The δ1 relay-based R-2R stereo attenuator

Resistor value calculator

Input:

Relays
Step size (dB)
Zatt (KΩ)
Zload (KΩ)
Resistor standard
Output format

 
Output:    Maximum attenuation: −127.5dB

K0: −0.5dB
A: −0.50dB
Z: 25.0KΩ
RS0
1.40KΩ

RP0
422KΩ
K1: −1.0dB
A: −1.01dB
Z: 25.0KΩ
RS1
2.74KΩ

RP1
205KΩ
K2: −2.0dB
A: −1.99dB
Z: 25.0KΩ
RS2
5.11KΩ

RP2
97.6KΩ
K3: −4.0dB
A: −4.02dB
Z: 25.1KΩ
RS3
9.31KΩ

RP3
43.2KΩ
K4: −8.0dB
A: −7.99dB
Z: 24.9KΩ
RS4
15.0KΩ

RP4
16.5KΩ
K5: −16.0dB
A: −15.93dB
Z: 25.0KΩ
RS5
21.0KΩ

RP5
4.75KΩ
K6: −32.0dB
A: −31.91dB
Z: 24.9KΩ
RS6
24.3KΩ

RP6
649Ω
K7: −64.0dB
A: −63.96dB
Z: 24.9KΩ
RS7
24.9KΩ

RP7
16.0Ω
Term
 
Z: 24.9KΩ
RT
25.5KΩ

One channel shown, other channel is identical.

Use this to calculate the attenuator resistor values to use with your δ1 board. You specify the following inputs:
Relays
The number of relays you will install (5..8).
Step size
The attenuation per step (1.0dB, 0.5dB or 0.1dB).
Zatt
The attenuator input impedance in KΩ, as seen from the source.
This field accepts a positive number in simple integer, decimal notation or scientific notation.
Zload
The load impedance in KΩ, as seen by the attenuator. This is the input impedance of the next amplifier stage.
(e.g., For the α20 , β22 or amplifiers, it is the summed resistance of R1 + R2 on those boards).
This field accepts a positive number in simple integer, decimal notation or scientific notation.
Resistor standard
The EIA standard resistor values to use, as follows:
  • E48: 2% tolerance
  • E96: 1% tolerance
  • E192: 0.5%, 0.25%, 0.1% or better tolerance
For performance reasons, standards worse than 2% are not listed.
Output format
The calculator's output display format (graphic or table)
The calculator generates the closest specified EIA resistor standard values for RS and RP corresponding to each relay stage, as well as for the RT resistor. It also displays the real attenuation (A) and impedance (Z) of each stage, assuming perfect resistor tolerances.
If the RT resistor does not appear in the calculator's output area, then you should leave it unpopulated.


Resistor calculator program rcalc.cgi 1.12 by AMB, using an AMB-modified backend by LinuxWorks.

Main: δ1 Main | Prev: Parts list | Next: Instructions