Stepped attenuator - possibility or pipe dream

RFP

RFP

Active Member
I don’t know why I am so obsessed with the idea of having a stepped attenuator in my 500C; perhaps it’s leftover fondness for the one that was in my Sonic Frontiers SFL-2 preamp. Really liked that.

Anyway, poking around on the internet I came across these folks: Dimensions - Mini Attenuators (very complete website, lots of info on lots of pages). Looking at the data, they can make a 24-stepped attenuator that’s (only?) 1.4” X 1.5” and about 2” in depth. So, that raises three questions for me: (1) could one of those be “shoehorned” into the available space, (2) has anybody around here done it, and (3) does anybody but me care?

I realize when I get to thinking about stuff like this, I should probably just go lie down until I regain my sanity; after all, thanks to Dave Gillespie, this thing is already glorious!

Robert
 
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Well, I must be the only one. With all the heartburn over nearly-unavailable volume controls for the 500C (and others?), I thought there might be a bit of interest in this. I will likely check this out further.
 
Electrically it should work fine, its just mechanical fitment and the power switch that you have to figure out. If its a ladder type you can even tap in the loudness, just need to figure out which tap to solder into.

I'm just lazy and cheap so I'm not inclined to swap any of my stuff over. I'd be more prone to using something like this in a new build but trying to shove one into an existing crowded unit may be easier said than done.
 
Thanks for your reply. I too, am lazy and crazy-cheap, but this idea just won’t go away. The next time I have the bottom off this receiver, I am going to carefully measure the available “space.” I don’t care about the ON/OFF switch, I use a rack mounted power switch. If the stepped attenuator would fit, the next challenge would be shaft length and “D” position. I think that’s “overcome-able.” well maybe.
 
If you pursue this, you might be able to include this microswitch mod with a relay to replace the power switch. But then you would have to turn the volume down every time to switch the power off.

eduarsan1

Post in thread 'Fisher 400 with Power Relay'

For the people has seen in the improving the fisher 400 thread in version with Ibam and EFB file I added in the drawing this power switch!!

Sony good for you because this is the weakness in the fisher amps: this damn switch :whip: .

You are showing the improvement to limit the current throught the power switch, BUT with the time this damn switch starts to damage the tracks in the pots (due to to angular speed when you switch on the amp), So that what I did in my amp is replace this switch by a microswitch due to I´m using my amp daily...
 
You might also take a look at this stepped attenuator. It's only 21 steps but is about the same size as a dual potentiometer. I bought one a couple of years ago for a Marantz amplifier project but didn't use it.

Search on ebay for "DACT Type SMD Stepped Attenuator 21 step"
 
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