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Stepped Attenuator
Resistor Lists
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The Goldpoint Taper:
The
Goldpoint taper is an audio taper which has been optimized for use with
24 position rotary switches. It is the taper used on all off-the-shelf
Goldpoint stepped attenuators: 5K, 10K, 25K, 50K, 100K, and 250K. |
| Shown
here is the attenuation level for each switch position (in decibels), as
well as the size of each step from one switch position to the next adjacent
switch position: (see bottom of page for info about linear taper stepped
attenuators) |
Stepped Attenuator Resistor Lists:
The
following resistor lists all use the Goldpoint audio taper. You can use
any brand of 1% or 0.1% resistors you choose. If an exact value is not
available, simply select the next closest value resistor. Resistor values
shown below which are less than 10 ohms are 5% carbon resistors, (5% carbon,
in this case; KOA Speer brand, CF series, available from www.mouser.com.) |
| The overall value or impedance
of the stepped attenuator is shown at the top of each column, and the precise
total value (all of the individual resistor values added together)
is shown at the bottom of each column. |
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| To make your own stepped
attenuators, use 24 position switches, such as the Goldpoint Mini-V
Custom (MVC-1, MVC-2) switches (which were designed just for this this
purpose.) |
| For
most applications you can use 1% tolerance, less expensive, easy to get
resistors. The resistor lists
above are for the (expensive) 0.1% tolerance IRC brand resistors from www.mouser.com.
The 0.1% resistors are ideal for precision Balanced Line level controls. |
| Metal film, carbon film,
carbon composition, and bulk foil resistor types can sound slightly different.
When going through the trouble and expense of building a stepped attenuator,
you should use good quality, low noise, resistors when possible. |
| The resistor brands above
and below are all available from www.mouser.com.
Note: If a resistor value from one of these lists is not available at the
time you are ordering them, you can use an adjacent (in stock) value resistor
for that position - just use that same value for both channels (both of
your switch wafers). |
| Xicon brand 1%, 1/2w
resistors: Most affordable, quite acceptable sounding resistors, light
blue/green color with the resistor values in color bands. (Mouser keywords:
273-1K-RC) |
| Vishay/Dale 1%, 1/4w
resistors. Their sound receives positive comments from many audiophiles.
Medium priced, light brown color (1/4 watt specification, but 1/2 watt
size), with values stamped on them numerically. (Mouser keywords: Vishay/Dale
RN60D-F) |
| IRC RC55 0.1%, 1/4w
precision resistors. The sound of these resistors rivals the surface mounted
resistors used on standard Goldpoint stepped attenuators. Really excellent,
but expensive. They are recommended for Pro Audio balanced line or any
really precision stepped attenuator. Black color with values stamped on
them numerically. (Mouser keywords: IRC resistors) |
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| Below: Sample (600 ohm)
resistor list - showing where to place the resistors. The resistors
are typically installed on the front side of the printed circuit board
- so that they point towards the knob end of the Mini-V Custom switch.
(shown below is the rear side of the printed circuit board.) |
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