Modify a Silvertone 1448 amp-in-case

Discussion in 'Amp Central Station' started by dkevin, Jun 24, 2019.

  1. dkevin

    dkevin Tele-Meister

    Mar 13, 2011
    Seattle, WA
    Let us imagine a world where someone has time on his hands and wants to redesign a Silvertone 1448 amp-in-case. Originally this amp is a transformerless amp using a 12AU6, 50C5 and 35W4 half wave rectifier. If this certain individual wanted to replace these tubes with a 6AT6, 6AQ5 (similar to a 6V6) and a 6X4 full wave rectifier what is the most economical ($) way to power this amp? The original operating voltages seem to be irrelevant for our purposes because the tube lineup has been altered. I...I mean HE would be looking for a modest 250vdc on the output plates. If my math is close, that would require a 230-0-230 PT to provide the plate voltage I need. Anyways, if you have a helpful suggestion, drop a line and I will make sure this guy hears about it.

    Attached Files:

  2. Dacious

    Dacious Poster Extraordinaire

    Mar 16, 2003
    You could back-back two 6.3 volt filament heaters - I did this to create a one tube amp with a 6GW8, which has a triode plus preamp . Use a 6AU6 with your 6AQ5.

    You will easily get a watt or two with that. Don't bother with a rectifier tube, just use a full bridge.

    So you connect the two filament heaters 6.3 to 6.3 volt, and use the HT off the second with a voltage doubler to get you 240 volts which rectified to DC is enough.

    The filament transformers cost almost nothing. If you really want, you can use a little line transformer for the output, pennies.

    Or, get really trick and use two 6AQ5s in push-pull.....
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