| highbias |
Here are a few pictures of the Mini that I built over last Christmas. Its been giving flawless performance since it was first turned on, driving a pair of Yamaha NS-10's.
Specs......
Tranny: Victoria Magnetics 320VA, 2X15 volt secondaries
Filtration: One Panasonic 120,000 mfd per rail
Outputs: IRFP-240
Wire: Silver plated Teflon covered 16 & 18 ga.
Board: Mike W. This board split in two
Resistors 1% mf RN65 surplus
Board Caps: Nothing fancy... but are 105 deg C.
Heatsinks: Surplus
Misc Parts: Surplus
Size: 14.75 W X 7 H X 6 D
P.S. Sorry for the less than adaquate shots as I am still trying to figure out this new D camera that I bought an hour ago.
Mark
Front view showing on-off Switch and blue LED. |
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| highbias |
Top view down into one end of the Mini. You can see the use of turrett terminals in much the same way that I previously used on the pair of 2's that I built. The power supply is built as a module that is inserted through the bottom of the amp. This will make disassembly and servicing in the future very easy.
Mark |
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| highbias |
Bottom view where you can see how the power supply module which is built onto the plate in the center is attached to the front and rear panels. The heat sinks are also attached to the front and rear making this a very strong chassis. The other advantage is that the entire amp acts as one huge heatsink.
Mark |
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| highbias |
The rear panel. The cheapo jacks will remain till its anodized and otherwise complete....some day...... Then replaced with higher quality stuff.
Mark |
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| highbias |
Another bottom view from one end showing routing of wore from board to heatsink. The general layout for the power supply module can also be discerned from this view.
Am building an Aleph 30 in a similar way for a friend. The difference is that it will be two heat sinks long each side and which will be spaced a bit further apart. This will allow more chassis length for larger the power supply components and chokes.
Mark |
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| MikeW |
| Very nice mini. How much bias are you running? How hot does it get? |
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| cowanrg |
congratulations! i know how good it feels to be nearing completion.
do you have any pictures that would show scale? its heard to tell how big/small it is. |
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| highbias |
With an ambient room temp of 24.6 drg. C The running temp is 48 deg C on the top center of the heat sink. Never measured the actual current draw really accurately, just did it with a DC amprobe but have since forgotten what it was. The drop across the source resistors is about .52 volts. Weight is about 28 lbs. Photo attached for size comparison.
Mark |
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| kilowattski |
| Wow! I am very impressed. Excellent build quality. I can see you have done this before. Do you plan on anodizing the chassis? |
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| highbias |
Thanks for all the compliments... I definately plan on anodizing it. The black pieces will actually get black hard coat instead of just a regular anodize because its far more durable than plain anodize and the fade rate is much lower. Front panel will be pewter and the rest black. I am planning on having the Mini, my pair of Aleph 2's and the Aleph 3 all done at the same time to get the overall cost per unit down. It'll be a good project for this winter and then on to a couple of no holds barred Aleph Ps. I plan on machining those chassis from a solid block of 6061 alumnium. The power supply for the P will be a thermo electric power generator.....(just kidding)..... I know you have the only Flux Capicators that were available!
Mark |
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| Dennis Hui |
Very nice design! Are you putting a top plate on?
Cheers,
Dennis |
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| highbias |
Dennis,
Probably a clear lexan top. I'm still undecided really so could go either way, but there will be a top. Some day when I ever get enough time to do it......:xeye:
Mark |
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| GeorgeBoles |
Dear High Bias
What constituteth an Aleph-Mini. Is it a lower voltage Aleph 2? Fewer output devices? Does it have balanced inputs?
Regards,
George. |
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| GeorgeBoles |
A search for Aleph Mini answered most of the above questions
leaves more!
Which is the schematic you actually used? I found a series of them, apparently often wrong. All slightly confusing.
Is there an "original" or "final recipe" which you used or referenced?
Regards,
George.
PS I thought I used to be able to edit my posts. I cannot seem to be able to do that now. What has happened?
GB |
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| GRollins |
Blame the original Mini-A on me.
There's a thread somewhere back about two or three years ago called The Mini-A. It's basically an Aleph 3 cut down to run on 15V rails. My target wattage was 10W. The circuit will take a reasonable amount of variation in the rail voltage, but as you start getting up near 25V rails, you'd be better off looking at Nelson's "real" Aleph 3 instead of mine.
I have a few new things in mind that I'd like to try. If I can get some time (ha ha!) I'll try to cobble together a Ver. 2.0
Grey |
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| highbias |
Grey,
I would love to see a version 2! Go to it please...... Although this Mini is really tight hopefully I'll be able to cram in Ver. 2 somewhere.
GeorgeBoles,
This Mini Aleph was built using Mike W's board and drawing. Mike has done an excelleent job with these amps! Its worked just fine since first turn on just before last Xmas. It stays on more than its been off so I can hinestly say that it probably has a couple thousand hours running time on it. Output power with 120 volt AC in if I remember is about 9.8 watts into 8 ohms and 14 watts into 4 but I'd have to double check it to be exactly sure. Contact Mike through his e-mail. He posted in this thread near the beginning.
Mark |
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| MikeW |
I sent the films for the second version to Trigon. He may do a group buy.
There were 12 of the first version and 22 of the second version. I gave all the boards and the five amps I built to different board members. I hope they enjoy them. I expect to get one back, but he hasn't started building his mini yet so it may be next year until it returns.:bawling: :clown: :D |
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