Mike,
It's about time...................we need pics...........time to spring for a digital camera. 😉
Jam
It's about time...................we need pics...........time to spring for a digital camera. 😉
Jam
Pictures
I can't get the pictures the correct size. Jam post the ones you have along with your review.
I can't get the pictures the correct size. Jam post the ones you have along with your review.
I just received the IRFP power Mosfets and some other components from Tarasque who offered to bring them from Germany.
Hoping to get both assembled within a week or two.
The circuit i've got does not contain RC values for frequency compensation, only question marks.
Did you choose values already, Mike ?
Hoping to get both assembled within a week or two.
The circuit i've got does not contain RC values for frequency compensation, only question marks.
Did you choose values already, Mike ?
Jacco,
When I designed the amplifier I added places for compensation capacitors in case of instability...............but as Mike has found out the amplifier seems to work fine without them.
The amp sounds pretty good..........but then I am biased.........the higher the bias the better it sounds, as long as you have enough heatsinking and don't go crazy.
I would like to thank Mr.Pass for his help and inspiration.
Some pictures of the prototype.
When I designed the amplifier I added places for compensation capacitors in case of instability...............but as Mike has found out the amplifier seems to work fine without them.
The amp sounds pretty good..........but then I am biased.........the higher the bias the better it sounds, as long as you have enough heatsinking and don't go crazy.
I would like to thank Mr.Pass for his help and inspiration.
Some pictures of the prototype.
Attachments
Happy
I will be happy when.... You find those P-channel MOSFETS, the Donzi is back in the water, and I get to the Buffet after six weeks at home.😀
Thanks, Jam and Nelson.
I will be happy when.... You find those P-channel MOSFETS, the Donzi is back in the water, and I get to the Buffet after six weeks at home.😀
Thanks, Jam and Nelson.
I'll be posting pictures of my MA-40s shortly.
(waiting for binding posts from jrsun and aluminium oxide insulators from Mark G to arrive in the mail)
Just wanted to say thank you to both of you: Jam for designing and Mike for sending me the boards.
For some reason these were the nicest boards to solder that i've ever done.
I've been using WBT silver solder for a long time, soldering the boards was a treat.
Thanks.
(waiting for binding posts from jrsun and aluminium oxide insulators from Mark G to arrive in the mail)
Just wanted to say thank you to both of you: Jam for designing and Mike for sending me the boards.
For some reason these were the nicest boards to solder that i've ever done.
I've been using WBT silver solder for a long time, soldering the boards was a treat.
Thanks.
Yep, SK53, about the only Fischer heatsink profile that does what its heat transfer curve says.
The SK53 is both in volume and cost a very economical heatsink, compared to its thermal resistance ratio.
And i bought so much of it 15 years ago that i still have 10 feet of it left.
The holes in the square connecting rods on the picture are threaded, the heatsinks will be thermally coupled with the 4" high aluminium box they rest on. The entire rig can handle 110 watts at 50C.
That was the estimate i got from a finite elements model i made of the chassis with a program to calculate heat distribution in ship constructions.
(and if it doesn't i'll staple the thing shut with Papst vents
)
Thermal calculation is without the 5 lbs marble fronts i am having made by a cemetery stonery.
(thinking of calling these the A40 Tomb Raiders)
The SK53 is both in volume and cost a very economical heatsink, compared to its thermal resistance ratio.
And i bought so much of it 15 years ago that i still have 10 feet of it left.
The holes in the square connecting rods on the picture are threaded, the heatsinks will be thermally coupled with the 4" high aluminium box they rest on. The entire rig can handle 110 watts at 50C.
That was the estimate i got from a finite elements model i made of the chassis with a program to calculate heat distribution in ship constructions.
(and if it doesn't i'll staple the thing shut with Papst vents
)Thermal calculation is without the 5 lbs marble fronts i am having made by a cemetery stonery.
(thinking of calling these the A40 Tomb Raiders)
Mike W. sent me an A-40 for the next Pass shootout session.... I've done just a little listening to it so far and its an excellent amp.... very different from an Aleph.
Mark
Mark
Jacco,
Very good work...😎 . You need to teach Mike how to build an amp...........he gives new meaning to the words 'rat's nest'..😀
Regards,
Jam
Very good work...😎 . You need to teach Mike how to build an amp...........he gives new meaning to the words 'rat's nest'..😀
Regards,
Jam
Jam,
Yes its a MOSFET version. Nice warm mids and seemingly better bottom end than an Aleph. The high are very detailed and clear but it does not have the bottom end of the KSA-50.
Mark
Yes its a MOSFET version. Nice warm mids and seemingly better bottom end than an Aleph. The high are very detailed and clear but it does not have the bottom end of the KSA-50.
Mark
lets see!!!!!....... the last design i have seen for a mosfet amp was about 20 years old ..... how about one using the buz....dp mosfets or the newer IRF 6xx, 7xx series ...... give us something that we can chew and participate!!!! .... try using one of the arrays combos npn/pnp ....
😱 ....
😱 ....
Mosfet A40 Mk2?
Mark,
The KSA-50 might have the bigger bass but I have not compared the two but you might be able to do the comparison and let us know.
Kaluchka,
..............................you will have to wait on the next version that I happen to be working on.................😉 ....Newer devices does not usually mean better sound (I do not like the sound of the BUZ devices....wimpy bass)...........newer version will possibly have the option of bipolar or mosfet output devices.
Jam
Mark,
The KSA-50 might have the bigger bass but I have not compared the two but you might be able to do the comparison and let us know.
Kaluchka,
..............................you will have to wait on the next version that I happen to be working on.................😉 ....Newer devices does not usually mean better sound (I do not like the sound of the BUZ devices....wimpy bass)...........newer version will possibly have the option of bipolar or mosfet output devices.
Jam
So little time, too many amps to build.........
...........next version might be a 50 watter........that will bridge into 200 watts..........any comments?
I am still trying to keep in the spirit of the original A40 which after all these years is still one heck of an amplifier.
Thanks again for the inspiration Mr.Pass.
Jam
...........next version might be a 50 watter........that will bridge into 200 watts..........any comments?
I am still trying to keep in the spirit of the original A40 which after all these years is still one heck of an amplifier.
Thanks again for the inspiration Mr.Pass.
Jam
- Status
- Not open for further replies.