So I've got this Silvertone 1485.I like it a lot (especially the fact that it sounds like an electrified cardboard box) but recently I considered reconfiguring it. As of now the 1485 has 6 x 10" speakers. I was thinking about taking these out and connecting a bunch of 15" Jensens to it, main reason being to get more bass. Anybody have any ideas about what I should do? I know how to solder and I know to match ohlms and that is about it. I am figuring it is not rocket science?

Yeah cool, so it's just a bit of maths then (about 2.6ohms per tap I reckon).

But I would go down the road that Jamie suggested, Make another cab instead of butchering the one you've got. Trust me, I trashed my share of cool old vintage gear and some of it I really regret while some of it was just broken old shit that got what it deserved! But that setup you've got is really cool, I'd keep it original.

Ryan Thomas LeGere said:

Mardy Pune,

 

It's sounding more and more complex to me. I thought it would be as easy as doing a little math, matching ohlms, and soldering. I have looked at the speakers. I actually had to solder the wire back on one because it came undone. The speakers are wired in parallel. No transformers on the speakers as far as I can tell. One output transformer to 3 speakers. I am wondering if I should just find a tech that knows old amps. I  don't want to get fried.

Now if I could get that extra bass boost with an intact brightness from the mids along with that cardboard crunch I'd be happy.

Jamie said:

I'm thinking you might actually save money by just getting a different cab. A 6x10 Silvertone cab is probably pretty rare. I built one for my 1484 out of pine from Lowes. I just stained the bare wood and put some polyurethane on it. I ordered a fender style grillcloth online. It looks pretty decent. I might put a picture up here sometime.

 

I used some 12" Eminence Legends because 1. I found them cheap on ebay and 2. supposedly they have a vintage Jensen/JBL vibe to them. I've never played through any vintage speakers so I couldn't tell you how they compare. They are very loud and clean. They don't really break much at all. They have good bass but are also pretty bright. They're just about right for the Silvertone as far as clean speakers go but are just a little too bright for my blackface Bassman head. They might continue to break in.  

I think I'm going to build another cab and try to find some lower powered speakers so I can get that cardboard box sound you're talking about. I may try some tens.

Mardy Pune,

 

It's sounding more and more complex to me. I thought it would be as easy as doing a little math, matching ohlms, and soldering. I have looked at the speakers. I actually had to solder the wire back on one because it came undone. The speakers are wired in parallel. No transformers on the speakers as far as I can tell. One output transformer to 3 speakers. I am wondering if I should just find a tech that knows old amps. I  don't want to get fried.

I'm thinking you might actually save money by just getting a different cab. A 6x10 Silvertone cab is probably pretty rare. I built one for my 1484 out of pine from Lowes. I just stained the bare wood and put some polyurethane on it. I ordered a fender style grillcloth online. It looks pretty decent. I might put a picture up here sometime.

 

I used some 12" Eminence Legends because 1. I found them cheap on ebay and 2. supposedly they have a vintage Jensen/JBL vibe to them. I've never played through any vintage speakers so I couldn't tell you how they compare. They are very loud and clean. They don't really break much at all. They have good bass but are also pretty bright. They're just about right for the Silvertone as far as clean speakers go but are just a little too bright for my blackface Bassman head. They might continue to break in.  

I think I'm going to build another cab and try to find some lower powered speakers so I can get that cardboard box sound you're talking about. I may try some tens.

Yeah, you would still get speaker break up from some vintage 15" speakers but it still wouldn't sound the same as the 10's you've got in the cab. It's not really the quality of the speaker that causes the break up it's more the spec's.

Have you opened up the cab and and looked at the speakers to see how they are wired? And do they have little transformers mounted on each of them?

After looking at the schematic again there's a 500volt tap coming off the power transformer and connecting to the output transformer(s), I'd be careful, that's not something that I've seen in a guitar amps before. I don't wanna see you get fried!

 

Thanks to the both of you for quick replys. I love this amp but my band currently needs a bass player so I need more bottom end as we are a two piece guitar and drums. The thing that got me started on swapping out speakers was that I also own a 1484.  You may or may not know, the 1484 model is a lower watt version of the 1485 and powers two 12 " Jensens. This larger speaker circumference intensifies the lower frequencies. i thought if I could throw in some 15s into my 1485 I could replicate or surpass the tone offered by the smaller amp. However, if I lose that cardboard box sound, well... that's a sacrifice I'm not willing to make.

 

When the speakers breakup, is that because of the quality of the speaker? If I were to use vintage 15s would I get breakup?

 

Oh, and yes it has two taps (I'm assuming that is what you mean by the 2 jack inputs on the head receiving the jacks from the cab).

 

 Mardy Pune, good idea about the EQ pedal. I"ve gotta graphic I used to use. Maybe I can save myself the hassle and just employ that to amplify my bass frequencies.

 

First thing: Valve/tube amps contain dangerous voltages that can kill you. If you don't understand how these kind of amp's work and want to do some work inside one you should get a qualified technician to do the work for you. In other words; just look after yerself.

 

here's a link to a schematic for the 1485: Silvertone

I don't know if it's original or correct.

Although it looks like it has two output transformers I would think it has one output transformer with two taps (output sockets).

Is your amp a combo or head and cab?

According to the schematic each speaker is 8 ohms which equates to 24 ohms per tap. It's kind of an odd number by modern standards but back when these were made there were all sorts of values used, I've seen amps with 32 ohms and 56 ohms required and I've got an old Rola speaker at home that is rated at 30 ohms.

 

So the minimum amount of 15" speakers you would need in total would be 4. You would need a 8 ohm and a 16 ohm wired in series per tap so you get your 24 ohms. I looked at some pictures of a 1485 and you might be able fit 4 15's into the cab.

 

Everything the Jamie said is true as far as I'm concerned. I also think that you would change the overall tone of the amp in a big way. That electrified cardboard box sound you like is probably due to the speakers breaking up, I don't think you'll retain that sound if you rebuild the cab and put new speakers in.

 

Personally I would go and buy a eq pedal and try to modify the tone that way for a start. It will cost you a lot less money, won't de-value your amp and save you a lot of time and stress.

I might be tempted to leave it stock just to keep it original. I think the price on those amps have gone up quite a bit due to the Jack White connection. You would have to change the baffle I'm assuming. A speaker change probably would give you a lot more bass. Look up wiring diagrams online. If you know how many ohms each speaker is and how many ohms the amp needs then just google "series" or "parallel" speaker wiring find out which one you need in order to match up the ohms and you're good to go.