mcrracer Posted November 9, 2008 Share Posted November 9, 2008 Would a Hammond 155H choke be an improvement in the power supply of the Epi Valve Jr ? 5Henries, 50mA, 270ohm, 400V I want to improve on the power supply voltage. Link to comment Share on other sites More sharing options...
layboomo Posted November 9, 2008 Share Posted November 9, 2008 In a word...No. Most of the experts agree that there is little to no benefit to a choke over resistors in the simple SE valve Jr. design. Mercury Magnetics puts one in their kit...but ,hey they have to give you something for all that $$! There are few discussions on the subject over at SEwatt.com if you dig around a little. Link to comment Share on other sites More sharing options...
wolf13 Posted November 9, 2008 Share Posted November 9, 2008 Would a Hammond 155H choke be an improvement in the power supply of the Epi Valve Jr ? 5Henries' date=' 50mA, 270ohm, 400V I want to improve on the power supply voltage.[/quote'] My experimentation lead to this 1H reduces enough ripple to make the supply hum low enough to be acceptable sounds very aggressive. 3H will produce a similar result to the mm kit (make sure that it does not have endbells or results will change ) above this will make the amp have a softer less aggressive sound also with the choke the cap values in the lc network can be lower than if an rc network is used to achieve the same ripple reduction. A choke does react differently as current is drawn than a resistor. The output transformer being single ended should also not have endbells due to if it does it will have a dc charge that keeps the speaker held just away from free floating (like when amp is off) as far as improve the supply voltage question I'm not sure what You mean I have a couple 5 gallon buckets full of vj power and outputs if anyone smoked theirs you pay the shipping. got a bunch of blackheart little giant fender champion600 and orange tt sets too. Link to comment Share on other sites More sharing options...
layboomo Posted November 9, 2008 Share Posted November 9, 2008 My experimentation lead to this 1H reduces enough ripple to make the supply hum low enough to be acceptable sounds very aggressive. 3H will produce a similar result to the mm kit (make sure that it does not have endbells or results will change ) above this will make the amp have a softer less aggressive sound also with the choke the cap values in the lc network can be lower than if an rc network is used to achieve the same ripple reduction. A choke does react differently as current is drawn than a resistor. The output transformer being single ended should also not have endbells due to if it does it will have a dc charge that keeps the speaker held just away from free floating (like when amp is off) as far as improve the supply voltage question I'm not sure what You mean I have a couple 5 gallon buckets full of vj power and outputs if anyone smoked theirs you pay the shipping. got a bunch of blackheart little giant fender champion600 and orange tt sets too. Clearly wolf13 knows what he's talking about and if I'm reading your question right(?)...my reply was based on a thread over at sewatt.com that basically came to this conclusion from several EE's on that site and 18watt: "And the VJ doesn't really need a choke. Chokes help reduce power supply ripple, but the same effect can be had by replacing the first cap in the power supply with a 100uF/400v electrolytic. " Link to comment Share on other sites More sharing options...
cGil Posted November 10, 2008 Share Posted November 10, 2008 Those are some very interesting tidbits on the chokes and endbells! Good stuff to know. Thanks for posting that. And sure, I can always use some replacement iron around here; especially replacement PT's at this particular moment, but OT's would certainly be handy, too. Hey, you never know what'll walk through the door begging for repairs. I'm also interested in PT's with 5v taps for tube rectified projects. However, the pthers don't normally use rectifier tubes, so may we assume Mercury's Blackheart PT has 5v taps since the stock iron has 'em for the option? If so, another important question is, how much current can it supply for the HT and heaters? Enough current for an 18watt lite project perhaps? Gil... Link to comment Share on other sites More sharing options...
mcrracer Posted November 11, 2008 Author Share Posted November 11, 2008 Thanks guys. I was asking because of the MM kit including a choke. Thought they knew something I did not. A cap is a lot cheaper than a choke. Link to comment Share on other sites More sharing options...
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