Sorry, couldn't resist...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
How you doing Eva
So what have we got here.... Hmmm
Input Gate and Base Capacitance
And your point is???
This might have and would have everything to do with High S
Speed switching when the device is completely turned on and the need to discharge the Gate Charge as quickly as possible.
Gate C does have a huge effect
But in Analog Amplifiers this is far less important and the fact is My amplifier already has a Ft of well over a 1mhz. for Audio I think that is more than fast enough.
I have been using for years and do use on a daily bases IRF devices and other types Mosfets. I don't have a problem with them as you seem to have and I don't have a problem with getting very high speed from them.
Anyway thank you for your input....
So what have we got here.... Hmmm
Input Gate and Base Capacitance
And your point is???
This might have and would have everything to do with High S
Speed switching when the device is completely turned on and the need to discharge the Gate Charge as quickly as possible.
Gate C does have a huge effect
But in Analog Amplifiers this is far less important and the fact is My amplifier already has a Ft of well over a 1mhz. for Audio I think that is more than fast enough.
I have been using for years and do use on a daily bases IRF devices and other types Mosfets. I don't have a problem with them as you seem to have and I don't have a problem with getting very high speed from them.
Anyway thank you for your input....
I have used IRFD120 and IRFD9120 in my monster headphone amp, pretty nice.
The glued transistor is a BS170 for temperature stablisation. The amp is an advanced experiment in class A but unfortunatly it was only good in theory, the class A regulator that is. The rest works like clockwork. The idea was class A with constant temperature but this requires more development. A MCU would have been very nice to use here.
Big picture here
An externally hosted image should be here but it was not working when we last tested it.
The glued transistor is a BS170 for temperature stablisation. The amp is an advanced experiment in class A but unfortunatly it was only good in theory, the class A regulator that is. The rest works like clockwork. The idea was class A with constant temperature but this requires more development. A MCU would have been very nice to use here.
Big picture here
The Saint said:
If you want any special hints in general, let me know. I have made hundreds of pcb's for production so I know at least some (don't dare to say "much" 
). have also made pcb's with thick copper, 95 um (almost 3 oz. 105 um = 3 oz.).I you want a review you know where you can reach me.
Hugh, what about you, an AKSA Nirvana DeLuxe Special Edition.
Wouldn't it be something? I'm pretty sure, no very sure, that you could create interest for such a board.
Per Anders,
Very nice boards, I agree, it might make a difference, but remember, you cannot always use the more complicated pcbs for DIY since people like it simple and easy to assemble.
However, the use of a ground plane might be a very good idea....
Anthony,
Congratulations on your new amp, I am sure it will be successful! Can I get in touch with you later to ask your Indian contact for the pcbs? (perhaps Kanwar knows someone too, I tell you, I'm done with the pcb makers from China, every order had some niggling fault, wrong holes, missing overlay, etc, and every time they blamed me for it when my local guy gets it 100% every time!!)
Cheers,
Hugh
Very nice boards, I agree, it might make a difference, but remember, you cannot always use the more complicated pcbs for DIY since people like it simple and easy to assemble.
However, the use of a ground plane might be a very good idea....
Anthony,
Congratulations on your new amp, I am sure it will be successful! Can I get in touch with you later to ask your Indian contact for the pcbs? (perhaps Kanwar knows someone too, I tell you, I'm done with the pcb makers from China, every order had some niggling fault, wrong holes, missing overlay, etc, and every time they blamed me for it when my local guy gets it 100% every time!!)
Cheers,
Hugh
Please separate the complexity of the board and how easy it is to build. Two different things. A well designed doublesided board is much easier to solder and you have a bigger chance to optimize it for optimum performance. It's also a distiction between a design which will manage with single sided board or not.AKSA said:
Don't take the cheapest one. Try to get some experience from someone that others have recommended you. I'm sure we can get 10's or hundred's of good companies.AKSA said:
I have seem Olimex boards, not very exciting
Coffin's super regulator boards were OK (meaing normal quality according to my standards), also ALW's super regulator boards (high quality feeling). The TDA1541 DAC from Taiwan with black pcb, golden pads, excellent! The board from Audio Xpress, Super Regulator,
not very exciting
Greetings Everyone
A conceptual Schematic of the NX150 has been posted on my web site at the following link.
For those that are interested...
http://www.aussieamplifiers.com/nx150.htm
A conceptual Schematic of the NX150 has been posted on my web site at the following link.
For those that are interested...
http://www.aussieamplifiers.com/nx150.htm
The Saint said:Hey Workhorse
I didn't see the final schematic of your R2R amp
Do you reckon you could email it to me...
I should have the conceptual Schematic posted on my website in
the next day or so...
Hi Anthony,
Your Schematic looks good..........
I would post my schematic shortly on this forum...just giving the final touches...thats all
regards,
K a n w a r
Hi Terry
I am waiting for the PCBs to arrive before I do any serious
measurements.
The Mosfet front end greatly reduces the input offset voltage
and helps to achieve a low output offset voltage.
In theory I would expect to be able to remove the cap in the feedback if so desired.
The other reason for the use of mosfets in the first stage is pure sonics really and they have excellent frequency response, actually better than a bipolar in its place I believe.
Or should I say their F response is softer in the roll off than that of a bipolar in its place.
The Fet in the cascode area again is Sonics, Better Frequency Response and match for driving the Lateral Mosfet O/P stage.
You could use a bipolar in this stage such as the 2sc4793 and 2sa1837, both very good devices, but it wouldn't be a Hexfet and I get better power handling with a Hexfet anyway.
I know a lot of you will not agree with what I have said, but then
But then you are most like would never build any thing like this anyway...
Thanks Kanwar Look forward to seeing your design...
I am waiting for the PCBs to arrive before I do any serious
measurements.
The Mosfet front end greatly reduces the input offset voltage
and helps to achieve a low output offset voltage.
In theory I would expect to be able to remove the cap in the feedback if so desired.
The other reason for the use of mosfets in the first stage is pure sonics really and they have excellent frequency response, actually better than a bipolar in its place I believe.
Or should I say their F response is softer in the roll off than that of a bipolar in its place.
The Fet in the cascode area again is Sonics, Better Frequency Response and match for driving the Lateral Mosfet O/P stage.
You could use a bipolar in this stage such as the 2sc4793 and 2sa1837, both very good devices, but it wouldn't be a Hexfet and I get better power handling with a Hexfet anyway.
I know a lot of you will not agree with what I have said, but then
But then you are most like would never build any thing like this anyway...
Thanks Kanwar Look forward to seeing your design...
AKSA said:
Hugh,
You should try http://www.elprint.com
They have a Nordic department and a large scale production i China.
To get a Qoute simply load your gerberdata into their Macaos program and choose the number of boards and delevery date.
Mail me for more help and or initial quotes.
\Jens
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