Astroid/Express OT question

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tsl602000
Posts: 103
Joined: Sat Mar 03, 2007 10:47 am
Location: Netherlands

Astroid/Express OT question

Post by tsl602000 »

Hi all,
I was wondering if anyone can tell me "how close" the Express and "Astroid" (K*met) OT's are.
I have a Toneslut OT in a wreck of which I changed the preamp to a Astroid/K*met. Although I like the amp, I wonder what'd happen if I change the Power amp section and filer board to a Astroid/K*met too.

Are the PT voltages of the Express and Astroid/K*met in the same range?

Thanks!
Sven
Posts: 137
Joined: Fri Jan 12, 2007 8:46 am
Location: Sarajevo

Re: Astroid/Express OT question

Post by Sven »

Greetings,

For the Asteroid amp design that appeared on this page this summer (the one with valve rectification, choke, touch switch,etc.), someone posted the following specs for PT and OT, which need to be confirmed and/or corrected:

Asteroid PT you want something along the lines of

365-0-365V @250-300mA;

3,15-0-3,15V @5–6A

5V @3A rectifier winding.

Bias winding on there, say 70- 80V (i.e. 365-0-80-365V @250-300mA)


Asteroid Output transformer (OT) is the same physical size as a 50Watt Marshall.

It was noted on the weber forum many moons ago that the pri. was like 5.8k - essentially a slightly larger Express OT with a different pri. imp. , more or less. there are plenty of options to try, all of which would give a slightly different tone.

Also, 5k2 and 6k6 Ohm OT primaries are used, with 6k6 Ohm primary favored.

end quote.
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tsl602000
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Re: Astroid/Express OT question

Post by tsl602000 »

Thanks for the info, Sven!
Sven
Posts: 137
Joined: Fri Jan 12, 2007 8:46 am
Location: Sarajevo

Re: Astroid/Express OT question

Post by Sven »

Greetings,

Well, this is the best I got, but these specs require CONFIRMATION from the members who know whether they are OK, or they need to be different. So, the question is still not answered firmly.

Sven
Roe
Posts: 1918
Joined: Thu May 31, 2007 2:10 pm

Re: Astroid/Express OT question

Post by Roe »

specs look good to me
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