I have noticed that there are a lot of people asking about various types of attenuators, how to make them and what the values should be. I have attached the values and resistance curves for a 600r Bridged-T Attenuator. As you will see from the resistance curves you can't buy off the shelf pots. You have to get them custom made. Universal Audio gets them made by PEC.
Attenuators - Calculations for making them
- Thread starter SLB
- Start date
Help Support GroupDIY Audio Forum:
Harpo
Well-known member
welcome and thanks.
(you might revisit the 'Voltage Ratio' column for the correct values =power(10;(dB value / 20)) and fix the typo '200r' for 600 ohm in the headline)
(you might revisit the 'Voltage Ratio' column for the correct values =power(10;(dB value / 20)) and fix the typo '200r' for 600 ohm in the headline)
Harpo
Well-known member
your 'Voltage Ratio' column is giving wrong numbers. (this is an attenuator, so voltage ratio K >=1)
have a look at my version to get the idea.
edit: just added some other sheets to this excel file
edit2: .. and the next
same as =1/(10^(dB value/20)) if you like it better.
have a look at my version to get the idea.
edit: just added some other sheets to this excel file
edit2: .. and the next
I see what you are saying. The R1 and R2 values are right the voltage ratio column had the -1 subtracted from it so it was not technically the voltage ratio. It was the voltage ratio -1. I have fixed this miss leading bit up. Thanks for pointing it out.
I have updated the pdf files in the earlier posts and added the XL sheet.
Bridged-T Attenuator Calculator.xlsx
Regards,
Brezo
I have updated the pdf files in the earlier posts and added the XL sheet.
Bridged-T Attenuator Calculator.xlsx
Regards,
Brezo
