Try 1K8 man...in the place of the resistance you have from base to colector
Also you can try to install...under the board...a parallel one, that will reduce the resulting ohmic value be carefull.
Let's imagine 10000 ohms (10K) in parallell with 2200 ohms (2k2)
10000 multiplied by 2200 22000000
-------------------------------------------------- = ------------------- =
10000 added to 2200 12200
The result is 1803 ohms...near the 1K8....this may fit your needs dear Nordic.
This is NOT in parallel with the trimpot...it must be over (or under) the 2K2 fixed resistance already in place.
What is your trimpot value..is it 1000 ohms?
regards,
Carlos
Also you can try to install...under the board...a parallel one, that will reduce the resulting ohmic value be carefull.
Let's imagine 10000 ohms (10K) in parallell with 2200 ohms (2k2)
10000 multiplied by 2200 22000000
-------------------------------------------------- = ------------------- =
10000 added to 2200 12200
The result is 1803 ohms...near the 1K8....this may fit your needs dear Nordic.
This is NOT in parallel with the trimpot...it must be over (or under) the 2K2 fixed resistance already in place.
What is your trimpot value..is it 1000 ohms?
regards,
Carlos
Thanks uncle Charly will look now... quickly makeing a short signal cable with a 3.5mm jack to use ipod for testing... will use old speaker first... only to listen softly....
I have 1k8 resistors thanks
will be easier to swap out than solder on extra one... safer in long run... don't want tracks to touch heatsink.
I have 1k8 resistors thanks
will be easier to swap out than solder on extra one... safer in long run... don't want tracks to touch heatsink.
Nordic..good idea to place a fuse..at least in the output.
Some bad solder joint can create huge problems related the outpud DC voltage... it can may jump to stratosphere.
hehe.. within the supply voltage limits of course....supplie's Stratosphere.
Cold solder joints happens....yeah...it is not too much hard to find those cold solder joints.
I am excited (the image) as we gonna listen this amplifier today.
Speaker inside the enclosure...please!!!!
regards,
Carlos
Some bad solder joint can create huge problems related the outpud DC voltage... it can may jump to stratosphere.
hehe.. within the supply voltage limits of course....supplie's Stratosphere.
Cold solder joints happens....yeah...it is not too much hard to find those cold solder joints.
I am excited (the image) as we gonna listen this amplifier today.
Speaker inside the enclosure...please!!!!
regards,
Carlos
Attachments
nope first speaker will be in my hands... lol don't worry I always test amps this way... I know its sound, and I adjust the bass by changeing distance to floor, holding it up towards my face... then I will leave it to play at least an hour before I let it touch my good speakers... will out 5A fuse on output...
Nordic, your bias should be adjustable from below 10 mA minimum.
1.4A rail-current is huge !
DON'T attach your main loudspeaker(s) before this works properly.
Did you connect the vbe-multiplier from A to C as shown on Greg's website ?
Did you omit r14 an vr2 ? you should.
Best regards,
Klaas
1.4A rail-current is huge !
DON'T attach your main loudspeaker(s) before this works properly.
Did you connect the vbe-multiplier from A to C as shown on Greg's website ?
Did you omit r14 an vr2 ? you should.
Best regards,
Klaas
I think he had already fixed this Klaas
The last inform i had was 3 milivolts off set...33 Vdc supply and 135 miliamps each rail.
I suppose he could reduce and may be listening...and dancing..for sure..so happy that will not remember to come here to tell us some news.
Hello Klaas...happy to have you once again.
take your seat...today we gonna have a party here..
BTW..i am waiting for the lunch time..and observing this lamp....remembers me something..hehe..i do not know what?
regards,
Carlos
The last inform i had was 3 milivolts off set...33 Vdc supply and 135 miliamps each rail.
I suppose he could reduce and may be listening...and dancing..for sure..so happy that will not remember to come here to tell us some news.
Hello Klaas...happy to have you once again.
take your seat...today we gonna have a party here..
BTW..i am waiting for the lunch time..and observing this lamp....remembers me something..hehe..i do not know what?
regards,
Carlos
Attachments
baah,,, ok i broke something... on replaceing the 2k2 resistor with 1k8, I soldered badly and there was no connection to VBE base...
I did not see it, was like a microfracture.. looked perfect.
Anyhow on powerup the 10R resistors started to smoke... DMM was on 20V range.. and voltage was above that scale...i.e. showing 1.
I then found the mistake on the solderjoint with continuity tester...
Now on power up the resistors only carry 15mA and it does not change with turning the trimpot... I assume the bd139 is dead and the trimpot too probably... will test em later... anything else likely to have died... nothing smells...yet
Yes, Klaas, VBE circuit is correct according to scematic... and needed components omitted..
I have spare transistors, tell me where to start looking...
I did not see it, was like a microfracture.. looked perfect.
Anyhow on powerup the 10R resistors started to smoke... DMM was on 20V range.. and voltage was above that scale...i.e. showing 1.
I then found the mistake on the solderjoint with continuity tester...
Now on power up the resistors only carry 15mA and it does not change with turning the trimpot... I assume the bd139 is dead and the trimpot too probably... will test em later... anything else likely to have died... nothing smells...yet
Yes, Klaas, VBE circuit is correct according to scematic... and needed components omitted..
I have spare transistors, tell me where to start looking...
Maybe your trimpot center tape is open
of course the VBE is something to suspect..you are in the correct track.
Soon you will find the guilty one.
I was simulating and your power, using 33 volts rails will be 86,7 Watts over 4 ohms..sensitivity at 750 milivolts and 1 Kilohertz.
Your Vr1 trimpot adjusted to 6100 ohms.
Your R10 resistance adjusted to 2370.
The upper VBE base to colector resistance at 1800 ohms
The lower VBE base to emitter trimpot adjusted to 600 ohms
Offset adjusted to 100 microvolts
Upper rail stand by current at 56 miliamperes
Lower rail stand by current at 45 miliamperes.
3.3 watts of dissipation during stand by mode.
regards,
Carlos
of course the VBE is something to suspect..you are in the correct track.
Soon you will find the guilty one.
I was simulating and your power, using 33 volts rails will be 86,7 Watts over 4 ohms..sensitivity at 750 milivolts and 1 Kilohertz.
Your Vr1 trimpot adjusted to 6100 ohms.
Your R10 resistance adjusted to 2370.
The upper VBE base to colector resistance at 1800 ohms
The lower VBE base to emitter trimpot adjusted to 600 ohms
Offset adjusted to 100 microvolts
Upper rail stand by current at 56 miliamperes
Lower rail stand by current at 45 miliamperes.
3.3 watts of dissipation during stand by mode.
regards,
Carlos
Uops..i forgot to tell you that the amplifier is flat, using your transistors
from 10 hertz to 103 Kilohertz.
Losses at 3db are 5 Hertz and 125 Kilohertz... and sinusoidal signal does not triangulate within those limits.
Rail current consumption, full undistorted power, sinusoidal sinal at 1 Kilohertz, 4 ohms load.... current informed was 2.1A to each rail
Specifications are fine...distortion is lower than 0.3% to maximum undistorted signal.
of course the power will be half of it using 4 ohms loads.
regards,
Carlos
from 10 hertz to 103 Kilohertz.
Losses at 3db are 5 Hertz and 125 Kilohertz... and sinusoidal signal does not triangulate within those limits.
Rail current consumption, full undistorted power, sinusoidal sinal at 1 Kilohertz, 4 ohms load.... current informed was 2.1A to each rail
Specifications are fine...distortion is lower than 0.3% to maximum undistorted signal.
of course the power will be half of it using 4 ohms loads.
regards,
Carlos
Ok fink i fixed it...
Made new VBEM board, as I damaged tracks on the ohter one...
All seems fine now, bias measurements seem to correspond with predicted levels now... although it seems to sllllloooooowwwly increase.. left it with +- 50 and 60 mA.... will have to wait till morning for further testing... or late tonight, as momy wants to watch tv now.
Made new VBEM board, as I damaged tracks on the ohter one...
All seems fine now, bias measurements seem to correspond with predicted levels now... although it seems to sllllloooooowwwly increase.. left it with +- 50 and 60 mA.... will have to wait till morning for further testing... or late tonight, as momy wants to watch tv now.
Do not worry..relax Nordic....BERNHIX...i have made your tone amplifier.
It is providing a small gain...not too much....at least it is not "eating" the input signal.
The bass control are adjusted to my personal taste.... it improves low frequencies...lower than the traditional 100 hertz centered... amd this will depend from the 47N capacitors...you can increase them and your center (the most actuating frequency..the one you will have bigger volume) will decrease...with 100N you will be pumping enormous levels of sound into 20 hertz....using lower values..as 22N...you will amplify those bass and drum spectrum...to those kind of music.
Yeah..of course you can make switches to change capacitors..but they will have the need to be very close related the circuit...hummm....you may have noises.....not a safe practice.
The high frequencies are determined by those small capacitors (always in groups of two)...the 4.7N...and it is a very large bandwidth...you may have adjustments from 5 till 15 Kilohertz.
If you decide to use 100N (i love this one) you will perceive that the tone will seem not working....it is working, for sure..the problem is that normal, standard music do not have those deep tones that will be amplified by this system.
The transistor is a need..and all NPN transistor, able to work with 20 volts at the colector (BC548 will fit..maybe better...or 2SC945)...the current is 1.3 miliamps and the base to emitter voltage is around 639 milivolts.
Those resistances you see in the top of the image...6K8 and 4K7 are there to reduce the 35 volts supply into 20 volts...as this circuit will work with 20 volts...and because of that, can use general, standard, common, npn, audio frequency transistors.
Of course you can use a 20 volts supply..but the one will need a good filtering not to produce low frequency noises.
Even two 9 volts batteries will last for a very good time..as power consumption is very small....those bateries are 50 miliamperes and will hold 9 volts for an hour.....using 1 miliampere you will have many hours... to power using two 9 volts batteries... connect the positive into the left side of the 6K8 resistance and the negative will go to the ground...use a switch to avoid drain the battery when not using.
Using an amplifier supply..you will select the positive rail and ground...do not worry ...condensers will block DC and will make the amplifier swing without problems.
The needed series attenuator resistance..in this case, was around 12K to reduce 15 volts.... as the current is around 1.2 miliamperes (around).... 12K was a result of add 6K8 and 4K7...not exactly trhe value..but near enougth.
You can calculate this value, to adapt to your own DC supply voltage...from an amplifier....just deduce the voltage you have (bigger than 20 volts) to the needed 20 volts...the result, expressed in volts will be divided by the current....and this one is 0.0012A...the result will be your resistance in ohms...the needed series resistance to reduce your supply voltage to match this little circuit need.
Well....i can tell you a long story...and also the history of this circuit...adapted by me...simulated by Dx..for you Bernhix...but let's see if you will use it...not to loose my finger tips typing here.
Of course... every standard tone control will be good into Dx amplifier, as it has standard sensitivity and do not have exotic input impedance too...so....use the one you have and he happy my friend.
regards,
Carlos
It is providing a small gain...not too much....at least it is not "eating" the input signal.
The bass control are adjusted to my personal taste.... it improves low frequencies...lower than the traditional 100 hertz centered... amd this will depend from the 47N capacitors...you can increase them and your center (the most actuating frequency..the one you will have bigger volume) will decrease...with 100N you will be pumping enormous levels of sound into 20 hertz....using lower values..as 22N...you will amplify those bass and drum spectrum...to those kind of music.
Yeah..of course you can make switches to change capacitors..but they will have the need to be very close related the circuit...hummm....you may have noises.....not a safe practice.
The high frequencies are determined by those small capacitors (always in groups of two)...the 4.7N...and it is a very large bandwidth...you may have adjustments from 5 till 15 Kilohertz.
If you decide to use 100N (i love this one) you will perceive that the tone will seem not working....it is working, for sure..the problem is that normal, standard music do not have those deep tones that will be amplified by this system.
The transistor is a need..and all NPN transistor, able to work with 20 volts at the colector (BC548 will fit..maybe better...or 2SC945)...the current is 1.3 miliamps and the base to emitter voltage is around 639 milivolts.
Those resistances you see in the top of the image...6K8 and 4K7 are there to reduce the 35 volts supply into 20 volts...as this circuit will work with 20 volts...and because of that, can use general, standard, common, npn, audio frequency transistors.
Of course you can use a 20 volts supply..but the one will need a good filtering not to produce low frequency noises.
Even two 9 volts batteries will last for a very good time..as power consumption is very small....those bateries are 50 miliamperes and will hold 9 volts for an hour.....using 1 miliampere you will have many hours... to power using two 9 volts batteries... connect the positive into the left side of the 6K8 resistance and the negative will go to the ground...use a switch to avoid drain the battery when not using.
Using an amplifier supply..you will select the positive rail and ground...do not worry ...condensers will block DC and will make the amplifier swing without problems.
The needed series attenuator resistance..in this case, was around 12K to reduce 15 volts.... as the current is around 1.2 miliamperes (around).... 12K was a result of add 6K8 and 4K7...not exactly trhe value..but near enougth.
You can calculate this value, to adapt to your own DC supply voltage...from an amplifier....just deduce the voltage you have (bigger than 20 volts) to the needed 20 volts...the result, expressed in volts will be divided by the current....and this one is 0.0012A...the result will be your resistance in ohms...the needed series resistance to reduce your supply voltage to match this little circuit need.
Well....i can tell you a long story...and also the history of this circuit...adapted by me...simulated by Dx..for you Bernhix...but let's see if you will use it...not to loose my finger tips typing here.
Of course... every standard tone control will be good into Dx amplifier, as it has standard sensitivity and do not have exotic input impedance too...so....use the one you have and he happy my friend.
regards,
Carlos
Attachments
CARLOSSSSSSSSSSSS!!!!!!!!!!!!!
IT WORKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Bass was a bit rough at first, but I decided what the heck and turned the bias pot using my ear for best sound...like I did with my headphone amp
My first reaction was the hair on my arms are standing up and I am a little teary... partly with relief... Got it hooked to a 40W speaker at the moment I could feel its whole frame rumble with bass, even at low volume...
In one hour I will test on my "nice" speakers...
IT WORKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Bass was a bit rough at first, but I decided what the heck and turned the bias pot using my ear for best sound...like I did with my headphone amp
My first reaction was the hair on my arms are standing up and I am a little teary... partly with relief... Got it hooked to a 40W speaker at the moment I could feel its whole frame rumble with bass, even at low volume...
In one hour I will test on my "nice" speakers...
YEAH!...FINE!.... was a long road man! i am extremelly happy!
We have made it!...YESSSSSSSS!
I am sure sounded great and have eated your chip with ketchup!
regards,
Carlos
.......................................................................................................
Bernhix
Count on me....i will help you.
I had a wonderfull teacher...was in the Army...the Officer was Ottmar Albert Furrer...from a Switzeland family that imigrated to Rio de Janeiro...this man, that born in Swiss, had teached me the basic things about electronics.
With his nice dark Pipe making constrast with the white blond hair..and smoking that nice chocolate perfum smoke, he used to order me to install a germaniun 2N408 into a wooden board...and them he used to decided the colector resistance....was big the first stage one...and them all stages will go beeing assembled... the last one with small resistances.(more current)...hummmm...i still remember that amplifier sonics...i was astonished!..that thing worked till the output melt.... what a nice spider..that P2P construction (point to point)
The reasons to have lost that transistor, was what have ligth my fire into research....that made me frustrated and extremelly curious about that subject.. and till now a days i am trying to visit those wires and transistors, tring to perceive myself as an electron... and beeing an electron i use to travel into circuits trying to understand the problems i will face.
Ottmar Albert Furrer, now with God (the one your prefer..no problems..i am Christian and i know that no one is perfect..ahahahahha),...... his family had keept Albert Einstein hidden during some time..the second world war was in its peaks...and Einstein used to keep conversations and to stay with Ottmar..... What a friend to play with!....The theories of everything were already published 8 years ago....Einstein was jewish...and Adolph wanted to put his hands on him.
He teached me all the basic things, during 1970, the tips and tricks and i used to pick the jeep to the distant beaches to test Radio Transceivers that we used to construct...also automatic systems to sequence of 350 milimeters Artillery cannon shots.
He told me:
" One day you will be teaching too ! "....so.... this is my obligation.
Someone did it to me...now i will gladly pay... giving, for free, the same way i have received, all i have inside my mind.
It is not really too much..i am not a gênius alike MikeB...not a researcher alike Hugh Dean from Aspen amplifiers....not so clever as Graham Maynard, with his ideas about first cicle distortion..but i have a lot of practice and burns into my fingers holding soldering irons
regards,
Carlos
We have made it!...YESSSSSSSS!
I am sure sounded great and have eated your chip with ketchup!
regards,
Carlos
.......................................................................................................
Bernhix
Count on me....i will help you.
I had a wonderfull teacher...was in the Army...the Officer was Ottmar Albert Furrer...from a Switzeland family that imigrated to Rio de Janeiro...this man, that born in Swiss, had teached me the basic things about electronics.
With his nice dark Pipe making constrast with the white blond hair..and smoking that nice chocolate perfum smoke, he used to order me to install a germaniun 2N408 into a wooden board...and them he used to decided the colector resistance....was big the first stage one...and them all stages will go beeing assembled... the last one with small resistances.(more current)...hummmm...i still remember that amplifier sonics...i was astonished!..that thing worked till the output melt.... what a nice spider..that P2P construction (point to point)
The reasons to have lost that transistor, was what have ligth my fire into research....that made me frustrated and extremelly curious about that subject.. and till now a days i am trying to visit those wires and transistors, tring to perceive myself as an electron... and beeing an electron i use to travel into circuits trying to understand the problems i will face.
Ottmar Albert Furrer, now with God (the one your prefer..no problems..i am Christian and i know that no one is perfect..ahahahahha),...... his family had keept Albert Einstein hidden during some time..the second world war was in its peaks...and Einstein used to keep conversations and to stay with Ottmar..... What a friend to play with!....The theories of everything were already published 8 years ago....Einstein was jewish...and Adolph wanted to put his hands on him.
He teached me all the basic things, during 1970, the tips and tricks and i used to pick the jeep to the distant beaches to test Radio Transceivers that we used to construct...also automatic systems to sequence of 350 milimeters Artillery cannon shots.
He told me:
" One day you will be teaching too ! "....so.... this is my obligation.
Someone did it to me...now i will gladly pay... giving, for free, the same way i have received, all i have inside my mind.
It is not really too much..i am not a gênius alike MikeB...not a researcher alike Hugh Dean from Aspen amplifiers....not so clever as Graham Maynard, with his ideas about first cicle distortion..but i have a lot of practice and burns into my fingers holding soldering irons
regards,
Carlos
Attachments
Good to read of your success Nordic.
Hairs standing - tears in your eyes ....
Carlos' artistry has given us an amplifier with a good open loop bandwidth, which in his technicians terms means that internal circuitry is not 'caught' out and making unnecessary audible errors due to additional components and devices increasing affectations due to NFB sensed loudspeaker demands.
Thus I call Carlos an 'artist' with the best meaning possible.
Make sure you have your favourite beverage to hand so that you might properly savour the Dx via your 'nice' speakers.
Cheers ........ Graham.
Hairs standing - tears in your eyes ....
Carlos' artistry has given us an amplifier with a good open loop bandwidth, which in his technicians terms means that internal circuitry is not 'caught' out and making unnecessary audible errors due to additional components and devices increasing affectations due to NFB sensed loudspeaker demands.
Thus I call Carlos an 'artist' with the best meaning possible.
Make sure you have your favourite beverage to hand so that you might properly savour the Dx via your 'nice' speakers.
Cheers ........ Graham.
Hi Carlos,
LOL. Sure burnt fingers come with the territory !
(And flash dazzle in the eyes, and feeling sick with the smoke, and having to climb back into your skin after being attacked by a speaker cone ... )
Ever been in front of a LS stack when some decides to 'test' it?
Was once sitting astride a 500W infra-red spotlight with invisible beam (pointing at my nether regions) whilst setting the daylight current on a CCTV camera mounted above it - when someone decided to 'test' it.
Laughs all around in both situations as I was taken by surprise.
Cheers ...... Graham.
LOL. Sure burnt fingers come with the territory !
(And flash dazzle in the eyes, and feeling sick with the smoke, and having to climb back into your skin after being attacked by a speaker cone ... )
Ever been in front of a LS stack when some decides to 'test' it?
Was once sitting astride a 500W infra-red spotlight with invisible beam (pointing at my nether regions) whilst setting the daylight current on a CCTV camera mounted above it - when someone decided to 'test' it.
Laughs all around in both situations as I was taken by surprise.
Cheers ...... Graham.
- Status
- Not open for further replies.