LEDs
The LEDs on the bases of the output devices are current limiters.
When the base to emmitter voltage plus 5.1 times the output current equals about 1.8 Volts (turn on voltage for green LED). The LED steals current from the base of the output transistor. this provides short circuit protection. Leave the 100 resistor in the output for stability into capacitive loads (like cables for example) Simulation will tell you very little about distortion. This circuit may be too low in distortion for you to measure with your set up.
H.H.
The LEDs on the bases of the output devices are current limiters.
When the base to emmitter voltage plus 5.1 times the output current equals about 1.8 Volts (turn on voltage for green LED). The LED steals current from the base of the output transistor. this provides short circuit protection. Leave the 100 resistor in the output for stability into capacitive loads (like cables for example) Simulation will tell you very little about distortion. This circuit may be too low in distortion for you to measure with your set up.
H.H.
Distorsion
Harry thank you I have changed the LED to blue but the original says red did it makes any difference or... how low THD ?? if so this little circuit must be rather good is it not.
Other parameters is noise and frequency response but was is the most important your ears yes but you must know all about its behavior temperature drift long term stability and so on, yes...
Harry thank you I have changed the LED to blue but the original says red did it makes any difference or... how low THD ?? if so this little circuit must be rather good is it not.
Other parameters is noise and frequency response but was is the most important your ears yes but you must know all about its behavior temperature drift long term stability and so on, yes...
The LED's
Ooh! that was not good for my ears to hear. I must say one of the best solid state amplifier that I listen to was an old Danish Arena with an class A single ended output with transformer just wonderful I would like to try a modern version if I can find the schematics, sounds you remember can't be bad.
Ooh! that was not good for my ears to hear. I must say one of the best solid state amplifier that I listen to was an old Danish Arena with an class A single ended output with transformer just wonderful I would like to try a modern version if I can find the schematics, sounds you remember can't be bad.
My previous post was mostly for entertainment purposes, since I didn't check the effect of LEDs myself yet. And I know, you like to use them as voltage reference, Art. I'm also using LEDs as power indicators and in my Ono preamp.
But If someone is claiming that they do something to the sound, it would be interesting to investigate. Somebody eventually checked the skinned caps and it came out that there is a difference. Maybe the same is with LEDs.
But who's gonna be the first to undertake such a complicated task? I'm too busy with my AX amp, not to mention my Home Theatre project I just started yesterday. My wife can't stand that the basement is not done yet.
But If someone is claiming that they do something to the sound, it would be interesting to investigate. Somebody eventually checked the skinned caps and it came out that there is a difference. Maybe the same is with LEDs.
But who's gonna be the first to undertake such a complicated task?
I'm too busy with my AX amp, not to mention my Home Theatre project I just started yesterday. My wife can't stand that the basement is not done yet.
But of course a LED will cause a colouration, except for the
white and infrared ones, maybe.
Art,
I have seen the photos under your name change repeatedly,
and I am getting worreid about you. You seem to have been ageing at rocket speed during the past week or two. Maybe it
is those read and green things you are eating?
white and infrared ones, maybe.
Art,
I have seen the photos under your name change repeatedly,
and I am getting worreid about you. You seem to have been ageing at rocket speed during the past week or two. Maybe it
is those read and green things you are eating?
Peter Daniel said:I would be carefull with all those LEDs. I've read somhere on the forum that they degrade the sonics.
I think that white ones would be least intrusive.
Normally the LED's don't conduct but they are like (somewhat) unlinear caps. The _might_ influence the sound but they are a simple solution for current limitation. I suggest that you start with them. If you change colours you will also change current because of different voltages across the LED's. Is some colour better than any other, don't know. White and blue LED's have much higher voltage. IR-LED's has the lowest.
My advice is to start with LED's and if you are unhappy because of them, replace them with a transistor limiter.
Re: Gasping for
Leiade reading your posts I have a kind of déjàvue feeling.... Is leiade the same person as Groman???
I apologize leiade, if this is not true.
I would advice concrete 1000mmleiade said:I have ordered a faceplate made of 10 mm stainless steel can I use this material or it is better to order a 10 mm aluminium faceplate.
Leiade reading your posts I have a kind of déjàvue feeling.... Is leiade the same person as Groman???
I apologize leiade, if this is not true.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.