The TRUTH attenuator/buffer

[rickmcinnis]

Just recently heard about this thing.

Arthur Salvatore who has a site about audio obsessions (he is a music listener first and foremost) brought it to my attention. He says it is the closest to a perfect component he has ever heard.

Made by a fellow a couple of hundred miles from me in South Carolina using a different approach with a device used to make light meters for photography. Nothing like the optocoupler attenuators. This one is much more consistent when it comes to settings and the buffer aspect (using BUF03s) eliminates loading problems. I have never used a BUF03 (and, yes, I know they are no longer available through the normal channels). Salvatore is a valve guy and is flabbergasted that he is praising a IC.

This will soon be replacing my Slagle autoformers. Salvatore had used those in the past and says this is more than a little better.

Ed Schilling, the man who has brought us the TRUTH, is a genuine character. An audio tinkerer of the highest order. He has been making a back loaded horn for many years that strikes me as similar to the Forum's founder's speaker though nowhere near as nice looking. I have never heard them but I bring it up to say he has not appeared out of nowhere.

Ed swears that no one can copy this thing. Somehow I figure that will ignite the passion of a certain person here ...

As soon as it arrives I will let you know how well it compares to the Slagle which had been superior to any other volume control I have ever used. It has a single control for attenuation and a balance control which I will enjoy. Got tired of a control for each channel/

[nige2000]

http://www.high-endaudio.com/RC-Linestages.html ???????

[rickmcinnis]

That's the one.

This fellow is dedicated. Can you imagine buying a (used) JADIS JP80 preamp and using only the phono stage before the cathode followers? Helps to have plenty of money!

I am mystified by the JADIS phone stage. Seems to be the typical 12AX7 circuit with negative feedback RIAA correction, nothing unusual. Maybe it is all about the power supply? Wouldn't be the first time that happened

He mentions in the article about trying to use a transformer, or an autoformer, as a step up to get some gain. From what I understand he was surprised that this took away some of the transparency of the TRUTH. Hardly surprising. The question would be could you get the gain in any other way that would be better?

Ed is very accommodating. I am getting mine with separate power supplies for left and right since I have found,m as have many others, that a system that dual mono from start to finish has a spaciousness that can be got no other way. He uses MEANWELL switchers and swears they make no audible difference from the linear supplies he was using previously. One would think buffers would be close to immune. The box Salvatore auditioned had the switchers so he has (yet) to hear a problem with them. I suspect I will eventually try linears just to satisfy my curiosity.

Those BUF03s are current hungry so I will not be able to use what I would normally. Tempted to try a brute force LCLCLC supply. But I will listen to it, as is, until I think there is a problem. Wouldn't mind there not being one ...

[nige2000]

He mentions in the article about trying to use a transformer, or an autoformer, as a step up to get some gain. From what I understand he was surprised that this took away some of the transparency of the TRUTH. Hardly surprising. The question would be could you get the gain in any other way that would be better?

what article is that?
my feel of of autoformers especially transformers is that they are kinda like a gearbox in car truck etc in the way they have an inherent loss or conversion inefficiency, i think a large step down will correct this maybe something like 3:1 or greater would work fine overcoming the losses
i assume a step up will exacerbate the issues

Ed is very accommodating. I am getting mine with separate power supplies for left and right since I have found,m as have many others, that a system that dual mono from start to finish has a spaciousness that can be got no other way. He uses MEANWELL switchers and swears they make no audible difference from the linear supplies he was using previously. One would think buffers would be close to immune. The box Salvatore auditioned had the switchers so he has (yet) to hear a problem with them. I suspect I will eventually try linears just to satisfy my curiosity.

Those BUF03s are current hungry so I will not be able to use what I would normally. Tempted to try a brute force LCLCLC supply. But I will listen to it, as is, until I think there is a problem. Wouldn't mind there not being one ...

not sure exactly how the volume control works he states no resistors or caps in signal path, i had guessed he used a photocell and ldr in an adjustable gain metod for vol control the buf-03 has no gain setting ?

there was talk of transformers "ultimate truth" with increased gain that hints to a step up conversion but i can only imagine that wouldnt work so good ?

very hard to know how good these things are

[rickmcinnis]

No need for step down, the output impedance of BUF03 is plenty low and as a buffer why throw away the gain unless you have a whole lot.

I had the same thought as Salvatore about using an autoformer for gain. Luckily I do not need any gain. Even with the phono stage driving everything WIDE OPEN is too loud.

I had considered a "buffer - step up - buffer" positioned before the SLAGLE (before learning about the TRUTH) since Dave says at the highest settings there is high frequency loss and with the phono that is where I am, top four positions are used, one's below much too soft. With the TRUTH this is not a problem so no need for additional gain.

I am asking the SLAGLE to drive the SIT 1s and a buffer that is part of my LC low pass filter (buffer - LC filter - buffer, using the TOSHIBA 2SK170/2SK74 combo) - I hear no problems with that but I have to believe the BUF03s will do a better job. AS is usually the case for me I hear the problem after it is gone, rarely before. My skepticism is running high with all of the audio iconoclasm going on with this box - IC buffers, switching power supplies.

If it seems too good to be true - could it not work out at least once in one's audio lifetime?

From what I can gather there is an LED modulated by the incoming music signal and the photocell is the receiver. No resistors in the signal path other than the balance control which Ed swears is completely benign.

carlsor, whom you might remember from the DDDAC thread, got one and substituted one of the conventional "Lightspeed" style setups for the parallel element, replacing he balance control even though Ed told him it would make no difference and sure enough it made no difference. Ed says the quality of the pot makes no difference.

Ed swears the Chinese will copy the device but he says the trick is the photocell he is using which I suspect will be suitably disguised. And that makes all of the difference.

Funny how at 62 years of age I have already lapsed into that "last purchase" syndrome. But I can tell you sincerely I hope this IS the last volume control I ever buy. Always hoping for things to improve, don't get me wrong, but it would be a bonus if this stayed REALLY GOOD until my ears start failing. And then I won't have to worry about it.

BUF03 is pure buffer - no gain possible without putting a gain stage in front of it. You can still find the data sheet.

Next I will tell you about my adventures with half wave rectification in the SALAS phono amp. Nothing so new as the oldest you can find? There is a reason to use the half wave in places like a phono stage. The noise reduction is akin to digital noise reduction. The noise you lose is of the same character - intertwined within the music and the space. Of course, one should not use just any rectifier ... Yes, there will be more of the obvious audible noise, very little but it is there, easy to ignore. The thing is: how much unpleasant noise have we introduced into our systems in attempting to get rid of low levels of hum? The old noise envelope ...

Take care,

[nige2000]

No need for step down, the output impedance of BUF03 is plenty low and as a buffer why throw away the gain unless you have a whole lot.

I had the same thought as Salvatore about using an autoformer for gain. Luckily I do not need any gain. Even with the phono stage driving everything WIDE OPEN is too loud.

I had considered a "buffer - step up - buffer" positioned before the SLAGLE (before learning about the TRUTH) since Dave says at the highest settings there is high frequency loss and with the phono that is where I am, top four positions are used, one's below much too soft. With the TRUTH this is not a problem so no need for additional gain.

I am asking the SLAGLE to drive the SIT 1s and a buffer that is part of my LC low pass filter (buffer - LC filter - buffer, using the TOSHIBA 2SK170/2SK74 combo) - I hear no problems with that but I have to believe the BUF03s will do a better job. AS is usually the case for me I hear the problem after it is gone, rarely before. My skepticism is running high with all of the audio iconoclasm going on with this box - IC buffers, switching power supplies.

If it seems too good to be true - could it not work out at least once in one's audio lifetime?

From what I can gather there is an LED modulated by the incoming music signal and the photocell is the receiver. No resistors in the signal path other than the balance control which Ed swears is completely benign.

carlsor, whom you might remember from the DDDAC thread, got one and substituted one of the conventional "Lightspeed" style setups for the parallel element, replacing he balance control even though Ed told him it would make no difference and sure enough it made no difference. Ed says the quality of the pot makes no difference.

Ed swears the Chinese will copy the device but he says the trick is the photocell he is using which I suspect will be suitably disguised. And that makes all of the difference.

Funny how at 62 years of age I have already lapsed into that "last purchase" syndrome. But I can tell you sincerely I hope this IS the last volume control I ever buy. Always hoping for things to improve, don't get me wrong, but it would be a bonus if this stayed REALLY GOOD until my ears start failing. And then I won't have to worry about it.

BUF03 is pure buffer - no gain possible without putting a gain stage in front of it. You can still find the data sheet.

Next I will tell you about my adventures with half wave rectification in the SALAS phono amp. Nothing so new as the oldest you can find? There is a reason to use the half wave in places like a phono stage. The noise reduction is akin to digital noise reduction. The noise you lose is of the same character - intertwined within the music and the space. Of course, one should not use just any rectifier ... Yes, there will be more of the obvious audible noise, very little but it is there, easy to ignore. The thing is: how much unpleasant noise have we introduced into our systems in attempting to get rid of low levels of hum? The old noise envelope ...

Take care,

what does the volume control bit?

[rickmcinnis]

That is a good question!

I have not bothered to think it through.

One would think a resistor is in there somewhere before the LED ...

That's why I write about these things in TIR NA!!!

[rickmcinnis]

I just figured it out, I think.

He is using some kind of shade between the LED and the photocell. Only thing possible?

[nige2000]

I just figured it out, I think.

He is using some kind of shade between the LED and the photocell. Only thing possible?

you think the audio signal is been passed between a photocell and ldr?

[nige2000]

has to be something like this

http://robmid42.wixsite.com/diyaudiokit ... eamplifier
http://buildanamp.com/Clone-Note-aka-Li ... oteKit.htm
only buffered
on my pass f5 prototype even going into j74/k170 front ends which are supposed to be a high impedance input still seems to benefit from a pre buffer