LED’S and such
To just test the led to see if it works get a 3 volt waffer style battery. Something like a 2032 the kind on your computer motherboard. As long as it’s 3 volts. You can also determine which leg is positive or negitive.
If I were you I would not worry about the led or it’s companion resistor, they are not needed. Does the channel power up?
Did you read those two posts I sent to you, about the power up and bias procedure?
OOOOOOOOHHHHHHHHHHH young Spark Maker, when you can take the Capacitor from my hand you will know you are ready!!!
Sometimes I just kill myself
To just test the led to see if it works get a 3 volt waffer style battery. Something like a 2032 the kind on your computer motherboard. As long as it’s 3 volts. You can also determine which leg is positive or negitive.
If I were you I would not worry about the led or it’s companion resistor, they are not needed. Does the channel power up?
Did you read those two posts I sent to you, about the power up and bias procedure?
OOOOOOOOHHHHHHHHHHH young Spark Maker, when you can take the Capacitor from my hand you will know you are ready!!!
Sometimes I just kill myself
Yes. I powered up successfully yesterday. And I did read everything you pointed me to.
I had read it before, but somehow this time it sunk in. Thanks for that.
And yes, I may just walk away from the LEDs to press to the finish line.
I had read it before, but somehow this time it sunk in. Thanks for that.
And yes, I may just walk away from the LEDs to press to the finish line.
Great News
You can always install them later.
Lets just get some Bob Seger on that crazy thing. “Katmandu” Loud
You can always install them later.
Lets just get some Bob Seger on that crazy thing. “Katmandu” Loud
The long leg/anode should go to the square hole.
You can also test an led using the diode testing capability of your multimeter:
Polarity - learn.sparkfun.com
As other members have pointed out, the LED is not necessary.
You can also test an led using the diode testing capability of your multimeter:
Polarity - learn.sparkfun.com
As other members have pointed out, the LED is not necessary.
Thanks. I did test the red LEDs. They appear ok. I'm moving on to blue. If they don't work life goes on.
Left channel is up.
Turns out the Red LED is the dimmest one I've seen.
Now I can return to Dirk's guide for biasing P1 & P2.
Turns out the Red LED is the dimmest one I've seen.
Now I can return to Dirk's guide for biasing P1 & P2.
Hmmm,
I have the amp on and up with R7 and R8 at 0.1
I started to adjust the right channel and turned R7 quite a bit and no change on the 3 meters.
But its been running for 30 minutes and there is no heat in the sinks or the capacitors.
Power is on, all LEDs are working.
Any thoughts?
I have the amp on and up with R7 and R8 at 0.1
I started to adjust the right channel and turned R7 quite a bit and no change on the 3 meters.
But its been running for 30 minutes and there is no heat in the sinks or the capacitors.
Power is on, all LEDs are working.
Any thoughts?
Chiptech,
Some clarification is needed. You said that R7 and R8 at 0.1. What did you measure? Is it Volts? Please provide units when you give measurements.
The pots to turn are P1 and P2. Were you adjusting those?
You mention "Dirk's guide for biasing". Please provide a link so we can see what procedure you are following.
Some clarification is needed. You said that R7 and R8 at 0.1. What did you measure? Is it Volts? Please provide units when you give measurements.
The pots to turn are P1 and P2. Were you adjusting those?
You mention "Dirk's guide for biasing". Please provide a link so we can see what procedure you are following.
R7 & R8 are at 0.1 and 0.2 mV
i was starting to adjust P1 and P2.
Here is the link:
"When I built my F5 these two posts cleared it all up for me.
#106 and#109. The entire thread is full of good Info."
Another F5 Build Another F5 Build
thanks
i was starting to adjust P1 and P2.
Here is the link:
"When I built my F5 these two posts cleared it all up for me.
#106 and#109. The entire thread is full of good Info."
Another F5 Build Another F5 Build
thanks
OK, let's check that the pot is increasing the Vgs voltage. Let's stick to P1
for now. Can you try the following:
First power down, and then take the meter off R8 and attach it across R5
(which is in parallel with P1). Set this meter to DC V scale. Now power up again.
What voltage do you see across R5? Try adjusting P1. Does the voltage across
R5 change?
for now. Can you try the following:
First power down, and then take the meter off R8 and attach it across R5
(which is in parallel with P1). Set this meter to DC V scale. Now power up again.
What voltage do you see across R5? Try adjusting P1. Does the voltage across
R5 change?
How much did you turn P1 and P2?
Take the voltmeter off R8 and connect it across R5 and set it to VDC.
Power up and take VDC measurement across R5.
Also measure VDC across R6.
I was typing and Dennis beat me to it.
Take the voltmeter off R8 and connect it across R5 and set it to VDC.
Power up and take VDC measurement across R5.
Also measure VDC across R6.
I was typing and Dennis beat me to it.
The reading from R5 started at 0.01 V DC when I first turned it on. By turning P1 counterclockwise I turned it up to 0.518 V DC. Then I turned it up to 1.008 V DC. And then stopped.
P2 started at 0.02 and I turned counterclockwise and got to 1.000 V DC.
Sorry for the delayed response, had to attend to the home scene.
P2 started at 0.02 and I turned counterclockwise and got to 1.000 V DC.
Sorry for the delayed response, had to attend to the home scene.
So P1 and P2 are turned all the way? If so, then the 1.0V at R5 and R6 are too low. It (Vgs) is too low to turn on the output Mosfets.
What is VDC across R3 and R4?
If P1 and P2 are at maximum, the resistance of R5/P1 paralleled and R6/P2 paralleled is 1532 Ohms, and I = 1.0V/1532R= 0.6mA. This is the current through the paralleled resistances and also through the jfets. This current is very low. It needs to be higher for the Vgs to be higher.
I suspect an issue with the jfets. However, you should wait for an expert opinion from someone with a better understanding of this part of the circuit to give you some definitive advice.
What is VDC across R3 and R4?
If P1 and P2 are at maximum, the resistance of R5/P1 paralleled and R6/P2 paralleled is 1532 Ohms, and I = 1.0V/1532R= 0.6mA. This is the current through the paralleled resistances and also through the jfets. This current is very low. It needs to be higher for the Vgs to be higher.
I suspect an issue with the jfets. However, you should wait for an expert opinion from someone with a better understanding of this part of the circuit to give you some definitive advice.
Chiptech, please measure the voltages across R3 and R4 as Ben
asked to check the jfets. I suggest using the mV DCV scale.
If the jfets are functioning correctly you you'll likely see numbers
in the 50 to 100mV range.
Now when you said the voltages across R5 and R6 got to around 1V and stopped,
did that mean you stopped turning or that P1 and P2 were maxed out and turning
did not increase the voltage further?
If it's the former, then it's likely you simply haven't turned P1 and P2 enough.
These voltage need to be in the 3 to 4 volt range before the
output mosfets start to conduct current.
If it is the latter, then please power down and then measure again the
resistances across R5 and R6 (with P1 and P2 max out) and see if they
are in the 1.5K ohm range.
Also, please confirm that the bulb tester is no longer attached for the bias procedure.
asked to check the jfets. I suggest using the mV DCV scale.
If the jfets are functioning correctly you you'll likely see numbers
in the 50 to 100mV range.
Now when you said the voltages across R5 and R6 got to around 1V and stopped,
did that mean you stopped turning or that P1 and P2 were maxed out and turning
did not increase the voltage further?
If it's the former, then it's likely you simply haven't turned P1 and P2 enough.
These voltage need to be in the 3 to 4 volt range before the
output mosfets start to conduct current.
If it is the latter, then please power down and then measure again the
resistances across R5 and R6 (with P1 and P2 max out) and see if they
are in the 1.5K ohm range.
Also, please confirm that the bulb tester is no longer attached for the bias procedure.
Chiptech, please measure the voltages across R3 and R4 as Ben
asked to check the jfets. I suggest using the mV DCV scale.
If the jfets are functioning correctly you you'll likely see numbers
in the 50 to 100mV range.
R3 measures -056.2 mV DCV
R4 measures 075.6 mV DCV
Now when you said the voltages across R5 and R6 got to around 1V and stopped,
did that mean you stopped turning or that P1 and P2 were maxed out and turning
did not increase the voltage further?
Yes, I stopped turning them further. Sorry for the imprecise language.
If it's the former, then it's likely you simply haven't turned P1 and P2 enough.
These voltage need to be in the 3 to 4 volt range before the
output mosfets start to conduct current.
So I can return to adjusting P1 and P2? I'm learning I will have to turn more than I was expecting.
If it is the latter, then please power down and then measure again the
resistances across R5 and R6 (with P1 and P2 max out) and see if they
are in the 1.5K ohm range.
Also, please confirm that the bulb tester is no longer attached for the bias procedure.
I am no longer using the bulb tester. Yea!
asked to check the jfets. I suggest using the mV DCV scale.
If the jfets are functioning correctly you you'll likely see numbers
in the 50 to 100mV range.
R3 measures -056.2 mV DCV
R4 measures 075.6 mV DCV
Now when you said the voltages across R5 and R6 got to around 1V and stopped,
did that mean you stopped turning or that P1 and P2 were maxed out and turning
did not increase the voltage further?
Yes, I stopped turning them further. Sorry for the imprecise language.
If it's the former, then it's likely you simply haven't turned P1 and P2 enough.
These voltage need to be in the 3 to 4 volt range before the
output mosfets start to conduct current.
So I can return to adjusting P1 and P2? I'm learning I will have to turn more than I was expecting.
If it is the latter, then please power down and then measure again the
resistances across R5 and R6 (with P1 and P2 max out) and see if they
are in the 1.5K ohm range.
Also, please confirm that the bulb tester is no longer attached for the bias procedure.
I am no longer using the bulb tester. Yea!
I will devote tomorrow to getting it done.
Again, thanks for all the help along the way to everyone.
Again, thanks for all the help along the way to everyone.
Chiptech, I had another look at Dirk's post you referenced earlier. He was writing about
the F5 Turbo. The biasing procedure is the same, but your final target voltages
across the source resistors R7 and R8 should be about 0.6V, corresponding to about 1.3A.
So I would probably start by bringing things up slowing to about 0.4V and
adjusting the DC offset to be close to zero.
Also, please keep the lid on when you are waiting for the amp to heat up.
the F5 Turbo. The biasing procedure is the same, but your final target voltages
across the source resistors R7 and R8 should be about 0.6V, corresponding to about 1.3A.
So I would probably start by bringing things up slowing to about 0.4V and
adjusting the DC offset to be close to zero.
Also, please keep the lid on when you are waiting for the amp to heat up.