Bogner Shiva 12V supply???

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Smokebreak3
Posts: 59
Joined: Wed Dec 28, 2022 12:45 am

Bogner Shiva 12V supply???

Post by Smokebreak3 »

What are you guys using for replacements? I've got one here with a burnt up screen resistor(unrelated??), but proper DCV everywhere. However the amp has no 12V supply, which apparently is for switching, heaters, pilot.
I see one on a UK site but figured I'd check here first.

Also of note, this screen resistor that burnt up clearly was replaced before, but the same 10 year old tubes are in here . Apparently the failure mode of this amp was motorboating, then silence
Smokebreak3
Posts: 59
Joined: Wed Dec 28, 2022 12:45 am

Re: Bogner Shiva 12V supply???

Post by Smokebreak3 »

Smokebreak3
Posts: 59
Joined: Wed Dec 28, 2022 12:45 am

Re: Bogner Shiva 12V supply???

Post by Smokebreak3 »

Ok thanks. I went with the one I linked as I saw it mentioned in a repair vid, and it has the exact same connections as the original failed one.
FourT6and2
Posts: 267
Joined: Wed May 31, 2017 11:11 pm

Re: Bogner Shiva 12V supply???

Post by FourT6and2 »

The one you linked to is a 120-watt, 10A supply. Is that what the Shiva needs? That's a bit of an overkill to be used in a guitar amp...

EDIT:
Is the video you found? I guess the original unit is indeed quite powerful haha. Other amps I've seen that use 12V SMPS are more like 20W and maybe 1.8A at most.

https://www.youtube.com/watch?v=7RCZFoqvgPA
Smokebreak3
Posts: 59
Joined: Wed Dec 28, 2022 12:45 am

Re: Bogner Shiva 12V supply???

Post by Smokebreak3 »

Yep that's the one, apparently it's a semi-common issue w the amp if Rheinhardt himself tested it and found it to be suitable.
As I understand , this decision was made in some point in production to lighten the entire amp, as originally there was just a 12V winding on the PT, which made the amp heavier.
I can confirm that this 2x12 combo is stoopid heavy, like 10lbs more than an ac30 and just as awkward. Also, the reverb tank is literally is exposed in the back of the amp and sticks out a bit.
I guess they went BACK to the 12V winding at some point, likely becasue these damn supplies failed and/or whined
FourT6and2
Posts: 267
Joined: Wed May 31, 2017 11:11 pm

Re: Bogner Shiva 12V supply???

Post by FourT6and2 »

Smokebreak3 wrote: Fri Sep 05, 2025 2:33 pm Yep that's the one, apparently it's a semi-common issue w the amp if Rheinhardt himself tested it and found it to be suitable.
As I understand , this decision was made in some point in production to lighten the entire amp, as originally there was just a 12V winding on the PT, which made the amp heavier.
I can confirm that this 2x12 combo is stoopid heavy, like 10lbs more than an ac30 and just as awkward. Also, the reverb tank is literally is exposed in the back of the amp and sticks out a bit.
I guess they went BACK to the 12V winding at some point, likely becasue these damn supplies failed and/or whined
Yeah, SMPS shouldn't be in a guitar amp IMO. They cause more headaches than they solve.

I just had a frustrating issue with the SMPS in my Hiwatt. The amp was humming like crazy and nothing fixed it. Thought it was bad ground, cold joint, bad tubes, bad socket, bad cap, bad filter, et. Turned out to be the SMPS.
Smokebreak3
Posts: 59
Joined: Wed Dec 28, 2022 12:45 am

Re: Bogner Shiva 12V supply???

Post by Smokebreak3 »

That was a success. Note for any future techs reading, the ACL and ACN on new unit was opposite of what the original was. TBH I'm not even even sure if this is the original unit, or if it was replaced in the past.
Nonethless, the new unit is clearly labled on the underside, and the Black wire feeding the original unit is indeed the ACL as expected.
The 4 wires on the output match what was on the original unit. There were no headers on mine
Now to work on what else is wrong with this thing haha
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