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In Reply to: Differences between 300B and 2a3 tube posted by Khamsin on April 3, 2007 at 13:03:35:
Hi,You better ask such questions to Audio Asylum Tubes and SET asylums.
I had asked this before. Please follow the link below (if it shows up) and also do a search
300B or 2A3 in the tubes and SET asylums.The links are (in case they dont show below):
http://db.audioasylum.com/cgi/m.mpl?forum=tubes&n=169663&highlight=zuheyr&r=&session=
http://db.audioasylum.com/cgi/m.mpl?forum=set&n=41005&highlight=zuheyr&r=&session=
Greetings,
Zuheyr
PS I am using the Kit1, 300B and it is great!
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I', not saying "in the fly", but I think, if will be great that yo can choose from 2A3 to 300B just with a toggle................
just a though,
beto
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it can be done, but twould be fairly complex. 2A3 filaments require less voltage, but higher current. 300B plate require higher voltage. your toggle switch would have to be between two power supply boxes.
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Just to clarify the new Mains transformer that we use on the Kit1 is designed to support either a 300B or 2A3 triode . To make the switch requires changing the two wires going to the 5U4G from the 425 taps to the 325 taps - also we make a resistor change in the filament board so that the adjustable voltage regulator outputs 2.5V for 2A3 or 5V for 300B and the last change is the cathode resistors on the triode - we use 1K5 for the 2A3 and 1K8 for the 300B - So with about 10 minutes of soldering you can go between 2A3 and 300B!
Brian Smith
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Hi Brian,
thanks for your info!.
So, besides some resistors, for the old kit owners, need the new mains. Are this a Hammond special design for AN kits?
Regards,
Beto
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The new transformer is called the H301067 and is specially designed for AN kits for the 2A3 / 300b operation of the kit1 !
Brian
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Hi, is there any changes to the PSU resistors to the 5687 and 6SN7?