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In the Forum: Melquiades Amplifier
In the Thread: Gas voltage reference 0A2 tubes.
Post Subject: Re: 0A2 tubes.Posted by guy sergeant on: 8/21/2005
National is the brand name of Richardson Electronics http://www.rell.com/
They buy and have bought tubes from factories all over the world and rebranded them 'National'
When I worked for a UK based tube amp manufacturer some 10 years ago we had a couple of pre-amps using OA2's in shunt regulator circuits. These (physically shorter than standard) OA2's came from Richardson and did work very well being both quiet and reliable. However those we used had silver coloured pins and were 'new' production, I believe from China. The compact glass envelope and printing looks similar though.
Can't be any more help I'm afraid.
best rgds,
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