Well Tempered Lab WTL Phono User manual

INSTRUCTION MANUAL
WTL Phono
Rev. June 21

A word from the Chief Engineer
The Well Tempered Phono stage is designed to accommodate both moving magnet (MM) and moving coil (MC)
cartridges and has a maximum gain of 68 dB for MC cartridges and the gain is switched for MM cartridges. The
necessary break points for the RIAA equalisation are distributed throughout the circuit in order to ensure
optimum overall time response of the circuit as well as to ensure the necessary frequency response. Normally,
the RIAA equalisation is effected with an arrangement of interconnected resistors and capacitors. Since the
RIAA recording process requires that the treble frequencies be substantially boosted relative to the bass
frequencies, control of the time response is an important requirement.!
The MM/MC Phono circuit employs state-of-the-art operational amplifiers. Using these devices ensures a low
noise, high gain, stable and predictable design result.!
I prefer using resistors of the carbon film type although metal film resistors might have an edge for noise
considerations. I prefer capacitors with polypropylene dielectric.!
The input shows a switch selected resistor to accommodate both MM and MC cartridges. In my experience, MC
cartridges loaded with 47K ohms yield an excellent result and 47K is what I have used for some time now."!
Testing of the Well Tempered Phono Stage will reveal excellent results both in the frequency response and the
time response. Testing with square waves equalised for the RIAA recording characteristic (the inverse of the
RIAA playback) will yield excellent results, verifying overall performance.
William Firebaugh
Chief Engineer
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Description
The Well Tempered Lab Phono is a William Firebaugh designed Phono Preamplifier suitable for all
cartridges both Moving Magnet (MM) and Moving Coil (MC)
Important Safety Instructions
1. Read the instructions
The safety and operating instructions should be read before using the Phono.
2. Retain Instructions
The safety and operating instructions should be retained for future reference.
3. Follow Instructions
All operating and use instructions should be followed.
4. Location
The Phono should be installed in a stable location with ample ventilation. We recommend that this phono
preamplifier be placed at a suitable distance away from all amplifiers.
5. Water and Moisture
As with any electrical equipment, this phono stage should not be used near water and moisture.
Connection and Operation
The Well Tempered Lab Phono is powered from a dedicated power supply (Supplied with the unit) or for Well
Tempered Lab owners with the Well Tempered Lab Ctrl there is the in-built facilities to power the Well Tempered
Lab Phono eliminating extra cables etc.
Connect the Well Tempered Lab Phono to either the dedicated power supply or Ctrl with he correct umbilical
cable supplied.
Output Connections: One set of single ended (RCA) type connectors labelled 'Output' are supplied. Ensure
correct polarity.
Input Connections: One set of single ended (RCA) type connectors labelled 'Input' are supplied. Ensure correct
polarity.
Important: Use the best available interconnects and ensure correctly polarity is maintained throughout the
system.
Earth: A dedicated earth terminal is supplied on the rear of the Well Tempered Lab Phono. Some
experimentation may be required to achieve optimum earthing but normally the earth wire from the turntable or
tonearm will connect to the earth terminal.
The Well Tempered Lab Phono has a shielded chassis but it is not recommended that it is placed close to the
turntable or cartridge.
Note: The Well Tempered Lab Phono requires a 24V DC power supply. Use only dedicated Well Tempered Lab
power sources (24VDC).
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Impedance and Gain
The Well Tempered Lab Phono is equipped with micro switches on the underside to facilitate both loading
and gain. There are many factors that contribute to the optimum loading for phono cartridges that include
cables, preamplifier etc. and we recommend starting with the lowest impedance setting closest to the
manufacturers recommendations.
Following is a table of settings available on the Well Tempered Lab Phono:
1
2
3
Gain
4
5
6
Impedance
Switch #
ON
OFF
OFF
43dB (MM)
ON
OFF
OFF
300Ω
OFF
ON
OFF
58dB (MC)
OFF
ON
OFF
150Ω
OFF
OFF
ON
62dB (MC)
OFF
OFF
ON
47Ω
ON
ON
OFF
58dB (MC)
ON
ON
OFF
143Ω
ON
OFF
ON
63dB (MC)
ON
OFF
ON
46Ω
OFF
ON
ON
65dB (MC)
OFF
ON
ON
36Ω
ON
ON
ON
66dB (MC)
ON
ON
ON
30Ω
OFF
OFF
OFF
38dB (MM / MC)
OFF
OFF
OFF
47KΩ
Specifications
• Harmonic Distortion (2V RMS Output)
0.001%
• Input Impedance
Variable (See table)
•Input Gain
Variable (See table)
• Input Connectors
1 group RCA
• Output Connectors
1 group RCA
• Ground Connector
Screw terminal
• Signal/Noise
96 dB
• Consumption
20 watts
• Dimensions (H x W x D)
105 x 150 x 260 mm, 220 x 360 x 440 mm (Shipping)
•Weight
7.6 kg, 8.6 kg (Shipping)
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Front Panel
Power LED
5

Rear Panel
24V DC Power
RCA Output
RCA Input
Earth Terminal
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Warranty & Service
Valid on completion of warranty card and confirmed date or purchase. Details can be registered at
www.welltemperedlab.net/welltemperedlab/contact/ or mailed to: Well Tempered Lab, P.O. Box 2650,
Christchurch, New Zealand.
This Well Tempered Lab product is warranted against defects in material and workmanship for one year from
date of purchase.
This warranty does not cover normal wear and tear and is void if the Well Tempered product has been subject
to mis-use, accident or negligence or if it has been tampered with or modified in anyway. Spillage of any fluids
supplied by the Well Tempered Lab is not covered within the scope of this warranty.
Warranty is restricted to the territory in which the product was purchased. Our distributors and dealers are
under contractual obligation to service under warranty products only sold through them. They are entitled to
make a non refundable charge for service to products purchased outside the territory if required.
Claims Under This Warranty
The product should be returned to the dealer or†nearest Well Tempered distributor, complete with warranty card
and confirmed date of purchase.
The European Waste Electrical and Electronic Directive
This product can be recycled. Products bearing this symbol must NOT be thrown away with normal household
waste. At the end of the product's life, take it to a collection point designated for recycling of electrical and
electronic devices. Find out more about return and collection points through your local authority.
The European Waste Electrical and Electronic (WEEE) Directive was implemented to dramatically reduce the
amount of waste going to landfills, there by reducing the environmental impact on the planet and on human
health. Please act responsibly by recycling used products. If this product is still useable, consider giving it away
or selling it.
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Registration Card
Name
Address
City
State
Post Code (Zip)
Country
Phone
Email
Model
Serial No.
Dealer
Date of Purchase
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