Phil, Ensure that you are using FR4 laminate or better. The cheaper Phenol laminates can easily "carbonise" if you have a single arc over. You get micro thin carbon tracks on the laminate between your copper and it is very difficult to find and repair. The only way I found to repair these hairline carbonised cracks is to drill holes in the to break up the carbon tracks.
Also, separate the PSU and the amp. I managed to suppress a lot of 50/100Hz humming by using toroidal transformers. Also, try finding the thickest possible FR4. That will reduce microphonic effects from the amplifier. //Dan On Friday 16 January 2009 10:48:41 electric_phil wrote: > Thanks to your prompt reply, Dan ... > > I'm working too on electron tubes, for a guitar amp ... :-), and > really need to seperate "the two worlds" ... > > So, I'll try your method promptly ...;-) > > Cheers, Phil > > -- In [email protected], Dan Andersson <d...@...> wrote: > > I'm having retro relapses occasionally and revert to doing electron > > tube > > > designs but still using PCB's. > > > > The simplest solution is to separate the "infrastructure" schematic > > from the > > > PCB schematic and define proper connectors where the two "worlds" are > > interconnected. > > > > This way, you have the netlist support for the PCB but you are on > > your own for > > > the rest. You really don't want to mix the two "worlds" except when > > doing DRC. > > > //Dan, M0DFI -- [email protected] [email protected] -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG v1.4.9 (GNU/Linux) mQGiBEkKSGERBADUIV5fUHZ2wDflx0EamVRfSQmP6k05WyB5v8d5+SmUimAkZ5qJ M/s2YEYngxfTwlbWvIOZ7JsIobtPwjVPiXZv2VQE26eKv2nSW1Hrl4Ct1kaepRO1 Lu6cc82E65soWxU+0zCoZyLTWS/6lcPfd38SIWo6bGCLe1epZxp8uNjXIwCgmL6U kfRn9xYyyua01MTkjnjApVUD/jNRy7JCRflvrWLdmqLybSyeyvfBKsYqfAvK53yo qtbrSvHzMfGDHciHmNZik422rVl9AJIObzZ9w6/LcaM4jeqUSbCMmabeLkE7hZPk MpsGSUPrwmFxN4eU7cGC3AjBDdwi+rEQGSauIjkPwx0KMk6sF5ZhtyM2xdoQmlBr FFnfBADH94kOU1kUN6rNbfjgLRanzTKAmWM91Jdhj3zWYYvgEKSK1y8o+AizXqvk bmx0c/GSqR8rfscWivTfxIVYeTw/sTtQ9WGUkL9hb2rU4ULHqNhZED6QMMFPGo2V cpgu1JnoyZPSUN3u3KTdI0mBCIcw0RNv9SJzM71zcfEt9kio3bQjRGFuIEFuZGVy c3NvbiA8ZGFuQGFuZGVyc3Nvbi5jby51az6IYAQTEQIAIAUCSQpIYQIbIwYLCQgH AwIEFQIIAwQWAgMBAh4BAheAAAoJEMORX6DwHoOEDbUAni7itZJ5GbozkstqS9MN 3e5uqkcTAJ9CxfvBQFtoY2277urGOxAC1OjkbrkCDQRJCkhhEAgAyFU58VGU5XW5 /kQIXquBDmbGUjX9l/enrmfJgXgr7BCyKgKSAbFQPYSo1ED2p6xWbh3s4k4GfAx2 4M/j7M3KxRp6rHfCN1dRL7b229cveRymUzx1Sa4oBwPkJufi0svLcwPJ096ENh// 0C7IxfY3GR3k0a2ncWn2J8fh78lraVugujpbl+5thei0m0LR6ZqLP/fU+0PGzeHD J2xHO4v47o+gMpDglkWRlL2t+SZ/YXCO5IGSRyxsecR3pAGcrDcyLtkqv8P3+57z Z/kIlRja6I8SW+uBbj/mCIfIpJcv6n9cWpJnvdDG5XISaocznNyMUhSiGgfML+Y2 x853A74ZbwAECwf8DdzpgVU1vLcMZG3BrnjnG8VXTHDucs94JxhtmGn5PKmA/IZS 0T/sdLBJMZ6oC2s/DjFJ+1Gphacp19eq01hdkyB+1GPTB5jYqFNz8Lmfekpv3D53 3haUfYns3Z2q4HAHPftrpUQ1p5+pmPfts0mppwGoCO/XYCEb5prpAbZRbeE/V0td T3cd3nLRka5L4PieRLS+RoYRLyKPO1EB3joup+Rqj5CG82I+t4wcP5UmsBgJc4A9 zCJ1RhLlyU1blaQHb12M0EuEsJutPkZxReX5YCuFFAoQf4LLDp+LDIJ62Ec9g9An VlJjnF8f0Fiq34zbixNEFJf0csJ0h1sCQfdh9ohJBBgRAgAJBQJJCkhhAhsMAAoJ EMORX6DwHoOEVlIAn1gL250p8OgmWUJ3Oq24oAJjCgkNAJkBfHsz5MVAfW2rYs7Y FE1sfMyP4g== =cRBJ -----END PGP PUBLIC KEY BLOCK-----
