New Aleph 30 In Progress

[highbias]

Attached is a photo of an Aleph 30 that I am building for a friend.... Hi Lyndon!

This layout worked pretty well for my Aleph 2's but I am open to suggestions to improve what ever might be......

The specs are as follows....

Transformer: Victoria Magnetics 500 VA feeding dual bridge rectifiers and 84000 mfd of caps..... through the 6mh torodial chokes and then another 42000,mfd of caps.

Lots of heat sinking! way more than the original 30 had so we can bring up the bias considerably.

Boards by Mike W.

Back panel will be home to Neutrik XLR jacks, Cardas posts, an IEC AC socket, Fuse holder, AC switch.

Chassis: All black hard coated 6061-T6....1/8" alumnium bottom and rear plate, Perforated alumnium top cover. 3/8" alumnium tooling plate front panel (Hard coated Pewter) will get a blue LED some where and there is a blue LED on each PCB inside the amp so there is a little internal glow. Its weight so far is 38 lbs!

Mark

[amp-guy]

man thats some serious alloy there
cant wait to start on mine!

[Taco]

Those chokes are huge! I see nothing wrong with your setup. Succes building this beast.

[wuffwaff]

Hi Mark,

nice amp! Are you planing to give it some kind of colour/coating?
What kind of chokes are you using? They don´t llook like air chokes. Any ideas on dc-saturation values?

William

[highbias]

wuffwaff ,

I am not familiar with calculating anything to do with chokes. I installed these in my Aleph 2's and it got rid of every last but of ac riding on the rails. Now all thats on the rails is a wee bit of noise. These are 6mh torodial chokes wound with 12 gauge wire. Perhaps if you have a couple of minutes you might be kind enough to enlighten me on info about saturation and such. I'd be very appreciative!!

Mark

[wuffwaff]

Hi Mark,

to enlighten one must be enlightened, the problem is that I am not........
I´ve got some 2mH torobar chokes from intertechnik I want to use in my Aleph-X but can´t get any decent info if they will saturate or not (at 8-10A bias). Even wrote to intertechnik but no answer.
It should be easy to see though just by looking at the ripple before and after the choke. In case of saturation it should work as a simple resistor. The problem is that when noticing this it is already too late

William

[Brian Donaldson]

I don't claim to be enlightened myself in this regard, but I don't think totiod inductors are ideal as high DC saturation types. DC inductors usually have an air gap to prevent (or postpone) saturation.
But that doesn't mean they wont do a lot of good to smooth out psu...even if they are well into saturation. They will still pruduce a back EMF untill they saturate, and produce voltage as soon as the current starts to fall. It just falls short of what the simulated ideal when it goes into saturation.
I'm interested in anyone elses info on this subject.
Looks nice and I wouldn't hesitate to put the toriod chokes in my amp if I had them. They'll work much better than a resistor (at smoothing ripple) and not make heat.

[Panelhead]

They look to be 8 - 10 amp judging by the size of the cores. They should be wide bandwidth also. I picked up some 2.2 ufd 6 amp toroids that are about 1/4 the size.
I have been using framed chokes for power supply filtering lately. They do a good job of knocking hum.
Good Luck, looks great so far.

George

[Nelson Pass]

Usually toroids don't make for good DC chokes, as they work
all too well and saturate. On they other hand, if they work,
they work.

[highbias]

They definately make a difference in the Aleph 2's rail noise level and they were just a few dollars each. They barely get warm after being powered up all day. I would think they'd work just fine in the Aleph 30 operating at the lower current level involved there.

One test that might be intresting would be to look at the waveform thats developed across them and see what kind of stuff is going on while its reproducing music.
Mark