The Mini-A - Page 5

grataku · 20th May 2002, 09:38 PM

Grey,
after I realized that I don't really need 50w on each channel of my active system I thought of using this little thingy for amplification. On top of that I would be well on my way of being fully Pass-ified with the last piece of the puzzle being the active Xover.
How does the DC offset behave over time? Basically, is this thing safe for use DC coupled to the driver?

GRollins · 20th May 2002, 10:16 PM

DC offset isn't likely to be a problem...at least any more than it would be for a "real" Aleph. A few tens of millivolts here and there at worst. It does have a bit of a turn-on thump, though, so I'd use a cap if you were going to use the circuit to run a tweeter. For a woofer...no problemo, go straight in.
Take note of earlier posts about current and rejigger the bias if you need to run a 4 ohm driver. Feel free to run it at a higher rail, if you want a bit more power. Once you get up into the low to mid-20s on the rail voltage, go ahead and build an Aleph 3 or 30. This is just sort of a cute 'toy' Aleph; something to burn up leftover parts.
I'm still waiting for someone to build one in a Pepsi can...

Grey

GRollins · 21st May 2002, 02:51 AM

Actually, come to think of it, you could simply mute the output for 5 or 10 seconds with a relay, then direct couple.

Grey

Dave Varner · 12th June 2002, 12:18 PM

I only need a few watts and am curious if this is a good route to follow.

Thanks,

Dave

Fuling · 17th July 2005, 03:13 PM

I finished a pair of monoblocks for a friend a couple of weeks ago, slightly beefed up compared to the original Mini A schematic.
I used a 150VA 2x12V transformer per channel that feeds a pi filter with 15000uF - 1,1mH - 47000uF.
Gives 14W/8ohms and 23W/4 ohms, but then I also raised the bias a bit since the guy I made them for has 4 ohms speakers.

GRollins · 17th July 2005, 09:15 PM

Splendid looking piece of hardware. May it give many hours of pleasure.

Grey

Madmike2 · 17th July 2005, 09:21 PM

Thats what i am talking about right there Fuling

Thats a sweet peice of kit. I am drooling imagining what it sounds like.

jleaman · 18th July 2005, 12:25 AM

GRollins,

Is the mini a schematic you posted Your design or Pass-Lab's.

jleaman · 18th July 2005, 12:27 AM

Quote:

Originally posted by mozfet
Grey Yoo Da Mann! really nice circuit, a lot of these babies will be built, any chance of the pcb layout being made available for us idle/incapable/software-less types.

Mozfet.

goodstuff57@hotmail.com

I'm Working on one. But i have question's FIRST

GRollins,

GRollins · 18th July 2005, 02:33 AM

Do I do the Mini-A?
...this is a trick question, perhaps?
As I said in the first post of this thread, the Mini-A was something I did as a stepping stone to the Aleph-X. It's basically a cut-down Aleph 3. Nothing particularly weird or original. Somewhat later, one of the installments in Nelson's Zen series featured an Aleph-style entry (#4, I think).
Other variations are possible and I've fiddled with a few of them.
If time permits, I may start another thread or two based on some of the things I've done here, but it's very time-consuming to support a thread; I've got more ideas than I can practically put out. I don't make any money at this, so I still have to show up at a non-audio job in order to keep my daughter in diapers. What with work and eating and sleeping and a few other odds and ends, there's little slack at the moment.
Nelson, incidentally, was not warned about this thread. With the Aleph-X, I kept him abreast of things pretty much from conception--that story has been detailed elsewhere--but the Mini-A was as much news to him as it was to anyone else. If I'm lucky, he'll forgive me sometime during our present incarnations. If I come back in my next life as a microbe, I'll know that I've got some kharma-balancing to do.
Sigh.
I have at least two or three other Aleph ideas that might make interesting threads. I fear that one of them might be close to the Aleph-J (no, I haven't seen a schematic for the J, just guessing), so I won't bother with that. I have not had time to try out the 'Maxi-A' idea yet, so I don't know if that's worth pursuing.
At any rate, I had artwork for PC boards, but lost it in one of the hard drive crashes, or perhaps when the virus set up shop in my machine a couple of years ago. If necessary I can recreate it, but at this point I'd rather move forward and do a new circuit than revisit the old one.
MikeW, bless his heart, was kind enough to adopt the Mini-A. He and a friend of his worked up boards, which then travelled to the four corners of the Earth. When those ran out, he did a revised version. Any audience the Mini-A has garnered has been his doing. Thanks, Mike.
Note that the Aleph patent is still active. Do not attempt to produce Mini-As for profit or a platoon of lawyers will infest your underwear. Your wife/girlfriend/(in)significant other will leave you. Perhaps all three of them at the same time. Don't tempt fate. Though Nelson did not draw the schematic for the Mini-A, it is based directly on his patent and is covered just as much as an official Aleph from Nelson, himself.
You can build one, play with it, use it for a paperweight, or even listen to music with it...just don't sell it at a profit. Don't say that you weren't warned.

Grey

P.S.: They are kinda cute, aren't they?

12th June 2002, 12:18 PM	#44
Dave Varner diyAudio Member Join Date: Feb 2002 Location: Arlington, Virginia	Has anyone built the Mini-A? I only need a few watts and am curious if this is a good route to follow. Thanks, Dave __________________ DV

17th July 2005, 09:21 PM	#47
Madmike2 diyAudio Member Join Date: Apr 2005 Location: Toronto	Thats what i am talking about right there Fuling Thats a sweet peice of kit. I am drooling imagining what it sounds like. __________________ Persistence is better then intelligence. Unless persistence kills you.

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20th May 2002, 09:38 PM	#41
grataku diyAudio Member Join Date: Dec 2000 Location: -	Grey, after I realized that I don't really need 50w on each channel of my active system I thought of using this little thingy for amplification. On top of that I would be well on my way of being fully Pass-ified with the last piece of the puzzle being the active Xover. How does the DC offset behave over time? Basically, is this thing safe for use DC coupled to the driver?

20th May 2002, 10:16 PM	#42
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	DC offset isn't likely to be a problem...at least any more than it would be for a "real" Aleph. A few tens of millivolts here and there at worst. It does have a bit of a turn-on thump, though, so I'd use a cap if you were going to use the circuit to run a tweeter. For a woofer...no problemo, go straight in. Take note of earlier posts about current and rejigger the bias if you need to run a 4 ohm driver. Feel free to run it at a higher rail, if you want a bit more power. Once you get up into the low to mid-20s on the rail voltage, go ahead and build an Aleph 3 or 30. This is just sort of a cute 'toy' Aleph; something to burn up leftover parts. I'm still waiting for someone to build one in a Pepsi can... Grey

21st May 2002, 02:51 AM	#43
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Actually, come to think of it, you could simply mute the output for 5 or 10 seconds with a relay, then direct couple. Grey

17th July 2005, 09:15 PM	#46
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Splendid looking piece of hardware. May it give many hours of pleasure. Grey

18th July 2005, 12:25 AM	#48
jleaman Banned Join Date: Apr 2002	GRollins, Is the mini a schematic you posted Your design or Pass-Lab's.

18th July 2005, 02:33 AM	#50
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Do I do the Mini-A? ...this is a trick question, perhaps? As I said in the first post of this thread, the Mini-A was something I did as a stepping stone to the Aleph-X. It's basically a cut-down Aleph 3. Nothing particularly weird or original. Somewhat later, one of the installments in Nelson's Zen series featured an Aleph-style entry (#4, I think). Other variations are possible and I've fiddled with a few of them. If time permits, I may start another thread or two based on some of the things I've done here, but it's very time-consuming to support a thread; I've got more ideas than I can practically put out. I don't make any money at this, so I still have to show up at a non-audio job in order to keep my daughter in diapers. What with work and eating and sleeping and a few other odds and ends, there's little slack at the moment. Nelson, incidentally, was not warned about this thread. With the Aleph-X, I kept him abreast of things pretty much from conception--that story has been detailed elsewhere--but the Mini-A was as much news to him as it was to anyone else. If I'm lucky, he'll forgive me sometime during our present incarnations. If I come back in my next life as a microbe, I'll know that I've got some kharma-balancing to do. Sigh. I have at least two or three other Aleph ideas that might make interesting threads. I fear that one of them might be close to the Aleph-J (no, I haven't seen a schematic for the J, just guessing), so I won't bother with that. I have not had time to try out the 'Maxi-A' idea yet, so I don't know if that's worth pursuing. At any rate, I had artwork for PC boards, but lost it in one of the hard drive crashes, or perhaps when the virus set up shop in my machine a couple of years ago. If necessary I can recreate it, but at this point I'd rather move forward and do a new circuit than revisit the old one. MikeW, bless his heart, was kind enough to adopt the Mini-A. He and a friend of his worked up boards, which then travelled to the four corners of the Earth. When those ran out, he did a revised version. Any audience the Mini-A has garnered has been his doing. Thanks, Mike. Note that the Aleph patent is still active. Do not attempt to produce Mini-As for profit or a platoon of lawyers will infest your underwear. Your wife/girlfriend/(in)significant other will leave you. Perhaps all three of them at the same time. Don't tempt fate. Though Nelson did not draw the schematic for the Mini-A, it is based directly on his patent and is covered just as much as an official Aleph from Nelson, himself. You can build one, play with it, use it for a paperweight, or even listen to music with it...just don't sell it at a profit. Don't say that you weren't warned. Grey P.S.: They are kinda cute, aren't they?