one xformer , one (CT) secondary for both channels
18 caps
divide them properly , to still have whats needed
first C (in CRC) common for both channels , then RC (in CRC) separate for each channel
then mirror that for negative rail
18 caps
divide them properly , to still have whats needed
first C (in CRC) common for both channels , then RC (in CRC) separate for each channel
then mirror that for negative rail
Clever cat!
I must design myself a PSU PCB like that.
For my VFET and M2 I bought 2 donuts for each. But for my F6 maybe an arrangement like this. Nelson said a while ago that you don't really need 2 donuts if you are clever.
I must design myself a PSU PCB like that.
For my VFET and M2 I bought 2 donuts for each. But for my F6 maybe an arrangement like this. Nelson said a while ago that you don't really need 2 donuts if you are clever.
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I usually like to err on dumb side (brute force) but I certainly agree - when space is critical , you must cut corners somewhere and turn on da brain
example - Donut with separate secondaries for each channel , in Papa's Koan .... thus separate rectifiers and C banks for each channel
all roads lead to Rome ......
example - Donut with separate secondaries for each channel , in Papa's Koan .... thus separate rectifiers and C banks for each channel
all roads lead to Rome ......
... But for my F6 maybe an arrangement like this. Nelson said a while ago that you don't really need 2 donuts if you are clever.
The BA article describing the original F6 shows such a power
supply arrangement for stereo use (p. 15):
http://www.firstwatt.com/pdf/art_f6_baf.pdf
Thanks. I looked at those pages so many times in the past, but only now do I really see it. 😱
I'm wondering why NP seems to never use inductors in his power supplies... and even prefers to use higher value resistors requiering heatsinking.
It must add some more warmth to the sound 🙂
It must add some more warmth to the sound 🙂
Out of curiosity, is there a practical upper limit to the resistance value for a CRC filter in a FW style amp? I ask, as I'm considering using about 3R to dump some voltage from a transfo secondary that's a bit high...
...obviously dissipation is a factor, but I reckon I've the cooling to manage that.
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My friend and me did experiment with P.S. filters.
There was 6 caps 33mF.
Clean C banks has best punch on the bass.
We start with 33mF+0.1ohms+33mFll33mF and we notice that bass lousing punch, start to be soft. It come backs with around 0.02-0.03ohms resistance.
Then we decided to try to keep that resistance wich doesnot influencing bass response and to add some inductivity.
On the end that was the best compromise sound related, clearly it smoothing midrange and keeps good bass.
There was 6 caps 33mF.
Clean C banks has best punch on the bass.
We start with 33mF+0.1ohms+33mFll33mF and we notice that bass lousing punch, start to be soft. It come backs with around 0.02-0.03ohms resistance.
Then we decided to try to keep that resistance wich doesnot influencing bass response and to add some inductivity.
On the end that was the best compromise sound related, clearly it smoothing midrange and keeps good bass.
Attachments
The upper and lower bounds of that are occasionally an exercise in extremes in this hobby...
Hmm, how many lightbulbs would I have to parallel I wonder?
I'm not certain to fully understand... did you replace the resistor by an inductor with equivalent dcr?
In all honesty, I was watching your regulated power supply thread! In this case I've a couple of 625VA harbuch transfo's that are a bit hot for the vfet amp and a pile of 6R 25W resistors...
Edit: apologies for the OT! I'll continue this conversation elsewhere.
Edit: apologies for the OT! I'll continue this conversation elsewhere.
One (two) possible solution might be:
The PSU voltages are low for a 25W amplifier, and there is no mention of cascoding the input stage JFet transistors.
However it clearly says "two pairs of complementary Fets...", hence the parallell-coupled pairs of complementary Fets...
It is interesting to see how Mr Pass'es designs have evolved through the years:
- From complex to simple (it usually is the other way around ;-) ),
- From complementary to Single Ended,
- and then back to Complementary gain blocks again.
I have grown fond of SE amplifiers as they offer a level of immediacy not offered by their Push/Pull counterparts.
PP amps always sound more dynamic at first but less engaging in the long rum.
My best experience with hifi amps was an Aleph 3 clone - modified to run at higher Open Loop Gain and an output CONSTANT current source realized by p-channel Fets.
Absolutely seductive...
Cheers
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