Yes. But it depend of the tools you use on it.I have one at job to make unique board that goes into equipments in the power plant where i am, when the original parts are no longuer available, very handful and priceless .
I can do 4mils traces with 4-6 mils separation, ideal for surface mount. It just don't make plating thru via...
It's very fast compared to hobbyist technique.
DRZ1 said:
I have one at job to make unique board that goes into equipments in the power plant where i am, when the original parts are no longuer available, very handful and priceless .
I can do 4mils traces with 4-6 mils separation, ideal for surface mount. It just don't make plating thru via...
It's very fast compared to hobbyist technique.
Denis
I envy you!
Go ahead and make the rmi-fc100 pcb. There's no need for plating thru vias because you can solder on both sides where is necessary.
If you have teflon PCB don't hesitate to use it - you can make compensation caps on pcb!
Mihai
AKSA said:
Hi Hugues
The machine i'm using is a MITS Eleven T (Japanese router). We have paid it about 15000$ here in Canada in 2001. It's enough for making PCB for audio board, and it drill the holes and cut the boards to.
I am surprised that you don't know about theses routers, i think that's a VERY handful tool for developpers like you. You can make a 2 side PCB of 3 by 6 inches in about 2 hours from any Gerber and NC drill files from any PCB software, and the result is perfect.
LPKF sells good machine to . http://www.lpkfusa.com/
Denis
Hi Denis,
Aha, $US15K!! It is cheap - I should buy two, have one spare!
When I saw the Tokyo address I knew it would not be cheap, but like all things Japanese, it works flawlessly..... ah well, we shall have to wait until China makes barely serviceable ones at low cost...... then I will buy the entry level model!!
I build 3D ratsnests to check proof of concept, then spend hundreds of hours perfecting the pcb design, then have large numbers of boards made in Thailand, this way I avoid the cost of the machine. And you will be interested to know that I work with a very clever young Canadian on circuit development - he lives in Vancouver. He is an expert at making pcbs in an old tray using simple chemicals, and his speed is incredible........
Cheers,
Hugh
Aha, $US15K!! It is cheap - I should buy two, have one spare!
When I saw the Tokyo address I knew it would not be cheap, but like all things Japanese, it works flawlessly..... ah well, we shall have to wait until China makes barely serviceable ones at low cost...... then I will buy the entry level model!!
I build 3D ratsnests to check proof of concept, then spend hundreds of hours perfecting the pcb design, then have large numbers of boards made in Thailand, this way I avoid the cost of the machine. And you will be interested to know that I work with a very clever young Canadian on circuit development - he lives in Vancouver. He is an expert at making pcbs in an old tray using simple chemicals, and his speed is incredible........
Cheers,
Hugh
By dozen it's cheaper....
I know it's not cheap .
And i know also that possible to make good PCB with chemichal and photos, more today with these small inkjet printers to make the films, i have made hundreds.
But these small machines are incredible,and make real good job.
I am lucky to have one at job, but after convincing my boss to buy one, it was paid in only one job of 2 PCB.
I know it's not cheap .
And i know also that possible to make good PCB with chemichal and photos, more today with these small inkjet printers to make the films, i have made hundreds.
But these small machines are incredible,and make real good job.
I am lucky to have one at job, but after convincing my boss to buy one, it was paid in only one job of 2 PCB.
Roender, i have problems to have NJL0302D and his complement. Is there a problem with the NJL1302D in place ? And what is the reason to put 3 Pairs of 200W transistors on a 60W Amp ? more linear ???
About your Gerbers files, i am able to import the top and bottom Gerber in my soft (Altium) but not the drill file. Is it possible for you to export the Eagle board in other format like AutoCad or Pcad or others?
Thanks in advance.
Denis
About your Gerbers files, i am able to import the top and bottom Gerber in my soft (Altium) but not the drill file. Is it possible for you to export the Eagle board in other format like AutoCad or Pcad or others?
Thanks in advance.
Denis
Hi Denis,
Drill file is in Exelon format. I'll try to export it in other format until the end of the day.
I used as much output pairs as possible because i need as much as possible class A without over biasing in Class B.
It is possible to increase without any problem supply voltage if you want more output power. I don't need that for my 150W/90dB spl drivers.
I used 0302/0281 instead 1302/3281 because of Cob (400pF vs 600pF) and linearity. Three pairs of 0302/0281 has total Cob1200pF, equal with only two 1302/3281.
I think is should work with 1302/3281.
Regarding optimum classA classB biasing, take a look at an older response for a question similar with yours:
The classB crossover distortion is caused by variation in amplifier
output impedance with load current level at crossover point.
The optimal class B biasing for minimal crossover distortion requires
that R * gm =1 where R is the total ohmic resistance seen from the
emitter towards the base of one output emitter follower (one output
power BJT).
This resistance is : Re + re + Rs/(beta +1) where Re is the emitter
resistor on which you measure Vq, re is the parasitic internal emitter
resistance, Rs is the total base + source resistance
If Re is dominant, then the condition becomes gm * Re = 1 which means
Io * Re = Vt = 26mV. This is the usual condition (Self)
because gm = Io/Vt where Io is the bias and Vt is the thermal voltage
26 mV at room temp.
If Re is made smaller to avoid losses, then re may not be neglected in
front of Re and gmR=1 becomes gm ( Re + re ) =1
This means Io Re + Io re = 26mV and you are measuring the first term.
It is then normal that at optimum IoRe should be lower than 26mV.
In other words, if you want optimum class B bias and also as much as
possible Class A, you can not do it by increasing bias over 20 ...
26mV (20mV for 0302/0281 with 0.1ohm Re), voltage measured over one
emitter resistor. What other option do we have if we want more A
class? - to increase the number of output devices biased at optimum
class B current.
Mihai
Drill file is in Exelon format. I'll try to export it in other format until the end of the day.
I used as much output pairs as possible because i need as much as possible class A without over biasing in Class B.
It is possible to increase without any problem supply voltage if you want more output power. I don't need that for my 150W/90dB spl drivers.
I used 0302/0281 instead 1302/3281 because of Cob (400pF vs 600pF) and linearity. Three pairs of 0302/0281 has total Cob1200pF, equal with only two 1302/3281.
I think is should work with 1302/3281.
Regarding optimum classA classB biasing, take a look at an older response for a question similar with yours:
The classB crossover distortion is caused by variation in amplifier
output impedance with load current level at crossover point.
The optimal class B biasing for minimal crossover distortion requires
that R * gm =1 where R is the total ohmic resistance seen from the
emitter towards the base of one output emitter follower (one output
power BJT).
This resistance is : Re + re + Rs/(beta +1) where Re is the emitter
resistor on which you measure Vq, re is the parasitic internal emitter
resistance, Rs is the total base + source resistance
If Re is dominant, then the condition becomes gm * Re = 1 which means
Io * Re = Vt = 26mV. This is the usual condition (Self)
because gm = Io/Vt where Io is the bias and Vt is the thermal voltage
26 mV at room temp.
If Re is made smaller to avoid losses, then re may not be neglected in
front of Re and gmR=1 becomes gm ( Re + re ) =1
This means Io Re + Io re = 26mV and you are measuring the first term.
It is then normal that at optimum IoRe should be lower than 26mV.
In other words, if you want optimum class B bias and also as much as
possible Class A, you can not do it by increasing bias over 20 ...
26mV (20mV for 0302/0281 with 0.1ohm Re), voltage measured over one
emitter resistor. What other option do we have if we want more A
class? - to increase the number of output devices biased at optimum
class B current.
Mihai
I will construct it Roender..for sure i will...but will happens
after December 19...when i will receive some input transistors from Nordic and Dudainc.
Then i will make it.
Thank you by the offer of support..... i will use it if needed.
I feel you made a real winner Roender, the excelent prize of design will go to you, for sure...... my deep congratulations, you are a great designer.
You son is lovely too.... search for nice image from you and let us see your eyes man!
regards,
Carlos
after December 19...when i will receive some input transistors from Nordic and Dudainc.
Then i will make it.
Thank you by the offer of support..... i will use it if needed.
I feel you made a real winner Roender, the excelent prize of design will go to you, for sure...... my deep congratulations, you are a great designer.
You son is lovely too.... search for nice image from you and let us see your eyes man!
regards,
Carlos
No!... i am sorry...will assemble with other parts
And because of that, i will not publish review about your amplifier...unless very very positive.... because i know i will use some wrong parts compared to your schematic.
The same way i have made into Symassym thread... the unit worked fine with different transistors...i have tested many different ones and worked fine with almost all them...with some small differences in performance.
Using other parts, than the suggested, we can disturb a lot the amplifier performance and sonic evaluation results.... there are circuits that becames very wrong biased with other transistor's gain.
Because of that, to be fair, i will send to your direct mail using forum mailing services to obtain your home adress (not saved yet)... and this will be after finish my tests... will tell you what i have perceived and will inform the parts i have used.
Observing your circuit.... of course i can be wrong...but i think there's no chance to sound bad...it is an excelent design with some sub circuits and ideas already tested in other schematics and worked fine in separate...for sure will work great all together.... and you have some new ideas too...very good circuit.
I will use big heatsinks and fans...so...the thermall track may not be too much missed related thermal stability....maybe will disturb gain and performance a little.
To control those things, people using other parts than the suggested you will need to "find a Nordic in your life".... to produce boards and parts kit.... this way quality control is safe...other way we have always risks to have people constructing with the parts they have, and this can contribute positive or negative.
regards,
Carlos
And because of that, i will not publish review about your amplifier...unless very very positive.... because i know i will use some wrong parts compared to your schematic.
The same way i have made into Symassym thread... the unit worked fine with different transistors...i have tested many different ones and worked fine with almost all them...with some small differences in performance.
Using other parts, than the suggested, we can disturb a lot the amplifier performance and sonic evaluation results.... there are circuits that becames very wrong biased with other transistor's gain.
Because of that, to be fair, i will send to your direct mail using forum mailing services to obtain your home adress (not saved yet)... and this will be after finish my tests... will tell you what i have perceived and will inform the parts i have used.
Observing your circuit.... of course i can be wrong...but i think there's no chance to sound bad...it is an excelent design with some sub circuits and ideas already tested in other schematics and worked fine in separate...for sure will work great all together.... and you have some new ideas too...very good circuit.
I will use big heatsinks and fans...so...the thermall track may not be too much missed related thermal stability....maybe will disturb gain and performance a little.
To control those things, people using other parts than the suggested you will need to "find a Nordic in your life".... to produce boards and parts kit.... this way quality control is safe...other way we have always risks to have people constructing with the parts they have, and this can contribute positive or negative.
regards,
Carlos
Re: No!... i am sorry...will assemble with other parts
Ok, fair enough.
Please try to use as many output pairs as possible. I'll recommend you c5200/a1943.
If you don't have very well matched pairs please use .22 ohm emitter resistors and don't use diode string as constant bias voltage source. Instead use an good Vbe multiplier
Have a nice day,
Mihai
destroyer X said:
Ok, fair enough.
Please try to use as many output pairs as possible. I'll recommend you c5200/a1943.
If you don't have very well matched pairs please use .22 ohm emitter resistors and don't use diode string as constant bias voltage source. Instead use an good Vbe multiplier
Have a nice day,
Mihai
