Simple radio using PM1 PM2 valves - UK Vintage Radio Repair and Restoration Discussion Forum

jay_oldstuff · 23rd Feb 2009, 11:08 pm

Hi all, been rumageing round in my boxes of valves and have uncovered a coupple of mullard PM1 and PM2 valves and fancy having a go at makeing a simple homebrew radio with them. can anyone sugest some curcuits that would work with these valves,
i have plenty of circuits from the 50's for one and two valve sets but all use 50's valves and i fancy having a go at something 20's/30's. did any sets from this era use a resistive reaction controle rather than a veriable cap? i am planning to use bits from the junk box for this set, i have a nice vintage verable cap for tuneing but nothing suitable for a reaction controle.

Jay

KeithsTV · 24th Feb 2009, 2:02 pm

Here's a picture of the inside of my BC3250, which I'll get round to fixing one day. It can use PM1 and PM2 valves. I've drawn out the circuit which I can post when I get home. The reaction is controlled by the variometer and the variable resistor is to contol the filament current.

Keith

jay_oldstuff · 24th Feb 2009, 8:04 pm

Thanks the circuit would be most welcomed.
i would'nt mind finding some one valve circuits from this era too i'm guessing there should be some good circuits in old coppies of practical wireless and the like but my earliest copy is 1941.

Jay

KeithsTV · 24th Feb 2009, 8:20 pm

Here's the hand drawn circuit. The transformer has a turns ratio of approx 3:1.
The tuning cap has a value of approx 500pf fully closed and the tuning coil has an inductance of approx 110uH. The reaction coil inductance is approx 48uH.

There was an article in PW on building a vintage type radio which I posted here. May be worth looking at.

https://www.vintage-radio.net/forum/...ad.php?t=35620

edit Just found this circuit in a book I'd forgotten I had!

Keith

Hunts smoothing bomb · 24th Feb 2009, 9:03 pm

Hi Jay,

Here is the link for the set I built a few years back, it uses a resistive reaction and works very well

https://www.vintage-radio.net/forum/...ead.php?t=5759

All the best.

Lee

jay_oldstuff · 24th Feb 2009, 9:23 pm

Many thanks chaps, some stuff there for me to look through. I've also just bought some early 30's bound volumes of wireless world hopefully some good early circuits in there, I'll let you know when they arrive.

Jay

jay_oldstuff · 2nd Mar 2009, 12:13 am

ok chaps had a play tonight and i think i have come up with what can only be the simplest one valve receiver possible, it uses one valve, (a PM2) the only cap in it is the tuneing cap no resistors a coil out of the junk box with two windings on it one about 22 micro henries and one about 150 micro henries, and an old earphone of about 30 ohms and 100ft of wire for an arial. and it works quite well, only reveveing a coupple of stations and quite faint as there is no amplification but still it works, next i am going to rig up an af section.
this is grate fun.
Jay

Robert-UK · 3rd Mar 2009, 1:14 pm

Just picked up on this thread.

The attached pages describe what I think is just about the simplest possible one valve receiver with reaction. It should be OK with almost any battery triode valve. I've always been surprised at just how well sets like this can work!

I must confess to being the author of the 1980 PW article referred to in the thread https://www.vintage-radio.net/forum/s...ad.php?t=35620
(but my excuse is I was a lot younger and more inexperienced then).

Robert

jay_oldstuff · 3rd Mar 2009, 8:44 pm

Many thanks for posting that circuit, i think i'll have a bash at that one before progressing two a two valver.
happely after a chance conversation with a collegue at work i've just been given a box of old radio componients which include a couple of reaction condensors plus a coupple of interstage transformers all look early 30's in vintage.

Jay

23rd Feb 2009, 11:08 pm	#1
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Simple radio using PM1 PM2 valves Hi all, been rumageing round in my boxes of valves and have uncovered a coupple of mullard PM1 and PM2 valves and fancy having a go at makeing a simple homebrew radio with them. can anyone sugest some curcuits that would work with these valves, i have plenty of circuits from the 50's for one and two valve sets but all use 50's valves and i fancy having a go at something 20's/30's. did any sets from this era use a resistive reaction controle rather than a veriable cap? i am planning to use bits from the junk box for this set, i have a nice vintage verable cap for tuneing but nothing suitable for a reaction controle. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

24th Feb 2009, 2:02 pm	#2
KeithsTV Nonode Join Date: Aug 2007 Location: South Bradford, West Yorkshire, UK. Posts: 2,573	Re: Simple radio using PM1 PM2 valves Here's a picture of the inside of my BC3250, which I'll get round to fixing one day. It can use PM1 and PM2 valves. I've drawn out the circuit which I can post when I get home. The reaction is controlled by the variometer and the variable resistor is to contol the filament current. Keith Attached Thumbnails

24th Feb 2009, 8:04 pm	#3
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Simple radio using PM1 PM2 valves Thanks the circuit would be most welcomed. i would'nt mind finding some one valve circuits from this era too i'm guessing there should be some good circuits in old coppies of practical wireless and the like but my earliest copy is 1941. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

24th Feb 2009, 9:03 pm	#5
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: Simple radio using PM1 PM2 valves Hi Jay, Here is the link for the set I built a few years back, it uses a resistive reaction and works very well https://www.vintage-radio.net/forum/...ead.php?t=5759 All the best. Lee __________________ Lee

24th Feb 2009, 9:23 pm	#6
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Simple radio using PM1 PM2 valves Many thanks chaps, some stuff there for me to look through. I've also just bought some early 30's bound volumes of wireless world hopefully some good early circuits in there, I'll let you know when they arrive. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

2nd Mar 2009, 12:13 am	#7
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Simple radio using PM1 PM2 valves ok chaps had a play tonight and i think i have come up with what can only be the simplest one valve receiver possible, it uses one valve, (a PM2) the only cap in it is the tuneing cap no resistors a coil out of the junk box with two windings on it one about 22 micro henries and one about 150 micro henries, and an old earphone of about 30 ohms and 100ft of wire for an arial. and it works quite well, only reveveing a coupple of stations and quite faint as there is no amplification but still it works, next i am going to rig up an af section. this is grate fun. Jay Attached Thumbnails __________________ The light at the end of the tunnel is probably the headlight of an oncoming train

3rd Mar 2009, 8:44 pm	#9
jay_oldstuff Octode Join Date: Jan 2005 Location: Hyde, Greater Manchester, UK. Posts: 1,074	Re: Simple radio using PM1 PM2 valves Many thanks for posting that circuit, i think i'll have a bash at that one before progressing two a two valver. happely after a chance conversation with a collegue at work i've just been given a box of old radio componients which include a couple of reaction condensors plus a coupple of interstage transformers all look early 30's in vintage. Jay __________________ The light at the end of the tunnel is probably the headlight of an oncoming train