That's the thing, high capacitance high voltage caps are $$$. The ones I
have are 5,000 uF each and I have four of em. They were not too expensive,
but they are big and putting more of these will mean having the power supply
in its own chassis.
I was looking at some 100V 22,000 uF ones, but that is probably cutting it too
close. I'm playing with chokes and resistors, but there is still some residual hum.
The choke supply sounds simply superb though. Astonishing improvement in sound.
Now, is it true that if I connect two, say 10,000 uF 100V caps, in series I get a
5,000 uF 200V cap?
have are 5,000 uF each and I have four of em. They were not too expensive,
but they are big and putting more of these will mean having the power supply
in its own chassis.
I was looking at some 100V 22,000 uF ones, but that is probably cutting it too
close. I'm playing with chokes and resistors, but there is still some residual hum.
The choke supply sounds simply superb though. Astonishing improvement in sound.
Now, is it true that if I connect two, say 10,000 uF 100V caps, in series I get a
5,000 uF 200V cap?
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True, but I think I would still try to run them near that (magic?) 75%-80% rather than
50% of rating. Perhaps there are others on here that can explain that better as I
really don't remember that far back about the details.
The industry standard increments in that range are usually 50V, 63V, 75V, 100V,
I think 150V, then 200V. There may be an intermediate 120V, 160V and 180V also.
So something like a couple 63 volters would be in that ideal range.
What you have is safe for sure, but I guess some people have some preference to
push them a little closer to the rated voltage and I just can't for the life of me tonight
remember what that or those reasons are.
Well, I wouldn't mind having 120 V caps, but its tough to find these in
proper the capacitance and price range. I went for higher voltage, but
kind of cheaper.
I have some 18,000 uF 63V which I could put in series.
Thanks!
proper the capacitance and price range. I went for higher voltage, but
kind of cheaper.
I have some 18,000 uF 63V which I could put in series.
Thanks!
My amp did this also: the bulbs dropped luminance when an input connection was made. The article recommends 47 ohms in series with the gate. I tried this and it works. I guess my amp was oscillating also.
Will try more capacitance today.
Humm is usually coming from suboptimal grounding scheme not from PSU-ripple.
You can beef up PSU first, if humm is still present, have a look at your wiring scheme 😉
Hannes
Yes, I'm investigating the grounding scheme. I have it in a star ground scheme right now, but there is still some hum.
Tea-bag, where did you source the caps from and what is their voltage rating?
Btw, I snagged some of those IXTH20N50Ds available as singles from Mouser. Quite a premium they are charging.
Tea-bag, where did you source the caps from and what is their voltage rating?
Btw, I snagged some of those IXTH20N50Ds available as singles from Mouser. Quite a premium they are charging.
Mine are a mix of 100v 5600uf caps from Nippon (I think) and 63v United Chemi-Con ones I got from Apex JR. I am not running that high of a voltage, so don't need such expensive caps.
Yes, the price even for 60 of them went up on Digikey and them.
Still cheaper than tubes, but probably easier to blow up 🙄
Well, I'm happy to report that my Delite is now hum free... well, nearly.
I got some monster caps from Uriah... 68,000uf and 75 VDC. The plan was to use them in series to get 34,000uf and 150VDC. I needed the high voltage because my supply voltage was 100V.
Then, it suddenly dawned on me that I could use two bulbs in parallel to get the same amount of bias but with a lower supply voltage. I tried it and it worked. Papa does it in ZenLightenment to get more bias, although not necessarily to reduce supply voltage. The reduced voltage is vital for me, as I can now use caps rated at almost half the voltage as before.
I'm using two 200W Sylvania beauties, giving about 2A per channel with a supply of 68V. The drain of the FETs is at 25V. On a pair of alnico Coral full range drivers (courtesy Paul of Wild Burro), the hum is inaudible from the listening position, but you can hear it at the speaker. These Coral alnicos are surprisingly good, btw. They are nearly flat from 200 to 10kHz with no resonances. Midrange is gorgeous and they fall off cleanly after 10kHz without any nasty peaks.
Of course, I intend to pile on the capacitance. Right now it is a CLC with 68,000uf each and a no name coil. Bigger coils are on order 🙂
I got some monster caps from Uriah... 68,000uf and 75 VDC. The plan was to use them in series to get 34,000uf and 150VDC. I needed the high voltage because my supply voltage was 100V.
Then, it suddenly dawned on me that I could use two bulbs in parallel to get the same amount of bias but with a lower supply voltage. I tried it and it worked. Papa does it in ZenLightenment to get more bias, although not necessarily to reduce supply voltage. The reduced voltage is vital for me, as I can now use caps rated at almost half the voltage as before.
I'm using two 200W Sylvania beauties, giving about 2A per channel with a supply of 68V. The drain of the FETs is at 25V. On a pair of alnico Coral full range drivers (courtesy Paul of Wild Burro), the hum is inaudible from the listening position, but you can hear it at the speaker. These Coral alnicos are surprisingly good, btw. They are nearly flat from 200 to 10kHz with no resonances. Midrange is gorgeous and they fall off cleanly after 10kHz without any nasty peaks.
Of course, I intend to pile on the capacitance. Right now it is a CLC with 68,000uf each and a no name coil. Bigger coils are on order 🙂
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And the Delite has already ousted the Miniwatt, which in my mind was a pretty good little amp. The Delite is just better in every aspect.
It's a great amp to cut your teeth on... let's you hear each improvement you make in the circuit, especially the power supply.
It's a great amp to cut your teeth on... let's you hear each improvement you make in the circuit, especially the power supply.
The De-Lite is a cute little amp, but there are some
seriously more interesting things coming in this category
that you will be able to kludge into your existing versions -
there is an upgrade future for these that will make your
initial efforts worthwhile.
😎
seriously more interesting things coming in this category
that you will be able to kludge into your existing versions -
there is an upgrade future for these that will make your
initial efforts worthwhile.
😎
After putting the Delite in my main system, driving a pair of AN8s on OB, I found that it has a little less juice than what I would like. Is there any way to get more power? Can we parallel devices?
That output capacitor, the dreaded output capacitor... can we lift the source resistor from ground to -V and remove the output cap? I'm assuming there have to be some other changes to circuit in relation to the gate-source voltage. I was trying to study the mini-Aleph circuit which has a -V rail, but haven't been able to absorb anything yet.
That output capacitor, the dreaded output capacitor... can we lift the source resistor from ground to -V and remove the output cap? I'm assuming there have to be some other changes to circuit in relation to the gate-source voltage. I was trying to study the mini-Aleph circuit which has a -V rail, but haven't been able to absorb anything yet.
What FETs are we refering to? That would be the lead time we would worry about other than Papa's lead time?
Stefano, can you post your schematic of the CCS? I've been playing in spice with a CCS that uses the same FET - IXTH20N50D.
I've not been able to setup the top FET correctly yet.
I've not been able to setup the top FET correctly yet.
Sorry for the delay here, didn't realize I was going to be asked a question.
right now dual mono
2x5600uf @ 100v 1R-25Watts heatsinked, 3x 15,000 @ 63v
I run a 40v-0-40v @ 370VA tranny on it.
