The TRUTH attenuator/buffer

[nige2000]

on second thoughts its probably much simplier like this buffered


stole from "diy paradise"

[rickmcinnis]

He says it is not like any of the LIGHTSPEED style devices.

There is a discreet LED of some sort and a discrete device to receive the light.

So how many ways are there to attenuate the output of an LED without using resistance?

I would not know.

[nige2000]

looks like here to be
signal in > buf-03 > LDR > buf-03 > signal out




thank you and goodnight.....

and im here all week.....

all joking aside id be thinking along the same lines
buffer the input before you trim and after to reconstitute

whether an ldr is better than a super sexy fancy resistor i really dunno
ill have to put it on my list

[rickmcinnis]

I don't think he could sell them if it was just something like that.

Discreet light source (LED, I am almost sure) and some kind of receptor. There has been mention of efforts to control the light within the enclosure.

The question is how is the output to the LED modulated?

Ed says when he dies his wife will reveal the schematic.

I do not think even if one COULD build it the savings would be worth the trouble so did not hesitate to get one.

Have a couple of weeks to wait until it arrives.

[rickmcinnis]

You made that last post while I was writing.

I have not seen those pictures. I thought I had looked thoroughly

From what I understand he is using a PCB now.

I am a little disappointed that it is an LDR as if I know what one looks like ...

I know I tried my complementary buffers before and after the Slagle and did not think it helped at all but that is not a resistor.

Thanks for the sleuthing!

[rickmcinnis]

Got the magic box.

Been listening to it for two weeks now.

As you wound expect even from the first it sounded different from the SLAGLE. Really different. I was not happy with the tonal balance but you could hear an incisiveness that was not there before and now it is here in realistic proportions.. Not like those paint by numbers presentation with the lines defining each space.

After a few hours it occurred to me the SLAGLE is much bigger in the bass so I adjusted the subs and that took care of the tonal balance problem.

One realizes that the SLAGLE compresses the signal in both macro and micro dynamics. I turn it up to what i think is the level I usually play a record and all of a sudden it is much louder than I remembered in the loud parts. Small sounds have much more life to them.

I am glad I got the thing. It has made more than a subtle improvement to what I am hearing. The balance control is great to have. There is something to be gained by getting the levels right. never could with the SLAGLE due to it having pretty broad steps of attenuation.

The one I have looks much better inside than the pictures posted. This was a relief. But this is a very simple device as far as parts count.

I got him to use two of the MEANWELL switchers instead of one. I keep trying to hear ill effects of either the BUF03 or the switchers. It has yet to occur. Since I get the feeling the BUF03 really likes smps I will eventually install Didden's SILENTSWITCHER which is a DC-DC converter with a quiet linear reg on the output and power it with a LiFePo volts battery pack just to keep some batteries in the system. None at the moment.

Could it be that one should not use the same power supply configuration for each component? What is worse? One big "kind" of sound or spreading the noises around? If one could figure out a way to cancel the one big sound that would be best but i am thinking that it might be the best compromise to use various types in our systems. One of those things you think about while sipping whiskey and listening to music.

On a side subject - after years of thinking about it I removed the regulator from the SALAS phono and am using a brute force unregulated supply. Using PSUD to give me a little guidance it tells me the supply I am using has 100 nanovolts of ripple. Now whether that is even possible in the real world I would not know but I figure the end result has to be decent.

Inspired by Jim Smith, Mr. Yazaki and SOUND PRACTICES magazine this is the supply.
36 volts 300VA toroid - STTH6110 diode (half wave) - 20 uF input cap (half PP/half motor run) - 5 hys/26R choke - 1500 uF PP DC Link cap to ground - a second filter just as the first - 300mHy/10R choke with 6000 uF to ground - mix of electrolytics/ a couple of BGs/ and a PP GTO cap.
There is a 3000R bleeder to fine tune voltages. Of course the input cap is used for this, too.

It is at least as quiet as the reg and sounds better. Even a MOSFET in a shunt regulator has that haze. One of those easy to ignore things that I cannot hear until it is gone.

The same CLCLC part, with a higher voltage power transformer was the raw supply for the SALAS reg. I added the last stage for this. I had wondered if the reg was getting in the way of the raw supply? I think it was.

This supply was built with parts i had laying about for years/decades so I am not recommending it. It is huge and expensive if bought at one time. But if one is interested in what is possible ...

[nige2000]

any chance of a pic?

ive some buf-03 on route for testing