SET12
Super Member
Hi all,
Some Photo's First
The project was brought about because I have been aware of how bad volume controls in general are and thought it would be extremely interesting to hear just what a passive shunt volume control can do!
What it does was very shocking to me in several ways.
Lately I have taken an interest in watching movies with two channel sound.
I have an Adcom DAC but it has no volume control.
I was in a thrift store and found a Radio Shack Audio Video Enhancer! I thought what the heck $3 and I bought it. It has 10db of gain. It has no balance control.
I connected it up to the Adcom and ran an Optical cable to my ATT U-Verse Box and I was in business.
I watched Avatar on HBO, I was shocked at how good the movie sounded even in 2-channel. The little Radio Shack Enhancer threw out a huge stage many feet beyond my living room side walls and was very deep.
I knew this wasn't the last bit of transparency but still it was way better than it ought to be IMO.
That got me thinking! AKer NoRegrets gave me his passive to try and because of its size I couldn't quite use it due to the length of my cables.
I measured his passive and found it to be pretty high in its impedance 110K total, with 10K of it in series with a 100K Alps Blue Velvet.
Essentially this works especially with tube gear but there is a price to be paid and thats perhaps some high frequency response being rolled of into a cables capacitance necessitating the need for short cables.
The same is basically true with a lower impedance control even, you have to watch those cable lengths.
Well, in a quick comparison as many might note typically there is something to be said about gain! And yes I heard it. The Radio Shack device seemed warmer and a bit more authoritative on the lower end.
But that's were it ended!
While I have never been hurting for warmth in my system there was vastly more space and definition with the shunt control. It really grabbed my attention, and I was pleased with what I was hearing. But it made me think about that line of gain having its place!
Well, Next I thought OK, lets see what my CDP equipped with Burson Discrete Op Amps Here http://www.audiokarma.org/forums/showthread.php?t=185971 does with it as I was thinking of converting its volume control over to a Shunt Type.
Well people, It was shockingly good! And just the opposite of what I expected nearly.
I really expected the CDP's dynamics to be the same!
I expected I may hear lots more information or more vividness.
Well the first thing that grabbed my attention was the dynamics.
The player was expressing a level of authority that I felt I hadn't heard before.
Not only that but everything had dynamic expressions that at a couple of points made me jump in my chair.
What the heck is this I told myself!
Wow that 10x increase of supply (With Muse and Panasonics) was really expressing itself.
I'd almost swear the the conductive plastic was compressing the sound cause my systems dynamics and spatial expression was of my recollection off the charts! Oh My!
So much for gain, I thought. Well The Bursons are really hungry Op Amps they use 5x more current than most standard Op Amps. The loading of the the Bursons is 1/2 or less of what the internal conventional control is. And of course the resistor feeding the cables capacitance is 5x or more less so there should be less loss of information.
But what kills me is the level of dynamics heard not to mention the increased information of course.
I would have to say the result of this project has yielded a least a magnitude of improvement if not more.
And all I can say is never again will I use a pot in the conventional sense.
I had all materials on hand, The pots were from a long ago passive project that never yield these kind of results that I remember but then again I didn't have system with the capability of this kind of expression.
The Pots are 10K TDK's, From here http://www.percyaudio.com/Catalog.pdf
Resistors are Metal Film 2.2k Philps's ECG's, wire is Cary Teflon over Silver Plated Copper Wire.
The Box is a Ten-Tec Box 4inx2inx6in Standard T Series.
Here
http://www.tentec.com/?s=enclosures
Be careful how you look at the measured specs. I think the front might be the width rather then the length and so on.
I attached wood side panels via standoff's so the black top piece would fit. RCA's are a Home Theater RCA Chassis Mount with what appears to be Teflon Insulators but don't know for sure, A jack that I have used in much of my work they have never melted under intense heat.
Here, http://www.philmore-datak.com/mc/Page 57.pdf
Knobs I think are Welborne Labs from yrs agao but I could find them.
http://welbornelabs.com/
So The Project turned out very well I think.
SET12
Some Photo's First
The project was brought about because I have been aware of how bad volume controls in general are and thought it would be extremely interesting to hear just what a passive shunt volume control can do!
What it does was very shocking to me in several ways.
Lately I have taken an interest in watching movies with two channel sound.
I have an Adcom DAC but it has no volume control.
I was in a thrift store and found a Radio Shack Audio Video Enhancer! I thought what the heck $3 and I bought it. It has 10db of gain. It has no balance control.
I connected it up to the Adcom and ran an Optical cable to my ATT U-Verse Box and I was in business.
I watched Avatar on HBO, I was shocked at how good the movie sounded even in 2-channel. The little Radio Shack Enhancer threw out a huge stage many feet beyond my living room side walls and was very deep.
I knew this wasn't the last bit of transparency but still it was way better than it ought to be IMO.
That got me thinking! AKer NoRegrets gave me his passive to try and because of its size I couldn't quite use it due to the length of my cables.
I measured his passive and found it to be pretty high in its impedance 110K total, with 10K of it in series with a 100K Alps Blue Velvet.
Essentially this works especially with tube gear but there is a price to be paid and thats perhaps some high frequency response being rolled of into a cables capacitance necessitating the need for short cables.
The same is basically true with a lower impedance control even, you have to watch those cable lengths.
Well, in a quick comparison as many might note typically there is something to be said about gain! And yes I heard it. The Radio Shack device seemed warmer and a bit more authoritative on the lower end.
But that's were it ended!
While I have never been hurting for warmth in my system there was vastly more space and definition with the shunt control. It really grabbed my attention, and I was pleased with what I was hearing. But it made me think about that line of gain having its place!
Well, Next I thought OK, lets see what my CDP equipped with Burson Discrete Op Amps Here http://www.audiokarma.org/forums/showthread.php?t=185971 does with it as I was thinking of converting its volume control over to a Shunt Type.
Well people, It was shockingly good! And just the opposite of what I expected nearly.
I really expected the CDP's dynamics to be the same!
I expected I may hear lots more information or more vividness.
Well the first thing that grabbed my attention was the dynamics.
The player was expressing a level of authority that I felt I hadn't heard before.
Not only that but everything had dynamic expressions that at a couple of points made me jump in my chair.
What the heck is this I told myself!
Wow that 10x increase of supply (With Muse and Panasonics) was really expressing itself.
I'd almost swear the the conductive plastic was compressing the sound cause my systems dynamics and spatial expression was of my recollection off the charts! Oh My!
So much for gain, I thought. Well The Bursons are really hungry Op Amps they use 5x more current than most standard Op Amps. The loading of the the Bursons is 1/2 or less of what the internal conventional control is. And of course the resistor feeding the cables capacitance is 5x or more less so there should be less loss of information.
But what kills me is the level of dynamics heard not to mention the increased information of course.
I would have to say the result of this project has yielded a least a magnitude of improvement if not more.
And all I can say is never again will I use a pot in the conventional sense.
I had all materials on hand, The pots were from a long ago passive project that never yield these kind of results that I remember but then again I didn't have system with the capability of this kind of expression.
The Pots are 10K TDK's, From here http://www.percyaudio.com/Catalog.pdf
Resistors are Metal Film 2.2k Philps's ECG's, wire is Cary Teflon over Silver Plated Copper Wire.
The Box is a Ten-Tec Box 4inx2inx6in Standard T Series.
Here
http://www.tentec.com/?s=enclosures
Be careful how you look at the measured specs. I think the front might be the width rather then the length and so on.
I attached wood side panels via standoff's so the black top piece would fit. RCA's are a Home Theater RCA Chassis Mount with what appears to be Teflon Insulators but don't know for sure, A jack that I have used in much of my work they have never melted under intense heat.
Here, http://www.philmore-datak.com/mc/Page 57.pdf
Knobs I think are Welborne Labs from yrs agao but I could find them.
http://welbornelabs.com/
So The Project turned out very well I think.
SET12
Last edited:
