Hiwatt SA412 Schematic.

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gingertube
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Joined: Mon Nov 14, 2011 2:29 am
Location: Adelaide, South Oz

Hiwatt SA412 Schematic.

Post by gingertube »

Guys,
Don't usually get into these pages of Amp Garage.

Many years ago now I did a full restoration of a SA412 , I drew up the schematic as part of that job. I note that the SA412 is not on Huss'es site.
I thought to find that schematic trace and post it here but as usual any schematic draw that gets posted anywhere eventually ends up on somones site.
Mine has ended up here:
http://bmamps.com/Schematics/hiwatt/hiwatt_sa412.pdf

Accurate Schematic of the amp I restored with a couple of restoration notes.

For general EL34 Amp builders note the screen voltage 40V lower than the anode voltages - I'm sure that is part of that amps "Hiwatt Sound".

As the originator of that schemtic trace - Please feel free to use that schematic or post elsewhere as you see fit.

Regards,
Ian
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xtian
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Re: Hiwatt SA412 Schematic.

Post by xtian »

Wow. Lots of good stuff in there. Intrigued.
I build and repair tube amps. http://amps.monkeymatic.com
gingertube
Posts: 530
Joined: Mon Nov 14, 2011 2:29 am
Location: Adelaide, South Oz

Re: Hiwatt SA412 Schematic.

Post by gingertube »

I had another look at that schematic with the benefit of 10 + more years experience.

I think the screen supply could be improved for new builds.
For equal volatge sharing C6a and C5 should be the same value and then C6b -ve would need to go to 0V.
Obviously that would require separate C6a and C6b caps.
Cheers,
Ian
Stevem
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Re: Hiwatt SA412 Schematic.

Post by Stevem »

A lot of the Highwatt sound are those Partridge OTs, big lows and highs!!

A good buddy of mine has 5 of them and on the two he uses for gigs playing thru the stocker Fane drivers I had to bypass the plate resistor on one stage to kill off the ice pick highs he was getting with his strat!
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!😊

Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Matt D
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Re: Hiwatt SA412 Schematic.

Post by Matt D »

Thanks for sharing and taking the time to post your schematics over here!
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