Do valve radios use more power?

[startreksteve]

Im thinking of buying an old Eddystone 830 valve radio, do they use a lot more power than say a Yaesu FRG-7? Im also a bit concerned about the safety aspect, would it be a big job to convert to a more modern/safer power supply?
Steve

[ms660]

Originally Posted by startreksteve

Im thinking of buying an old Eddystone 830 valve radio, do they use a lot more power than say a Yaesu FRG-7?

Yes, look at the power consumption specs:

http://eddystoneusergroup.org.uk/Man...3%20Manual.pdf

http://www.repeater-builder.com/yvs/...nst-manual.pdf

Lawrence.

[Cobaltblue]

The FRG7 is a solid state receiver and uses around 14W

The 830 uses a lot of valves the filaments alone consuming more than that.

Not sure what you think is unsafe about the 830 supply?

Cheers

Mike T

[Nuvistor]

The user manuals state
FRG7 14VA
830. 85VA

So not entirely accurate but that’s similar to a 14watt light bulb and a 85watt light bulb.

Apologies Crossed posts.

[paulsherwin]

Valve equipment will always be more power hungry than solid state for an equivalent level of functionality, simply because valves need cathode heaters.

[broadgage]

There might be the odd exception, but in general valve equipment will use more power than solid state equipment of similar performance.

Domestic valve radio receivers tend to be among the worst the low voltage heater supply is generally obtained by a dropper resistance from the mains, thereby wasting most of the energy. A heater transformer would be more economical but adds to the cost and prohibits operation from DC mains, no longer a consideration, but was important decades ago.

Consider a 0.15 amp heater chain with five valves each dropping 6.3 volts.
Heater wattage is about 5 watts, or from a transformer perhaps 7 watts after losses. With a dropper, the heater consumption will be about 36 watts, plus a couple of watts for the HT.

Decades ago this was seldom considered for several reasons, firstly a radio set was expensive, and if you afford one then you could presumably afford the electricity to run it.
Secondly other pastimes were limited, reading was popular for both education and entertainment. So 40 watts for a valve radio was less than a 60 watt lamp to read by. And of course a whole family could listen to the radio, still only 40 watts. But four people reading might need several 60 watt lamps, or a centrally placed 150 watt lamp.

And for both news and entertainment, listening to the radio was a lot cheaper than a visit to the cinema, which probably involved bus fares as well as the ticket price.

[startreksteve]

Originally Posted by Cobaltblue

The FRG7 is a solid state receiver and uses around 14W

The 830 uses a lot of valves the filaments alone consuming more than that.

Not sure what you think is unsafe about the 830 supply?

Cheers

Mike T

Im thinking of a live chassis in a metal case with no earth..
Surely not as safe as a modern rig, I have a Cossor Melody Maker which is in a wooden case so safer I think.

Steve

[ms660]

Originally Posted by broadgage

plus a couple of watts for the HT.

And the rest...

Lawrence.

[Cobaltblue]

As far as I know (could be wrong) all versions of the 830 have a mains transformer so are not live chassis.

I think the 840 is AC/DC

Cheers

Mike T

[Radio Wrangler]

From Eddystone 830 manual, mains consumption is 85VA

Looking at HT and LT currents there is 70.24W but there is transformer and rectifier losses to include, so 85VA in this case likely means 85W.

The 830 has full mains transformer isolation, so the chassis is earthed.


The FRG-7 manual says it uses 14VA and can run off of internal dry cells. So 14W is believable.

So yes, the Eddystone uses much more power than the frog 7. 85/14 = just over six times more. a bit more than still running the FRG-7 and a 60W desk light of old.

The FRG-7's valve-stuffed grandad, the RACAL RA117 (block diagram is closer than the RA17 and has silicon rectifiers) is quoted as 100W

Racal's attempt at transistorising the RA117 gave us the RA1217 which takes 40VA

So that sets the 830 and the FRG-7 in perspective.

Me? I have an RA1217, RA1792 and an Eddystone EA12. Had an RA117 some years ago.

David

[startreksteve]

Thanks guys..
You've put my mind at rest... Are they a good rig for SWL?

At least it will keep the loft warm!!!

Steve

[startreksteve]

Originally Posted by Radio Wrangler

From Eddystone 830 manual, mains consumption is 85VA

Looking at HT and LT currents there is 70.24W but there is transformer and rectifier losses to include, so 85VA in this case likely means 85W.

The 830 has full mains transformer isolation, so the chassis is earthed.

David

Its only a two core power cable, so how can it be earthed?

[Radio Wrangler]

Via the earth connection as part of the antenna system. They had a far more relaxed attitude to safety etc back in those days!

Also, that may look like a 2-pin connector between the set and the mains cable, but Eddystone used a side-contact as well to connect the earth, so you can wire it with a 3-core mains lead and get mains-earth to chassis connection.

David

[Mr 1936]

Hi

If you are worried about running costs, 85 Watts even at today's 34 pence per kWh still works out at less than 3p per hour.

A plasma TV would be two or three times as much

In winter, that's all useful heat going into the house so you will save a bit on heating costs.

Or give up radio and TV and go down the pub instead. If you drink a pint an hour that's about £3.80 where I live.

[Nuvistor]

Mains input of the 830.

[startreksteve]

Originally Posted by Mr 1936

Hi

If you are worried about running costs, 85 Watts even at today's 34 pence per kWh still works out at less than 3p per hour.

A plasma TV would be two or three times as much

In winter, that's all useful heat going into the house so you will save a bit on heating costs.

Or give up radio and TV and go down the pub instead. If you drink a pint an hour that's about £3.80 where I live.

£4.50 round here! £5.50 in the posh pubs!!

[Dave757]

Originally Posted by startreksteve

Thanks guys..
You've put my mind at rest... Are they a good rig for SWL?

At least it will keep the loft warm!!!

Steve

Hi Steve,

If the 830 is in good condition, it was in its day one of the finest receivers
you could get, and I bitterly regretted the day when I foolishly parted with
mine.

I guess some of the modern receivers available today may beat it, but
mine was a pleasure to use.

Incidentally I remember that they are usually fitted with 2 Jones type plugs
on the rear panel, one for accessories and one for external power connections.
Check that they are in place, - I believe that there are links
in the External power plug which are needed for the set to work.

Good luck
Dave G0ELJ

[dave walsh]

Hi Steve. This is quite a different thread and you have clearly built up a very interesting collection of [now vintage] radio receivers when there is a general decline in terrestrial broadcasting overall going on around the world. That's in favour of the Internet of course but what comes around?.,. goes around- like vinyl records It's much easier to just switch off everything for everybody including cell phones from an Internet Server and ATM's, as they do in the Far East. That's why people cry when cell phones don't work in a Hurricane in Florida or New Orleans . I think you choose radio sets from an external, intuitive, viewpoint [it's fair enough some people collect sets to simply preserve them, I'm more like that myself ]. In a crisis old technology will still work if you have a good aerial

Best Wishes,

Dave W

[startreksteve]

I think the pleasure I get from these old rigs is the tactile experience, tweaking the tuning knob a smidge to the left or right, no DSP or auto tuning, nice as they are, I had a mate round last week, who was the person who got me into SWL, and he was amazed by the pre-selectors etc, I think Ive persuaded him to get a Yaesu FRG-7700. He only has a Realistic DX 394. I enjoy the 80's rigs immensely and I think the joy would only increase with something like an Eddystone. Im still tweaking my long wires every few months...

Steve