Dear uncle Charly let me put something in your attention...
Often people use your phrase """Kerosene (aviation fuel) """ expecting that Kerosene is some super fuel with billions of octanes that can fly rockets or so ..some also expect that use of this type of fuel in a car will boost performance of the car in sky rocket speeds .
This is so wrong ...eventhough in aviation a super boost fuel could be very useful the problem is that most of these super fuels will fire up and blast with a single spark ...
JEt fuel is even lower in octanes than standard diesel used in cars or heating ....Only its extremely very very clean ..some 10 times cleaner than the standard diesel .
The intention is not to have fuel tanks shelf blasting cause of electrical spark or statics or thunder .
Friend had his son working for the aviation supply and every night this guy was actually picking up a small tank of aviation fuel about 10lt or more to give to the father who was a taxi owner
mercedes 240 lasted for a bit more than 2.000.000 klm with this fuel before the engine died and while opening it they found warn inside but everything was so shiny and clean ...
Just to add in your spherical knowledge !!
Kind regards
Sakis
Often people use your phrase """Kerosene (aviation fuel) """ expecting that Kerosene is some super fuel with billions of octanes that can fly rockets or so ..some also expect that use of this type of fuel in a car will boost performance of the car in sky rocket speeds .
This is so wrong ...eventhough in aviation a super boost fuel could be very useful the problem is that most of these super fuels will fire up and blast with a single spark ...
JEt fuel is even lower in octanes than standard diesel used in cars or heating ....Only its extremely very very clean ..some 10 times cleaner than the standard diesel .
The intention is not to have fuel tanks shelf blasting cause of electrical spark or statics or thunder .
Friend had his son working for the aviation supply and every night this guy was actually picking up a small tank of aviation fuel about 10lt or more to give to the father who was a taxi owner
mercedes 240 lasted for a bit more than 2.000.000 klm with this fuel before the engine died and while opening it they found warn inside but everything was so shiny and clean ...
Just to add in your spherical knowledge !!
Kind regards
Sakis
Nice comments...very valuable dear Sakis
Thank you.
I do have a friend that works with the stuff too.
He said they are very carefull about the presence of water inside the Kerozene, or Querozene in my language....because water can freeze in high altitude and block the engine fuel supply...they use filters of small grain and pump the fuel througth to remove any kind of contamination.
There's a technology around that.... temperature influences a lot, density and a lot of other things...it is fascinating subject dear Sakis.
regards,
Carlos
Thank you.
I do have a friend that works with the stuff too.
He said they are very carefull about the presence of water inside the Kerozene, or Querozene in my language....because water can freeze in high altitude and block the engine fuel supply...they use filters of small grain and pump the fuel througth to remove any kind of contamination.
There's a technology around that.... temperature influences a lot, density and a lot of other things...it is fascinating subject dear Sakis.
regards,
Carlos
Brazilians assembling the Dx Super A
Zimmer, from Brasil, produced a batch of pcboards and all them sold.
We are not offering to outside Brasil because we are facing hard problems with out postal system...it is starting to fail and we cannot trust them anymore...it was reliable....but not anymore reliable now a days.
You see people is building, and i am scared about the " L" shape adaptors..not touching perfectly the main heatsink....also no thermal compound....i am working hard to explain to them these problems..the area of contact in between the " L" shape adaptor and the main heatsink is important, the thermal compound also and several screws to "pull" the material to have good contact is mandatory.
Now the real job gonna start to me...... problems will come...already one complained that had no range to adjust the stand by current to the suggested value
regards,
Carlos
Zimmer, from Brasil, produced a batch of pcboards and all them sold.
We are not offering to outside Brasil because we are facing hard problems with out postal system...it is starting to fail and we cannot trust them anymore...it was reliable....but not anymore reliable now a days.
You see people is building, and i am scared about the " L" shape adaptors..not touching perfectly the main heatsink....also no thermal compound....i am working hard to explain to them these problems..the area of contact in between the " L" shape adaptor and the main heatsink is important, the thermal compound also and several screws to "pull" the material to have good contact is mandatory.
Now the real job gonna start to me...... problems will come...already one complained that had no range to adjust the stand by current to the suggested value
regards,
Carlos
These transistors are not that huge
They are very good....but the power dissipation derated is not that good..also the maximum continuous current is not that big too..
It can be used, sound will be excellent, no doubts, but you will not be able to connect 2 ohms loads anyway neither 4 ohms speakers that have valleys of impedance lower than 4 ohms (almost all them have these lower impedance frequencies...so...all them are very dangerous)
So..... not completely or entirelly guaranteed at 4 ohms.... where power is 150 watts RMS each channel... some care will be needed.... not to push it too much hard for too much long time.
Better is not to use 42 volts....better to go down to 40, or 38 volts or even 36 volts aproximately....or to install another pair in the output.
You see this is because of 70 degrées centigrades..the worst case scenario of bad heatsinks, bad flan blower and bad installation inside the enclosure with bad vent holes and all bad stuff joining together to produce a big trouble.
Of course, to operate 8 ohms it is very safe and the power amplifier can reach, easy, 80 watts RMS with low distortion when feeded by 42 volts supplies.
30 plus 30 volts alternated and 550 to 600 watts or 600 VA transformer will be good to feed two channels of these amplifier to operate 4 ohms full rated power.
Good luck!
regards,
Carlos
They are very good....but the power dissipation derated is not that good..also the maximum continuous current is not that big too..
It can be used, sound will be excellent, no doubts, but you will not be able to connect 2 ohms loads anyway neither 4 ohms speakers that have valleys of impedance lower than 4 ohms (almost all them have these lower impedance frequencies...so...all them are very dangerous)
So..... not completely or entirelly guaranteed at 4 ohms.... where power is 150 watts RMS each channel... some care will be needed.... not to push it too much hard for too much long time.
Better is not to use 42 volts....better to go down to 40, or 38 volts or even 36 volts aproximately....or to install another pair in the output.
You see this is because of 70 degrées centigrades..the worst case scenario of bad heatsinks, bad flan blower and bad installation inside the enclosure with bad vent holes and all bad stuff joining together to produce a big trouble.
Of course, to operate 8 ohms it is very safe and the power amplifier can reach, easy, 80 watts RMS with low distortion when feeded by 42 volts supplies.
30 plus 30 volts alternated and 550 to 600 watts or 600 VA transformer will be good to feed two channels of these amplifier to operate 4 ohms full rated power.
Good luck!
regards,
Carlos
Attachments
post813 shows the de-rating and how to determine a maximum operating dissipation for driving a resistor load.
Driving a speaker, that is a reactive load, is very much more stressful.
A 2pair output stage using 100W devices can do 150W into 4r0 resistor, but it will not be reliable working at near maximum powers into a 4ohms speaker, if the devices get hot.
The de-rating for a reactive load can be either using 8ohms speaker, or domestic listening into a 4ohms speaker, where the average power output is ~20dB below max power.
Driving a speaker, that is a reactive load, is very much more stressful.
A 2pair output stage using 100W devices can do 150W into 4r0 resistor, but it will not be reliable working at near maximum powers into a 4ohms speaker, if the devices get hot.
The de-rating for a reactive load can be either using 8ohms speaker, or domestic listening into a 4ohms speaker, where the average power output is ~20dB below max power.
Hello Carlos!
I finally met all the elements of my amp and assembly has begun.
The heat sinks, the Sanken and two transformers were stored for over twenty years and are now used to this amp.
Here are some pictures from the beginning and as soon as I finished all the amp I am sending others.
Thank you for this achievement!
I finally met all the elements of my amp and assembly has begun.
The heat sinks, the Sanken and two transformers were stored for over twenty years and are now used to this amp.
Here are some pictures from the beginning and as soon as I finished all the amp I am sending others.
Thank you for this achievement!
Attachments
Boards and parts arrived to build a Dx Super A
Here you have some pictures.
We are NOT offering to the international community due to the lack of confidence we have related Brazilian Postal System...in other words..we cannot guarantee the package will arrive your place...if you want to take the risk by yourself..then go to Zimmer:
imap.eletro@gmail.com
regards,
Carlos
Here you have some pictures.
We are NOT offering to the international community due to the lack of confidence we have related Brazilian Postal System...in other words..we cannot guarantee the package will arrive your place...if you want to take the risk by yourself..then go to Zimmer:
imap.eletro@gmail.com
regards,
Carlos
Attachments
Brazilian group buy pcboards arrived at my home
Here you have them:
Placas para Dx Super A chegaram - YouTube
Carlos
Here you have them:
Placas para Dx Super A chegaram - YouTube
Carlos