Fairchild 670 Sola Constant Voltage Filament Transformer Part ID

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Matt D

Member
Joined
Feb 22, 2011
Messages
21
Does anyone here know the catalog and/or part number for the Sola Constant Voltage Filament Transformer used in the original Fairchild 670?  I came across a Sola in my shop that looks like the one in gunshot photos of the 670.  It is Cat. No. 20-02-015, 95 to 130v in, 6.3v out.  I understand these are known to fail so if I have the right part I figure I probably ought to get it into the hands of an original 670 owner. Thanks.
 
Also, anyone know the best way to test one of these?  Can I just hook it up to ac on the primary and measure the secondary for the correct voltage?
 
you might have to hook up a tube with a 6.3 heater to check that thing,

wall voltage back east was all over the place when those Fairchilds were built,

but now there is really no need for those constant voltage transformers,

however, a serious 670 owner will want one to keep the vintage value up,

a studio owner would probably just buy a 6.3 heater transformer  as those things use to blow up quite a bit,

i use to have the part number for the 670, can  not seem to find it,  will keep looking,

cj
 
wow, cool photo!  looks like a 660, built by Rein,

FYI he told me that the reason for the Sola was to protect the 6386 tubes as they were the most important, and stabilizing the heater voltage keeps the matching up to snuff as when you increase heater voltages, one tube might start conducting more than the other,

 

Latest posts

Back
Top