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In Reply to: Try a 12A4 posted by danlaudionut on March 26, 2007 at 18:11:23:
any Schematic you can show me ?
is has 12A4 better Sound Quality than 417a ?what's ATC ?
Follow Ups:
12A4 sounds like a 12B4 - same family
Use the same circuit as the 12B4.
ATC = Autotransformer Volume Control
Edcor makes a cheap one :
http://www.edcorusa.com/products/transformers/ex/ex-103.html
Dave Slagle and Silk make good ones :
http://www.intactaudio.com/
http://www.sacthailand.com/
depends where you are ...
As far as schematics - what is you 12B4 design?
I did not design my 12B4, I never can design a thing :)as far as I know it only use 7 komponen, no Transformer.how big is the ATC ?
well if it's the same SQ of 12B4, then I still prefer better than that.
any idea ?
If you have poor sound quality from a 12B4
then the design must be really bad.
If it's dry sounding then current is too high
and if it's too warm it's too low current.
The 12B4 and 12A4 have GREAT sound quality!
Mine are choke loaded with ATC output.
If you open up your preamp and give me
the B+ and the cathode resistor value and
voltage across it I might be able to help.
You probably have a poor operating point.
You can post me direct for more info.
(Just click on danlaudionut above)
Who made it?
Dan, What current would you recommend for the 12B4? My linestage runs at 21ma and it is dark sounding.
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