Aleph 2 power supply

[dshortt9]

This link has some 33,000 @ 50 V for $8 each.
http://www.brigarelectronics.com/

 

[dshortt9]

They do not have to be very close. The real Aleph 2's have 4 x 25,000 uf caps per monoblock. Most clone builders are using at least this much and adding inductors to make a pi filter. 4 x 33,000 uf and 2 x 2 - 4 mh inductors would work fine.

 

[MikeZ]

dshortt9, That sounds better using fewer components, it would save some space in the amp. Is there any possibility you can sketch or explain the circuit "Most clone builders are using at least this much and adding inductors to make a pi filter. 4 x 33,000 uf and 2 x 2 - 4 mh inductors would work fine"

thanks mike

 

[dshortt9]

Look at the previous schematic and substitute one 33000 capacitor wherever two of other values are specified. A pi filter means that ain inductor is used between two capacitors, C-L-C. Two pi filters are needed, one for each polarity, + and - .

 

[MikeZ]

dshortt9, good explanation. Is 14 awg wire adequate for the wiring of the power supply? Any suggestions for some wirre that WOuld work for the power supply?

Thanks Mike

 

[dshortt9]

14 should work fine. Have you looked at the Pass DIY page to get some layout ideas? http://www.passdiy.com/ Look in the Gallery.

 

[MikeZ]

dshortt9, No I have not studied the gallery yet, I wanted to get all the parts together first. Next I will lay them out and compare to what others have done in the gallery and try to create the best setup. I called http://www.brigarelectronics.com/ and ordered 8 of the caps today....thanks for telling me about that place.

What do you think about the inductors for the power supply earlier you said "2 x 2 - 4 mh inductors would work fine", would you use air core or copper foil? I used the copper foil for my speakers but I didnt know if it mattered for the power supply.

Thanks Mike

 

[dshortt9]

I also used copper foil in my ProAc 2.5 clones but air core inductors are fine for the Aleph PS

 

[dshortt9]

4 mh ar quite large, 2.5's should do OK. What speakers did you build?

 

[Mark A. Gulbrandsen]

I am using 14 ga. silver plated copper that is teflon covered for my Aeph 2's. As usual I found his silver plated wire at the local Surplus place. Geez, they ahve everything there someplace......even 12 ga silver plated teflon covered wire that has a very unique 3 layer twist to it.......the 12 ga is a bit unweildly to work with though......
Also my toroids have a frame ground wire as well as allthe other primary and secondaries. Connecting this wire really quiets things down a bit so those looking ofr power transformers may want to be sure to get one with the extra ground wire.
Mark

 

[MikeZ]

dshortt9
I built a pair of 2 way speakers, woofer is a seas magnesium cone and tweeter is a seas too. If you are familiar with the Seas Odin, my speaker is exactly the same except I have one less woofer and a smaller enclosure. I really like them. My wife even liked them and could tell a difference. I enjoy building them myself hence the aleph 2 project.

Mike

 

[MikeZ]

Mark A. Gulbrandsen
I live in a relatively small town and havent found any good surplus stores. I end up mail ordering everything.
Mike

 

[Mark A. Gulbrandsen]

Mike, I used to live in Chicago and there was not any really good surplus place there either...just for metal. I am very lucky to have two good places here in SLC...One that has electronics parts in general and another that just has millions of vacuum tubes.
Mark

 

[MikeZ]

any suggestions where to get 4 inductors 2.5 mH 12 or 14 gauge?

Thanks Mike

 

[dshortt9]

Try this http://www.mcmelectronics.com/Home/level_5.jhtml?PRODID=35103&SKUID=34347 They do not specify the gauge of wire so I would call them first but the price is good and 2 mh will work just fine. You may as well order the 4.7 uf caps also as they have AXON Metallized Polypropylene which ar good.

 

[grataku]

Mike, any speaker supplier should stock good quality inductors for relatively cheap. Madisound or parts express come to mind. I would try to stay with a higher reactance and larger possible gauge wire to avoid excessive heating of the coil, it's always better to have the reactance do the filtering work for you. 2mH is good for 120 Hz, 4mH would be better. In Europe with 100Hz ripple 4mH is almost a must. The transformer would be the last thing to get. Before you buy that you should simulate the PS and make sure you don't end up with to much or too little voltage.


The MCM coils are CHEAP! You get what you pay for. They are probably going to heat up quite a bit and the voltage is going to drop quite a bitt too as a result.
I would dunk these in stycast or at least use a few wire wraps to hold them together a little bit better.

 

[dshortt9]

grataku

I simulated this PS and came up with 20mv of ripple, excellent compared to the commercial Aleph 2 of about .5 v. If the MCM inductors are 16 gague at .5 ohm and 1.5 ohm reactance they are dissipating 18 watts of heat at 3A, not too bad. Tie wraps would be good for mechanical strength. Madisound wants 16.40 each for 14 ga. 2 mh inductors, and they are .31 ohm. They would still dissipate 15 watts of heat but over a larger area. Take your pick. Parts Express has them for a bit cheaper. 14 ga. at 2mh for 15 something each. http://www.partsexpress.com/pe/show...86&St3=57879983&DS_ID=3&Product_ID=6793&DID=7

 

[MikeZ]

I will probably just use the air core from parts express as I am ordering some other items from them.

I appreciate all the help from everyone on the power supply and next I will be compilling the components for the main boards.

Any advice on what components are worth upgrading that are on the main board?

Thanks Mike

 

[dshortt9]

The Parts express inductors will be an excellent choice. Most people upgrade the source and sense resistors to non-inductive ones and upgrade the electrolytic coupling caps to high grade ones. Some say they cannot hear the difference in caps compared to Panasonic FC type and some swear they do.

 

[MikeZ]

dshortt9
I got 8 of the caps today from the place you referred me too, thanks Mike