thanks a lot Uriah!
will take a look at Jung's article and later try stabilize Salas reg. Indeed, it might be more than 15min when voltage starts to drop/ increase, unfortunately do not remember precisely. Anyway it would be good to compare this shunt reg with 7805 as no one reported any results here before. Hope to find some time for that in December 🙂
will take a look at Jung's article and later try stabilize Salas reg. Indeed, it might be more than 15min when voltage starts to drop/ increase, unfortunately do not remember precisely. Anyway it would be good to compare this shunt reg with 7805 as no one reported any results here before. Hope to find some time for that in December 🙂
As AndrewT has stated "A 7805 or 317 is perfectly good enough for the LDR supply."
In posts by me way back, I did noise/hum measurements on the production Lightspeed Attenuator with standard 7805 regulated power supply and linear wall wart.
With the input shorted the noise (there is no hum) on the output was at 100uV!!!!(microvolts) not mV(millivolts), this is so low that even my Tektronic scope had trouble measuring it above it's own noise floor, sure if you put on a smp wall wart this went up to around 200uV but this is still considered to be very low.
I've always stated my dislike for smp wall warts as the noise from these comes in anywhere even the air. They are dirty as can be.
As far as driving this circuit, it consumes so little it can almost be driven by rubbing two sticks together.
Cheers George
In posts by me way back, I did noise/hum measurements on the production Lightspeed Attenuator with standard 7805 regulated power supply and linear wall wart.
With the input shorted the noise (there is no hum) on the output was at 100uV!!!!(microvolts) not mV(millivolts), this is so low that even my Tektronic scope had trouble measuring it above it's own noise floor, sure if you put on a smp wall wart this went up to around 200uV but this is still considered to be very low.
I've always stated my dislike for smp wall warts as the noise from these comes in anywhere even the air. They are dirty as can be.
As far as driving this circuit, it consumes so little it can almost be driven by rubbing two sticks together.
Cheers George
I have three sticks..... 1xOak, 1xBeech, and 1x Yew.
Which combination would you recommend.... ?
EDIT...... now a moot point as the Beech broke when I first tried rubbing it together with the Yew.
Then the dog ran off with the Oak and I can confirm that one stick is not enough to power the unit. :-(
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Noise floor of Beech vs oak - scope pictures soon
Just make sure the Beech and the Yew do not create noise and you will get great sound. If they do make a higher noise floor, you'll still get darn good sound, maybe just a little wooden sounding .
Just make sure the Beech and the Yew do not create noise and you will get great sound. If they do make a higher noise floor, you'll still get darn good sound, maybe just a little wooden sounding .
George,
I found a little problem on my volume lately. I had it on 24/7 for several months and it sang for me with no problem, but lately I've found the left channel sounds louder than the right when I turn it up to above 11 o'clock. I have both channels checked and the resistance of both channels are the same when in 9 o'clock but starts to vary from 1100 ohms to 1306 ohms when I turn the pot up to 11 o'clock. The more I turned the volume the larger the variation. I have the 1k pot tuned but with no avail. I then put another 1k pot on the other channel but it doesn't work either. The 5v B+ is absolutely stable. Is something fired or ?? Please do advise.
Thanks
Albert
I found a little problem on my volume lately. I had it on 24/7 for several months and it sang for me with no problem, but lately I've found the left channel sounds louder than the right when I turn it up to above 11 o'clock. I have both channels checked and the resistance of both channels are the same when in 9 o'clock but starts to vary from 1100 ohms to 1306 ohms when I turn the pot up to 11 o'clock. The more I turned the volume the larger the variation. I have the 1k pot tuned but with no avail. I then put another 1k pot on the other channel but it doesn't work either. The 5v B+ is absolutely stable. Is something fired or ?? Please do advise.
Thanks
Albert
Did you flip the RCA's from the source into the attenuator to prove it was the attenuator?
Just being thorough... 😉
I can't remember Albert did you build this diy Lightspeed inside a pre or poweramp or is it a stand alone unit?
Cheers George
Cheers George
Seems to me then if it was not a fluctuating heat issue, that can happen if instaled inside pre or poweramps.
That maybe you could have had some very strong dc offset or test bench type audio signal come into the input or output that has given your ldr's a bit of a hammering, this can change their resistance character and unmatch them. Time to get another matched set.
Am I right from your pictures that you have separtate left and right led volume controls? And did you say they were 1Kohm?
Cheers George
That maybe you could have had some very strong dc offset or test bench type audio signal come into the input or output that has given your ldr's a bit of a hammering, this can change their resistance character and unmatch them. Time to get another matched set.
Am I right from your pictures that you have separtate left and right led volume controls? And did you say they were 1Kohm?
Cheers George
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George,
Seems to me then if it was not a fluctuating heat issue, that can happen if instaled inside pre or poweramps.
No, mine is a separated / stand alone unit. I posted it on this thread but couldn't find it.
That maybe you could have had some very strong dc offset or test bench type audio signal come into the input or output that has given your ldr's a bit of a hammering, this can change their resistance character and unmatch them.
Don't understand either, It has been playing for me after finished. I didn't touch it until couple days ago.
Am I right from your pictures that you have separtate left and right led volume controls?
A single Alps dual 100k pot.
And did you say they were 1Kohm?
There was only one 1k trimmer on the louder side, but I put another one on to test after I found the problem.
Time to get another matched set.
Oh, is there anyway I could try / test it before I talk to Uriah for a new set.
Thanks
Albert
Seems to me then if it was not a fluctuating heat issue, that can happen if instaled inside pre or poweramps.
No, mine is a separated / stand alone unit. I posted it on this thread but couldn't find it.
That maybe you could have had some very strong dc offset or test bench type audio signal come into the input or output that has given your ldr's a bit of a hammering, this can change their resistance character and unmatch them.
Don't understand either, It has been playing for me after finished. I didn't touch it until couple days ago.
Am I right from your pictures that you have separtate left and right led volume controls?
A single Alps dual 100k pot.
And did you say they were 1Kohm?
There was only one 1k trimmer on the louder side, but I put another one on to test after I found the problem.
Time to get another matched set.
Oh, is there anyway I could try / test it before I talk to Uriah for a new set.
Thanks
Albert
It is possible that a dual 100k pot can have problems, but this would show in both channels equally, as a jump or lowering of both channels equally. But seeing you have a single dual pot and have wired it as I've shown in the Lightspeed Attenuator circuit, controlling both channels it takes the pot out of the equation because it's only happening on one of the channels.
Before installing another quad set of led/ldr's you could question your 1k trimmers they are far less costly to replace than the matched ldr's.
And btw you only need one trimmer, and it goes on the louder of the two channels.
Cheers George
Before installing another quad set of led/ldr's you could question your 1k trimmers they are far less costly to replace than the matched ldr's.
And btw you only need one trimmer, and it goes on the louder of the two channels.
Cheers George
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George,
After replacing the 1k trimmer on the louder side, the case remains. I then move to question the Alp volume pot. I couldn't find the dual 100k, but there are 2 single turn Bourne 100k pot, blue in color, sitting on the bench. I make the conversion in no time and it works perfect on test, and I put it to the system and it sings flawlessly well. The only drawback is the pots are not log pots and it's too sensitive to make adjustment. I just have to turn 2 mm to the volume I need. Is there anyway I could make improvement with these pots, or I have to buy new ones ????
Thanks
Albert
After replacing the 1k trimmer on the louder side, the case remains. I then move to question the Alp volume pot. I couldn't find the dual 100k, but there are 2 single turn Bourne 100k pot, blue in color, sitting on the bench. I make the conversion in no time and it works perfect on test, and I put it to the system and it sings flawlessly well. The only drawback is the pots are not log pots and it's too sensitive to make adjustment. I just have to turn 2 mm to the volume I need. Is there anyway I could make improvement with these pots, or I have to buy new ones ????
Thanks
Albert
RV24BF-10-15R1-A100K Alpha (Taiwan) | Mouser
And they probably have the singles as well.
Cheers George
And they probably have the singles as well.
Cheers George
George,
I brought 2 single A100k pots in local store to replace the Bourne and now I have more room to tune. Everything back to normal as before. I can recall I read somewhere that you mentioned I should put the volume half way when not in use, say 12 o'clock. I'd love to know more since my intention is to keep it on 24/7.
Thanks
Albert
I brought 2 single A100k pots in local store to replace the Bourne and now I have more room to tune. Everything back to normal as before. I can recall I read somewhere that you mentioned I should put the volume half way when not in use, say 12 o'clock. I'd love to know more since my intention is to keep it on 24/7.
Thanks
Albert
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Good to see you have got it going again, but you know you still have a damaged/unmatched set of ldr's, but by using separate l & R volume controls you have, band-aid fixed your problem.
Yes volume left at the half way posistion will turn on the led's at only half brightness when your not using it, and hence make them last twice as long.
Cheers George
Yes volume left at the half way posistion will turn on the led's at only half brightness when your not using it, and hence make them last twice as long.
Cheers George
Funny I just got an diyaudio pm/email from "shaker" I don't know if that's his forum name or not but he has not activated his return pm via this forum.
He asks
"Hello,
I wanted to ask you (being the designer), is there any way I can use unmatched resistors? How can I do it and get away with it. I can solve this issue in case I understood what to do, I can use controllers, may be this helps?
thanks"
Shaker by unmatched resistors I asume you mean unmated ldr's, to answer your question, you can get around it depending how unmatched they are by doing what Albertli did above by using separate l & r volume controls.
PS Just found out his forum name is "metal"
Cheers George
He asks
"Hello,
I wanted to ask you (being the designer), is there any way I can use unmatched resistors? How can I do it and get away with it. I can solve this issue in case I understood what to do, I can use controllers, may be this helps?
thanks"
Shaker by unmatched resistors I asume you mean unmated ldr's, to answer your question, you can get around it depending how unmatched they are by doing what Albertli did above by using separate l & r volume controls.
PS Just found out his forum name is "metal"
Cheers George
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