Sears Silvertone 1484 Build

[buildafriend]

Hi,

I've decided to take a crack at building a sears silvertone 1484, mostly turret boarded. Hopefully I can pull this off. I already have the mercury magnetics transformers and choke and now im ordering parts on mouser. Wish me luck, this will probably take a while since I'll be piecing it together over time to decrease the burn in my wallet.

The first road block I've hit is I dont know what to use for c26, c27, c28, and c29. They are near the power transformer on the schemo. maybe the schemo is designating 100uF and 150V? I'm starting to think thats what it means..
http://harmony.demont.net/documents/schematics/amps/silvertone_1484.pdf

I'm wondering since the original used 20% tolerance carbon comp resistors if using 1% metal film will take away from the crappy/awesome explodiness this thing does when you crank it. I think there might be some beauty in the push pull output crossover distortion.. Or maybe it wont affect anything in the end besides the noise floor and making it a bit brighter. I don't want to provoke the whole resistor and cap taste war but just a thought..

 

[Brian Roth]

The parts list on page two verifies they are 100 uF/150V.  That is rather an oddball PSU design, but whatever.  It might be a good idea to parallel each of those four caps with a resistor to act as bleeders.

Bri

 

[buildafriend]

The parts list on page two verifies they are 100 uF/150V.  That is rather an oddball PSU design, but whatever.  It might be a good idea to parallel each of those four caps with a resistor to act as bleeders.

Bri

Thanks Bri

I'm currently trying to figure out what I can use to sub what is listed as a light sensitive tremolo unit. It looks like some kind of photoresister on the schemo.

From the literature below, I'm finding out that it used two voltage doublers which is very rare and might have been done as a budget decision. These things seem to need a bit of tweaking according to some sources but they kick plenty of butt the way they are if you ask me. Hopefully I can hot rod this one out into a monster.

 

[jstark]

a couple of (maybe) useful links:

http://www.premierguitar.com/articles/Tweaking_a_Silvertone_1484

http://books.google.com/books?id=atKgmVvv-BgC&lpg=PA211&dq=silvertone%201484&pg=PA211#v=onepage&q=silvertone%201484&f=false


of all the guitar amps I own; the 1484 is without doubt my favorite.

 

[buildafriend]

There was a lot of great information in there! Thanks.

heres all i have so far




I hope the reverb tank works, im not sure how standardized those are. It was given to me by a good friend. It reads "accutronics cary IL." and then the serials on it are partially worn off.

I'll be adding the bleeder resistors that brian suggested. I'm not sure what size resistors to use for that but I'll do a little HW.

The guitar amp head cabinet kit is on the way with turret boards and an aluminum 3" high X 17" wide X 7" deep aluminum enclosure. I'll post pics when they come in.

Turret boarding is fairly new to me. Hail Mary.

 

[buildafriend]

got this far and then realized my sovtec 6l6's wont fit between the hammond enclosure and the inside of the box... SH*T

they are 4.75 inches tall. now im wondering if anyone makes a decent low profile 6L6..?



now that I think about it the PT wont fit either.. I guess I'll have to use that enclosure for another project.. maybe a marshall 18w.. so here we go again with another 1484 box..  :

 

[mjrippe]

Measure twice, cut once...

 

[CJ]

or get some RCA tubes,  can be pricey,

can you mount the pwr xfmr sideways?

 

[buildafriend]

is that 4" from the top of the tube to the bottom of the pins? if yes, those should work.

I could mount it sideways but it would have to be mounted to the wood part of box instead of on the aluminum hammond enclosure.. getting the guts in and out would be wacky.. maybe I can fabricate an enclosure that allows me to pull this off. I did just invest in a sheet metal break and a spot welder..

 

[CJ]

that RCA measures 3 3/4" from the phenolic base orientation pin to the top of the glass,

you can get horizontal end bells for some lam sizes from Edcor, about $4,

or Ram Sales>  http://ramsales.net/

so you would pull off the old vertical  bells and bend the leads 90 degrees ,

about $3.95 a set,

or you could ditch the bells and make a couple of core brackets from some sheet metal, or small angle iron,

here is a set for bells 100 EI lams>

 

[buildafriend]

im hung up on what to use for the photocell.

part number says 306-2H.

 

[buildafriend]

that RCA measures 3 3/4" from the phenolic base orientation pin to the top of the glass,

you can get horizontal end bells for some lam sizes from Edcor, about $4,

or Ram Sales>  http://ramsales.net/

so you would pull off the old vertical  bells and bend the leads 90 degrees ,

about $3.95 a set,

or you could ditch the bells and make a couple of core brackets from some sheet metal, or small angle iron,

here is a set for bells 100 EI lams>

okay, getting real here while I have CJ's attention.. ill make a dang fool of myself which is necessary.

I'm assuming end bells are the covers for the windings that one typically sees on the sides of the transformer. also what is in the picture above. horizontal sounds smarter because that sounds lower profile.

the end bells im using would be the ones that came on my mercury magnetics transformer set.

Phenolic?  ??? I'll have to do a bit of research on that.

Ramsales eh? (im not canadian, but I just got back from there so I'll say eh a few times) I'll be lurking that site real soon.

$3.95, eh thats nothing!

core brackets.. never heard of em.

what's EI mean? Top google result is employment insurance. I bet its not that.

 

[CJ]

employment insurance hah!  good one! 

here is a shot of some vert and hor bells for 100 EI and a stack of EI lams,

any luck on the lamp yet?

tried to download the pdf schemo to see if it is the standard lamp/LDR thing that Fender uses but the download stalls out,

you can still buy the lamp/Light Dependent Resistor from a number of sources,

 

[buildafriend]

after stepping back from this project for a while, I decided I want to try to make it smaller so that if fits in my marshall 18w enclosure while not being a perfect copy of the original. I just want the preamp, EQ, interstage tube, and 6L6 output stage. This eliminates a lot of "extra stuff."  I would like to drop the reverb (while adding an effect in and out in the back) and the tremolo. Also, I have no need for the second channel input. This saves money and leaves room for a reverb setup that doesnt sound like the doo doo.

so now I guess it's time for some tube circuit simulation

I downloaded LTspice and I see that there is some kind of Pspice thing for tubes. Does anyone have any experience with this? I'm not sure if I keep finding bad links or if I just stink at getting it going.

 

[soapfoot]

One thing to realize about those amps is that a big part of the sound was the masonite cabinet.

In a pine cab, it will sound a lot more like "any other guitar amp," and doubly so in a more rigid plywood cab.

 

[buildafriend]

I think I'll be happy with my head cabinet.. Thanks for the insight though!

 

[soapfoot]

Yeah, I'm sure you'll be happy! It's a cool amp regardless of cab, probably.

But I love the sound of those old silvertone amps... there's a certain "paperiness" about the sound due to the way the masonite cabinet resonates. It's really curious how much cabinet material affects sound in a guitar amp, and how often the "wrong" material ends up imparting a coloration that's very "right."