On Apr 22, 2:48=A0pm, "Dave.H" <the19...@googlemail.com> wrote:
> On Apr 23, 3:23 am, Don Bowey <dbo...@comcast.net> wrote:
>
> > On 4/22/08 8:54 AM, in article
> > 90e54e91-01ec-4bc6-9e68-3662d7e70...@b64g2000hsa.googlegroups.com, "Dave=
.H"
> > The schematic is incorrect, so it's hard to tell what's up without guess=
ing.
> > Also, no tube type is shown.
>
> I'm planning on using a 1C5GT tube.
Here's what I think. I don't claim it's the only way, or even the
best way, it's just what I would be inclined to do. Take the money
you would spend on the 1:3 interstage transformer and spend it instead
on a power transformer and build yourself a battery eliminator that
will give you 90-110V to run a power output stage. Tap it down to run
your other stage(s). If you want, add a low voltage regulated DC
output for filaments/heaters. Then just use RC coupling between the
detector and the AF stage.
That's unless you were planning to use the radio away from AC power,
in which case ignore everything I said.
Mike
Reply by Don Bowey●April 22, 20082008-04-22
On 4/22/08 10:40 AM, in article
4e96a299-af7d-419e-a6c8-e7053078c38e@c65g2000hsa.googlegroups.com, "Mike
Silva" <snarflemike@yahoo.com> wrote:
> On Apr 22, 1:23�pm, Don Bowey <dbo...@comcast.net> wrote:
>> On 4/22/08 8:54 AM, in article
>> 90e54e91-01ec-4bc6-9e68-3662d7e70...@b64g2000hsa.googlegroups.com, "Dave.H"
>>
>> <the19...@googlemail.com> wrote:
>>> On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
>>>> Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
>>>> go with a regenerative radio. �Does not have to be the best, but needs
>>>> to drive at least 250 mW speaker, preferably 1 watt or more.
>>
>>>> Thanks, Dave
>>>> Australia
>>
>>> Going off topic a bit here, concerning the regen radio previously
>>> mentioned, that I've yet to build, there are some connections I'm not
>>> sure of, first is the A connection, this doesn't appear to be the
>>> antenna connection,
>>
>> The "A" on the top end of the coil is the antenna. �The "A" terminal strip
>> is the 1.5V filament battery + connection.
>>
>>> second is the B+ 1 1/5 v connection. �Do they mean
>>> A+ 1 1/5, even though it's not connected to the + filament pin?
>>
>> The schematic is incorrect, so it's hard to tell what's up without guessing.
>> Also, no tube type is shown.
>>
>> The lower grid in the tube schematic is drawn out of place. �It should be
>> drawn above the grid that is connected to the grid-leak R/C parts. �The grid
>> with the grid-leak parts is called the control grid. �The out of place grid
>> is, I' sure, a screen grid. �A screen grid requires a positive voltage, and
>> in *most* circuits it is provided by a suitable resistor from B+. �I don't
>> really understand what the "B+ 1 1/2 V" note is intended to mean, *unless*
>> it is the authors intention to denote it is 1.5V "B+" for the screen. �In
>> any case it indicates you should use a 1.5 V battery, connecting the +
>> terminal to the screen grid, and necessarily connecting the - terminal to
>> the E/B-/A buss.
>
> Actually the circuit is employing a trick that was sometimes used in
> low voltage applications. The tube control grid is connected to a
> small positive voltage to help accelerate the electrons towards the
> plate to obtain reasonable plate current, and the tube screen grid is
> then used as the circuit control grid. Unless you've run across that
> trick you'd be justified in thinking "what the heck?!"
>
> Mike
>
>
I had wondered about such a thing, but dismissed it. I need to try it and
compare the result with the more conventional use of the grids.
Thanks
Also, I should have caught the use of that extra 1.5V cell to boost the B+.
Reply by Dave.H●April 22, 20082008-04-22
On Apr 23, 3:23 am, Don Bowey <dbo...@comcast.net> wrote:
> On 4/22/08 8:54 AM, in article
> 90e54e91-01ec-4bc6-9e68-3662d7e70...@b64g2000hsa.googlegroups.com, "Dave.H"
> The schematic is incorrect, so it's hard to tell what's up without guessing.
> Also, no tube type is shown.
I'm planning on using a 1C5GT tube.
Reply by Mike Silva●April 22, 20082008-04-22
On Apr 22, 1:23=A0pm, Don Bowey <dbo...@comcast.net> wrote:
> On 4/22/08 8:54 AM, in article
> 90e54e91-01ec-4bc6-9e68-3662d7e70...@b64g2000hsa.googlegroups.com, "Dave.H=
"
>
> <the19...@googlemail.com> wrote:
> > On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
> >> Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
> >> go with a regenerative radio. =A0Does not have to be the best, but need=
s
> >> to drive at least 250 mW speaker, preferably 1 watt or more.
>
> >> Thanks, Dave
> >> Australia
>
> > Going off topic a bit here, concerning the regen radio previously
> > mentioned, that I've yet to build, there are some connections I'm not
> > sure of, first is the A connection, this doesn't appear to be the
> > antenna connection,
>
> The "A" on the top end of the coil is the antenna. =A0The "A" terminal str=
ip
> is the 1.5V filament battery + connection.
>
> > second is the B+ 1 1/5 v connection. =A0Do they mean
> > A+ 1 1/5, even though it's not connected to the + filament pin?
>
> The schematic is incorrect, so it's hard to tell what's up without guessin=
g.
> Also, no tube type is shown.
>
> The lower grid in the tube schematic is drawn out of place. =A0It should b=
e
> drawn above the grid that is connected to the grid-leak R/C parts. =A0The =
grid
> with the grid-leak parts is called the control grid. =A0The out of place g=
rid
> is, I' sure, a screen grid. =A0A screen grid requires a positive voltage, =
and
> in *most* circuits it is provided by a suitable resistor from B+. =A0I don=
't
> really understand what the "B+ 1 1/2 V" note is intended to mean, *unless*=
> it is the authors intention to denote it is 1.5V "B+" for the screen. =A0I=
n
> any case it indicates you should use a 1.5 V battery, connecting the +
> terminal to the screen grid, and necessarily connecting the - terminal to
> the E/B-/A buss.
Actually the circuit is employing a trick that was sometimes used in
low voltage applications. The tube control grid is connected to a
small positive voltage to help accelerate the electrons towards the
plate to obtain reasonable plate current, and the tube screen grid is
then used as the circuit control grid. Unless you've run across that
trick you'd be justified in thinking "what the heck?!"
Mike
Reply by Don Bowey●April 22, 20082008-04-22
On 4/22/08 8:54 AM, in article
90e54e91-01ec-4bc6-9e68-3662d7e70470@b64g2000hsa.googlegroups.com, "Dave.H"
<the1930s@googlemail.com> wrote:
> On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
>> Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
>> go with a regenerative radio. Does not have to be the best, but needs
>> to drive at least 250 mW speaker, preferably 1 watt or more.
>>
>> Thanks, Dave
>> Australia
>
> Going off topic a bit here, concerning the regen radio previously
> mentioned, that I've yet to build, there are some connections I'm not
> sure of, first is the A connection, this doesn't appear to be the
> antenna connection,
The "A" on the top end of the coil is the antenna. The "A" terminal strip
is the 1.5V filament battery + connection.
> second is the B+ 1 1/5 v connection. Do they mean
> A+ 1 1/5, even though it's not connected to the + filament pin?
The schematic is incorrect, so it's hard to tell what's up without guessing.
Also, no tube type is shown.
The lower grid in the tube schematic is drawn out of place. It should be
drawn above the grid that is connected to the grid-leak R/C parts. The grid
with the grid-leak parts is called the control grid. The out of place grid
is, I' sure, a screen grid. A screen grid requires a positive voltage, and
in *most* circuits it is provided by a suitable resistor from B+. I don't
really understand what the "B+ 1 1/2 V" note is intended to mean, *unless*
it is the authors intention to denote it is 1.5V "B+" for the screen. In
any case it indicates you should use a 1.5 V battery, connecting the +
terminal to the screen grid, and necessarily connecting the - terminal to
the E/B-/A buss.
On Apr 22, 1:14=A0pm, "Dave.H" <the19...@googlemail.com> wrote:
> I'll use the 2 watt IC amp I have sitting around, easiest option.
>
> =A0If I have this right, and usually I don't, I connect the plus end of
> the filament battery to the terminal simply marked "A", and a separate
> "C" battery to the B+ 1 1/5v connection. =A0Why is there only one
> connection for the bias battery?
>
> Will I get good lifetime out of a 9 volt transistor battery? I intend
> on using a "D" cell for the filament, as I do with my other regen
> radio (which BTW, you will find on Dave Schmarder's web page, very
> first radio on his tube radio page.
Wire up the batteries exactly as shown on the schematic at the bottom
of the page I linked (http://www.schmarder.com/radios/tube/
hikers1.htm). Yes, you should get good life out of your 9V battery.
Mike
Reply by Dave.H●April 22, 20082008-04-22
On Apr 23, 3:00 am, Mike Silva <snarflem...@yahoo.com> wrote:
> On Apr 22, 11:54 am, "Dave.H" <the19...@googlemail.com> wrote:
>
>
>
> > On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
>
> > > Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
> > > go with a regenerative radio. Does not have to be the best, but needs
> > > to drive at least 250 mW speaker, preferably 1 watt or more.
>
> > > Thanks, Dave
> > > Australia
>
> > Going off topic a bit here, concerning the regen radio previously
> > mentioned, that I've yet to build, there are some connections I'm not
> > sure of, first is the A connection, this doesn't appear to be the
> > antenna connection, second is the B+ 1 1/5 v connection. Do they mean
> > A+ 1 1/5, even though it's not connected to the + filament pin?
>
> > Link to the schematichttp://www.oldradios.co.nz/hikers/51hikers11.jpg
>
> "A" is the filament voltage, "B" is the plate voltage and "C" is the
> grid bias voltage (which is not present in the schematic you show).
> When you see things like B+1.5V and B+9V that's referring to taps on
> the B+ battery (many of them were made with such taps). Of course for
> B+1.5V you could also use a separate 1.5V battery. Here's a schematic
> that shows such a separate battery.http://www.schmarder.com/radios/tube/hikers1.htm
>
> BTW, the amplifier you're looking at won't give anywhere near 250mW,
> much less 1W. The specs for the tubes show that they just get to
> 250mW output at 90V B+. At the 18V given in the schematic you'll only
> be in the tens of mW. And also, you'll need an output transformer to
> connect the amplifier to a speaker.
>
> Mike
I'll use the 2 watt IC amp I have sitting around, easiest option.
If I have this right, and usually I don't, I connect the plus end of
the filament battery to the terminal simply marked "A", and a separate
"C" battery to the B+ 1 1/5v connection. Why is there only one
connection for the bias battery?
Will I get good lifetime out of a 9 volt transistor battery? I intend
on using a "D" cell for the filament, as I do with my other regen
radio (which BTW, you will find on Dave Schmarder's web page, very
first radio on his tube radio page).
Reply by Mike Silva●April 22, 20082008-04-22
On Apr 22, 11:54=A0am, "Dave.H" <the19...@googlemail.com> wrote:
> On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
>
> > Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
> > go with a regenerative radio. =A0Does not have to be the best, but needs=
> > to drive at least 250 mW speaker, preferably 1 watt or more.
>
> > Thanks, Dave
> > Australia
>
> Going off topic a bit here, concerning the regen radio previously
> mentioned, that I've yet to build, there are some connections I'm not
> sure of, first is the A connection, this doesn't appear to be the
> antenna connection, second is the B+ 1 1/5 v connection. =A0Do they mean
> A+ 1 1/5, even though it's not connected to the + filament pin?
>
> Link to the schematichttp://www.oldradios.co.nz/hikers/51hikers11.jpg
"A" is the filament voltage, "B" is the plate voltage and "C" is the
grid bias voltage (which is not present in the schematic you show).
When you see things like B+1.5V and B+9V that's referring to taps on
the B+ battery (many of them were made with such taps). Of course for
B+1.5V you could also use a separate 1.5V battery. Here's a schematic
that shows such a separate battery.
http://www.schmarder.com/radios/tube/hikers1.htm
BTW, the amplifier you're looking at won't give anywhere near 250mW,
much less 1W. The specs for the tubes show that they just get to
250mW output at 90V B+. At the 18V given in the schematic you'll only
be in the tens of mW. And also, you'll need an output transformer to
connect the amplifier to a speaker.
Mike
Reply by Dave.H●April 22, 20082008-04-22
On Apr 22, 2:12 am, "Dave.H" <the19...@googlemail.com> wrote:
> Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to
> go with a regenerative radio. Does not have to be the best, but needs
> to drive at least 250 mW speaker, preferably 1 watt or more.
>
> Thanks, Dave
> Australia
Going off topic a bit here, concerning the regen radio previously
mentioned, that I've yet to build, there are some connections I'm not
sure of, first is the A connection, this doesn't appear to be the
antenna connection, second is the B+ 1 1/5 v connection. Do they mean
A+ 1 1/5, even though it's not connected to the + filament pin?
Link to the schematic http://www.oldradios.co.nz/hikers/51hikers11.jpg
Thanks, Dave
Australia
Reply by Dave.H●April 21, 20082008-04-21
On Apr 22, 11:14 am, Tim Wescott <t...@seemywebsite.com> wrote:
> On Mon, 21 Apr 2008 09:12:56 -0700, Dave.H wrote:
> > Hi, I'm looking for plans for a 1 or 2 tube low voltage amplifier to go
> > with a regenerative radio. Does not have to be the best, but needs to
> > drive at least 250 mW speaker, preferably 1 watt or more.
>
> > Thanks, Dave
> > Australia
>
> I don't know what's available in Oz, but some ARRL or RSGB handbooks from
> the '40s, '50s or early '60s will give you tons of sample circuits.
>
> --
> Tim Wescott
> Control systems and communications consultinghttp://www.wescottdesign.com
>
> Need to learn how to apply control theory in your embedded system?
> "Applied Control Theory for Embedded Systems" by Tim Wescott
> Elsevier/Newnes,http://www.wescottdesign.com/actfes/actfes.html