|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
150.148.14.5
In Reply to: RE: Best is to Incorporate Control into the Build (pics) posted by Maxamillion on August 26, 2014 at 11:24:20
I know it is customary to gush over photos of other people's projects, but I cannot help saying that you've done beautiful work there. Can you show a photo of the fully assembled unit, including the front panel? What is the 9V battery doing? Thanks.
Follow Ups:
Here's the completed preamp.
The 9V battery applies grid bias to the 26. It is fed through the LL1676 input transformer secondary so that there is no need for a DC blocking cap in the grid circuit. It makes for a much cleaner sounding preamp; I tried it with a cap first (Duelund CAST, no less) and it sounds better without it. Here's a schematic:
Just for completeness, the 26 has a cascoded CCS on the plate, with the mu output of the CCS feeding Bent Audio (Slagle nickel core) autoformer volume controls at the output in a lossy parafeed configuration; the autoformers function as both volume control and output transformer in this arrangement.
Power supply is LCLC for plate and filament. B+ is regulated using CCS-fed VR tubes (0A3 +0D3 to get 225V). Filament is regulated using Rod Coleman regulators.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: