Can i measure it with a maudio 24/192 and fft software? How?
Another thing i was reading was the explanation about the rectifying stage and the ripple current. My caps are Cornell dubilier with 5.6a ripple current and the diodes are ixys hyperfred bought according psu v3 bom list. My toroid is from toroidy - audio grade.
https://www.digikey.pt/product-deta...nics-cde/380LX153M035J052/338-2423-ND/1699409
https://www.digikey.pt/product-search/en?keywords=DPG60C200QB-ND
Another thing i was reading was the explanation about the rectifying stage and the ripple current. My caps are Cornell dubilier with 5.6a ripple current and the diodes are ixys hyperfred bought according psu v3 bom list. My toroid is from toroidy - audio grade.
https://www.digikey.pt/product-deta...nics-cde/380LX153M035J052/338-2423-ND/1699409
https://www.digikey.pt/product-search/en?keywords=DPG60C200QB-ND
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The vast majority of Members are not EE.
You don't need to be EE.
Just measure the output voltage with the input shorted.
Use the 199.9mVac setting of your DMM.
It's not accurate, but it does allow you to make comparisons after you make various modifications to your wiring. Do one mod at a time and see what difference it makes to H+N.
You don't need to be EE.
Just measure the output voltage with the input shorted.
Use the 199.9mVac setting of your DMM.
It's not accurate, but it does allow you to make comparisons after you make various modifications to your wiring. Do one mod at a time and see what difference it makes to H+N.
i have 0.3-0,4 readings in the 200mva scale. what do you think? any guess on what should be my next move?
My fft images for hum reducing
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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this is not the right section to post this info...but i've been fidling with the P3 pot and made the 3rd order higher by ~11db compared to 2nd order harmonic. Well, i know that i have a lot of noise on my amp but...i got a new amp...the sound is amazing right now. i lost the the kind of feeling that the higher frequencies were harsh. Justo don't know what to do with my amp to reduce noise...
my amp
my amp
An externally hosted image should be here but it was not working when we last tested it.
I am about to start building my first Pass amp (Sony VFET part2). I really appreciate all the guidance and valuable information in this thread on how to build the powersupply.
I did not order the transformer yet (PRI: 230V SEC: 2x22V) what is the ideal VA rating for the Pass Sony VFET part2 amp? is 400VA adequate or should I go higher?
I can get the panasonic TSHA 15.000uF 35V in Europe. But not sure voltage rating is on the lower side for 28v rails. I am also considering the EPCOS B41231 15.000uF as mentioned earlier by AndrewT. Digikey have them in 50V rating at a decent price. Would that be a better match for this amp?
Thanks
Best Regards
Rolle
I did not order the transformer yet (PRI: 230V SEC: 2x22V) what is the ideal VA rating for the Pass Sony VFET part2 amp? is 400VA adequate or should I go higher?
I can get the panasonic TSHA 15.000uF 35V in Europe. But not sure voltage rating is on the lower side for 28v rails. I am also considering the EPCOS B41231 15.000uF as mentioned earlier by AndrewT. Digikey have them in 50V rating at a decent price. Would that be a better match for this amp?
Thanks
Best Regards
Rolle
Rolle - 300 or 400VA is more than enough, the Vfet is a 2x15W amplifier. 
Look into Toroidy, people who have used them have reported that they are of wonderful quality. Power transformers - Internet shop Toroidy.pl
I would make the PSU from 15,000uF 50V capacitors. Epcos caps are very good.
Look into Toroidy, people who have used them have reported that they are of wonderful quality. Power transformers - Internet shop Toroidy.plI would make the PSU from 15,000uF 50V capacitors. Epcos caps are very good.
The transformer humming mechanically could have three causes
a.) loose core laminations or windings.
b.) operating at high core flux due to design not adequate for high UK voltages.
c.) DC from the mains causing high flux.
It is unlikely to be due to selecting a 500VA transformer.
Rolle - 300 or 400VA is more than enough, the Vfet is a 2x15W amplifier.
I would make the PSU from 15,000uF 50V capacitors. Epcos caps are very good.
Thanks alot for your quick reply and advice 6L6
I have sent a mail to toroidy for the 300VA transformer. Will go for the 50V EPCOS capsHi Andrew T,
Its been bugging me where i came up with the 500va thing. Just so you dont think i was making it up (whether its correct or not is a different matter)...
On esp here:
Mains DC and Transformers
"It's also worth noting that DC is usually not a problem with toroidal transformers of 300VA or less. Their primary resistance is usually high enough that any DC will have little effect. With larger transformers (500VA and above), the DC resistance is usually so low that even a very small offset will cause mechanical noise due to saturation."
However, as i have put a dc blocker on mine its most likely to be loose windings, which is annoying as it wasnt cheap. (maybe it was, around £100 for a sedlbauer).
Its been bugging me where i came up with the 500va thing. Just so you dont think i was making it up (whether its correct or not is a different matter)...
On esp here:
Mains DC and Transformers
"It's also worth noting that DC is usually not a problem with toroidal transformers of 300VA or less. Their primary resistance is usually high enough that any DC will have little effect. With larger transformers (500VA and above), the DC resistance is usually so low that even a very small offset will cause mechanical noise due to saturation."
However, as i have put a dc blocker on mine its most likely to be loose windings, which is annoying as it wasnt cheap. (maybe it was, around £100 for a sedlbauer).