It's far a longue time since i begin to work on this little amp. Recently i take some of my hifi material to my office at work : my Nmos 200 and and my bookshelfs speakers (troels XT25/PL14).
I am building two stands for speakers to have more space bettween them. I have a raspberry music server with a smsl sanskrit 10th dac. Nice sound at all. Quasi Nmos would be a nice amp for my office (20m² room). So i decided to finalize this project. New amp and PSU board are ordered as the lefting electronic parts. For PSu i will use Epcos 4700uf/63V cap (3 per rail in CRC). I have two 300Va 2x25Vac trafo. I will begin with these, may be i will change them later for 250Va 2x30Vac. This amp will be build in smal cubic mono blocs (24x24x24cm). Attach : new amp and PSU board. My quasi will use 2n5401/KSC1845/KSA1381/FQA40nN25/MJL4281
I am building two stands for speakers to have more space bettween them. I have a raspberry music server with a smsl sanskrit 10th dac. Nice sound at all. Quasi Nmos would be a nice amp for my office (20m² room). So i decided to finalize this project. New amp and PSU board are ordered as the lefting electronic parts. For PSu i will use Epcos 4700uf/63V cap (3 per rail in CRC). I have two 300Va 2x25Vac trafo. I will begin with these, may be i will change them later for 250Va 2x30Vac. This amp will be build in smal cubic mono blocs (24x24x24cm). Attach : new amp and PSU board. My quasi will use 2n5401/KSC1845/KSA1381/FQA40nN25/MJL4281
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I built this amp with the same transistors. Sound quality and stereo imaging are excellent. I have run it on +-52VDC rail voltage and it runs pretty warm. Also have run it on +-35VDC power supply and it sounds the same but runs much cooler. Either transformer, 2x25VAC or 2x30VAC, should power this amp very well with little to no difference in sound. I hope you already have the MJL4281, they are difficult to find currently.
Nice pcb, Idefix!!
I think you will find this a very enjoyable amp; it has a high level of H2, which confers warmth and engagement, something you can't measure.
Myles, do you have yours going now? With 248 pages on this thread, a lot of people built it and from what I hear they all loved its 'fun-loving' sound quality.
I take this opportunity to express my sincere condolence to Bandol83's family and fellow DIYers; I had a lot of contact with Marc, and such was the integrity and strength as he was dying no one on the forum knew what was happening; he never mentioned it.
That takes a very strong person, quite resigned to his death. This happened with Andrew T, sadly. I hope I can be the same when my time comes........
Ciao,
Hugh
I think you will find this a very enjoyable amp; it has a high level of H2, which confers warmth and engagement, something you can't measure.
Myles, do you have yours going now? With 248 pages on this thread, a lot of people built it and from what I hear they all loved its 'fun-loving' sound quality.
I take this opportunity to express my sincere condolence to Bandol83's family and fellow DIYers; I had a lot of contact with Marc, and such was the integrity and strength as he was dying no one on the forum knew what was happening; he never mentioned it.
That takes a very strong person, quite resigned to his death. This happened with Andrew T, sadly. I hope I can be the same when my time comes........
Ciao,
Hugh
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yes time comes for every one... But be positive think positive .. i wish to meet you one day ... truth can't be hidden ..as your contribution to this forum is immense.(as AS .. audiostar has said). my wish is that you take care of your health and have healthy food and do some walking . you can still do wonders in audio .
Hello Idefixes
greetings can you please post schematic you are following i would
like to try this amplifier.
warm regards
Andrew
greetings can you please post schematic you are following i would
like to try this amplifier.
warm regards
Andrew
I have some in stock, but i order some more from digikey. They have both FQA40N25 and MJL4281 in stock
Hi Andrew. Schematic is the stock one provided by ranchu in the Rev 2. I will just add as Hugh said inf to 2.2nf between MJL B-C legs.
Yes, all ready sad news....For Bandol i see that just for a couple of day, as i was away for long time from Diyaudio.
I have an another amp project on road : Tubsomo+ns-ops from Valery Zaichenko (an another quite nice guy here). But these is more time consuming and i want to have my CNC machine finished for achievinh the casing. Quasi-Nmos is more simple rapid to built at moment for me.
Past few days a read the whole topic an another time and coments give the lust to finish the project. Today i will go to home depot to purchase some MDF and multiplex plywood for the tww mono blocs amp case
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Some parts taken out from my stock : 2x 300Va 2x25VAc trafo., 2x heatsink (230x195x40mm) that need some cleaning job and spraypainting to be ok for project
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By chance I discover this circuit diagram.
This I have see in a similar kind first time 11 years ago in a commercial amplifier from NAD - go to post #1+11 under
New Push Pull Buffer Approach for special Kind of THD - MOSFET & BjT - New for me
and
NAD 310 - need some info
What actually is the benefit for using a MOSFET in the upper half and a BjT power device in the lower half of the power output (buffer) stage (sorry - I haven't read the whole thread) ?
The dissimilar but complementary outputs create higher evens over odds.
This leads to a pleasing sound presentation, although if some perceive higher THD the technique is bagged as an 'effects box'.
This leads to a pleasing sound presentation, although if some perceive higher THD the technique is bagged as an 'effects box'.
Electronic parts from TME and Digikey, and PCB from JLCpcb are on the way. Next week i will cut my wood part for casing. I think i will paint them in glossy white with somme black touch (push button, speakon connector, air grill out take, ...)
Marc,
When I suggested FQA40N25 and MJL4281A they were relatively inexpensive.
Since Covid however availability AND cost has increased a lot in just about everything from Digikey/Mouser.
But you will be very happy with this excellent amplifier.......
Hugh
When I suggested FQA40N25 and MJL4281A they were relatively inexpensive.
Since Covid however availability AND cost has increased a lot in just about everything from Digikey/Mouser.
But you will be very happy with this excellent amplifier.......
Hugh
YEs price goe up, but quasi-nmos doesn't requier so much of them even don't need matching. Some poeple spend over 30$ each for sony fet....
