single transistor projects?

[Allison]

>
>Subject: Re: single transistor projects?
>   From: woodelf <bfranchuk at jetnet.ab.ca>
>   Date: Wed, 21 Mar 2007 19:28:29 -0700
>     To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Tony Duell wrote:
>
>> 
>> These days, you can get 9V (PP3, 006P, 6F22, whatever you call them) 
>> batteries very cheaply in the 'Everything's a pound' shops (I assume you 
>> have similar shops that sell all sorts of things for a dollar a time). 5 
>> to 10 of those in series will work as B battery, of couse.
>
>Well you can still buy a B battery here on this side of the pond.
>http://www.tubesandmore.com/

Its way OT but I run a RCA tube portable off 10 9V and 4 "C" cells
and it's very satisfactory.  I took the old battery skin (cardboard label)
and made a wood box inside of it to hold the batteries so it even looks 
like the real thing.  Besides being the best AM broadcast radio I have
it's an attention getter.  Runs for about 20 hours on alkaline C cells
and the 10 9V batteries usually outlast 3 to 4 sets of C cells.

>> Personally, I'd use a mains supply. a 30V transformer (15-0-15, ignoring 
>> the centre tape or a pair of 15V windings in series) feeding a voltage 
>> doubler rectifier (2 diodes, 2 capacitors) will give about 85V, ideal for 
>> most 'battery' valve circuits.
>
>They also sell a power pack kit too for small radios.
>I suspect if you dig around over there you can scounge up
>a better power supply, for the simple reason parts are whole
>lot cheaper now than in one's youth.

I have a PS I did using power mosfets and a tapewound toroid
I wound up. Full wave bridge and filter. Also it's adjustable 
and regulated from 80 to 200V which makes it ideal for small
tube projects (power limit is ~40W).


Allison