I would have started on the A2 for sure. It's a long story... but the A2s really swing the Magnepan 1.7 and 12 extremely well. I also tried them on the Acoustic Energy AE1 speakers and that is one incredible set up. Currently they are hooked up to the 1.7s.
At one point I thought I also wanted a pair of F5 turbo 3... I had an F5 and the A5 monos. Thinking about it, though, I decided to go with the A2 first, planning on going to the F5T-3 later. I really preferred the sound of the A5 and the F5 was hooked up to my ADS L810 vintage speakers -and later the Elac Unifi2 B52.
But then I had a taste of the F4 so now I'm on the path to also have a second F4 so I can drive them in bridged mode, mostly because I want... it will also drive the Maggies, so I'm curious. (1) But I don't really need them.
Let me state this about the Alephs:
There is this guy in SoCal who has been in the High End Audio business for 50 years... he's semi retired. Mostly he just tweaks turntables and is a Master at that. A little back, when I only had the A5s, he redid my Linn Lp12: installed the Lingo, Trampolin and Grado Master 2. Cleaned it all, up, tried a couple of motors, new lube, etc, etc.... so then he returned it to my home and we set it up on the rack and did some listening.
Not only did he love the sound of the Maggies but he was curious about the amps... the system sounded very good. He was truly impressed. Mind you, this is a complete High End guy, he knows manufacturing, R&D, marketing, sales, listening, etc.... And my little Maggies with the DIY A5 (with the Conrad Johnson PV9 with teflon caps ) blew him out of the water. What should have been a 15 minute listen to make sure the turntable set up was working ended up in a four hour listen.
So, yeah, the Alephs are that good. So good that I'm keeping the A5 monos.
When the A2s arrived, the sound became much more A5... tonally very much alike but with a deeper soundstage, an added octave of bottom bass and
Now then, nothing is clear in our Audio World though.... the F4 sounds (2) better than the A2. But, it is a more complicated affair. You need to make sure your preamp is good because the F4 is really all about the preamp... whereas the Alephs will impose their own 2nd harmonic which is sweet without being syrupy. Nelson Pass did a great job designing them and the guy who built mine -he can take this deserved credit (3)- did an awesome job.
So, you see... I would wholly recommend the A5s and A2s depending on the speaker you use. If the speaker has reasonable efficiency, then I'd recommend the A5s. If the speaker is a current hog, I'd recommend the A2s.
But then, I've heard that bigger Maggies and other electrostatics need more power than even the A2s can deliver... Maybe that's why the Pass XS300 and the Aleph 1.2 exist.
And just to throw a curb ball.... the F4 exists.
But, to answer your question... yes, I would start with the A2s. They will do everything the A5s do and more.
After that, you can go on and build more, MORE.... SiTs any one?
ZM ought to retire! I can't retire so long as I get more amps.... ;-)
(1) The thing is that I can not compare the A2s with the F4 directly. They are hooked up to different speakers. In my current set up, I take the outputs of the preamp directly to the amps and I select which set up to listen to by turning on the appropriate amps. So, my goal is to reach a point where either amp can drive the Maggies... yes, there is a latent issue there.... why don't I hook up the A2 to the Audio Note speakers? Well... the A2 are in bottom shelf of the rack, the F2 on the 2nd top shelf... and I'm fundamentally lazy: I'd rather listen to music than do all of that extra work. When I get two F4s they both will be on the top shelf. Work, work, work.... pfft... Maybe I need one of them speaker switching devices they used to have at the old Pacific Stereo listening rooms in the 70s and 80s...
(2) Only in the sense that the F4 has no sound of its own. In that respect it "sounds" better.
(3) I don't build anymore. Once upon a time I used to build all kinds of stuff... remember Heathkit, Dynaco, etc? I used to build power supplies and instrumentation amplifiers for the lab and all kinds of signal conditioning hardware for ATE.... but that's long gone, I only build simple things -mostly on Raspberries- and I found someone who knows what he's doing and willing to push the art of it doing it, so I just sort of go along and goad him on his quest even as his musical taste can be sort of avant garde in his own way.. must be that Mid Western water ...
https://www.dw.com/en/why-germany-loves-david-hasselhoff/a-59048932
https://randysdonuts.com/ 🍩🍩
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Alephs will make you lazy real quick. Both the sound and the weight of them That was a terrific writeup. Thank you for taking the time to do it
I just went to that Randy's Doughnuts site after the hasselhoff thing and got stuck on the video in the background for a good 2 minutes and thought of this song:
That was a terrific writeup. Thank you for taking the time to do it I just went to that Randy's Doughnuts site after the hasselhoff thing and got stuck on the video in the background for a good 2 minutes and thought of this song:
Behold. The Hoff doing a song in a Swedish cinematic masterpiece called “Kung Fury”. The music video has clips from the movie. I can suggest building a surround system with all aleph amps for optimizing your experience with the film, but 2 aleph channels is all you need to bring out the best in the music video.
You know, I could whip out the Maggie 12s and power them with the A5s... now all I'll have to worry about is getting the center channel.
But the old Sony EP9ES does a good job with four channel.
I wonder what my wife will think about such a thing?
..
Randy!!!! Yikes! I made it half way through the video. Every bad cliche from the 80s, with the gated drum sound, the Tron like graphics, the monochrome CRTs with preGUI interfaces.... the haircuts, the obligatory Lambo with a wing... When they brought out Hitler... well you know... one of the rules of Usenet use groups was that as soon as the Nazis or Hitler appeared, the entire conversation was moot. Ay! Ay! Ay!
No, what that video needs is a quad Bose system... I doubt Nelson Pass had thought much about VFETs in the 80s.
But the old Sony EP9ES does a good job with four channel.
I wonder what my wife will think about such a thing?
..
Randy!!!! Yikes! I made it half way through the video. Every bad cliche from the 80s, with the gated drum sound, the Tron like graphics, the monochrome CRTs with preGUI interfaces.... the haircuts, the obligatory Lambo with a wing... When they brought out Hitler... well you know... one of the rules of Usenet use groups was that as soon as the Nazis or Hitler appeared, the entire conversation was moot. Ay! Ay! Ay!
No, what that video needs is a quad Bose system... I doubt Nelson Pass had thought much about VFETs in the 80s.
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Okay, so I have gone through the build guide for the Aleph 2. I have a few questions for you guys.
First, would it be a bad idea to use 16 IRFP240s per channel rather than the 12 and bias each device a little lower? Or would this take some of the magic away from the sound? The thought is maybe lower distortion, and better at driving 4 and 2-ohm loads. Maybe a little extra emphasis on the bottom.
Second, stepping up to a 800va transformer seems reasonable. How about a 1000va? The cost jump isn't significant. Do you think I will notice a difference in sound?
Third, caps suggested are 22000uf. Would it be a bad idea to go with 33000uf x8 or does the CRCRC pretty much cut the ripple down so much it won't make a difference?
Also, since we are dealing with a purely class A amplifier, I assume the bass won't be improved from these power supply changes. But tell me if I am wrong.
Thanks!
First, would it be a bad idea to use 16 IRFP240s per channel rather than the 12 and bias each device a little lower? Or would this take some of the magic away from the sound? The thought is maybe lower distortion, and better at driving 4 and 2-ohm loads. Maybe a little extra emphasis on the bottom.
Second, stepping up to a 800va transformer seems reasonable. How about a 1000va? The cost jump isn't significant. Do you think I will notice a difference in sound?
Third, caps suggested are 22000uf. Would it be a bad idea to go with 33000uf x8 or does the CRCRC pretty much cut the ripple down so much it won't make a difference?
Also, since we are dealing with a purely class A amplifier, I assume the bass won't be improved from these power supply changes. But tell me if I am wrong.
Thanks!
1000va - go for it.
22 crcrc vs 33kuf 8 pack crc, model in Duncan power supply designer. Or if you’re talking 22 vs 33 crcrc of course 33 will be lower ripple. But the extra RC makes a nice difference. Run the sim and see if it’s worth the extra money to you. Then decide
16 MOSFETs instead of 12, it’s possible but you’ll potentially need to tune the source and output resistor values. There’s an Aleph spreadsheet floating around out there that could help. Feel like experimenting? On the other hand, you can say “ain’t broke, don’t fix it”. I can’t say how the additional MOSFETs will impact the sound.
22 crcrc vs 33kuf 8 pack crc, model in Duncan power supply designer. Or if you’re talking 22 vs 33 crcrc of course 33 will be lower ripple. But the extra RC makes a nice difference. Run the sim and see if it’s worth the extra money to you. Then decide
16 MOSFETs instead of 12, it’s possible but you’ll potentially need to tune the source and output resistor values. There’s an Aleph spreadsheet floating around out there that could help. Feel like experimenting? On the other hand, you can say “ain’t broke, don’t fix it”. I can’t say how the additional MOSFETs will impact the sound.
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That is what I was thinking. If the difference is minute or worthwhile. I haven't tried LT spice yet but this would be a nice simple thing to try. I will give it a shot.
Thanks
PSUD sounds familiar but something else I haven't tried. I will try that first. I opened LT spice and started playing with it just a little bit and can already tell there is a learning curve. I found some tutorials which I will go through.
Is this it the PSUD you are mentioning:
https://www.duncanamps.com/psud2/
Is this it the PSUD you are mentioning:
https://www.duncanamps.com/psud2/
Here's one I whipped up quickly.
25V transformer with 0R5 Ohm winding (close enough for this exercise)
Bridge rectifier
2.1A constant current load
Then I simulated a CRCRC with 22kuF caps and 0R11 R's. This is parallel 0R22's on the board.
Play with changing the caps and the R's. Watch the ripple and voltage drop. Take out the last RC. More ripple, higher voltage. All tradeoffs.
I click the voltage on the caps to compare. In the table you can look at the "diff" column to see peak to peak ripple voltage.
Don't sweat the details of the exact voltages. You're looking at differences between scenarios. How much does the overall voltage raise or drop based on variations of the supply? What does ripple look like at the final cap?
25V transformer with 0R5 Ohm winding (close enough for this exercise)
Bridge rectifier
2.1A constant current load
Then I simulated a CRCRC with 22kuF caps and 0R11 R's. This is parallel 0R22's on the board.
Play with changing the caps and the R's. Watch the ripple and voltage drop. Take out the last RC. More ripple, higher voltage. All tradeoffs.
I click the voltage on the caps to compare. In the table you can look at the "diff" column to see peak to peak ripple voltage.
Don't sweat the details of the exact voltages. You're looking at differences between scenarios. How much does the overall voltage raise or drop based on variations of the supply? What does ripple look like at the final cap?
Attachments
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I'm still noodling the PSUs for my builds. I may combine a few efforts/projects and make the transition to separate PSUs for my new Alephs (TBD which ones I will build).
I STILL have not gotten around to incorporating the Hammond 159ZLs commonly used around the forums into my PSUs. I have some ... somewhere. I have also seen the recommendation to have at least one cap bank close the amp boards, along with using "motor run" caps in that position...
Onto the actual question...
I don't want to get rid of my old FW PSUs. I may run lower 24V (ish) rails on the new Alephs, but I can sneak a bit higher with the 35V caps if needed. Trying not to get over 30V at the first cap bank. I can also build new PSUs as needed, but repurposing is fun.
IF I were to take an existing "FW" style CRC and add the Hammonds into the new "PSU" chassis along with some "motor run caps" in the ballpark of 10mF (in the amplifier chassis close to the boards) would it look something like this?
Existing PSU filter ... 36mF => 0R11 => 36mF
New PSU filter ... 36mF => 0R11 => 36mF => 2.5H => small R for umbilical / other amp wiring => 10mF
Sim attached. Looks like a solid performer at the expense of a 'little' voltage. Am I close? Any drawbacks or considerations? I gotta be missing something.
Thanks!
I STILL have not gotten around to incorporating the Hammond 159ZLs commonly used around the forums into my PSUs. I have some ... somewhere. I have also seen the recommendation to have at least one cap bank close the amp boards, along with using "motor run" caps in that position...
Onto the actual question...
I don't want to get rid of my old FW PSUs. I may run lower 24V (ish) rails on the new Alephs, but I can sneak a bit higher with the 35V caps if needed. Trying not to get over 30V at the first cap bank. I can also build new PSUs as needed, but repurposing is fun.
IF I were to take an existing "FW" style CRC and add the Hammonds into the new "PSU" chassis along with some "motor run caps" in the ballpark of 10mF (in the amplifier chassis close to the boards) would it look something like this?
Existing PSU filter ... 36mF => 0R11 => 36mF
New PSU filter ... 36mF => 0R11 => 36mF => 2.5H => small R for umbilical / other amp wiring => 10mF
Sim attached. Looks like a solid performer at the expense of a 'little' voltage. Am I close? Any drawbacks or considerations? I gotta be missing something.
Thanks!
Attachments
As you might have noticed in the photo. I've switched back to the standard bridges to address a performance issue. That aside, upon my initial startup all my measured values to date are so close to perfect (Thanks to Randy) I think I'll skip the AC gain for now and go into service this weekend. Can't wait!
Regards,
Dan
Regards,
Dan
Dan, you think you can hold out two more days?! You are stronger than me
That PSUD program is really neat. I just doubled the capacitance for the first stage since the board is CCRCRC. I put the transformer at 45 volts accidently thinking that I was inputting the rail voltage but for all intents and purposes it gives results. 22000 seems to get a pretty small ripple coming out of C3. I adjusted it for 35v transformer and got 27mv coming out of C3. 33000 gives 10.143mv.
Here are some of screen shots:
22000uf caps
33000uf caps
That PSUD program is really neat. I just doubled the capacitance for the first stage since the board is CCRCRC. I put the transformer at 45 volts accidently thinking that I was inputting the rail voltage but for all intents and purposes it gives results. 22000 seems to get a pretty small ripple coming out of C3. I adjusted it for 35v transformer and got 27mv coming out of C3. 33000 gives 10.143mv.
Here are some of screen shots:
22000uf caps
33000uf caps
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