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    6 V bucking transformer

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    eickmewg

    Posts : 74
    Join date : 2014-08-29

    6 V bucking transformer

    Post by eickmewg on Thu Dec 08, 2016 11:09 am

    I'm interesting in either making or buying a 6 V bucking transformer. My wall voltage is a tad over 123 V and I'd like to drop that to around 117 V. So a simple BOM and a diagram of the circuit would be nice. Perhaps better yet, if you have a spare lying around I'd be happy with a purchase. Thanks in advance.

    Bill
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    Dave_in_Va

    Posts : 189
    Join date : 2013-04-02

    Re: 6 V bucking transformer

    Post by Dave_in_Va on Thu Dec 08, 2016 11:47 am

    I used this site...

    https://robrobinette.com/5e3_Modifications.htm#Bucking_Transformer

    ...and slightly simplified it as I didn't need the larger voltage drop. I have the same same situation as you and this works perfectly. I use the Belkin (Amazon) on/off switch just because I don't see the need for the transformer to be working 24/7.

    I got the box from Amazon, the plugs from Lowes and I think I got the tranny from Mouser.

    I have four of these and also use them for what I consider "delicate" '60's gear (i. e. non-Fender) like Silvertone amps, Vox/Farfisa organs.

    (I know this could be done smaller and more neatly but I went with what I had.)



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    corndog71

    Posts : 565
    Join date : 2013-03-19
    Location : It can get windy here

    Re: 6 V bucking transformer

    Post by corndog71 on Thu Dec 08, 2016 11:48 am

    Here's the one I bought earlier this year.

    http://www.mouser.com/search/ProductDetail.aspx?R=0virtualkey0virtualkey166Q6

    I added a 5 amp circuit breaker to mine. I wrote the circuit down somewhere but I'll have to dig it up. It's quirky.




    eickmewg

    Posts : 74
    Join date : 2014-08-29

    Re: 6 V bucking transformer

    Post by eickmewg on Thu Dec 08, 2016 2:19 pm

    OK, it looks like a 6.3 V center tap transformer is the way to go. What amperage should I use? I seem to recall folks used to use a 2 A Radio Shack transformer. Is 2A too little? Dave you used a 4 A and Corndog, you used a 6 A transformer. So what to get?
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    corndog71

    Posts : 565
    Join date : 2013-03-19
    Location : It can get windy here

    Re: 6 V bucking transformer

    Post by corndog71 on Thu Dec 08, 2016 2:26 pm

    I made mine bigger than needed just in case. Bigger is better! cheers
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    Dave_in_Va

    Posts : 189
    Join date : 2013-04-02

    Re: 6 V bucking transformer

    Post by Dave_in_Va on Thu Dec 08, 2016 2:55 pm

    I just went by the Robinette web page which calls for 4 amps. Robinette obviously knows more about it than I do Smile
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    wgallupe

    Posts : 114
    Join date : 2014-05-18
    Age : 63
    Location : Central Mass.

    Re: 6 V bucking transformer

    Post by wgallupe on Thu Dec 08, 2016 4:41 pm

    Could I use one of these to power 2 Mark III monoblocks or is it best to go with one bucking transformer for each monoblock?
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    sKiZo

    Posts : 1392
    Join date : 2013-04-01
    Location : Michigan USA

    Re: 6 V bucking transformer

    Post by sKiZo on Fri Dec 09, 2016 1:16 am

    I went with 7v 6a ... mostly because I had one in the parts bin ...



    Wiring is pretty straight forward with a two stage transformer ... careful to test before plugging anything in ... if you wire it up backwards, the output increases.



    The power strip is nice because it already has an power switch and breaker built right in.

    PS ... the transformer should be able to comfortably handle the max draw of whatever's plugged into it. I run an ST120 and an Eico mono tuber off this one.

    eickmewg

    Posts : 74
    Join date : 2014-08-29

    Re: 6 V bucking transformer

    Post by eickmewg on Tue Dec 13, 2016 6:16 pm

    The bucking transformer is a success. I used a Hammond 546-166Q6 which is a 6.3 V center tap.  I didn't bother with a pilot light or on-off switch for now.  With a wall voltage of 123 V, I can now drop to 119 and 115 V, which should cover me if wall voltage drops or rises a bit.  I even got it wired correctly the first time.  The transformer is 6 A so I should be pretty safe.  Thanks to all for your help.  A fun little project.

    Bill

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