Passive Shunt Volume Control Project Build

[SET12]

Check this out http://intactaudio.com/atten_FAQ.html

For purchasing check this page out http://intactaudio.com/atten.html

This is something to think about! I like the idea!

For more detail is this link http://intactaudio.com/module.html

The first control is for coarse adjustment the second is for fine. Making for +/- 1.25db steps in 32 total steps available

Very interesting indeed :scratch2:

I'm really thinking about them!

SET12

 

[Dave C]

I don't really like the idea of all the "click to contact" issues with this stuff. It reminds me of how TV sets were before digital tuning. I remember having to be so careful when changing channels to get a good contact made.

 

[Squidward]

cubby: Yeah, intactaudio is a good place to look for autoformer based line level attenuators. I'm not a big fan of the multiple switch solution, but they implement it that way to keep costs down and to provide more steps with a simpler autoformer.

Dade C: I'm not 100% sure about what you're saying, but I'm going to assume that your criticism has to do with concern over the switches used to implement the attenuation scheme. I'm with you there, man! A good switch is hard to find, a good multi-pole switch with lots of throws is even harder (and more expensive) to find. That's one reason for the multi-switch cheaper solution. You really have to deal with switches a lot, unless you go with a fully analog pot, and they have lot of drawbacks in their schemes, too. Let's just say that people who experiment with stepped attenuation find out sooner or later that about half the problem is switch selection and sourcing. Let's also say that a lot of people who end up with a stepped solution have arrived there after playing around a lot with analog pots...

 

[Squidward]

Oh, and FWIW, I use a pair of Slagle's 28 tap autoformers as attenuators in the main rig. They are excellent. I plan on eventually building my personal TOTL line stage around them, but for now they reside in a much simpler build.

http://www.flickr.com/photos/wigwam/2466224344/in/set-72157604885529162/

 

[Mike Stehr]

I've been wanting to try the Intact Audio autoformer attenuators for quite a while...

 

[Redboy]

I've got a pair I need to build up, still. A nice switch to go with them, too.

 

[Dave C]

I completed the conversion of my 300B amps to this passive volume system. I did one last night and the other this afternoon. I have 100K alps pots in the amps. I found a 51K Kiwame resistor kept the knobs clocked the same for me. I would say after about an hour of critical listening that it was worth the work. Nothing jumped out at me that didn't before but while they are very clean sounding amps anyhow this did refine the sound a bit. It seems like the upper mids and low frequencies are better, cleaner. The sound stage I get from these amps is really decent but I think I picked up more separation of instruments from this mod. I found this picture somewhere on line as a guide. You will have to reverse the pot in the circuit as this drawing shows to keep the taper in the pot working the right way.