Nimos 200
Hi Quasi
Any chance you could provide the copper side layout of the Nimos 200?
I tried to figure out the layout through the published parts layout but
I found an error on it. It's probably because the mentioned layout is
too smeared I can't trace the connection between base and collector of T3.
I would appreciated it
Hi Quasi
Any chance you could provide the copper side layout of the Nimos 200?
I tried to figure out the layout through the published parts layout but
I found an error on it. It's probably because the mentioned layout is
too smeared I can't trace the connection between base and collector of T3.
I would appreciated it
bigpanda said:
Photos of my amp are shown here http://www.diyaudio.com/forums/showthread.php?postid=586009#post586009 and here http://www.diyaudio.com/forums/showthread.php?postid=1181386#post1181386
I have never put more than one heatsink on one channel and do not recommend it, unless they are well joined as Tom Waits has done http://www.diyaudio.com/forums/showthread.php?postid=1148635#post1148635. I see also see no reason why you could not put more than one module on one heatsink, particularly the Nmos200.
I haven't done this myself because apart from the Nmos350 I have not put any other Nmos design in actual service, they only reside on my test bench next to many other projects that are simply designed for ....actually I'm not sure. I have single modules of some designs that may never see the inside of a case, but are used as reference modules for potential improvements.
Cheers
Q
Hi Quasi,
I plan to build this amp by using only 2 high power mosfet with 85 V. rail. The mosfet will be APT30 or APT40. The load is about 4 ohms or a little lower. I use 1.6QR Magnepan as my speaker. Is it possible to do this?
I saw Gamut used only one pair of mosfet in their poweramp with great results and feedback from Samuel was quite interesting when he discovered that one pair of mosfet sound better.
Can you recommend me any other good high power mosfets for this implementation?
Thanks, Kittikun
I plan to build this amp by using only 2 high power mosfet with 85 V. rail. The mosfet will be APT30 or APT40. The load is about 4 ohms or a little lower. I use 1.6QR Magnepan as my speaker. Is it possible to do this?
I saw Gamut used only one pair of mosfet in their poweramp with great results and feedback from Samuel was quite interesting when he discovered that one pair of mosfet sound better.
Can you recommend me any other good high power mosfets for this implementation?
Thanks, Kittikun
kittikun said:
1 pair of these Mosfets will not last long. A local constructor is using 3 pairs of IXFH26N50's (500v 300w) with rails of almost 80v for use in a DJ / Party system. In a domestic situation he may have got away with 2 pairs.
For 85v rails and using 300 watt FETs you will need 3 pairs. But this is going by the data and calculations. In real life you might et lucky with less. I happen to have some IXFH26N50's, let me know if you want to buy some. http://docs-europe.electrocomponents.com/webdocs/020f/0900766b8020fef7.pdf
Cheers
Q
Hello Quasi
I thank you the files for the Nimos 200, I received today.
My fault, I didn't mention that my Brother of Quasi is going strong
so far, I really like that amp and I use it all the time. Excellent amplifier.
But that made me think I should build the Mosfet version to see if
there is any difference in quality. I'm a bit reluctant as far as the
Mosfet are concerned, I've built 2 of them in the past and I didn't
like them, but again this one is QUASI so it might be different
whereas the others were fully complimentary.
I'll let you know my impressions when I completed this one.
Thank you very much again
I thank you the files for the Nimos 200, I received today.
My fault, I didn't mention that my Brother of Quasi is going strong
so far, I really like that amp and I use it all the time. Excellent amplifier.
But that made me think I should build the Mosfet version to see if
there is any difference in quality. I'm a bit reluctant as far as the
Mosfet are concerned, I've built 2 of them in the past and I didn't
like them, but again this one is QUASI so it might be different
whereas the others were fully complimentary.
I'll let you know my impressions when I completed this one.
Thank you very much again
Hi Andrew,
The Magnepan consumes a lot of power and current but I could not get the best of both world from power device. In real world, I have to choose or compromise between sonic quality and power rating. I may increase the output pairs to 2, 3 or more to ensure that it safe and working properly in the entire design range but I'm not sure for the best sonic quality. From reading this thread so far, there is not enough comparison and information between each design variants.
I'm end up choosing the higher power design. In my plan, I will use nmos350 or nmos500 pcb and gradually add mosfets onto the board starting from 1 pair and more and more. After each step, I will audition the system to see whether there is any different in sound quality and what is the relation between sound and number of output pairs.
Kittikun
The Magnepan consumes a lot of power and current but I could not get the best of both world from power device. In real world, I have to choose or compromise between sonic quality and power rating. I may increase the output pairs to 2, 3 or more to ensure that it safe and working properly in the entire design range but I'm not sure for the best sonic quality. From reading this thread so far, there is not enough comparison and information between each design variants.
I'm end up choosing the higher power design. In my plan, I will use nmos350 or nmos500 pcb and gradually add mosfets onto the board starting from 1 pair and more and more. After each step, I will audition the system to see whether there is any different in sound quality and what is the relation between sound and number of output pairs.
Kittikun
Quicky question. Here in the US, there the 2SC1845 seems unavailable. However, I may have located a suitable replacement for the 2SC1845, it is KSC1845 made by Fairchild. I briefly reviewed the specs and all appears to be the same. Can someone confirm? Datasheet Link
What is the desired hfe for T1 and T5?
What is the desired hfe for T1 and T5?
tommyp said:
The KSC1845 seems to be virtually identical so it should be ok to use although the NEC spec sheet is more comprehensive. If you have any doubts I have some still available for sale (min 10 units).
In terms of the gain required the 2SC1845 easily meets the requirement. The whole amplifier has a total gain of 33 (Nmos350).
Cheers
Q
quasi and anatech, Thanks for the tips. Maybe I should rephrase my question now that I did more homework in compiling a parts list. The BC556, BC546 and the x1845 transistors are available with different hfe's and I'm not positive of which ones I should order.
The BC556 and BC546 are available with hfe's of 110-220, 200-450 & 420-800
The x1845 is available with hfe's of 200-400, 300-600, 400-800 and 600-1200.
Also, can someone point me to a US source for the .33/5 watt resistors?
Thanks again from the noob!
The BC556 and BC546 are available with hfe's of 110-220, 200-450 & 420-800
The x1845 is available with hfe's of 200-400, 300-600, 400-800 and 600-1200.
Also, can someone point me to a US source for the .33/5 watt resistors?
Thanks again from the noob!
Hi tommp,
In the US try www.mouser.com or www.digikey.com. They have many different companies to select from. Vishay or Ohmite being two of the more popular types.
Regards,
Al
In the US try www.mouser.com or www.digikey.com. They have many different companies to select from. Vishay or Ohmite being two of the more popular types.
Regards,
Al
I would be interested to know if anyone has any ideas on how to 'disable'/mute an amplifer. I'm building a multi channel amp and was considering using relays for the front end of each amp, but it seems this may be a bad idea. I had heard someone in another thread talk of disabling the ccs.
