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Registered Member #1316
Joined: Thu Feb 14 2008, 03:35AM
Location: Cambridge, MA
Posts: 365
The GU-5b is not cheaper when you factor in shipping. I also belive someone was reporting that the shipping to the USA is rather rough on the tubes and can mess up the internals.
Also for those huge tubes the filament transformer becomes a problem. My 3cx5000 has a 7.5v 75 amp filament You can run the Gu-5b at 60 Hz, but you might want to try a big lead acid battery....
Registered Member #1403
Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968
Paying hundreds of dollars for some "NOS" tubes just because you want the 572B is a waste of money.
In my opponion its better to find the cheapest dollar to output triode on ebay or a localham fest, at ham fests you will get good stuff very cheap.
Experiment with that first and then build a new, big fine VTTC when you have the experience to make the right choices regarding tubes, transformers, capacitors, because the bigger the more expensive.
If you go with a too expensive build to start with and find out that you do not have the money for the complete build you might go with lower cost items that will decrease the end result. For a first it also does suck to destroy the good parts when learning :)
Registered Member #1225
Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253
Mads Barnkob wrote ...
Paying hundreds of dollars for some "NOS" tubes just because you want the 572B is a waste of money.
In my opponion its better to find the cheapest dollar to output triode on ebay or a localham fest, at ham fests you will get good stuff very cheap.
Experiment with that first and then build a new, big fine VTTC when you have the experience to make the right choices regarding tubes, transformers, capacitors, because the bigger the more expensive.
If you go with a too expensive build to start with and find out that you do not have the money for the complete build you might go with lower cost items that will decrease the end result. For a first it also does suck to destroy the good parts when learning :)
Agreed. This is the best... No, it is they ONLY way to go for a beginner. My Chinese tubes have always worked, but this damned GU-81M seems to have been dead upon arrival, though i do not think it was China made.
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NOS 572b vs. chinese remake
You can run the Gu-5b at 60 Hz, but you might want to try a big lead acid battery....
