PS for Aleph 2 and 4 - Air core inductors

trigon

Member
2002-05-09 4:35 am
Canada
Hi.

As I have been looking arround to get a litle cheaper air coils for the PS of either Aleph 2 or 4 and as per Kristian's web page
http://web.vip.hr/pcb-design.vip/power-4.html
I have came accros with this type
http://www.partsexpress.com/pe/showdetl.cfm?st=0&st2=0&st3=0&DID=7&Product_ID=6795&DS_ID=3
for which I may be willing to pay the price of ~ $18.00. Just got the e-mail from http://www.solen.ca and I was shoked :bigeyes: for one air core inductor of 3.9mH they are asking for ~ $33.00 Wooow.

So my question is - Can I use those inductors
http://www.partsexpress.com/pe/showdetl.cfm?st=0&st2=0&st3=0&DID=7&Product_ID=6795&DS_ID=3

for PS of my Aleph 4 ?

Any comments.?

Trigon.
 
trigon,

I think you could.
2.5mH is enough to get the ripple below 10mV even with 3A of bias. I´m using 1.8mH/0.38 Ohm chokes for my Aleph5 and I´m planing to use them for my future upgrade to something like an Aleph 2 with lower voltage and higher bias.

They claim 800watts of power handling wich seems to be a tad optimistic but they probably mean the speaker behind the choke;) You can calculate the power it absorbs if you know the dc-resistance.

Anyway, even 18$ seems to be a lot of mony for this very simple choke.

william
 

roddyama

Ex-Moderator
2002-01-19 9:25 am
Michigan
Hi Trigon,

I haven't got my Aleph together yet so you can take my word with a grain of salt, but IMHO the current draw of an Aleph 2 or 4 might be a bit high for a coil wound with 14AWG wire. It will probably work, but you'll get a larger range voltage drop across them as you might with a 12AWG or 10AWG wound coil. You also need to have a transformer with secondaries that are 1.1X your final desired rail voltage. Separate + and - rails for each channel with a coil in each rail will help spread the load.

What do you have for a transformer?
Rodd Yamas***a
 

trigon

Member
2002-05-09 4:35 am
Canada
Hi.

wuffwaff

You are absolutely right, it is steel a pricey for simple air coil but having in mind that wire is expensive overhere (and I think as well in Europe) than it is not surprise. I have been thinking of iron core inductors but not sure because of high saturation and magnetic influence. I may trough some money on them when I start thinking of those beautifully sounding Aleph engines. Thank you wuffwaff.

Peter.

I can only say that only one chance that I have had the option to listen to one of those beautifully sounding Alephs is your Aleph 5. Thank you for bringing your amps to my home.
Thanks Peter for the links. They are way cheaper from http://zalytron.com but having in mind shipping cost from US to Canada.... uuhhhh. But hey Active Surplus downtown Toronto sounds good to me. Thanks one more time.

Trigon :cool:
 

trigon

Member
2002-05-09 4:35 am
Canada
roddyama said:
You also need to have a transformer with secondaries that are 1.1X your final desired rail voltage. Separate + and - rails for each channel with a coil in each rail will help spread the load.

What do you have for a transformer?
Rodd Yamas***a

Hi Roddyama

What do you think of this. Don't you think this is a good filtering PS.
http://web.vip.hr/pcb-design.vip/power-4.html
Capacitors are going to kill me. (to expensive).:bawling:

I think I will go with Plitron 1.5kW and with 2 x 38V @ 19A each chanel (mono block version of Aleph 4)

Thanks.

Trigon.
 

roddyama

Ex-Moderator
2002-01-19 9:25 am
Michigan
Hi Trigon,

I like the stuff that KK has; and he provides good support for us DIY'ers as well.

I ran his PSU through Duncans PSU simulator using his cap values and your voltage. At a 3A/rail draw (idle) the rail voltages were a little over 47VDC with less then 3mV of ripple. When I kicked the current up to a 6A/rail draw (full current), the rail voltage dropped to about 43.5VDC with a little less then 4mV ripple. That's pretty good, and it's quiet.:sleep:

I thought that the PI filter would drop the rail voltage below the secondary AC voltage. I guess I have been mistaken.:scratch:

I see now that it's when the inductor is first after the bridge that the voltage drops to .9 of the secondary voltage.

That's what we're here for,
Rodd Yamas***a
 

roddyama

Ex-Moderator
2002-01-19 9:25 am
Michigan
Hi Trigon,

I ran the simulation again using 40 volt secondaries. The ripple was the same as before and the rail voltage ranged from 46.2VDC @ 6A/rail to about 49.9VDC @ 3A/rail. If the simulations is close to real life, I would say this is great.

A couple of notes:
When I cut the cap size in half in the simulation, I got 3 times the ripple with over 10mV @ 6A.
Your caps will need to be rated for greater then about 55V and the standard 63V wouldn't hurt.
1000VA would enough for one channel of an Aleph 2 or 4. 1500VA wouldn't hurt, but they will cost that much more.
There are a few guys finishing their Aleph's on the forum. Try to get what information you can from them as well.

Hope I can catch up to you guys soon,
Rodd Yamas***a