Silvertone 1483 Rebuild/revamp

[trevorus]

I traded for an OLD (mid 60's) Silvertone 1483 bass amp head. I got it and started testing it. Turns out the OT was dead on one side.

So I popped that out, and I have a new one installed. It's massively larger, and has better power handling than original. This will probably end up being my lower volume gig/recording bass amp, and also double as a guitar amp, too.

The original tube complement is pretty sweet.

[trevorus]

And tonight I got around to building a new cabinet for it.
















I just ordered new electrolytics from Ted Weber, and they should be here next week. The output is weak and fuzzy, and I am sure 40 years+ on the caps is not too good.

[bob p]

a few years ago i had posted a long-assed thread about restoring a silvertone twin twelve over at the LPF. i reformed the original caps, restored all of the original PTP wiring and I kept the original chassis. totally stock silvertones are becoming as rare as hen's teeth, and i just couldn't bring myself to mod the amp. now mine is a museum piece.

i don't know if you're aware of this or not, but mercury magnetics makes an exact reproduction of the original twin twelve OT.

the original twin twelve OT is quite a bit smaller than the triad. as a result its going to saturate very early, and that's going to roll off a lot of the high end. IMO that's what's responsible for the "thick and creamy" milkshake type distortion that the silvertones are famous for. i think that if you switch over to a better OT like the triad, the voice of the amp might be noticeably different. i would expect it to become a LOT brighter. let us know how it works out.

[trevorus]

a few years ago i had posted a long-assed thread about restoring a silvertone twin twelve over at the LPF. i restored all of the original PTP wiring and I kept the original chassis. totally stock silvertones are becoming as rare as hen's teeth, and i just couldn't bring myself to mod the amp. now mine is a museum piece.

i don't know if you're aware of this or not, but mercury magnetics makes an exact reproduction of the original twin twelve OT.

the original twin twelve OT is quite a bit smaller than the triad. as a result its going to saturate very early, and that's going to roll off a lot of the high end. IMO that's what's responsible for the "thick and creamy" milkshake type distortion that the silvertones are famous for. i think that if you switch over to a better OT like the triad, the voice of the amp might be noticeably different. i would expect it to become a LOT brighter. let us know how it works out.

Sure will, once I get a good solid clean out of it!

I might get a stock-style OT, but this one was pretty much given to me for cost of shipping, and it will find use later if I do restore this to original. I basically made the case to house the transformer, and I am keeping the original case, as it is in quite good shape. The tubes are also going to be used sparingly. I am doing some slight mods to it, but nothing irreversible. I've not cut any wiring, except for the output stuff, removal of the "death cap" and installing a 3 prong plug so far. I might add a cathode bypass cap and see how I like the tone after adding it. One mod I might do is a true standby switch. The stock one only cuts signal to the power stage, and doesn't actually cut B+ at all. Any way I go about it, it ought to be interesting.

[bob p]

the twin twelve standby merely connected the two out of phase signals coming from the PI to silence the amp. is that what you meant?

i know that i'm probably the only guy in the world who will say this, but i don't think that old silvertones that are as-yet unmoded should be modded from factory spec. because they're so cheap, they've all been cobbled, and there are almost no like-new original unmolested specimens out there. those that have been "reveribly modded" are still modded in my book. but i have to admit, i'm different in my opinion on this than most people.

that's one of the reasons that i chose not to do any mods on my amp once i got it working. i didn't need a cheap amp as a modding platform, and to me it was more desirable to keep something original becuase nobody else was bothering to do it. ymmv, of course.

[trevorus]

I'm kind of going for an in-between here. I want an amp that really works for me, modded the way I like, but in a way that I can easily change it back if the need arises. I don't buy gear to sit on a shelf, usually, I buy it to play. I do understand the vintage value here, though.

[Bruce / Mission Amps]

I'm kind of going for an in-between here. I want an amp that really works for me, modded the way I like, but in a way that I can easily change it back if the need arises. I don't buy gear to sit on a shelf, usually, I buy it to play. I do understand the vintage value here, though.

Vintage value? Ha ha ha... one and a half click away from PURE CRAP IMHO.
I like what you've done so far and I'm all for doing what ever you want to those turds because it is the only way to really make them work well and sound good.
Yes, with some work, time and energy, they can be made to sound fairly good. Never as good as a Princeton reverb, Deluxe Reverb or an old Ampeg Reverb. It takes a lot of replacing cheap parts, changing a few values and using good Hi-Q caps on the tone controls... plus dump those POS Planet filter and bypass caps... which have a lifespan of 1-5 years... reform them!!???... get rid of them and use something with some real filtering capability.
Trust me on this, I have modded a number of these amps over the years and was the one that gave the consultation, special mods and tweaks to MOJO for White Stripes, who seemed to have an affinity for that cheap junky sound.
However, I am still ASTONISHED that some home brewer/players will pay good $$ for a cheap piece of junk made from pressed paper, wood blocks, U channel aluminum and a handful of terminal strips.

[trevorus]

Yeah, I guess old doesn't always mean vintage. Ah well, this is a fun project any way you slice it.

[bob p]

ok bruce, please do tell -- what are your preferred mods???

[Steve Conner]

Wow, you weren't kidding when you said the new O.T. was "massively larger" I think if I was modding this, I'd start by tossing out everything except the tubes and the snakeskin cabinet

[Bruce / Mission Amps]

... Ah well, this is a fun project any way you slice it.

Exactly!!
That is the reason I said I'm all for modded the hell out of these amps... and they can be made to sound pretty good... not a do-all amp but lots of fun in the process and a good platform for that.. "Sleeper" amp you always wanted....you know, the one that your friends will laugh at and then be stunned at the difference.

[soundmasterg]

Those Silvertones sound ok stock if you're going for that lo-fi Velvet Underground and White Stripes sound. They can be modded to sound pretty good, but because of the poor design and components, there will always be compromises involved. For example....a favorite mod on many old amps is to raise the preamp plate voltages to increase gain and get more top end. Well on these amps when you do that, the hum greatly increases because of where they put the power transformer. I spent a year modding a 1484 and it sounds really cool now, but they are such a PITA to work on, that I don't think I'd bother with all of that again. I've got a perfectly original and stock 1484 that has a couple issues and I plan to fix the issues, replace the caps with stock values, and call it a day. I'd rather work on amps that are more fun and easy to work on.

Greg

[IsraelHagen]

2 Questions!

Hey I found your post after Google-ing Silvertone 1483.
I have owned a 1483 for 15 years, and aside from practicing with it at the inset of my bass-playing life, it hasn't gotten much use. Just recently I had a tech replace the old power cable with a 3-prong grounded cable and I had the hard-wired speaker cable replaced with a 1/4" out so I could attach it to any cab I wanted.
In preparation for an upcoming recording session, I decided to experiment with my 1483 head and 4x10 bass cab to coax some bass overdrive. I found that while cranking the amp could get some pretty cool sounds, I achieved desirable results when I used a compressor to crank the gain between the instrument and the input jack. The tone was blistering. Which brings me to the questions...

1. Do I risk damage to the amp and/or the speakers by cranking the gain into the front of the amp like I described? I know that with some other amps, when you increase the gain like that, sometimes the "clip" light comes on and speakers could start shredding (I know this from experience). As much as I love the overdrive I got, I could do without destroying any of my gear right now.

2. Do you know what ohms ratings are safe on a speaker cab when matching to a 1483? I read once that you should use a 4-ohm cab, which is what I was doing in the scenario described. But I've read elsewhere that some have match a 1483 to 8 and even 16-ohm cabs. I don't know too much about it; I simply always try to match what's printed on the output of the amp and the input of the cab. Is it ok to use a 1484 with 8-ohms, 4-ohms?

Any info you could provide would be great. I'll get ya some sound samples when the work's done!

[olddawg]

I have a 1484 with the original speaker cabinet setting under my bench. It is bone stock down to the tubes, never modded or even repaired. I got it for nothing and it probably hasn't been powered up in 20 years. I'll get to it someday.

[tboy]

Do you know what ohms ratings are safe on a speaker cab when matching to a 1483?

The 1483 schematic calls for 8 ohm speaker.