WTB: 20/22/30/33 uF filter caps

[TmcB]

Presumably its just the first capacitor that needs to be under the max capacitance of the rectifier , not the total capacitance of the filter brigade?

Yeah, first cap is the one that matters.

I get a bit wary of running it right at the limit

[Jay]

5U4G valve rectifier max capacitance - see attached.

Hey Mike, have you wrapped your head around load lines? Tube data sheets are the next frontier for me and I am not yet understanding quite what they're telling me

Start with reading the valve wizard website. He explains it quite well imo. Also Robinette goes into it a bit I believe.

I draw load lines for valves in existing amps that are not 'behaving' and when I am not sure what their operation point is. Also, because valves are so forgiving, plenty of old circuits are actually operating outside valve spec so verifying load lines might be helpful if you want to fix that.

[StrummersOfThunder]

5U4G valve rectifier max capacitance - see attached.

Hey Mike, have you wrapped your head around load lines? Tube data sheets are the next frontier for me and I am not yet understanding quite what they're telling me

Start with reading the valve wizard website. He explains it quite well imo. Also Robinette goes into it a bit I believe.

I draw load lines for valves in existing amps that are not 'behaving' and when I am not sure what their operation point is. Also, because valves are so forgiving, plenty of old circuits are actually operating outside valve spec so verifying load lines might be helpful if you want to fix that.

Thanks Jean, ive been dipping in and out of those respective guys sites for info. Starting to get my head around things.

[NippleWrestler]

Did you find a reliable source of decent filter caps? I can see Evatco, and there's always ebay, but is there anywhere closer? NZTubes' site has been down for ages now.

[StrummersOfThunder]

Did you find a reliable source of decent filter caps? I can see Evatco, and there's always ebay, but is there anywhere closer? NZTubes' site has been down for ages now.

Evatco dont have shipping to NZ at check out and when I asked the guy responded once then went quiet. Bit out off by that.
Ebay yep some decent stuff but prices high plus shipping.
Ended up putting in another order with Banzai. Cheapest shipping by far (around $15NZD from germany). Needed some pots and thought id stock up on valve sockets etc. The F+T prices from banzai are excellent.

[jeremyb]

Have you checked out Mouser? I ordered a bunch of pedal parts from there and it was free shipping when you spend over about $66 NZD...

[NippleWrestler]

Did you find a reliable source of decent filter caps? I can see Evatco, and there's always ebay, but is there anywhere closer? NZTubes' site has been down for ages now.

Evatco dont have shipping to NZ at check out and when I asked the guy responded once then went quiet. Bit out off by that.
Ebay yep some decent stuff but prices high plus shipping.
Ended up putting in another order with Banzai. Cheapest shipping by far (around $15NZD from germany). Needed some pots and thought id stock up on valve sockets etc. The F+T prices from banzai are excellent.

Ah I see. Last time I used evatco I went through eBay but they don't have what I need in stock this time.

I just went to eBay and got 3x 30uf/500v f&t caps for a suspiciously cheap price from Japan, but 68 prior sales with positive feedback eased my mind somewhat.

[StrummersOfThunder]

Did you find a reliable source of decent filter caps? I can see Evatco, and there's always ebay, but is there anywhere closer? NZTubes' site has been down for ages now.

Evatco dont have shipping to NZ at check out and when I asked the guy responded once then went quiet. Bit out off by that.
Ebay yep some decent stuff but prices high plus shipping.
Ended up putting in another order with Banzai. Cheapest shipping by far (around $15NZD from germany). Needed some pots and thought id stock up on valve sockets etc. The F+T prices from banzai are excellent.

Ah I see. Last time I used evatco I went through eBay but they don't have what I need in stock this time.

I just went to eBay and got 3x 30uf/500v f&t caps for a suspiciously cheap price from Japan, but 68 prior sales with positive feedback eased my mind somewhat.

Yep i saw those ones from Japan. Unusual store. Im sure theyll be fine

[RectifiedAmps]

Axial caps are overpriced and hard to source these days, but Mouser or Element14 has them I think. Otherwise CEdist is a good source from the USA. But if you’re designing the layout yourself it’s a good idea to allow for radial filter caps- so much cheaper and easier to find.

If anyone wants to learn about load lines I recommend the preamp design book by Merlin Blencowe. He steps through the process really well and the focus is on guitar amps - not hifi stuff. I also have a load line calculator spreadsheet I found on the web - really easy to use and gives graphs for the common 12A_7 family. Will dig it out and share it round later.

[StrummersOfThunder]

Axial caps are overpriced and hard to source these days, but Mouser or Element14 has them I think. Otherwise CEdist is a good source from the USA. But if you’re designing the layout yourself it’s a good idea to allow for radial filter caps- so much cheaper and easier to find.

If anyone wants to learn about load lines I recommend the preamp design book by Merlin Blencowe. He steps through the process really well and the focus is on guitar amps - not hifi stuff. I also have a load line calculator spreadsheet I found on the web - really easy to use and gives graphs for the common 12A_7 family. Will dig it out and share it round later.

Totally agree re: radial caps