Power supply inductors (what specs?)

[Salas]

Hello,

In my post of zen revisited pcb I describe a 3mh, 2 Ohm aircore.
It worked best. Sometimes Rdc is a tool to shape ripple and damp harmonics. Plus you can use it to control the V+ value if your trans and bridges stray upwards. Especially in a Zen too much V+, and you get it on the sinks to no avail.
Dont be afraid of Rdc in class A. Tube stuff incorporates it spledindly for ages. Just play and shape your final sound checking out 1,2,3 mh cheap aircoils. Some combination will come up right with your individual PSU and sound will flow. Cut and try.

Thanx

Nick Salamouras

[Coulomb]

I use Accusonic coils. 3.2 mH Iron core 18 Gauge wound. He has 16 Gauge wound as well, I am not sure about 14 or 12 Gauge.

They were $4.63 CAD Each.

Copntact Info.
Accusonic
Vince
416 663 3135
134 Martin Ross Rd.
North York, On
Canada

[stadams]

Nick,

I agree with your statements however, I would rather have an extremely low DCR if possible. This allows the designer of the supply to optimize the power supply response by choosing the necessary R (type or device) for proper damping as alluded to by Erik.

I try to ensure that the combination of the inductance, capacitance and internal resistance of the choke (+ any actual resistors) is it at least critically damped.

If this is of no concern, the benefit is that you can generally find much cheaper inductors as the DCR rises.

Later,

[audionut]

Incorporating a 2mh air cored choke in a CLC type of filter, would the choke filter out the high frequency ringing from the bridge rectifier? or do you use snubbers on the rectifiers?

[Clun]

I see that many talks about air core chokes but how about toroid types for speaker crossover can they be used as psu chokes?

/Clun

[BrianGT]

Originally posted by roddyama
You could roll your own. It’s pretty tedious work unless you have a machine and they’ll never be as neat as you would like them to be. I made the coils for my first x-over for my horns. They worked fine, but it was 16 gauge. 12 gauge will be a lot tougher to work with.

Rodd Yamas***a

Rodd,

I wasn't going to do it myself, but the guy in charge of Victoria Magnetics told me he could make me inductors if I told him how I wanted them made and what specs. He has all of the transformer making machines, and would to make nice tightly would inductors if I told him the specs.

--
Brian

[Bertie]

I've wound myself some chokes on a toroid core using 1.7mm diameter wire, 18 turns, giving me 2.4mH @100Hz and a DC resistance of 0.064 ohms.

I'm going with these in combination with 47,000 uF before the choke and 22,000uF after per rail in my Aleph 5 monoblocks.

It's got 2 chances, and if it doesn't work I guess I'll be busy a little longer!

[Salas]

Hello again,

I do agree that using a low Rdc choke and then judge the proper
resistance to add for damping is a better approach if you are going to be thorough, and free from this embeded element.
In a Zen though, to my ears, the 1-3 Ohm Rdc of cheap normally wound aircore coil for speakers -avoid metal cores- is just what the doctor has ordered.
Avoid snubs, -they sound zingy- ,yes the coil do filter the nasties towards your amp.
It will not choke em out of your powerline though.
So for the less adventurous and ill bench equipped of us, trying out 2 or 3 cheap coils is a good alternative.

Cheers

Nikos

[Petter]

Typically you need an air gap in a coil. A toroid does not per se have an air-gap. To fix this you basically have 3 choices:

1. Choose a low H material (typically not practical). One such material is air or plastic. Not recommended.
2. Choose a material with distributed air-gap such as www.mag-inc.com Kool-mu
3. Cut the core and add spacers, then glue back together. I have a few of these.

Petter

[Salas]

Hello Petter,

You have a strong point there. I wanna add:
Only an air gap sounds non muddy with cores on DC. An air gap in SE tube amps output transformers is essential for example. There they loose coupling and go big, but its no concern to this thread.
Fellas,
In a Zen if you think you must check using a very low Rdc core follow Petter. Dont miss the damping check with some resistors after applying the CLC. Maybe you can tune the sound better.
Ah, another thing. Always use the smaller cap before the L.

Thanx

Nikos