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    bias pot query

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    Captain Coconut

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    bias pot query

    Post by Captain Coconut on Mon Oct 27, 2014 10:49 am

    Will an Alpha or a PEC bias pot with its 314 degree turn be fine enough for setting bias? I use a small Bournes multi-turn pot now which dials in bias quite nicely. I like the idea of a larger chassis mounted pot for a new amp build, but wonder if they can handle the job with D. Gillespie's EFB.

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    Re: bias pot query

    Post by Guest on Mon Oct 27, 2014 10:59 am

    Captain Coconut wrote:Will an Alpha or a PEC bias pot with its 314 degree turn be fine enough for setting bias? I use a small Bournes multi-turn pot now which dials in bias quite nicely. I like the idea of a larger chassis mounted pot for a new amp build, but wonder if they can handle the job with D. Gillespie's EFB.

    like the standard one turn trimmers, it works, but of course you will get finer adjustment out of multi turns. Have you looked at larger multi turn pots, they cost more, but are generally the same size as your average every day pot.
    Here is one option https://www.bourns.com/ProductLine.aspx?name=precision_pots_multiturn

    corndog71

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    Re: bias pot query

    Post by corndog71 on Mon Oct 27, 2014 11:41 am

    I have a PEC pot in my ST35 with EFB. Works just fine.

    sKiZo

    Posts : 1310
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    Location : Michigan USA

    Re: bias pot query

    Post by sKiZo on Mon Oct 27, 2014 1:39 pm

    You can get some nice "bourns" 50k multi-turns offa da bay for $6 each - including the locking knob and wrench ...


    I got a five pack of those a while back just for shitzengiggles and tested them on the meter ... solid build, smooth movement, within tolerance, and they all track accurately throughout the range.

    Captain Coconut

    Posts : 213
    Join date : 2009-10-13
    Age : 64
    Location : Great White North

    Re: bias pot query

    Post by Captain Coconut on Mon Oct 27, 2014 3:34 pm

    Thanks for the input fellers.

    stewdan

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    Age : 78
    Location : Houston Texas

    Re: bias pot query

    Post by stewdan on Mon Oct 27, 2014 4:48 pm

    Hi sKiZo --- do you remember the "seller at the bay" that you dealt with?  

    I just checked for "Bourns 50K multi pot" and "Bourns 50K pot locking knob" but I did not see any with the locking knob and wrench.  I found the bottom part of the pot but they were not $6, more like $20 to $40+.

    Any insight would be appreciated.

    Thanks,
    Stew

    sKiZo

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

    Re: bias pot query

    Post by sKiZo on Mon Oct 27, 2014 6:34 pm


    5ps 50K Ohm 3590S-2-503L With Turn Counting Dial Rotary Potentiometer 10Turn

    These will actually be the third set of pots in this build. First ones were cheepo Chinese - one of those went open and dusted a tube and bias resistor. Currently running some really good Fender pots, but those aren't true linear and get a bit tweaky right where I need them. I figure the 10 turns should dial right in.


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