Aleph 4 LED

jduncan · 15th November 2001, 02:27 AM

So I've been staring at the Aleph 4 schematic for awhile trying to work out what the LED tied into the output does....

I'm assuming that this is some kindof indicator, possibly indicating clipping?

If this is an indicator though, wouldn't there be some set parameters for the diode? It just indicates some random LED there so that's what's confusing me....

tortello · 15th November 2001, 09:36 AM

Hello Jduncan,
I think that this is only due to a layout convenience, in fact the blue led is positioned on one of the 4 of the output Hexfet PCBs.
Of course the LED's light is modulated by the output signal, but the audio frequencies are too fast for our retinas, we only see his mean value, that is constant, from 0 to the maximum output power.

[Edited by tortello on 11-15-2001 at 09:39 AM]

Joe Berry · 15th November 2001, 02:05 PM

jduncan,

I think this is just an error in the earlier schematics. More recent drawings (Aleph 30/60) show the LED and its current-limiting resistor connected between + and ground, which is what you'd expect.

cp642 · 15th November 2001, 04:19 PM

Joe,
Can you point to me on where to obtain the Aleph 30 / 60 drawings?

Freddie · 15th November 2001, 04:54 PM

cp642,

Schematics for Aleph 30/60 can be found here:
http://www.volksamp.com

/Freddie

jduncan · 15th November 2001, 07:47 PM

the reason I asked is that ALL the aleph schematics have it connected into the output (or close enough) and when they corrected the other mistakes on those schematics (the aleph 4 in particular had things like x3 instead of x6 for the number of output mosfets etc) they didn't change this.

It's also a pretty monumental "mistake" to draw that into the output rather than straight to ground.....

So I'm thinking that it was there for a reason, but that volksamp decided not to keep it when they moved to the aleph 30/60.

I'm just interested in the reason

Joe Berry · 15th November 2001, 08:07 PM

jduncan,

There's no harm I can see in connecting the LED as shown in the earlier schematics. In fact, it could be useful as a DC fault indicator, if you knew how to read it. I'm only supposing it to be an error in light of the later schematics which show the more conventional connection.

jduncan · 15th November 2001, 08:15 PM

Yeah I'm sure there's no harm in doing it either way! I was just intrigued as to why it was done in that way and precisely what the error it signaled would be.....

but thanks!

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15th November 2001, 02:27 AM	#1
jduncan diyAudio Member Join Date: Nov 2001 Location: Boston, MA, USA	So I've been staring at the Aleph 4 schematic for awhile trying to work out what the LED tied into the output does.... I'm assuming that this is some kindof indicator, possibly indicating clipping? If this is an indicator though, wouldn't there be some set parameters for the diode? It just indicates some random LED there so that's what's confusing me....

15th November 2001, 09:36 AM	#2
tortello diyAudio Member Join Date: Jul 2001 Location: Genoa (ITALY)	Hello Jduncan, I think that this is only due to a layout convenience, in fact the blue led is positioned on one of the 4 of the output Hexfet PCBs. Of course the LED's light is modulated by the output signal, but the audio frequencies are too fast for our retinas, we only see his mean value, that is constant, from 0 to the maximum output power. [Edited by tortello on 11-15-2001 at 09:39 AM]

15th November 2001, 02:05 PM	#3
Joe Berry diyAudio Member Join Date: Mar 2001 Location: USA	jduncan, I think this is just an error in the earlier schematics. More recent drawings (Aleph 30/60) show the LED and its current-limiting resistor connected between + and ground, which is what you'd expect.

15th November 2001, 04:19 PM	#4
cp642 diyAudio Member Join Date: Aug 2001	Joe, Can you point to me on where to obtain the Aleph 30 / 60 drawings?

15th November 2001, 04:54 PM	#5
Freddie diyAudio Member Join Date: Oct 2000 Location: Sweden	cp642, Schematics for Aleph 30/60 can be found here: http://www.volksamp.com /Freddie

15th November 2001, 07:47 PM	#6
jduncan diyAudio Member Join Date: Nov 2001 Location: Boston, MA, USA	the reason I asked is that ALL the aleph schematics have it connected into the output (or close enough) and when they corrected the other mistakes on those schematics (the aleph 4 in particular had things like x3 instead of x6 for the number of output mosfets etc) they didn't change this. It's also a pretty monumental "mistake" to draw that into the output rather than straight to ground..... So I'm thinking that it was there for a reason, but that volksamp decided not to keep it when they moved to the aleph 30/60. I'm just interested in the reason

15th November 2001, 08:07 PM	#7
Joe Berry diyAudio Member Join Date: Mar 2001 Location: USA	jduncan, There's no harm I can see in connecting the LED as shown in the earlier schematics. In fact, it could be useful as a DC fault indicator, if you knew how to read it. I'm only supposing it to be an error in light of the later schematics which show the more conventional connection.

15th November 2001, 08:15 PM	#8
jduncan diyAudio Member Join Date: Nov 2001 Location: Boston, MA, USA	Yeah I'm sure there's no harm in doing it either way! I was just intrigued as to why it was done in that way and precisely what the error it signaled would be..... but thanks!