Ohh damn, waste of time!
That shitty speaker is not sounding good at all.
In the video ofcourse.
Not sure why but it sounds so boomy in the video.
But theres A good thing... It sounds great, The output power is limited due low supply voltage, around 10W peak and ~1,5W seriously low noise, havent measured btw... If I do i might get results that I cannot accept .
192kbit/s 1 minute and 3 seconds of noise but now with a Picture!
https://www.youtube.com/watch?v=kphu1V8zl2I
It sounds alot better in real life, might try to record with CD player and build mic for dat PC that has sound card but its silent...
But the noise was surprisingly low even with that rubbish headphone wire, not shielded or anything :O
That shitty speaker is not sounding good at all.
In the video ofcourse.
Not sure why but it sounds so boomy in the video.
But theres A good thing... It sounds great, The output power is limited due low supply voltage, around 10W peak and ~1,5W seriously low noise, havent measured btw... If I do i might get results that I cannot accept .
192kbit/s 1 minute and 3 seconds of noise but now with a Picture!
https://www.youtube.com/watch?v=kphu1V8zl2I
It sounds alot better in real life, might try to record with CD player and build mic for dat PC that has sound card but its silent...
But the noise was surprisingly low even with that rubbish headphone wire, not shielded or anything :O
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One more video, fixed that bass problem by using other mic...
OPA27GP + 2SC5200/2SA1943 boosted opamp - YouTube
The cam is a bit slow and muddy, my cameraman skills are permanently rotten
OPA27GP + 2SC5200/2SA1943 boosted opamp - YouTube
The cam is a bit slow and muddy, my cameraman skills are permanently rotten
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Few picstures of amplifier case that survived nuclear bomb blast. Anyway I added another layer of varnish just to make it look a little bit better, its probably not the finale case the amp is going to be inside, its too damn cold to work in my workshop -32° C ...
Even spray varnish was frozen.
http://s6.postimg.org/s1r8p5vo1/PIC_4237.jpg
http://s6.postimg.org/xfq0wple9/PIC_4242.jpg
http://s6.postimg.org/qb87noe4x/PIC_4238.jpg
Even spray varnish was frozen.
http://s6.postimg.org/s1r8p5vo1/PIC_4237.jpg
An externally hosted image should be here but it was not working when we last tested it.
http://s6.postimg.org/xfq0wple9/PIC_4242.jpg
An externally hosted image should be here but it was not working when we last tested it.
http://s6.postimg.org/qb87noe4x/PIC_4238.jpg
An externally hosted image should be here but it was not working when we last tested it.
Ohh hell no
Destroyed my transformer today, managed to drill hole into the primary.
I dont know how badly but I have to get new one before i can record highest possible sound quality with my other PC thats located at my department where I normally do my work.
So far so good right now its powered by 2 car batteries... I can compare it to LM4766 but it puts out alot more heat, less power and better sound
I want to try 8 ohm speakers, at 4 ohms the output power is around 5-8W RMS maybe even more but at full power the speakers start to move really weird.
Cant wait till I sit down and listen to this amp for hours.
My circuit........... I must reduce gain its a bit noisy when theres no pot on the input, even if cable is shielded it takes whatever it can and amplify it till your ears explode
I know yall will laugh your ***** off
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Destroyed my transformer today, managed to drill hole into the primary.
I dont know how badly but I have to get new one before i can record highest possible sound quality with my other PC thats located at my department where I normally do my work.
So far so good right now its powered by 2 car batteries... I can compare it to LM4766 but it puts out alot more heat, less power and better sound
I want to try 8 ohm speakers, at 4 ohms the output power is around 5-8W RMS maybe even more but at full power the speakers start to move really weird.
Cant wait till I sit down and listen to this amp for hours.
My circuit........... I must reduce gain its a bit noisy when theres no pot on the input, even if cable is shielded it takes whatever it can and amplify it till your ears explode
I know yall will laugh your ***** off
An externally hosted image should be here but it was not working when we last tested it.
bilder kostenlos hochladen
Sorry to hear about or mishap!!!!
I can see why your amp is doing weird things as you crank up the volume.
It has no way of maintaining DC stability as the output voltage swings to the rails due to the capacitive coupling you are using to the output devices.
Also the 1k and 47uf should be on the other side of the 100k feedback resistor connecting to the + input instead of the output.
This could be what is causing it to try and oscillate as well.
Anyhow you got it working and that is great!!!
At .85 amps per rail your are pretty much running Class A up to 5.78 watts into 8 ohms.
In to 4 ohms you would only get 2.89 watts running class A.
jer
I can see why your amp is doing weird things as you crank up the volume.
It has no way of maintaining DC stability as the output voltage swings to the rails due to the capacitive coupling you are using to the output devices.
Also the 1k and 47uf should be on the other side of the 100k feedback resistor connecting to the + input instead of the output.
This could be what is causing it to try and oscillate as well.
Anyhow you got it working and that is great!!!
At .85 amps per rail your are pretty much running Class A up to 5.78 watts into 8 ohms.
In to 4 ohms you would only get 2.89 watts running class A.
jer
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Got the transformer fixed, luckly I only had to take one turn of the primary off and solder a bit, didnt have to rewind or anything.
One opamp isnt working so I had to order new one...
I tried to compare it to LM1875 both running at the same supply voltage..
My amp sounds somehow better, I dont know but again those highs are just best ive heard.
The capacitors are bad idea... not sure what to do with them.
And yes, that 1k and 47 uF come directly from feedback pin not after the 100k
One opamp isnt working so I had to order new one...
I tried to compare it to LM1875 both running at the same supply voltage..
My amp sounds somehow better, I dont know but again those highs are just best ive heard.
The capacitors are bad idea... not sure what to do with them.
And yes, that 1k and 47 uF come directly from feedback pin not after the 100k
Few pictures of the PCB making, designed in 1 hour.
I lost the design, deleted or I didnt save it before I left home... Got PDF if anyone needs..
Voltage measured across output-gnd there was silent on the output until i touched the input cable... then i added resistor before the input cap and got it silent, permanently.
It took me 5 hours to turn my workshop upside down
I lost the design, deleted or I didnt save it before I left home... Got PDF if anyone needs..
Voltage measured across output-gnd there was silent on the output until i touched the input cable... then i added resistor before the input cap and got it silent, permanently.
It took me 5 hours to turn my workshop upside down
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Ironing method.
I print my design on thin shiny sheet...
Then i put in on PCB with piece of tape to hold it on place...
Then i put it on a piece on veneer and add a bit thicker A4 on top and press on with hot iron and hold it on for 30 seconds under intense pressure.
Its a random "brother" on there just a sheet from a catalog.
I print my design on thin shiny sheet...
Then i put in on PCB with piece of tape to hold it on place...
Then i put it on a piece on veneer and add a bit thicker A4 on top and press on with hot iron and hold it on for 30 seconds under intense pressure.
Its a random "brother" on there
just a sheet from a catalog.
Ohh, if anyone needs high power headphone amp this would be fine choice.
I cant hear any hissing, humminh nothing Its DEAD SILENT when idle.
Just a pic of the design on PDF.. I can make it better anytime.
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I cant hear any hissing, humminh nothing Its DEAD SILENT when idle.
Just a pic of the design on PDF.. I can make it better anytime.
An externally hosted image should be here but it was not working when we last tested it.
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You are having loads of fun there !
I would still recommend considering the schematic I posted earlier (post 118?) as it offers better drive for the output - even if you don't use the drivers you will find the bootstrap will ensure better current is available for the output pairs than what you have now. And the Vbe multiplier is much more accurate. For low power maybe you can get away with very simple circuit but it will fall apart at higher powers.
I would still recommend considering the schematic I posted earlier (post 118?) as it offers better drive for the output - even if you don't use the drivers you will find the bootstrap will ensure better current is available for the output pairs than what you have now. And the Vbe multiplier is much more accurate. For low power maybe you can get away with very simple circuit but it will fall apart at higher powers.
The Vbe multiplier is needed indeed.
Theres a little delay with diodes at low volumes... I dont know if it can be heard..
The opamp cannot put out enough current to drive output stage directly...
I will add Vbe multiplier and driverstage in my next attempt.
Its a must
This one is just made for fun, it sounds fine Somehow I love it even if theres a little (maybe no crossover distortion at all) I dont have scope and I cant find out too
This one:
Theres a little delay with diodes at low volumes... I dont know if it can be heard..
The opamp cannot put out enough current to drive output stage directly...
I will add Vbe multiplier and driverstage in my next attempt.
Its a must
This one is just made for fun, it sounds fine
Somehow I love it even if theres a little (maybe no crossover distortion at all) I dont have scope and I cant find out too This one:
An externally hosted image should be here but it was not working when we last tested it.
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I had a free day today... but nothing to do, too damn cold outside..
So i made this: Just a drawing.
bild hochladen
So i made this: Just a drawing.
An externally hosted image should be here but it was not working when we last tested it.
bild hochladen
Try to avoid loops in long traces.
They act as antennas and the extra inductance that they have can also cause parasitic oscillations as well.
Use thicker traces when feeding the output device as well.
Not only for the current handling capability but thicker traces also have a lower inductance value.
jer
They act as antennas and the extra inductance that they have can also cause parasitic oscillations as well.
Use thicker traces when feeding the output device as well.
Not only for the current handling capability but thicker traces also have a lower inductance value.
jer
The supply wires are connected directly to output device collectors
Those supply rails going to the opamp are nice inductors
Maybe resistors ... 100ohms could cut some noise off. I mean the noise coming from output devices...
This PCB has minimal amount of components... On your circuit theres like 3 times as many... Hah, just an idea...
Those supply rails going to the opamp are nice inductors
Maybe resistors ... 100ohms could cut some noise off. I mean the noise coming from output devices...
This PCB has minimal amount of components... On your circuit theres like 3 times as many... Hah, just an idea...
"On your circuit theres like 3 times as many" ?
Three times as many what?
You must have me confused with the other design that was presented to you.
My circuit has a total of 16 components, as one capacitor can be eliminated and 7 resistors can be reduced to 4.
http://www.diyaudio.com/forums/chip...own-supply-what-could-happen.html#post3695968
I have a LTC6090 on the way to try out finally.
Yes, I think that resistors may do a better job but you really can't tell unless you are using a scope to see if there are any oscillations.
I only got them when I used a higher gain bandwidth opamp.
The resistors will form a lowpass filter to feed the opamp.
Such as R11 and C5, and, R12 and C6 in the new circuit you have posted.
The extra inductance will form a series resonate circuit.
The higher the inductance of the trace lowers its resonate frequency and could bring it in to a range that the opamp will pickup or respond to, especially if you are using a higher gain bandwidth type opamp such as the LT1037.
The fact that I had my circuit bread boarded on a protoboard with long wires connecting everything certainly didn't help things this is why I know this.
I have been playing with opamps for many many many years and it doesn't take much for to set them into HF oscillations sometimes.
FWIW
jer
Three times as many what?
You must have me confused with the other design that was presented to you.
My circuit has a total of 16 components, as one capacitor can be eliminated and 7 resistors can be reduced to 4.
http://www.diyaudio.com/forums/chip...own-supply-what-could-happen.html#post3695968
I have a LTC6090 on the way to try out finally.
Yes, I think that resistors may do a better job but you really can't tell unless you are using a scope to see if there are any oscillations.
I only got them when I used a higher gain bandwidth opamp.
The resistors will form a lowpass filter to feed the opamp.
Such as R11 and C5, and, R12 and C6 in the new circuit you have posted.
The extra inductance will form a series resonate circuit.
The higher the inductance of the trace lowers its resonate frequency and could bring it in to a range that the opamp will pickup or respond to, especially if you are using a higher gain bandwidth type opamp such as the LT1037.
The fact that I had my circuit bread boarded on a protoboard with long wires connecting everything certainly didn't help things this is why I know this.
I have been playing with opamps for many many many years and it doesn't take much for to set them into HF oscillations sometimes.
FWIW
jer
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I had a free day today... but nothing to do, too damn cold outside..
So i made this: Just a drawing.
In the schematic I made, which you re-posted above, the transistor Q1 must be able to 'sense' the temperature of the output devices or their heatsink to ensure proper thermal control of the amplifier (or it may blow up). My own preference is always to mount Q1 in direct physical contact with one of the output power transistors.
This can be done simply enough if you make a place for Q1 on the pcb but instead of soldering Q1 into the pcb you connect wires from the holes in the pcb to the legs of the transistor - just make sure these legs are insulated and can't touch each other - then you can mount Q1 onto one of the power devices. Mounting Q1 on top of one of the output power devices is not too hard, you can probably have the mounting screw go through both devices, with the smaller one sitting on top of the bigger one. Or you can glue the smaller one on top of the larger one with some silicone glue. T
If the heatsink isn't too big and therefore, has a small thermal mass, you can mount Q1 onto the heatsink in between the two output devices. This is a very common way to do it. You will have to move Q1 on your pcb so that it is at the edge between the power devices.
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