Does someone have built UDNess 32V version with 4 MOSFET-s per channel? How does it sounds comparing with UDNess with 2 MOSFET-s?
I was asked by PM for information on ProUDNeSS, the double MOSFET parallel version.
All I have on that is the schematics posted in post #1.
I don't have PCB for that. I have not built myself.
So you should only attempt if you are experienced and skilful enough to debug or solve any possible stability issues.
There is a spice file in post#2 which you can modify to any variants you want.
Again, you have to know LTSpice well enough to do so.
I don't have ready made ones to cover all possible individual configurations.
But if you are serious about DIY, then LTSpice is worth investing time to learn.
Patrick
All I have on that is the schematics posted in post #1.
I don't have PCB for that. I have not built myself.
So you should only attempt if you are experienced and skilful enough to debug or solve any possible stability issues.
There is a spice file in post#2 which you can modify to any variants you want.
Again, you have to know LTSpice well enough to do so.
I don't have ready made ones to cover all possible individual configurations.
But if you are serious about DIY, then LTSpice is worth investing time to learn.
Patrick
Hi Patrick
Do you have experience with the difference of onsemi vs Fairchild at FQA9P25 ?
kr
chris
Someone just sent me a while ago picture of his newly built UDNeSS.
Nicely done.
Many Congratulations,
Patrick
Nicely done.
Many Congratulations,
Patrick
Those interested to build should not wait too long.
FQA9P25 is EOL, but still 9k at Mouser.
Nice price too.
🙂
Patrick
FQA9P25 is EOL, but still 9k at Mouser.
Nice price too.
🙂
Patrick
I just received UDNess V2.0 PCB-s and going throught the BOM. I do not see any info for C2, is it same as C4? What R value Bourns 3296X Trimmer should I get? Is there any sonic performance I can hear if I replace J113 with 2 x 2SK209GR?
The amp pictured in post #387 is mine, and the congratulations go to Patrick.
I've always been a tube guy, but a friend of mine let me borrow his Aleph 3 and I knew right away that I had to build a Class-A amp of my own before he asked for it back. I studied the various Pass designs, but the designs that interested me all involved various unobtania. The UDNess, however, seemed like a path of low resistance with available parts. Since I'm basically cheap and lazy, I chose to pursue this path. I ordered pcb's from my favored supplier, pcbway, and gathered up the parts. Fortunately, I had an unused chassis that I was able to repurpose. It took a few hours of drilling and tapping, but I'm pleased with the results. I.e you can't see my mistakes.
I chose to utilize SMPS's as I'm getting too old to hoist 60-lb amplifiers around. The design uses a pair of Meanwell LRS150-24's, one for the plus and one for the minus supplies. Although I regularly use SMPS's in audio to good effect, I didn't know how the switcher noise might affect this particular design, so I designed a pcb that combined 2 of the switcher filters, documented elsewhere on diyaudio, in a +/- fashion. To enable fast changes, I used 1/4" quick-connects wherever possible.
The amp worked correctly from the get-go. I did need to change the resistor R6 to set the current through the output transistors to about 1.22A. Offset is very low and stable after tweaking Rdg; I did not use the servo. After stabilizing, the heatsinks run right around 55 degrees C, even after I forgot to turn it off one night. And there is NO noise. Try that with tubes. There are some very slight turn-on and turn-off thumps, but they don't cause very much woofer cone movement.
Anyway, the amp is a pleasure to listen to. My thanks to Patrick for a great design.
I've always been a tube guy, but a friend of mine let me borrow his Aleph 3 and I knew right away that I had to build a Class-A amp of my own before he asked for it back. I studied the various Pass designs, but the designs that interested me all involved various unobtania. The UDNess, however, seemed like a path of low resistance with available parts. Since I'm basically cheap and lazy, I chose to pursue this path. I ordered pcb's from my favored supplier, pcbway, and gathered up the parts. Fortunately, I had an unused chassis that I was able to repurpose. It took a few hours of drilling and tapping, but I'm pleased with the results. I.e you can't see my mistakes.
I chose to utilize SMPS's as I'm getting too old to hoist 60-lb amplifiers around. The design uses a pair of Meanwell LRS150-24's, one for the plus and one for the minus supplies. Although I regularly use SMPS's in audio to good effect, I didn't know how the switcher noise might affect this particular design, so I designed a pcb that combined 2 of the switcher filters, documented elsewhere on diyaudio, in a +/- fashion. To enable fast changes, I used 1/4" quick-connects wherever possible.
The amp worked correctly from the get-go. I did need to change the resistor R6 to set the current through the output transistors to about 1.22A. Offset is very low and stable after tweaking Rdg; I did not use the servo. After stabilizing, the heatsinks run right around 55 degrees C, even after I forgot to turn it off one night. And there is NO noise. Try that with tubes. There are some very slight turn-on and turn-off thumps, but they don't cause very much woofer cone movement.
Anyway, the amp is a pleasure to listen to. My thanks to Patrick for a great design.
Does someone have compared UDNess V2 sound with some other amplifiers (F5, Aleph J, FW J2 etc) and can comment that. I am hesitating if I should go on with this or wait for some F5, Aleph J or other class A group buy or kit to arrive to diyaudiostore?
What is the max Idss for Q2, Q3 (2sk209) ? Would be also ok to use JFE150 or JFE2140 in this position? What should I know about other parts replacement for Q2, Q3?
What would be the minimum chassis for this amp? 3U/400 or 4U/400 or?
What is the max Idss for Q2, Q3 (2sk209) ? Would be also ok to use JFE150 or JFE2140 in this position? What should I know about other parts replacement for Q2, Q3?
What would be the minimum chassis for this amp? 3U/400 or 4U/400 or?