Silvertone Meteor 1430 Amp

[angelodp]

Hi, I have this Silvertone 1430 Meteor amp. I am looking at Robinettes article on adding an Isolation Transformer. Just wondering if anyone has done that specific mod and could share a gut shot. I also see several Isolation transformers at Antique Electronics and not sure which one would be appropriate.
169RS 60VA 435 mA
169SS 90VA 650mA
169VS 175VA 1300mA

Any projects that actually did all this would be helpful.

Thanks Ange

[Stevem]

That silvertone model has a 1 amp fuse and was listed as running on 117 volts, so the math is easy, you need a transformer with a rating of at least 117 va
If there’s room inside the amps speaker area for this transformer then it should be a breeze to mount it in there and then wire it in.

[sluckey]

I would use the 169RS 60VA 435 mA transformer. The schematic shows 40W consumed from line. Fuses are often rated much higher than actual current draw.

[angelodp]

1430 Isoaltion T.jpg

Screen Shot 2021-12-14 at 2.23.27 PM.png

I have a schematic re-work, I tried to follow the prompts from Robinette, somehow I think I may have it wrong?

Thanks for looking and commenting.

A

[sluckey]

(EDIT... attached correct schematic)

I would do it like this...

[angelodp]

Thanks Steve, very simple and elegant as always. So I don't have to pull the deathcap and R just jumper over right?

Thanks Ange

[angelodp]

Steve, I just realized that what I have is a 1390 amp, but when I look at the Silvertone world they seem to indicate that the 1390 and 1430 are one in the same, as is the 1330.

A

[imjonwain]

I have a Silvertone 1448 case amp I plan to add an isolation transformer and fuse into. I think all those no PT amps are pretty similar.

Also Triad makes some similar transformer for around $16. Not trying to take money away from Hammond either though.

triad n-68x

[angelodp]

Just looking at that now. Would that be fine for this 1390/1430 amp?

A

[imjonwain]

It's a 50VA isolation transformer and the schematic says 40W input so it should be fine. From the tubes in this thing it should only draw a couple hundred mA.

[angelodp]

Cool, thanks,

https://www.youtube.com/watch?v=jXf6xf7i2Es&t=1341s

Nice vid on Isolation T install and some mods

[angelodp]

Question, where is the heater transformer? On my amp those wires go to the Speaker transformer.

[martin manning]

Could be a version without the transformer for V1. Are all the heaters in series across the line?

[sluckey]

Question, where is the heater transformer? On my amp those wires go to the Speaker transformer.

The 1430 is different from your amp. All three tubes have their filaments in series with a power resistor connected to the fuse holder. Look at yellow wire.

[angelodp]

To be clear the above image with text is from the Robinette site, now here are pics of my amp. No heater transformer, rather a power R.