In message , Stewart
Pinkerton writes
On Sun, 8 Jan 2006 09:32:40 +0000, Chris Morriss
wrote:


You're quite right, I've never seen the internals of a Quad II. I am
most surprised that it had components on a pcb though!

You shouldn't be. A printed circuit board ensures good consistency of
performance in production, and reduces parisitic inductance. Not a
matter of 'mass production', but of better engineering.


All the stuff I design for work is on nice 4-layer FR4 glass-fibre pcbs
(and nearly all the parts are SM), but they are a far cry from the
single-sided SRBP boards that I imagine are in the old Quads.

The problem with pcbs with so few components on them, when they are
connected to so many large wire-ended devices, such as the
chassis-mounted valve sockets and the transformers and electrolytic
smoothing caps is that they tend to increase the amount of wiring
required and certainly doesn't reduce the parasitics compared with a
'Radford-like' construction on high quality ceramic tag-strips.

Perhaps on the old Quad, the valve sockets are on the pcb. In which
case then the parasitics are reduced, but in my experience, valve bases
on an SRBP pcb are very bad news for long term reliability.
--
Chris Morriss