Is there a thread on that X?
I've got an F5Tv2 build that just needs heatsinks/case. The 'ALA' sounds interesting, and similar power output.
I will make a new thread soon. It will be called the ALPHA actually. Debugging the amp now. Real close to first sound. The circuit was designed around 35v rails and I am using much more modest 24v so some dc set points had to be redone.
Aksa Lender P-mos Hybrid Aleph (ALPHA) power amp
Presenting the ALPHA (Aksa Lender P-mos Hybrid Aleph) SE Class A amp.
Ok folks, it was a struggle for me but I got the amp fired up and singing finally. Hugh's design which incorporates the Aksa Lender front end, and the Pass Aleph CCS variable current source, with a P-channel MOSFET output stage, so technically it is a hybrid Aleph output stage, hence the name ALPHA. It is a very clever design and has the best of all worlds I think.
I will post in a new thread soon - just needed to confirm that the amp works before doing so. Happy to say it sounds pretty nice. Running 1.16amps bias at present with CPU cooler heatsink only at 31C so plenty of room to go. Very cost effective way to cool hot Class A amps for $12 (vs beaucoup bux for equivalent aluminum finned heatsink).
Here are some first sound photos...
Test rig with +/-24v linear PSU with Prasi./Project16 CRC:
Here is closeup of the amp (the two MOSFETs are clamped under the aluminum L section bar), heatsink temp is 31C with quiet mode fans going:
Here is an interesting fact, the DC offset is 0.0mV and I have no offset adjustment pot! I matched the Beta's on the input LTP and that was it.
More to come later in the new thread... 🙂
Presenting the ALPHA (Aksa Lender P-mos Hybrid Aleph) SE Class A amp.
Ok folks, it was a struggle for me but I got the amp fired up and singing finally. Hugh's design which incorporates the Aksa Lender front end, and the Pass Aleph CCS variable current source, with a P-channel MOSFET output stage, so technically it is a hybrid Aleph output stage, hence the name ALPHA. It is a very clever design and has the best of all worlds I think.
I will post in a new thread soon - just needed to confirm that the amp works before doing so. Happy to say it sounds pretty nice. Running 1.16amps bias at present with CPU cooler heatsink only at 31C so plenty of room to go. Very cost effective way to cool hot Class A amps for $12 (vs beaucoup bux for equivalent aluminum finned heatsink).
Here are some first sound photos...
Test rig with +/-24v linear PSU with Prasi./Project16 CRC:
Here is closeup of the amp (the two MOSFETs are clamped under the aluminum L section bar), heatsink temp is 31C with quiet mode fans going:
Here is an interesting fact, the DC offset is 0.0mV and I have no offset adjustment pot! I matched the Beta's on the input LTP and that was it.
More to come later in the new thread... 🙂
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Looks really interesting XRK!
If everything work as you are expecting, I’m guessing you’ll aim for a GB? If yes, would you be considering selling matched transistors (whichever need to be matched)? I would be willing to pay for a matching service.
All the best!
Do
If everything work as you are expecting, I’m guessing you’ll aim for a GB? If yes, would you be considering selling matched transistors (whichever need to be matched)? I would be willing to pay for a matching service.
All the best!
Do
Hi Pinocchio,
Thanks for your interest. Sure enough, if it works out well we can have a GB and JPS64 will make the layout. I’m debating whether or not it’s even worthwhile to do a 25v rail version. The 35v rail 53w version intrigued me but forces use of CPU coolers and fans. We are talking 140w dissipation per channel. Or maybe make one board big has two options for 24v or 35v. Just change resistor network and output MOSFETs.
Thanks for your interest. Sure enough, if it works out well we can have a GB and JPS64 will make the layout. I’m debating whether or not it’s even worthwhile to do a 25v rail version. The 35v rail 53w version intrigued me but forces use of CPU coolers and fans. We are talking 140w dissipation per channel. Or maybe make one board big has two options for 24v or 35v. Just change resistor network and output MOSFETs.
I have to say, I am really impressed with how much heat these CPU heatpipe coolers are. Did you know that the heat flux carried by the water vapor inside the pipes can be as high as the heat flux at the surface of the sun for the same cross secrional area? Nothing transfers heat at a higher flux than a heat pipe. Thermodynamics at work. Anyhow, 56w was nothing for this heatsink. I was running a slow fan. I think it could handle 120w no problem with a faster fan.
Dell Heatsink For Precision 690 T7400 W/ Screws FD841 0FD841 | eBay
This one is good for 150w and comes with a fan.
Amazon.com: be quiet! BK009 Pure Rock - CPU Cooler - 150W TDP- Intel LGA 775 / 1150 / 1155 / 1156 / 1366 / 2011(-3) Square ILM & AMD Socket AM2(+) / AM3(+) / AM4 / FM1 / FM2(+): Computers & Accessories
One reason I like the Dell above is it has a huge copper surface that easily holds two MOSFETs.
Dell Heatsink For Precision 690 T7400 W/ Screws FD841 0FD841 | eBay
This one is good for 150w and comes with a fan.
Amazon.com: be quiet! BK009 Pure Rock - CPU Cooler - 150W TDP- Intel LGA 775 / 1150 / 1155 / 1156 / 1366 / 2011(-3) Square ILM & AMD Socket AM2(+) / AM3(+) / AM4 / FM1 / FM2(+): Computers & Accessories
One reason I like the Dell above is it has a huge copper surface that easily holds two MOSFETs.
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You can most certainly count me in, X!
I really like the idea of a ~35v rail powered, ~45-50w Class A output amp, as I'm sure many others do.
New ALPHA amp thread here:
http://www.diyaudio.com/forums/soli...hybrid-aleph-alpha-amplifier.html#post5323512
Sneak preview:
http://www.diyaudio.com/forums/soli...hybrid-aleph-alpha-amplifier.html#post5323512
Sneak preview:
I will be on travel this week and may not have access to the Internet so orders may take until next week before I respond.
Has anyone besides Vunce able to build and get one working yet?
If you guys like this preamp, and have not see it yet, check out the new Class A amp based on this preamp as a front end here:
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
PCBs for the 20W version arrived today and they look great.
If you guys like this preamp, and have not see it yet, check out the new Class A amp based on this preamp as a front end here:
Aksa Lender P-mos Hybrid Aleph (ALPHA) Amplifier
PCBs for the 20W version arrived today and they look great.
Hmm, I still need to decide on what amp and speakers to build. Have you shipped boards yet? I may want a set of the 20 watt pcb’s added.