It is interesting - have been looking at some of the Plitron toroids on eBay and for the life of me I can't find the specs on these things. Getting info such as VA and secondary voltages seems elusive. Tried looking them up on the Plitron site to no avail.
Shameless plug for getting your own Quasimodo rig up and running. So much to learn and excellent fun all around. It really is a HUGE gift (from Mark) to the community.
hi - i am starting to build my PSU and i bought the diodes for the board on the recommendation that it should be min 30A, 220V. it dawns on me that this spec may be for the US as in the UK, we are 240v. (I bought the TO-3P type). Am i right on this or can i use the diodes ? thank you very much
The diodes only see the transformer secondary voltage, not your mains voltage. So as long as your secondary voltage is *well* under 220V (i.e.: you're not building this for a tube amp), your diodes are fine.
thank you but then i don't understand why the build guide suggests that it should be min 220v ? The secondary is only +-18v
You may have 240VAC from the wall, but what AC voltage is being applied to the diodes?
the secondary voltage is only 18v but the build specifies a min of 220v so i suspect that it is for other (probably safety reasons).
ripple
I am having trouble understanding capacitor specs—specifically Ripple current vs lifetime. Taking two aluminum electrolytic Nichicon caps, similar price,22,000uf,35v.
0ne is 3000hours@85* and 6.38A ripple, other is 5000hours@105* and 3.9A ripple. Intuitively one would think 5000hrs would be better, but the ripple is way lower. So which is better and why?
And yes I did google it, but the explanation goes over my head, so keep the second s in the “kiss” principal in mind 🙂
I am having trouble understanding capacitor specs—specifically Ripple current vs lifetime. Taking two aluminum electrolytic Nichicon caps, similar price,22,000uf,35v.
0ne is 3000hours@85* and 6.38A ripple, other is 5000hours@105* and 3.9A ripple. Intuitively one would think 5000hrs would be better, but the ripple is way lower. So which is better and why?
And yes I did google it, but the explanation goes over my head, so keep the second s in the “kiss” principal in mind 🙂
Pardon my inattention, you had already answered that question.
Also superior iso(insu)lation between AC and DC components.
Longer service life as well I'd think.
I just did a test of the completed PSU. I used the AS-3220 toroidal transformer. with no load, I'm reading 32V between GND and V+ although specs on the transformer from the manufacturer are are "300VA 20V" is this normal?
Also, it takes several minutes for the caps to drain. I tested R9 and R10 before installation and they are the prescribed 2.2k. Aren't those resistors designed to drain the caps? or is this a normal time period to reduce wasted power while the amp is on? (AS-3220 - 300VA 20V Transformer - AnTek Products Corp)
Also, it takes several minutes for the caps to drain. I tested R9 and R10 before installation and they are the prescribed 2.2k. Aren't those resistors designed to drain the caps? or is this a normal time period to reduce wasted power while the amp is on? (AS-3220 - 300VA 20V Transformer - AnTek Products Corp)
Alternate Transformer
If using one of the 20 volt versions of these transformers, what voltage is supplied to the "DIYstore" Ver 3.0 power supply rails. Does the higher voltage produce more heat in the amp "DIY F5"?
These amps produce enough heat. I use computer case fans to cool my ACA 1.6
If using one of the 20 volt versions of these transformers, what voltage is supplied to the "DIYstore" Ver 3.0 power supply rails. Does the higher voltage produce more heat in the amp "DIY F5"?
These amps produce enough heat. I use computer case fans to cool my ACA 1.6
everyone's favorite topic; input snubbers
I've been reading a bit of conflicting opinions between here and Q-Modo. It's been either "input snubbing isnt generally needed so don't bother" to the other camp "input snubbing is so easy to add, and when done with even a little care, can help proactively mitigate ringing".
So which is it?
As someone who "knows not what he is doing", doesnt have a scope, and would prefer not to buy one, should I be inclined to take Mark's advice and just use the .01/.15uF and a ~15ohm resistor for a dual mono build using AS-2218's/FEP30DP's or do nothing? Surely a zeta of ~.7 to 1.5 is preferable to having no damping at all?
Even if 15ohm doesnt achieve zeta approaching 1.0, it seems like there's enough people with these antek's ending up in this range, that I probably won't be too far off.
I've been reading a bit of conflicting opinions between here and Q-Modo. It's been either "input snubbing isnt generally needed so don't bother" to the other camp "input snubbing is so easy to add, and when done with even a little care, can help proactively mitigate ringing".
So which is it?
As someone who "knows not what he is doing", doesnt have a scope, and would prefer not to buy one, should I be inclined to take Mark's advice and just use the .01/.15uF and a ~15ohm resistor for a dual mono build using AS-2218's/FEP30DP's or do nothing? Surely a zeta of ~.7 to 1.5 is preferable to having no damping at all?
Even if 15ohm doesnt achieve zeta approaching 1.0, it seems like there's enough people with these antek's ending up in this range, that I probably won't be too far off.
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pardon the double post, but was trying to edit something above but had to walk away for a moment and then saw I was locked from editing;
After some additional thinking, would it not make more sense to bias the snubbing resistor to be slightly on the higher side of things to ensure the system is more on the overdamped side of things? Not talking crazy here, but having seen ~12-22ohm listed frequently for Antek AS series toroids from ~300-600VA, generally with the higher resistances being at the lower VA ratings, maybe a ~30-35ohm would be a better choice than 15ohm.
Thoughts?
After some additional thinking, would it not make more sense to bias the snubbing resistor to be slightly on the higher side of things to ensure the system is more on the overdamped side of things? Not talking crazy here, but having seen ~12-22ohm listed frequently for Antek AS series toroids from ~300-600VA, generally with the higher resistances being at the lower VA ratings, maybe a ~30-35ohm would be a better choice than 15ohm.
Thoughts?
That seems high as the 20VRMS at the secondary would translate to about 28V peak to the power supply resulting in something less than that at the rails.