Silvertone 1484 layout drawing (or hi-res gutshots)?

[rog951]

Guys,

Just picked up a Silvertone 1484 "twin twelve" in non-working condition. According to the previous owner, the fFailure mode is "lights up but no sound." I haven't really had a chance to mess with it yet to confirm. though; so far I've just verified that both speakers (Jensen P12Qs) are working, and that the wiring is a rat's nest. :huh I've heard that these are a pain to work on but holy moley!

Does anyone happen to have a layout drawing or maybe some hi-res photos of their 1484's innards? It'd be very helpful to have a reference as to what the stock wiring is supposed to look like. I'd appreciate any info/tips you guys might have, especially from the vets who've worked on these things before.

Thanks! :beer

[tlpruitt]

Before you spend too much time figuring out the rat's nest you should always suspect the tubes first, especially in old amps like this.

Next would be filter caps and any burnt looking component but if you have no sound my guess is it is a tube or a broken connection.

It may be a rat's nest but the circuit is not that complex and they do sound great when they are working properly.

Good luck.

[JerryP]

Here's a few things to look at on the Silvertone amps besides the normal tubes and stuff.
1 - Filter caps, if they're original change them. Every Silvertone I've had come thru needed caps. I've worked on quite a few.
2 - Check the resistor values. They used the bottom of the barrel parts in these amps and the resistors can drift quite a bit. Every Silvertone I've seen needed many resistors changed because they had drifted drastically.
3 - Output transformer, the 1484 like to eat them.
Jerry

[Structo]

Yeah, you don't really need a schematic or layout to fix it.

They are nice to have if somebody has modded the amp or if a component is so fried that you can't read the value.

That being said here is a schematic for a 1484.

http://www.schematicheaven.com/bargainbin/silvertone1484.pdf

[rog951]

Before you spend too much time figuring out the rat's nest you should always suspect the tubes first, especially in old amps like this.

Next would be filter caps and any burnt looking component but if you have no sound my guess is it is a tube or a broken connection.

It may be a rat's nest but the circuit is not that complex and they do sound great when they are working properly.

Good luck.

Thanks! I'll take all the luck I can get and it's always motivational to hear that it could be a great-sounding amp. I'll definitely check the tubes first. I'll have to order some 6CG7s though...this'll be my first experience with them so I don't have any laying around.

[rog951]

Here's a few things to look at on the Silvertone amps besides the normal tubes and stuff.
1 - Filter caps, if they're original change them. Every Silvertone I've had come thru needed caps. I've worked on quite a few.
2 - Check the resistor values. They used the bottom of the barrel parts in these amps and the resistors can drift quite a bit. Every Silvertone I've seen needed many resistors changed because they had drifted drastically.
3 - Output transformer, the 1484 like to eat them.
Jerry

Thanks Jerry. I'll keep this stuff in mind. I see that Mercury Magnetics makes an output transformer and it looks like Weber does now as well. At least the Weber one isn't too much $$$.

General transformer question: are rusty laminations really the "death knell" for a transformer? I noticed some oxidation on the 1484's power transformer. Reading some of Gerald Weber's books, he makes it sound like the instant you see rust, the tranny is done due to arcing (iirc). Just wanted to get others' opinions on that.

[rog951]

Yeah, you don't really need a schematic or layout to fix it.

They are nice to have if somebody has modded the amp or if a component is so fried that you can't read the value.

That being said here is a schematic for a 1484.

http://www.schematicheaven.com/bargainbin/silvertone1484.pdf

Thanks for the schematic link! The main reason I was hoping for a layout or gut shot is that I'm getting the feeling I'm not the first one who's been in this thing. Just wanna make sure my starting point is where it should be.

[SatelliteAmps]

Thanks Jerry. I'll keep this stuff in mind. I see that Mercury Magnetics makes an output transformer and it looks like Weber does now as well. At least the Weber one isn't too much $$$.

General transformer question: are rusty laminations really the "death knell" for a transformer? I noticed some oxidation on the 1484's power transformer. Reading some of Gerald Weber's books, he makes it sound like the instant you see rust, the tranny is done due to arcing (iirc). Just wanted to get others' opinions on that.

Rust is fine. There is a nice article on Mercury's website about it. Those amps do like to eat OT's though.

[rog951]

Rust is fine. There is a nice article on Mercury's website about it. Those amps do like to eat OT's though.

Thanks for that info! I just spent several hours reading those MM FAQs. They've got a lotta great info on their site! I also re-read Gerald Weber's take on the rusty tranny laminations. Amazing how two supposed "experts" can have such a differing opinion on a subject like this. :argue

[SatelliteAmps]

Thanks for that info! I just spent several hours reading those MM FAQs. They've got a lotta great info on their site! I also re-read Gerald Weber's take on the rusty tranny laminations. Amazing how two supposed "experts" can have such a differing opinion on a subject like this. :argue

There are a number of mistakes in almost every single book about guitar amplifiers. Most of them due to opinion rather than experience. It used to be "common" knowledge that rust was bad, but at that time there were very few transformer companies catering to guitar amp makers.

[Prairie Dawg]

Rust is fine. There is a nice article on Mercury's website about it. Those amps do like to eat OT's though.

+1. My old man had his degree in metallurgical engineering from MIT (science and properties of metals) and he'd been out of the engineering trade a long time when I first got a copy of the Texican amp wizard's book.

I asked him about this very question. He said "Hmmmm....transformer laminations....high permeability iron with a lotta silicon...I'd be surprised if they didn't rust. Clean it up with a good stiff brush, brass or otherwise, and then lay down some nice acrylic paint if you're worried about how they look."

[rog951]

There are a number of mistakes in almost every single book about guitar amplifiers. Most of them due to opinion rather than experience. It used to be "common" knowledge that rust was bad, but at that time there were very few transformer companies catering to guitar amp makers.

On no, so much for my plan to learn everything by reading books, and never actually doing anything! ;)