Site hosted by Build your free website today!


In order to prevent TID (transient intermodulation distortion) in their Beomaster 4400 (type 2417) tuner amp, B&O used a 50kHz filter before the power amp and feedback techniques to limit the systems' bandwidth. The Technical Product Information book, which accompanied the service manual for this model contained a very detailed explanation of these which can be useful for those interested. Images derived from same are set out below.

Bessel filter
Output Amplifier and Internal feedback
External feedback

Additional notes include

DC feedback and Constant-current generator for no-signal current
Constant current generator for differential amplifier and Dual Transistor output
Overload indicator
Current limiter
Speaker protection
Excess temperature protection

Contact me at
especially if you want additional content to this page
or if you find any links that don't work. Don't forget
to add the page title or URL. Take care!

Back to index, sound, tips or home.