leroy said:
Great heatsinks !
15 years ago i used 2 metres of SK47 to build hybrid 80 watts class A monaural amps, 8 hitachi mosfets 50/135's.
Sawn in lengths of 250 mill and bolted at the sides, very sturdy.
Got them at Burklin in Dusseldorf, Germany, the fanciest electronics store i have been inside.
now i just need a place to make the case..
wuffer said:
There is a thread here somewhere with a link to a store in Sweden that has big Rifa's capacitors.
(the ones i like are the white ones)
As you are in Denmark this might be the place for you.
http://svalanderaudio.com
Compared to prices in Holland theirs are low.
If you have access to surplus stores in Denmark you may look for outdated brands,like Roederstein,Philips.
You could save a lot with surplus caps.
Small capacitors have a lower inner resistance than bigger ones, thus theoretically faster. Two small caps parallel should be faster than one big cap.
If you take the advised capacity Mr Pass recommends for the amp design you have choosen its a personal choice to divide that in 2, 3 or more capacitors parallelled.
I started with huge amounts of parallelled 4700 uF caps.
I now use big capacitors and bypass them at the output pcb with a number of small electrolytic ones, also bypassed by some foil capacitors.
(MKP, MKC, MKT, MKS, styroflex)
Most just use a couple of big electrolytic capacitors .
You can go as big as you desire, the more capacity the lower the ripple.
The true ripple nerds step over to R-C or L-C filters.
You could combine by placing resistors in the current path creating an R-C filter, that is more effective but lowers the output voltage a bit and you need high power resistors
(like the gold metal Dale, from 25 watts up )
Or instead of the resitor use a coil, lots of info on that on threads here too.
jacco
btw
at 28 Vac you have 39.6 Volts max coming from the transformers, after rectifying down to 38.9 Vdc.
40 volts capacitors might do but safer would be a minimum of 50 volts capacitors, the potential coming from the toroid can be higher than 28 Vac.
If you look at manufacturers a lot of them go for higher voltage caps than strictly necessary.
Mr Pass used 75 volt caps in some of his designs where 63 volt types probably could has sufficed, availabillity may have played a role.
at 28 Vac you have 39.6 Volts max coming from the transformers, after rectifying down to 38.9 Vdc.
40 volts capacitors might do but safer would be a minimum of 50 volts capacitors, the potential coming from the toroid can be higher than 28 Vac.
If you look at manufacturers a lot of them go for higher voltage caps than strictly necessary.
Mr Pass used 75 volt caps in some of his designs where 63 volt types probably could has sufficed, availabillity may have played a role.
i shop for transformers at elfa i know i can get rifa there
i have 2 of 22000 100v rather expencive if i should have more than 2 of them
An externally hosted image should be here but it was not working when we last tested it.
i have 2 of 22000 100v rather expencive if i should have more than 2 of them
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