Home Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

I'm back...

Sorry I didn't respond sooner - I'm in the midst of moving and life has been hectic! I'm seriously behind on posting projects to my website, and probably won't catch up till the summer.

I originally tried the traditional cathode bias resistor on the first section, but the tube-to-tube variation was enough that I had to use a potentiometer or trim the value to each tube. The NiMH fix'd the problem nicely and is inexpensive. I have a pair of AA's in battery holders under the chassis.

As a side benefit the batteries charge nicely in the circuit and I've swapped them out when I needed batteries for something in my office.

My power supply is a 560vct transformer to a 5V4G. There is a CLC filter with a common 40uf cap, then separate 12H/390 ohm chokes to each channel, with a second 50uf cap per channel. It's a strange design based on what I had lying around but sounds fantastic. The amp is as quiet as any I've built.

There is no decoupling between the sections as Dave Slagle points out. Bob Danielak had suggested removing the decoupling in a previous design and I like the sonics better this way. I don't know why (?phase issues?) but it images better.

I'm glad others are enjoying the circuit!





This post is made possible by the generous support of people like you and our sponsors:
  McShane Design  


Follow Ups Full Thread
Follow Ups
  • I'm back... - Gary Kaufman 04/12/0209:16:22 04/12/02 (0)


You can not post to an archived thread.