Marvel Posted June 2, 2004 Share Posted June 2, 2004 I've been looking a a tube amp design that has a choke in the design, for filtering the dc. The schematic has a 10H/200ma choke. Hammond has a 10H/125ma choke (too small) or a 10H/5A choke (too big?). I can get an enclosed one that is exact, but the price is $42 each. Should I just aim for a different PS as I am not rolling in the dough. I don't want to get all choked up over this. Marvel Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 2, 2004 Share Posted June 2, 2004 Marvel: Check here: www.tubesandmore.com (Antique Electronic Supply -- in Arizona -- I order from them all the time. They have: Hammond filter choke -- 10 Henries @ 200mA AES part# P-T193J $41.13 (ouch....just a little high...) Also try a search on something like 'tube amp filter choke' on ebay, or just 'filter choke.' There is a guy who has an ebay store, and I can't remember his name off hand. You might be able to find a very suitable vintage choke there. I have bought them before on ebay. Good luck with your project, Erik Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 2, 2004 Author Share Posted June 2, 2004 Thanks Erik, The correct value I found of the Hammond was pretty much the same price. That is an enclosed choke, and the open ones are usually a lot cheaper. I guess if I try this, I'll just bite the bullet. Haven't found the right value any lower in price. A question: I know that the DC resistance value is different for the different models, but the open frame 10H @ 5A only costs $20. Is the 5A rating what it can handle without going up in smoke? In otherwords, could it be a reasonable substitution? Marvel Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 3, 2004 Share Posted June 3, 2004 Hey, Marvel. 5amps is just pretty big, but the value is what you need. What type of component are you working on? Based on the value and current rating, it looks like you might be using it for a high voltage filter choke in a power supply (maybe you mentioned this above already!). I would prefer to use an open frame choke, myself, which is what I'm using in my own amps. Have you checked ebay? I've found parts like this there pretty often. I'm actually looking for a transformer myself, and will check on this too. Erik edit: from ebay: Item# 3819667698 This is an example that's very close to what you need. I can't tell you to do this, but if it were my project, I would buy it and see how things work out. If it doesn't get hot, hum, or chatter, it should be ok. edit2: You could even use a dual choke filter section, with chokes in series and an electrolytic filter capacitor (say 100uf/500 volts)at the node connection of the two chokes. I have an 11uf film and foil input capacitor to the filter, with two 5H/100ma chokes connected in series after the input. Very quiet! Good luck, Erik Quote Link to comment Share on other sites More sharing options...
Marvel Posted June 3, 2004 Author Share Posted June 3, 2004 Yes, it is for a power supply filter. The 5amp rated one is actually smaller than the 200 ma one, and at $19 not too bad. Basically no DC resistance though. Since the power tranny is only spec'd for 200 ma, I figured this thing would coast along okay. Thanks for the help! Marvel Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted June 3, 2004 Share Posted June 3, 2004 5A would coast, for sure. Check the ebay item above if you're interested. It should be less expensive than the enclosed choke, but sometime enclosed types can look kind of cool on top of a chassis! Quote Link to comment Share on other sites More sharing options...
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