent input noise (EIN): 700nV (-120dBu), A-weighted in 20kHz. Input shorted
Max input: 70mV RMS (23dB above nominal level)
Phædrus Audio reserves the right to change specifications without notice.
Chapter 9 - Warranty and service
If you experience a problem with a Phӕdrus Audio
product, contact [e-mail]. We will
diagnose the problem remotely and advise you of the
warranty status. If a repair or replacement is required, we
will issue a Return Merchandise Authorization (RMA)
number and tell you where to send the unit to be
repaired. You MUST have an RMA number before you
return the equipment to Phӕdrus Audio's support
service.
We will also issue instructions as to how the equipment
must be marked to avoid unnecessary customs charges.
Where these instructions are ignored, Phӕdrus Audio will
re-charge these taxes or refuse to accept delivery of the
goods.
Phӕdrus Audio will not accept responsibility for loss or
damage in shipping or for equipment returned without
valid paperwork and/or a valid RMA number. Remember,
warranty is void if product serial numbers have been
removed or altered, or if the product has been damaged
by abuse, accident or unauthorized modification and/or
repair (see Phӕdrus Audio Limited Warranty for details).
There are no user serviceable parts inside.
PLEASE RETAIN YOUR SALES RECEIPT. IT IS YOUR PROOF
OF PURCHASE COVERING YOUR LIMITED WARRANTY.
LIMITED WARRANTY IS VOID WITHOUT SUCH PROOF OF
PURCHASE.
Phædrus Audio's Limited Warranty
Warranty service conditions are subject to change
without notice. For the latest warranty terms and
conditions and additional information regarding
Phædrus Audio limited warranty, please see complete
details online at www.phaedrus-audio.com.

Chapter 10 - Battery and
battery replacement
The internal battery in the Groove Sleuth MICRO is an
8.7V NiMH (nickel-metal hydride) E-block type battery. It
may be replaced with a battery of a similar type and
specification. The position of the battery in the unit is
illustrated in the blue block in the illustration opposite.
NiMH batteries are not tolerant to being overcharged
which can reduce their life. The Groove Sleuth MICRO
preamplifier uses an intelligent NiMH charger circuit such
that the external PSU provides an initial fast charge but
applies charging current reductions as the charge
progresses. This scheme continues until the battery is
fully charged. This method of charging is known as the
differential charge method and ensures the best life from
the internal battery.
However, no battery has an infinite life. NiMH types can
be expected to give about 3 years’ service. So, a battery
replacement will probably be necessary in the service
lifetime of the Groove Sleuth MICRO preamplifier unit.
Battery replacement
In the following description, the rear of the Groove
Sleuth MICRO unit is taken to be the panel with the four
RCA phono connectors.
Remove all signal and power connections to the unit and
undo the four panel screws at each corner of both panels
of the unit. When these are removed, the whole
assembly may be withdrawn rearwards from the case.
Feed the front panel carefully through the enclosure as
the PCB is withdrawn. Note the internal runner on which
the assembly is mounted. It’s second from the bottom
(see illustration).
The battery is held in place by the PCB and the wall of the
enclosure. It will free itself as the assembly is withdrawn
from the enclosure. The battery is connected by a
terminal clip connector. Remove this and replace the
battery with a new NiMH type (8.7V 200mA/H capacity).
Be sure to fit the connector to the battery in the correct
sense. Do not experiment to do this, the circuitry is not
protected against the battery being connected in the
wrong polarity.
Once the battery has been changed, the assembly and
new battery may be slid back into the housing on the
same set of internal runners in the case. Fit the front
panel first but don’t tighten the screws so that the panel’s
position can “float” a little.
Be careful not to force the assembly so that the rear of
the PCB sits flush with the back of the housing. If there is
some resistance of this kind, it is almost certainly because
one or both LEDs or the switch is fouling the front panel.
If the assembly is slid into the correct slot, gentle wiggling
should help the LEDs find the correct register with the
holes in the faceplate.
Refit the four screws in the rear panel and tighten the
screws retaining the front panel and rewire the unit.
Appendices
Appendix 1 - Model Codes
The model/order codes for Groove Sleuth MICRO preamplifier are:
GS-MICRO - Groove Sleuth MICRO preamplifier
GS-MICRO-PHLUX OPT –Time of order option for PHLUX-II support*
GS-MICRO-PHLUX-Bridge - PHLUX Bridge version of Groove Sleuth MICRO (no line-level output)
GS-TRANSFORMER 1 - Moving-coil step-up transformer (Input range 200µV to 500µV, 100Ω load)
GS-TRANSFORMER 2 - Moving-coil step-up transformer (Input range 400µV to 1mV, 500Ω load)
GS-TRANSFORMER 3 - Moving-coil step-up transformer (Input range 800µV to 2mV, 1.5kΩ load)
* Only free of charge at time of order. No retro-fit. Contact [e-mail] for more details.

Appendix 2 –Turntable ground-wire
Some turntables have a thin “ground” wire alongside the phono cables. This
wire normally connects to the metal components of the tonearm and to the
plate which carries the main turntable bearing.
A ground connection to these components is advantageous for a whole range
of reasons. Not only does it help with electrostatic screening from interfering
AC radiation, it also helps control static electricity build-up on the plastic disc
as it plays. If this wire is not earthed (grounded), the record-deck signal will
often be noisy and “buzzy”.
Here is how to connect the turntable earth (ground) wire - if present. The best
choice depends on the complexity and choice of the related equipment.
If the installation includes a preamplifier (or integrated amplifier) for
monitoring/ listening as illustrated in Chapter 4 and 5, there may well be a
suitable connection for the ground wire on the pre/amplifier itself, perhaps
even a dedicated earth (ground) terminal. Use this.
If the computer is stand-alone, the turntable ground wire may be
connected to the 0V reference of the Groove Sleuth MICRO. This is NOT an
earth connection but it will tie the turntable ground to signal ground. A
dedicated cable “tail” is provided as part of the power-supply connector to the
preamplifier as illustrated above. This connects directly to the 0V signal
reference point. The 0V reference cable is held to the main cable by heat-shrink
sleeving. If you need to use this connection, ease the “tail” from the sleeving
and connect this to the turntable ground wire.
Appendix 3 - Declaration of Conformity
The Manufacturer of the Products covered by this Declaration is
Phædrus Audio
Maidstone
Kent
UK
The directives covered by this declaration are:
2014/30/EU Electromagnetic Compatibility directive
2014/35/EU Low Voltage Equipment directive
The products covered by this declaration are:
Groove Sleuth MICRO non-equalising phono preamplifier
The basis on which conformity is being declared: The manufacturer hereby declares that the products identified above comply with the
protection requirements of the EMC directive and with the principal elements of the safety objectives of the Low Voltage Equi pment
directive, and that the following standards have been applied:
IEC INTERNATIONAL STANDARD 60065: 2005. - Audio, video and similar electronic apparatus –Safety requirements
The technical documentation required to demonstrate that the products meet the requirements of the Low Voltage Equipment directive
has been compiled and is available for inspection by the relevant enforcement authorities. The CE mark was first applied in 2020.
Signed:
Richard Brice, Technical Director Date: May 2020

Disposal - meaning of the
dustbin symbol
Protect our environment: do not dispose of electrical
equipment in domestic waste. Please return any
electrical equipment that you will no longer use to the
collection points provided for their disposal. This helps
the potential effects of incorrect disposal on the
environment and human health. This will contribute to
the recycling and reutilisation of electrical and electronic
equipment.
Information where the equipment can be disposed of
can be obtained from your local authority.
Batteries/ rechargeable batteries must not be disposed
of in domestic waste.
Appendix 4 - Recommended hardware and moving-coil cartridge
combinations
The cartridge listed are recommended with the following hardware solutions based on output levels and load impedance
requirements. Cartridges appear more than once where they work equally well with different hardware.
Groove Sleuth MICRO with TRANSFORMER 1
Audio Technica AT-ART9, AT-33Sa, AT-OC9XSL,AT-OC9XSH, AT-OC9XML, AT-OC9XEN, AT-OC9XEB, AT-33PTG/II, AT-33EV,
AT-ART1000
Benz Micro ACE S Low (Red Body), MC Gold
Clearaudio Talisman V2 Gold, Essence
Denon DL103, DL103 R EM
Dynavector DV XX2 MKII, DV-20 X2 (low-output), DR XV1-S, DRT XV-1T, Karat 17DX, Te Kaitora Rua
Gold Note Tuscany Gold
Goldring Ethos, Elite
Koetsu Urushi Gold, Urushi Sky Gold, Urushi Tsugaru, Urushi Black, Red T, Black K, Azule Platinum, Blood Stone Platinum,
Blue Onyx Platinum, Burma Jade Platinum, Rhodonite Platinum, Jade Platinum, Signature Rosewood
Lyra Kleos, Atlas Lambda SL, Etna Lambda SL, Kleos SL
Ortofon Cadenza: Blue, Red, Bronze, Black: Quintet Blue, Red, Bronze, Black: MC Anna (Diamond), SPU, MC Windfeld Ti
Rega Aphelion 2, Ania Pro, Ania
Roksan Shiraz
Shelter Harmony, Accord, Model 901 III, Model 5000, Model 501 II, Model 301 II
Shun Mook Reference
Sumiko Palo Santos Clebration, Pearwood Clebration, Starling, Blue Point Special EVO III
Groove Sleuth MICRO and TRANSFORMER 2
Audio Technica AT-ART9, AT-33Sa, AT-OC9XSL, AT-OC9XSH, AT-OC9XML
Benz Micro ACE S Medium (clear body), Gulwing SHR, ACE S Low (red Body), MC Gold
Clearaudio Goldfinger Statement, Titanium V2, Da Vinci V2, Stradivari, Concerto V2, Talisman V2 Gold, Essence
Gold Note Donaltello Gold, Machiavelli Gold Mk 2
Goldring Ethos, Elite
Koetsu Red K, Urushi Gold, Urushi Sky Gold, Urushi Tsugaru, Urushi Black, Red T, Black K
Lyra Delos, Atlas Lambda, Etna Lambda, Kleos
Ortofon Cadenza Red, Cadenza Blue, Cadenza Bronze, Quintet Blue, Quintet Red
Shelter Model 9000, Model 7000, Harmony, Accord, Model 901 III, Model 5000, Model 501 II, Model 301 II
Shun Mook Reference
Sumiko Blackbird Low, Palo Santos Clebration, Pearwood Clebration, Starling, Blue Point Special EVO III
Van den Hul White Beauty Special X, The Crimson, The Frog (standard & Gold), MC-One Special, MC-10 Special,
Grasshopper III (GLA), Grasshopper III (SLA), The Canary, Black Beauty GPX, Condor Gold high out, Condor (standard and
high out)
Groove Sleuth MICRO and TRANSFORMER 3
Denon DL110
Benz Micro ACE S Medium (clear body), ACE S High (blue body), Ebony S (high)
EMT HSD006, JSD 5, JSD 6, JSD P 6.0 Platinum, JSD Pure Black, JSD Pure Lime, JSD S 75, EMT JSD VM
Grado Statement 3, Opus 3 (Low), Sonata 3 (Low), Platinum 3 (Low), Reference 3, Master 3 (Low)†

Groove Sleuth MICRO (direct - no transformers)
Benz Micro ACE S High (blue body), Ebony S (high), MC Silver
Dynavector DV-10X5 MK11 (high-output), DV-20 X2 (high-output)
Gold Note Donatello Red
Goldring Eroica H (high out)
Ortofon MC-1 Turbo & MC-3 Turbo
Sumiko Blackbird High, Songbird High, Amethyst, Blue Point Special EVO III, Blue Point No. 2 High Out
Van den Hul White Beauty Special XO, Grasshopper III (high out), The Frog (High output), MC-Two Special, Black Beauty
GPX (High)
† The low output Grados (not MCs at all in fact), are specified for a higher input impedance, but they have been tested and
work well with TRANSFORMER 3: primary inductance is sufficient to give a bass response which is -3dB at 5Hz.