Silver tone 1485 build

[Powerkeg]

I just wanted to inquire if anyone might have any advice on where I should start with building a tube head. I want to build a clone of a silvertone 1485, but with some differences such as having the ability to plug into a 4x12 cabinet, and a switch to change the wattage of the amp and perhaps building it to where it could handle a higher wattage. I would prefer to leave out the effects(revervb/tremelo) so it would be more simple to build. Im also curios if the schematic of the 1485 floating around is accurate and trustworthy. I have almost no prior amp building experience, but I feel confident that with a guiding hand I am competent enough to get it done. Unless, this sounds like a ridiculous nd senseless undertaking. Thank you for your time

[pompeiisneaks]

I don't know your electronics knowledge or experience with schematics and layouts.

To do what you want requires decent amounts of both. You'd need to know how to edit the current 1485 schematic, and remove the reverb etc so that it doesn't cause problems...

You'd need to then build a layout from the schematic.

If this doesn't already exist somewhere of course. If it does you can just cookie cutter follow it and probably get it done.

Adding power scaling in can be complex, You'd have to figure out how to add that to the amp. (lowering output power)

Changing the power stage to have more power output isn't usually hard, but this amp has 4x6L6GC's or 100W of power. rarely have I heard anyone in modern times say, "My 100W amp is too quiet, I need more power" for guitar. Bass, yes, but guitar no. If you wanted more output power you'd need to add either more 6L6GC tubes (6 or and then find an output and power transformer that can handle that excess current. or you can use bigger bottle tubes like KT120 and do similar power/output transformer changes. etc.

The general way I'd recommend learning is to first build a stock simpler amp, like a princeton or tweed deluxe. then move on to more complex builds. If someone has an existing layout for the silvertone, then you could built it as is, and then when done, experiment with finding how to remove sections/stages of the amp etc.

I'm not saying you can't do this, just that you're diving into the deep end instead of wading into the shallow or carefully going down a ladder into the deep end.

No matter what you choose, be careful, as the 400+VDC of most amps can kill...

Hope you enjoy no matter what happens

~Phil

[dcribbs1412]

Mojotone has a 1484 kit with all the parts with a layout and schematic.
https://www.mojotone.com/kits/MojotoneA ... lifier-Kit

[pompeiisneaks]

That would be a great option I think. It omits the reverb and trem from the original it seems, so it fits what you were thinking no?

Great info dcribbs1412!

~Phil

[M Fowler]

Grab another OT and you have your 1485 100w amp.

The 1485 used 2 OT's

[sluckey]

Take a look...

http://tdsl.duncanamps.com/show.php?des=6CG7

[ViperDoc]

Take a look...

http://tdsl.duncanamps.com/show.php?des=6CG7

Indeed, I spoke too soon. I missed the 6CG7 label on the schematic, though it would be nice to see it on the layout! I have one of these kits in the wings. Now I know!

Thanks for the pinout diagram.

Would it make any difference whether pins 4 and 5 on a 6CG7 were connected or not? I would assume you would run one heater side to either pin, but if it's connected inside the tube, it would seem there would be no difference. ?

[Roe]

Mojotone has a 1484 kit with all the parts with a layout and schematic.
https://www.mojotone.com/kits/MojotoneA ... lifier-Kit

The pt and power supply seem wrong

[ViperDoc]

https://www.mojotone.com/amp-parts/Powe ... ransformer

https://www.mojotone.com/kits/MojotoneA ... lifier-Kit

There are two 120V primary windings on this PT. To your point, why would one of them have both leads connected to the mains fuse?

[sluckey]

https://www.mojotone.com/amp-parts/Powe ... ransformer

https://www.mojotone.com/kits/MojotoneA ... lifier-Kit

There are two 120V primary windings on this PT. To your point, why would one of them have both leads connected to the mains fuse?

This PT can operate on 120v or 240v, hence the dual primaries. The schematic shows the two primaries connected in parallel as required for proper 120V operation. There's nothing wrong with the power supply schematic, and although it looks nothing like the original Sears power supply drawing, it will work just fine. Don't believe the colors on the mojo layout!

[Roe]

https://www.mojotone.com/amp-parts/Powe ... ransformer

https://www.mojotone.com/kits/MojotoneA ... lifier-Kit

There are two 120V primary windings on this PT. To your point, why would one of them have both leads connected to the mains fuse?

This PT can operate on 120v or 240v, hence the dual primaries. The schematic shows the two primaries connected in parallel as required for proper 120V operation. There's nothing wrong with the power supply schematic, and although it looks nothing like the original Sears power supply drawing, it will work just fine. Don't believe the colors on the mojo layout!

Yes, its wrong for a 1484 but will work

[Stevem]

I have had a 1485 and I currently have a 1484 and both amps need to have more then the -40 volts of bias needed to bias in a really good testing set of 6L6 tubes, and at 40 volts that supply is maxed out.

If your not going to build a Mojotone kit you need to make sure that can have up to a -52 VDC to work with.

[gldtp99]

I question why the OP has picked a Silvertone 1485 as his first build.

I have a 1485 that I've had for many years, restoring it back into a safe player early in the process----- I've rebuilt/serviced many 1484's (and other old Silvertones) so I'm pretty familiar with these amps.

I'd suggest the OP focus on the BF Fender Showman head instead of a Silvertone 1485.

The 1485 build is possible but a BF Showman build would be much simpler and would result in a better sounding amp, IMO.

Also the BF Showman transformer set is available from Classic Tone and Mojo------ the two 1484 type OT's are available from Mojo but there is no direct replacement for the 1485 PT----- a Fender type Twin Reverb/Showman PT could be used but would need many changes to the Power Supply vs 1485 schematics.

So why not just go ahead and plan a single channel Showman type build with no Trem ?

It would be easier to plan out, parts are readily available, and it's a better sounding unit overall.

I'd suggest a BF Showman build (single channel), with a Raw control (to dial in progressively "hairer" preamp response), a PPIMV, and a 4/8/16 ohm OT to allow use with a wide range of speaker cabs.

I've already built a similar head but with 6L6GC x 2 and using BF Tremolux type transformer set.

It's a very good sounding build, can do a wide range of tones from stock BF Fender to early Marshall-ish grind using just the head itself----- it responds to OD and delay pedals wonderfully (used front ended).

The old Silvertone 1485 (and 1484's) have a coolness to them but in A/B tests against BF Fenders I'd take the Fender design over the Silvertone every time----- assuming both amps are operating properly.

And the parts to build the Fender design are relatively cheap and easy to source.

It seems like starting with the BF Fender design is a "Win/Win" to me.

[SoulFetish]

I don't know your electronics knowledge or experience with schematics and layouts.

To do what you want requires decent amounts of both. You'd need to know how to edit the current 1485 schematic, and remove the reverb etc so that it doesn't cause problems...

You'd need to then build a layout from the schematic.

If this doesn't already exist somewhere of course. If it does you can just cookie cutter follow it and probably get it done.

Adding power scaling in can be complex, You'd have to figure out how to add that to the amp. (lowering output power)

Changing the power stage to have more power output isn't usually hard, but this amp has 4x6L6GC's or 100W of power. rarely have I heard anyone in modern times say, "My 100W amp is too quiet, I need more power" for guitar. Bass, yes, but guitar no. If you wanted more output power you'd need to add either more 6L6GC tubes (6 or and then find an output and power transformer that can handle that excess current. or you can use bigger bottle tubes like KT120 and do similar power/output transformer changes. etc.

The general way I'd recommend learning is to first build a stock simpler amp, like a princeton or tweed deluxe. then move on to more complex builds. If someone has an existing layout for the silvertone, then you could built it as is, and then when done, experiment with finding how to remove sections/stages of the amp etc.

I'm not saying you can't do this, just that you're diving into the deep end instead of wading into the shallow or carefully going down a ladder into the deep end.

No matter what you choose, be careful, as the 400+VDC of most amps can kill...

Hope you enjoy no matter what happens

~Phil

Yean, I'm in total agreement with this. I've worked on a bunch of different Silvertone amps. I like them.
For the OP: If you want a Silvertone, build a Silvertone, not a Fender. But, you choosing a more difficult road right off the bat.
First, parts and resources for Fenders are everywhere. Second, if you wanted to wire it up like a Silvertone, it will be a much more complicated wiring and construction job.
The best advice is to forget about trying to build yourself the perfect amp for your first amp. If you can't help yourself, pick one of those things off your list and try and implement it in your build. Remember, if it looks easy, then it's probably being done by someone who really knows what they are doing.

[ezra1]

Still talking Silvertone, I seek a 1482 output transformer