You should go to the smaller ones ...
... as they will be able to face 30A going to the speakers.... when the big ones (less quantity) will tolerate maximum of 24A.
Well... this depends if your supply voltage is really 64 volts...also the impedance you will use.
To our supply voltage, the smaller ones match the big ones...so... the advantage goes to the ones are in bigger quantity.
The advantage is to the smaller ones, in your case.
regards,
Carlos
... as they will be able to face 30A going to the speakers.... when the big ones (less quantity) will tolerate maximum of 24A.
Well... this depends if your supply voltage is really 64 volts...also the impedance you will use.
To our supply voltage, the smaller ones match the big ones...so... the advantage goes to the ones are in bigger quantity.
The advantage is to the smaller ones, in your case.
regards,
Carlos
Attachments
My suggestion to use MJL4281A and counterpart is because
I have upgrading plans to increase power and supply voltage in the future...and then, the higher voltage transistors will be interesting.... also the 100 volts electrolitic condensers will be interesting, reason why i left them without correction to 63 volts.
One of these transistors accept 200 miliamps into 150 volts (VCE) and the other, the bigger one works with tree to four times more current...so, we can increase power when using MJL when we cannot do the same with MJW units .... MJL can work into 350 volts peak to peak when MJW will work maximum at 230 volts..... MJW will dissipate only 200 watts when MJL can go 230 (bigger case) ... and other advantages you can see in the datasheet observing graphics.... give a try to see datasheets.
regards,
Carlos
I have upgrading plans to increase power and supply voltage in the future...and then, the higher voltage transistors will be interesting.... also the 100 volts electrolitic condensers will be interesting, reason why i left them without correction to 63 volts.
One of these transistors accept 200 miliamps into 150 volts (VCE) and the other, the bigger one works with tree to four times more current...so, we can increase power when using MJL when we cannot do the same with MJW units .... MJL can work into 350 volts peak to peak when MJW will work maximum at 230 volts..... MJW will dissipate only 200 watts when MJL can go 230 (bigger case) ... and other advantages you can see in the datasheet observing graphics.... give a try to see datasheets.
regards,
Carlos
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"The best" 0R47 5watt emitter resistors
This is my first time that I put together a power amplifier.
I have now almost all components but what I have not yet ordered are the emitter resistors and the large heat sinks.
Now my question because here people who often have a power amplifier built, what are "the best" 0R47 5watt emitter resistors and is there really difference in sound quality, and should these emitter resistors always non inductive?
I know that this question was previously asked but have received no response.
Regards,
Rudy
This is my first time that I put together a power amplifier.
I have now almost all components but what I have not yet ordered are the emitter resistors and the large heat sinks.
Now my question because here people who often have a power amplifier built, what are "the best" 0R47 5watt emitter resistors and is there really difference in sound quality, and should these emitter resistors always non inductive?
I know that this question was previously asked but have received no response.
Regards,
Rudy
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I guess any resistor with the correct value and rating will do a good job. People like me tend to think these should not be wirewound. That's why I chose to go with some Xicon 286-0.47-RC.
Amp boards are now satisfying
In the seek for perfection, I've done some adjustments and fine tuning on some components. These are directly or indirectly suggested by Carlos-The-Great
At the bottom is a picture showing 5 mods i've done for it to suit exactly my needs and desire of perfection.
These are:
1st: The 22 ohms CCS resistor have been replaced by a 47 ohms. This has reduced the CCS and VAS heat sink temperatures by about 12 to 15 degres Celcius. Now with boards on the bench, not enclosed, they're stable at exactly at: CCS = 42C, VAS 40,5C. (Ambient temperature is 22C and RH is 40%) I cannot hear ANY difference. I can only recommend this, it's an easy fix for a potentially serious problem. I can't wait to put everything in the chassis to check the temperature rise of these and imagine what it would've been with the initial resistor.
2nd: The replacement of the CCS resistor had shifted the bias considerably. The 1.2K resistor initially planned renders the bias adjustment impossible, correct biasing cannot be obtained. The resistor of the resistor-trimpot network has been replaced with a 680 ohms unit. Now biasing can be achieved. On the positive side I got 0,9mV and on the negative side I got 1,0mV on both cards (my multimeter's resolution is of 100uV)
3rd: The 10nF capacitor in parallel with the 47uF. In his monologue, at 14:30 Carlos mentions about this. I simply did it.
4th: I replaced the 390 ohms resistor with a 330 ohms, this is to increase slightly the sensitivity of the amplifier by approx 18%. It's a personal decision it's only some fine-tuning to best match with my preamp.
5th: Resistor in palallel with the RIGHT current sink resistor down the differential pair is there to decrease offset, or more precisely to increase negative offset. Both my boards had +46mV and +49mV offset, now with a 1K in parallel with the 100 ohms, I have 0mV for one board, and +2mV for the other.
That's it for the boards. Now still gotta wait for the softstart and loudspeaker protection to arrive from Connex (takes very long ), then I will be able to assemble everything in the enclosure.
In the seek for perfection, I've done some adjustments and fine tuning on some components. These are directly or indirectly suggested by Carlos-The-Great
At the bottom is a picture showing 5 mods i've done for it to suit exactly my needs and desire of perfection.
These are:
1st: The 22 ohms CCS resistor have been replaced by a 47 ohms. This has reduced the CCS and VAS heat sink temperatures by about 12 to 15 degres Celcius. Now with boards on the bench, not enclosed, they're stable at exactly at: CCS = 42C, VAS 40,5C. (Ambient temperature is 22C and RH is 40%) I cannot hear ANY difference. I can only recommend this, it's an easy fix for a potentially serious problem. I can't wait to put everything in the chassis to check the temperature rise of these and imagine what it would've been with the initial resistor.
2nd: The replacement of the CCS resistor had shifted the bias considerably. The 1.2K resistor initially planned renders the bias adjustment impossible, correct biasing cannot be obtained. The resistor of the resistor-trimpot network has been replaced with a 680 ohms unit. Now biasing can be achieved. On the positive side I got 0,9mV and on the negative side I got 1,0mV on both cards (my multimeter's resolution is of 100uV)
3rd: The 10nF capacitor in parallel with the 47uF. In his monologue, at 14:30 Carlos mentions about this. I simply did it.
4th: I replaced the 390 ohms resistor with a 330 ohms, this is to increase slightly the sensitivity of the amplifier by approx 18%. It's a personal decision it's only some fine-tuning to best match with my preamp.
5th: Resistor in palallel with the RIGHT current sink resistor down the differential pair is there to decrease offset, or more precisely to increase negative offset. Both my boards had +46mV and +49mV offset, now with a 1K in parallel with the 100 ohms, I have 0mV for one board, and +2mV for the other.
That's it for the boards. Now still gotta wait for the softstart and loudspeaker protection to arrive from Connex (takes very long ), then I will be able to assemble everything in the enclosure.
Attachments
Thank you Cannonica...i have also found troubles
I have just received a sample to check... a red board from a brazilian friend, Fabio Zimmer, and i found troubles too... i will assemble to test and all these things you said will be plently checked.
I will test MKIII Hx red pcboards - YouTube
regards,
Carlos
I have just received a sample to check... a red board from a brazilian friend, Fabio Zimmer, and i found troubles too... i will assemble to test and all these things you said will be plently checked.
I will test MKIII Hx red pcboards - YouTube
regards,
Carlos
Well thought out and implemented modifications.
Can I suggest one more pair of mods.
Increase 100uF NFB cap to either 330uF or 470uF
Reduce 1uF input cap to 330mF, or 470nF, or 680nF, or keep 1uF. Choose to suit your taste in bass in the room with your speakers.
Let's see if DX bans them from his thread as he does to most other modifications that don't originate from himself.
Can I suggest one more pair of mods.
Increase 100uF NFB cap to either 330uF or 470uF
Reduce 1uF input cap to 330mF, or 470nF, or 680nF, or keep 1uF. Choose to suit your taste in bass in the room with your speakers.
Let's see if DX bans them from his thread as he does to most other modifications that don't originate from himself.
Here is the second part... video about board analisis and test
have three parts:
I will test MKIII Hx red boards - part 2 - YouTube
regards,
Carlos
have three parts:
I will test MKIII Hx red boards - part 2 - YouTube
regards,
Carlos
Dear friends... the forum allow us to block some members
using the "ignore" button.... and it is a clever function to avoid fights...if we perceive, or understand, someone as not kind, or if we detect some empathy troubles with someone, we program not to read the guy in order not to be bothered..not knowing...everything is sweet and peaceful... great feature we have.
Some friends copy and paste text from others.... and sometimes these texts belongs exactly to the one i do not want to read.... this results that i am forced to introduce the copy and paste guy into the ignore list too, in order to protect myself to feel bored or bothered.
thes ignore list guys, and a have a few guys there.... a small bunch of guys when you understand our forum has thousands .... allow us not to read message from some guys.... these guy's text does not appear....if my friends copy and paste...well..this way i will read because my interest to read my dear friends messages..... i have not another way i have to keep distant from fight is to include you too in the ignore list....so, if you asked something and had not answer may be because of that..... do not worry, i have not a trouble with you.... only the copy and paste is not a good idea in my feelings....come to my email and i will give you the attention you deserve:
nanabrother@hotmail.com
carlos.eugenio1951@yahoo.com
A big hug to all my dear friends.
regards,
Carlos
using the "ignore" button.... and it is a clever function to avoid fights...if we perceive, or understand, someone as not kind, or if we detect some empathy troubles with someone, we program not to read the guy in order not to be bothered..not knowing...everything is sweet and peaceful... great feature we have.
Some friends copy and paste text from others.... and sometimes these texts belongs exactly to the one i do not want to read.... this results that i am forced to introduce the copy and paste guy into the ignore list too, in order to protect myself to feel bored or bothered.
thes ignore list guys, and a have a few guys there.... a small bunch of guys when you understand our forum has thousands .... allow us not to read message from some guys.... these guy's text does not appear....if my friends copy and paste...well..this way i will read because my interest to read my dear friends messages..... i have not another way i have to keep distant from fight is to include you too in the ignore list....so, if you asked something and had not answer may be because of that..... do not worry, i have not a trouble with you.... only the copy and paste is not a good idea in my feelings....come to my email and i will give you the attention you deserve:
nanabrother@hotmail.com
carlos.eugenio1951@yahoo.com
A big hug to all my dear friends.
regards,
Carlos
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Of course BMW.... i am sure about that... relax
Here you have the last part about the red board test.
Meanman (Patrick Roovers) will change something in that board.
Here you have the last video:
I will test MKIII Hx board - part 3 - final - YouTube
regards,
Carlos
Here you have the last part about the red board test.
Meanman (Patrick Roovers) will change something in that board.
Here you have the last video:
I will test MKIII Hx board - part 3 - final - YouTube
regards,
Carlos
instead you wafer along like an Humber on 2 cylinders creating roadblocks instead of solutions.- Status
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