Silvertone 1481 mods...

[galaxiex]

I acquired this 1481 some time ago...





A little ratty but works ok.

First mod... new speaker and baffle...

[galaxiex]

Original speaker needs a re-cone...





Original baffle is quite rough...

[galaxiex]

I found some schematics on line but they all have the same mistake...



Re draw of the schematic...

[galaxiex]

Inside is fairly clean...

[galaxiex]

Added 3 wire power cord and clipped the death cap...



Unhooked the original cap can and added 3 new electro caps for the power supply...

Also added a speaker jack...

[galaxiex]

After much experimenting I ended up with these circuit mods...

Grid stoppers R3, R7, R11

Bypass caps C2, C5

Compare to original schematic redraw above...



For reference:
B+ 275V
Screen 260V
Pre 160V

HTR 6.4 AC

The mods turned this amp into a distortion monster...

Maybe not everyone's cup of tea, but I like it.

The grid stoppers are ABSOLUTELY necessary, as the amp will squeal and oscillate without them.

Sorry no sound clips, I have no way to record it.

Pic of the mods...

[galaxiex]

Now I'm looking for an 8 ohm output transformer as the original died, (truthfully, I damaged it) so I installed a Champ replacement TX that is 3.2 ohm.

The Warehouse speaker is a 4 ohm, but I'd like to be able to plug this into an 8 ohm cab.

Also 8 ohms would give me more options for the in-cab speaker.

Any suggestions for an 8 ohm output Tx?

Thanks!

[g1]

I have a mulched silvertone chassis around here somewhere. I think the tx's are ok. Not sure if it's single ended though. I'll check tomorrow.

[galaxiex]

Thanks g1.

[mozz]

Some of the Silvertones (or was it Airlines?) had a 4 and 8 ohm output, the unused wire was left hanging.

[g1]

Sorry, what I have was a 1472 (push-pull with 6V6's).

[galaxiex]

Sorry, what I have was a 1472 (push-pull with 6V6's).

Thanks for checking.

I have ordered a Mojo 771 Tx.

[olddawg]

I recently sold a ratty (but completely functional.. even the reverb worked) 1484 w/ the original speaker cab for $400. They are a one trick pony.... but they do that trick fairly well. The guy that bought it loved it. (I remember putting lots of them in the dumpster because they weren’t worth returning at the time, lol) If there is room I would suggest putting a 12” Eminence in it. Then you can use a tube screamer without cooking the voice coil and have a bit of bass response. Thinking that you will get better performance with a Mojo transformer seems a bit optimistic to me.. but whatever floats you boat.

[galaxiex]

I recently sold a ratty (but completely functional.. even the reverb worked) 1484 w/ the original speaker cab for $400. They are a one trick pony.... but they do that trick fairly well. The guy that bought it loved it. (I remember putting lots of them in the dumpster because they weren’t worth returning at the time, lol) If there is room I would suggest putting a 12” Eminence in it. Then you can use a tube screamer without cooking the voice coil and have a bit of bass response. Thinking that you will get better performance with a Mojo transformer seems a bit optimistic to me.. but whatever floats you boat.

The Mojo transformer is so I can use 8 ohm speakers or plug the amp into an 8 ohm cab.
More options are available in 8 ohm speakers, compared to 4 ohm.

With the 3.2 ohm Champ Tx that is in there now, it doesn't like an 8 ohm load.

[olddawg]

The Mojo transformer is so I can use 8 ohm speakers or plug the amp into an 8 ohm cab.
More options are available in 8 ohm speakers, compared to 4 ohm.

With the 3.2 ohm Champ Tx that is in there now, it doesn't like an 8 ohm load.

Yeah... I get that. I just meant there is pricy and pompous iron out there. If you like it.. that’s what matters.