Wavebourn said:
It seems you have really stayed in Randburg 🙂
For over a year i drove a car with bullet proof glass and run flat tyres. Suddenly night driving was a pleasure. Eventually i got exceedingly daring and wouldn't mind crossing town at night. Sadly, never got to test the glassware.
Wavebourn said:
Until recently this would not be viable due to the strong rand. Now it may really work. Missing the adrenaline?
analog_sa said:
Not always. Sometimes used to drive through the center of Joburg in darkness. Also, for a short period of time rented a house in the suburb that shared the same freeway exit with Alexandra. 😀
Once I stayed there with flat tire but no spare, and my cellphone battery got flat...
I had Dunlop RunFlat, and wearied them out completely with no single puncture. Before that I got nails 3 times in original tires. 😀
analog_sa said:
No, trying to catch economics slipping out of States. In 1940'th Dollar went abroad; later the manufacturing followed by it.
An usual option is China, but I believe SA may be a good alternative. Before I was afraid that African National Congress people got Socialist ideas with their education in Moscow; now I believe they got an immunity against it.
😀 😀 😀 some did get bullets from me , the ones that came to my home,were walking off with my cdplayer and brand new TV set, killed my dogs, trashed my livingroom, had a leak and a cr*p on my carpet and broke my Linn LP12 turntables arm thinking it a old piece of junk, they are still walking around those parts somewhere ableit with great limps as a 9mm can do great damage to kneecaps, they are able to walk thanks to ME paying for reconstructive surgery as demanded by court as compensation for my good deed for apprehending 2 members of a dangerous gang that were sought by police for the murder of 7 citizens during house breakins.
Wavebourn dont be too haste, Mbeki and the moderates are out of goverment, now soon those radicals educated in Moscow are going into goverment. Electricity shortage crisis wasnt due to economic growth but due to mismanagement of resources as planned future increases in capacity by Evkom by building new nuclear reactors and conventional coal powerplants was shelved by the fairly new goverment in 1996. More than ten years later doing nothing in this respect and they suddenly wake up and this only when the lights suddenly went out, we have a problem.
Drive through joburg centre, my last time was in 1995, fresh out of Wits U, now only if I have a trusted R4 friend with me. 😉
Sorry guys for our OT. Hopefully we will soon get some schematics from Steve to give us a pleasant topic of discussion and the reason we are here, AUDIO.
Wavebourn dont be too haste, Mbeki and the moderates are out of goverment, now soon those radicals educated in Moscow are going into goverment. Electricity shortage crisis wasnt due to economic growth but due to mismanagement of resources as planned future increases in capacity by Evkom by building new nuclear reactors and conventional coal powerplants was shelved by the fairly new goverment in 1996. More than ten years later doing nothing in this respect and they suddenly wake up and this only when the lights suddenly went out, we have a problem.
Drive through joburg centre, my last time was in 1995, fresh out of Wits U, now only if I have a trusted R4 friend with me. 😉
Sorry guys for our OT. Hopefully we will soon get some schematics from Steve to give us a pleasant topic of discussion and the reason we are here, AUDIO.
Well guys, sounds like a wild life! It feels better in Portugal and California I am sure! Now, I feels so lucky to be born where I am!
Hi Folks,
I'm very busy with my wife's situation in the hospital as she is still in intensive care. We seemed to have turned a corner today (Monday) when the 1st string players showed up and put things into high gear. She is showing great progress from her stroke and the heart has been stabilized and returned to a reasonable rate of 72 beats per minute - so this is good. In between visits with my wife I was able to talk with Steve D and found that he was also in physical rehab all day today. Steve wasn't prepared for such a rapid response to Carlos getting this thread started, and soon realized that he can redo some things that will make construction of his amplifier easier and straight forward for the DIY builder. He has very limited use of his hands and it takes him much longer to accomplish task such as working on a computer keyboard because he can only use about two of his fingers at a time - and that with a high degree of difficulty. So please - have some patience and a little understanding. Steve is WORKING on it!!! He is busy now redrawing schematics and circuit board layouts - so you kids that are making all the noise back there - quite down!!!! Don't make me come back there (Ya All Hear!). 😱
ps - thanks for all of your prayers and good thoughts for my wife Susan, AKA - Dances with Dachshunds
I'm very busy with my wife's situation in the hospital as she is still in intensive care. We seemed to have turned a corner today (Monday) when the 1st string players showed up and put things into high gear. She is showing great progress from her stroke and the heart has been stabilized and returned to a reasonable rate of 72 beats per minute - so this is good. In between visits with my wife I was able to talk with Steve D and found that he was also in physical rehab all day today. Steve wasn't prepared for such a rapid response to Carlos getting this thread started, and soon realized that he can redo some things that will make construction of his amplifier easier and straight forward for the DIY builder. He has very limited use of his hands and it takes him much longer to accomplish task such as working on a computer keyboard because he can only use about two of his fingers at a time - and that with a high degree of difficulty. So please - have some patience and a little understanding. Steve is WORKING on it!!! He is busy now redrawing schematics and circuit board layouts - so you kids that are making all the noise back there - quite down!!!! Don't make me come back there (Ya All Hear!). 😱
ps - thanks for all of your prayers and good thoughts for my wife Susan, AKA - Dances with Dachshunds
Soon your life will get back to normal
And we gonna be waiting.... in the reality we cannot be waiting..we are excited to see the amplifier schematic....but we will be here playing and exchanging ideas till Dunlap and you will be ready for us.
Now people talk about bullets...social problems...i will be silent not to burn my country image, more than it is already burned..but the problems i see seems alike children playing comparing to the military weapons the bandits use into Rio de Janeiro... they are up the hills using machine guns, military weapons, with the blood filled with drugs and sending bullets to imaginary enemies...people down the hill receive those bullets watching tv into the appartments... the Army is there, into the hills trying to control... at least they make the guys stop after some minutes.
Watch the brazilian movie.... Elite Troup..... "Tropa de Elite" and you gonna see what is a real problem.... the movie received many prizes, so, it may be available into your country too...but prepare your stomach...it is disgusting...and it is reality, i have lived the College reality they show there and i ensure you it is reality... different from Hollywood movies, there you have no US propaganda or country advertising..no heroes, just reality.
Wanna keep your pants dry?.... so do not watch this movie...you gonna feel afraid from your own shadow while watching it.... special police behavior is the one shown...violence is exactly that way..to burn people alive, sometimes entire passenger buses filled with people..corruption show are exaclty that way...college drugged rich folks are exaclty the same as shown...it is reality!
Bullet proof cars does not resist the weapons they use..... if needed they will stop you using Bazooka!
regards,
Carlos
And we gonna be waiting.... in the reality we cannot be waiting..we are excited to see the amplifier schematic....but we will be here playing and exchanging ideas till Dunlap and you will be ready for us.
Now people talk about bullets...social problems...i will be silent not to burn my country image, more than it is already burned..but the problems i see seems alike children playing comparing to the military weapons the bandits use into Rio de Janeiro... they are up the hills using machine guns, military weapons, with the blood filled with drugs and sending bullets to imaginary enemies...people down the hill receive those bullets watching tv into the appartments... the Army is there, into the hills trying to control... at least they make the guys stop after some minutes.
Watch the brazilian movie.... Elite Troup..... "Tropa de Elite" and you gonna see what is a real problem.... the movie received many prizes, so, it may be available into your country too...but prepare your stomach...it is disgusting...and it is reality, i have lived the College reality they show there and i ensure you it is reality... different from Hollywood movies, there you have no US propaganda or country advertising..no heroes, just reality.
Wanna keep your pants dry?.... so do not watch this movie...you gonna feel afraid from your own shadow while watching it.... special police behavior is the one shown...violence is exactly that way..to burn people alive, sometimes entire passenger buses filled with people..corruption show are exaclty that way...college drugged rich folks are exaclty the same as shown...it is reality!
Bullet proof cars does not resist the weapons they use..... if needed they will stop you using Bazooka!
regards,
Carlos
I was reading something about the brand
The idea behind the product is very good.
They match speakers with amplifiers.... this is advantage
They avoid passive crossovers, they use dedicated amplifiers to sub bass, low frequencies and mids plus highs...another very good idea..distorts less this way.
They offer enormous reserve of power, so you gonna be operating with the amplifier "almost" iddle...clever that too.
But they told 90 percent efficiency...hummmmmm, this is not very good if not a Class D amplifier... cutting bias to reduce iddle heat may result in crossover distortions into low power reproduction.
Well...just thinking about.... thinking loud and submiting the brain storm to you folks
Of course, a single speaker cannot reproduce basses and treble... sending the correct bandwidth to the bass driver will reduce a lot of intermodulation.... this is fine.... and coupling amplifiers without crossover is also fine...to reduce amplifier bandwidth is very good too.
So... they have used the brain.... that's it... have used the brain.
Amplifiers are good, almost all them use to be good...differences are, and you can feel them...but, you can manage to adjust speakers to standard, simple amplifiers, and this will result in excelent sonics too.... brain beeing used... this is what i feel about those guys.... imagine not adjusting speakers to standard amplifiers and creating them to the speaker, and then tuning a little the speaker, no mess because crossover, no passive crazy things between power amplifier and speaker.... maybe electronic crossover into amplifier input i think, as output will need a lot of sensors to adjust the whole thing..... good....interesting.
I just cannot wait to see the schematic...but the idea behind is already great..... and the speaker i have listened was poor, cheap Sony one....hummmmm.... imagine this amplifier with dedicated, custom made speakers..... paradise.... of course paradise!
I ensure you he is working on that ( he told me that hours ago).... soon we gonna have schematics and his presence too.
http://www.wisdomaudio.com/
regards,
Carlos
The idea behind the product is very good.
They match speakers with amplifiers.... this is advantage
They avoid passive crossovers, they use dedicated amplifiers to sub bass, low frequencies and mids plus highs...another very good idea..distorts less this way.
They offer enormous reserve of power, so you gonna be operating with the amplifier "almost" iddle...clever that too.
But they told 90 percent efficiency...hummmmmm, this is not very good if not a Class D amplifier... cutting bias to reduce iddle heat may result in crossover distortions into low power reproduction.
Well...just thinking about.... thinking loud and submiting the brain storm to you folks
Of course, a single speaker cannot reproduce basses and treble... sending the correct bandwidth to the bass driver will reduce a lot of intermodulation.... this is fine.... and coupling amplifiers without crossover is also fine...to reduce amplifier bandwidth is very good too.
So... they have used the brain.... that's it... have used the brain.
Amplifiers are good, almost all them use to be good...differences are, and you can feel them...but, you can manage to adjust speakers to standard, simple amplifiers, and this will result in excelent sonics too.... brain beeing used... this is what i feel about those guys.... imagine not adjusting speakers to standard amplifiers and creating them to the speaker, and then tuning a little the speaker, no mess because crossover, no passive crazy things between power amplifier and speaker.... maybe electronic crossover into amplifier input i think, as output will need a lot of sensors to adjust the whole thing..... good....interesting.
I just cannot wait to see the schematic...but the idea behind is already great..... and the speaker i have listened was poor, cheap Sony one....hummmmm.... imagine this amplifier with dedicated, custom made speakers..... paradise.... of course paradise!
I ensure you he is working on that ( he told me that hours ago).... soon we gonna have schematics and his presence too.
http://www.wisdomaudio.com/
regards,
Carlos
Some of you seem somewhat impatient. I'm not trying to put anyone off it's just that after more than a year away from my computer it has taken me a while to get back in the swing of things. I'm still trying to adjust to being a quadriplegic. Things that used to be quite simple are now very difficult and indeed in many cases painful. Also I spend a lot of time away from home at doctor's offices and physical therapy so I am not always sitting in front of my computer to make a reply.
As for whether the amp is class A not, I said it is what I consider class A. Both spice modeling and measurements show the outputs conducting current through the entire output cycle. Some of you obviously disagree and that is your prerogative.
The actual current draw at idle can vary from 10 W upwards. This is per channel and depends on the output power the amp has been designed for. For A 100 W amp, idle would be about 12 Watts. The bias is adjustable and I set it for minimum distortion at rated power.
As for how low the distortion can be, I have measured .005% THD at 400 W output into an eight ohm load. As with all DIY projects, your results will vary depending on the layout, transistor matching and desired output power. So far I've built nothing lower than 30 W and nothing greater than 1200 W at 8 ohms. Driving a lower impedance depends of course on power supply, number of output devices and of course the size of the heat sink.
Attached is a basic schematic of the output stage only. V1 is the input signal. V2 and V3 are power supply. R2 is the output load for modeling purposes. R10,R11 set current througe diodes D3,D4,D5and D6 at 1ma. R6,R5 set the currect soreces at app 10ma. Supplies are at plus and minus 50V in this example. R4 sets the bias. D1,2 mount on the heat sink.
Steve
As for whether the amp is class A not, I said it is what I consider class A. Both spice modeling and measurements show the outputs conducting current through the entire output cycle. Some of you obviously disagree and that is your prerogative.
The actual current draw at idle can vary from 10 W upwards. This is per channel and depends on the output power the amp has been designed for. For A 100 W amp, idle would be about 12 Watts. The bias is adjustable and I set it for minimum distortion at rated power.
As for how low the distortion can be, I have measured .005% THD at 400 W output into an eight ohm load. As with all DIY projects, your results will vary depending on the layout, transistor matching and desired output power. So far I've built nothing lower than 30 W and nothing greater than 1200 W at 8 ohms. Driving a lower impedance depends of course on power supply, number of output devices and of course the size of the heat sink.
Attached is a basic schematic of the output stage only. V1 is the input signal. V2 and V3 are power supply. R2 is the output load for modeling purposes. R10,R11 set current througe diodes D3,D4,D5and D6 at 1ma. R6,R5 set the currect soreces at app 10ma. Supplies are at plus and minus 50V in this example. R4 sets the bias. D1,2 mount on the heat sink.
Steve
steve ,its funny and peculiar how all this connects
But if quadripligia is your only option it is still limitless.you think.you are
love max
But if quadripligia is your only option it is still limitless.you think.you are
love max
Wavebourn said:
I did say it resembled the Diamond Buffer. I don't know the origin of that circuit but I have seen it used in many commercial products dating back over 30 years. And yes, that was my starting point. I added the bias circuit so I could use a Darlington output for more current. The bias circuit also allows easy adjustment of bias as well as thermal tracking when mounted to the heat sink.
Steve
Yes, each transistor is surrounded by the shortest as possible feedback path. However, thermal feedback path is quite long assuming all phase shifts, but if an idle current is enough it's variations are not very audible.
Nice!
Nice!
Thank you Steve, interesting circuit.
As I see it, the two current sources do around 12mA each, but as one output side turns on hard, increasing Vbe, the bias voltage between the two Darlington bases remains essentially constant, and so the inactive side turns off, the more so since the current through the bias diodes actually decrease owing to the drive current into the active darlington base (usually not more than 2mA max).
This means that the crossover disjunction is slightly better than most Class AB amps, but the switch off of the inactive side is still an issue, surely? Or am I missing something?
I'm presuming that V1 is the AC input source, not a DC source?
One point, how do you guarantee tight offset control?
Thank you for taking the trouble to post this circuit. It's worth discussing in some detail,
Cheers,
Hugh
As I see it, the two current sources do around 12mA each, but as one output side turns on hard, increasing Vbe, the bias voltage between the two Darlington bases remains essentially constant, and so the inactive side turns off, the more so since the current through the bias diodes actually decrease owing to the drive current into the active darlington base (usually not more than 2mA max).
This means that the crossover disjunction is slightly better than most Class AB amps, but the switch off of the inactive side is still an issue, surely? Or am I missing something?
I'm presuming that V1 is the AC input source, not a DC source?
One point, how do you guarantee tight offset control?
Thank you for taking the trouble to post this circuit. It's worth discussing in some detail,
Cheers,
Hugh
Hi, Steve,
Thanks for sharing the circuit.
There are some things I wanted to ask you.
1. Anode of D1 (//withR4) and cathode of D2, are they only going to bases of transistors, and not going anywhere else? This mean the current passing thru D1 and D2 only come from leaking current from transistor bases?
2. The emitor of first darlington, they connect just to base of second darlington. There is no resistor to the output node.
Is this on purpose to prevent turn-off (no discharge path for base charge of final transistor due to no resistor from base of final darlington to output node) or is this because the above drawing is only a basic schematic?
Thanks for sharing the circuit.
There are some things I wanted to ask you.
1. Anode of D1 (//withR4) and cathode of D2, are they only going to bases of transistors, and not going anywhere else? This mean the current passing thru D1 and D2 only come from leaking current from transistor bases?
2. The emitor of first darlington, they connect just to base of second darlington. There is no resistor to the output node.
Is this on purpose to prevent turn-off (no discharge path for base charge of final transistor due to no resistor from base of final darlington to output node) or is this because the above drawing is only a basic schematic?
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