Ok, first let me confess, I have a similar questioned posted in the power supply section, but I think the question will solicit different answers from the specifically "Pass" crowd here. Forgive me if I 2x wasted your time.
Here goes....
"
I was at a DIYer's house recently and noticed what he explained to me was a Nelson Pass Zen Variation 5 and right there in the amp was 4 laptop power supplies (the bricks you throw in your bag for when the battery dies...). 2 per channel powering each of the push-pull.
Now this amp design is a class A, so I am guessing its always pulling a lot of power.
So it got me curious and I did some research.
1.) on eBay you can buy 90 watt 19 volt power supplies all day, and cheap. They can deliver almost 5 amps each! Seems like enough if I'm intending to use it for a low mids and up on a tri-amp'd set up (horns, so no real need for lots of power).
2.) Nelson Pass himself says the PS in this amp has to be really clean.
"
In the PS forum, I've gotten a few answers and which included adding CL or CR filters. Of course, I can filter like mad and probably make almost anything work.
So the real question boils down to, does this approach economically produce a the same result? Remember I will be pushing some very efficient horns, so any noise will be more likely heard.
My goal is to avoid building the very big PS Mr. Nelson's design includes if I don't have to (360,000uF of caps alone!)
Thoughts?
Here goes....
"
I was at a DIYer's house recently and noticed what he explained to me was a Nelson Pass Zen Variation 5 and right there in the amp was 4 laptop power supplies (the bricks you throw in your bag for when the battery dies...). 2 per channel powering each of the push-pull.
Now this amp design is a class A, so I am guessing its always pulling a lot of power.
So it got me curious and I did some research.
1.) on eBay you can buy 90 watt 19 volt power supplies all day, and cheap. They can deliver almost 5 amps each! Seems like enough if I'm intending to use it for a low mids and up on a tri-amp'd set up (horns, so no real need for lots of power).
2.) Nelson Pass himself says the PS in this amp has to be really clean.
"
In the PS forum, I've gotten a few answers and which included adding CL or CR filters. Of course, I can filter like mad and probably make almost anything work.
So the real question boils down to, does this approach economically produce a the same result? Remember I will be pushing some very efficient horns, so any noise will be more likely heard.
My goal is to avoid building the very big PS Mr. Nelson's design includes if I don't have to (360,000uF of caps alone!)
Thoughts?
Found the JFET Babo ZenV5 thread...
http://www.diyaudio.com/forums/pass-labs/86012-papa-i-want-have-zen-v5-17.html#post1152539
http://www.diyaudio.com/forums/pass-labs/86012-papa-i-want-have-zen-v5-17.html#post1152539
Yup...
24V 4A Power Supply AC Adaptor for Strip or RGB LED | eBay
I will get to those JFETS and other transistors tomorrow...
24V 4A Power Supply AC Adaptor for Strip or RGB LED | eBay
I will get to those JFETS and other transistors tomorrow...
Imho If you're going to add the input jfets, might as well go the whole hog and make an F5
I had the same question posted in the switching power supply forum but I had even asked if you could parallel the bricks to get more than the 4.6 amps. The thread answered "maybe". There is no doubt connecting them in series with a center common tap for a dual rail supply will work. As you have seen at your friends's house - it works and indeed you get a low cost +/- 19 volt supply that is super efficient and compact. You should try measuring the noise from these, they are much quieter than you think, certainly, nothing a smaller bypass cap cannot handle. Even if it is noisy, the beauty is the noise is at 400 kHz and the 60 hz is wiped out with isolation transformer and switch mode operation. You can't hear 400 kHz even if it gets through. For the Amp Camp Amp, Nelson Pass recommends using SMPS bricks, and said to the naysayers, "get over it". The big iron power transformers used in class A projects has always been the single most expensive part not in including the chassis. You can get high quality HP or other name brand bricks for $5 to $8 ea on Amazon. I want to try the paralleling bricks to increase current.
When I asked about the laptop power supply here I was told it wouldn't work as it would be too noisy. I did it anyway, and tried it out on the Babo zen v5. There were no reservoir caps after the supplies. It sounded very good, and have yet to have someone say otherwise.
As far as going whole hog on an F5, I just didn't have all the remaining parts to build one, so it's an F5 lite.
As far as going whole hog on an F5, I just didn't have all the remaining parts to build one, so it's an F5 lite.
whenever you're in doubt , try and trust to your ears only
don't trust too much in what we , armchair racers , are speaking
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