pete_mac
Super Member
I've also made up two sets of 10dB attenuator links for both of my Sansui amps. These fit between the pre-outs/main-ins and help to improve the resolution of the volume control. It's extremely common the volume control knob on vintage amps to be extremely sensitive when used with CD players and modern digital sources. Most of these amps are specc'd with 150mv input sensitivity, so if you run equipment with 1-2V output. it's clear that there is quite a mismatch!
Constructing a pi attenuator is pretty straight-forward. Input your desired attenuation and input/output impedance here http://www.random-science-tools.com/electronics/PI_attenuator.html (in my case, 47000ohm for each, and 10db) and it spits out the resistor values that you need. Thanks to skippy124 (Dad) for putting me onto this one!
I managed to fit the three resistors within one of the RCA plugs which makes it quite neat. I pillaged some CAT6 cable that I had lying around and used two orange/white twisted pairs per link. Some techflex tidies them up nicely.
Very happy with the result - to my ears, they add no colouration and the music is just as dynamic as before. If anything, the amp may sound nicer at lower listening levels now, as I'm actually a 4-5 clicks on the volume knob, rather than 1-2 like before. The amp seems to prefer this - it just sounds 'right'. From what I've read, this will also bring the signal-to-noise ratio for the amp back into spec.
I can also easily remove these links from the signal path due to the switch on the rear panel of the Sansui which connects and separates the internal jumpers for the pre-outs/main-ins. Too easy really!
Constructing a pi attenuator is pretty straight-forward. Input your desired attenuation and input/output impedance here http://www.random-science-tools.com/electronics/PI_attenuator.html (in my case, 47000ohm for each, and 10db) and it spits out the resistor values that you need. Thanks to skippy124 (Dad) for putting me onto this one!
I managed to fit the three resistors within one of the RCA plugs which makes it quite neat. I pillaged some CAT6 cable that I had lying around and used two orange/white twisted pairs per link. Some techflex tidies them up nicely.
Very happy with the result - to my ears, they add no colouration and the music is just as dynamic as before. If anything, the amp may sound nicer at lower listening levels now, as I'm actually a 4-5 clicks on the volume knob, rather than 1-2 like before. The amp seems to prefer this - it just sounds 'right'. From what I've read, this will also bring the signal-to-noise ratio for the amp back into spec.
I can also easily remove these links from the signal path due to the switch on the rear panel of the Sansui which connects and separates the internal jumpers for the pre-outs/main-ins. Too easy really!