Sears Silvertone 1484 OPT

let's get down with a classic Silvertone amp with two stacked voltage doublers and a funky output transformer,

6L6 push pull feeds a 2 inch stack of small lams, 75 EI, so not your typical OPT,

aged single build insulation on the sec enameled wire had a breakdown (shorted turn) that would actually make noise when you cranked the volume and hit heavy bass notes,

here is the amp, kind of a porta flex design where the amp fits in the back of the cab for storage,

OPT has single end bell and exposed coil face inside chassis with the leads hanging out, just like a Marshall,

easy pri-sec wind,

flat past 20KC, peaks at 120KC and 280KC (biggest peak)

no carnage pics, but you can imagine wire and lams i imagine, 

this amp sounds good, two 12 Jensen's, loose cardboard cab for that mellow sound,

schemo here>

http://www.silvertoneworld.net/amplifiers/1484/1484_schematic.html

Thank you CJ, this will come in handy! 

How much paper between each primary  layer? 

Could add a 16r tap by adding some turns after the 8r?

Pri-Sec means pri goes down then the sec on top ya?  Easy geometry this time!  I like these amps too.

yes lay down the pri first,

they use 1 mil or smaller Glassine paper in between each layer,

you can use yellow 3M poly tape instead,  or buy the real McCoy  right here>

http://www.dickblick.com/products/glassine-interleaving-paper/

but it is a pain to cut,

there were 81 lams used in the original Sears xfmr = cheap, as that comes out to 0.025" each lam, almost twice as thick as the standard 0.014 used nowadays,

so using modern lams will  probably  give you more inductance, the 025 might even have been barn roof steel (non oriented silicon) so the sound is gonna change on this rewind  thing, hopefully for the better,

I only mentioned the 16r tap as mine didn't care much to drive it at any kinds of volume.  ARced over at one of the 6l6 sockets... new socket time. Tx survived (I think)  :

DC on the center tap with a 1x1 lace    what is really going on?

one of my 6L6 sockets arced over also, there might be some ultrasonic oscillations going on here, saw a thread about that  a while back, maybe starting from the preamp tubes,

push pull amps cancel the DC from the supply, but you want the tubes matched to keep unbalanced DC off the primary,

1 x 1 could go up to 3 x 3, we were going for max inductance off the small core,