184.6.48.13
This Post Has Been Edited by the Author
In Reply to: RE: I'm Melting... What a world, what a world... posted by jjhaz on December 18, 2011 at 21:18:27
Hi Jeff,I'm Jeff also. I custom design SE special custom power transformers and I will be the first to tell you there is nothing wrong with using Hammond Power Transformers..... IF you know how to spec them, and under-use their ratings by a fair margin. Your 372BX was only rated to do 92 VA / 100 mA. on the secondary.
Question one, are you really needing an INTERNATIONAL primary ??
By that, I mean do you need choices from 110 VAC home line voltage to 240 VAC home line voltage,... as in Europe? If so, simply use the 3XX series and just UP the current rating. Order the 372JX which does 250 mA. and costs $149.95 Your melted trannie, rated at 92 VA / 100 mA. costed you $100.78. and its a total loss now.
If you are USA only, or nominally use 120 VAC only, NEVER order the 3XX numbered series of Hammonds ever, (with all the fancy un-used primary taps hanging off them). Order the 2XX Hammond series, with the 115 and 125 VAC primaries only....MUCH more trannie for the money, and you can easily and cheaply upgrade the VA rating, so the trannie LOAFS rather than spills its guts out.
Would you rather drive a 49 CC China scooter, or a 1,300 cc BMW cycle ??
Your upgrade route, if in the USA, is to order a Hammond 272JX, it is rated at 236 VA and it can do 600 VCT at 287 mA. of current!!!!! Guess what, it retails for $65.54!!!!!!! A fraction of the 100 mA. melted one, and 2.36 times HIGHER the VA rating.
Three questions need to be answered still:
(1) Can you fit it on your chassis?? It will be physically larger that the P.U.ny 100 mA./92 VA power trannie. If it does not fit, rebuild the amp on a larger cahssis, or modify mounting holes and locations on your existing chassis so it will fit.
The amp (with the new trannie) will run cool to the touch, and it will sound at least 10 to 30 percent better, because now, the HEART of the amp, the power transformer, is STRONG and will self-regulate the B+ under the demands if music reproduction. Wait till you hear this !!
Two other questions need to be answered :
2) Has another part failed, that caused this transformer to have a ultra high load, and fail. If so, that needs to be fixed!!! First.
3) Was the size of the safety fuse in your amp too high in Ampere ratings, such that the power trannie blew before the safety fuse? If so, reduce the value of the fuse for MORE protection.
If you have questions, feel free to contact me. 272JX wow, $65.54 a steal.
Jeff Medwin
Edits: 12/18/11Follow Ups:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2011, Audio Asylum, all rights reserved ]
[ Take5 ]