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 Battery portable verses Transistor radio
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 Return to top of page · Post #: 1 · Written at 5:10:04 PM on 11 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

In the past I have moved on the battery portables I had. However I think I would now like one. I miss the 1T4's 3V4 etc. I played around with these when I was very young I know this is silly. However I feel I am at an age where I can be silly while I still can, before I move onto the next stage of silliness.
I have some questions I am sure some of you are well qualified to answer.
In regards to sensitivity how do these battery portables stack up to a good quality 8 transistor portable such as an AWA or Kriesler etc.
The next question is in regards to current draw. If I buy one I would like to use it as a portable. The HT would be a string of 9 volt batteries and the filament supplied by a couple of D cells in parallel.
What current draw can I expect? I was thinking the HT current may be around 20 to 30ma which would be fine for the little 9 volt cells. However the filaments are going to draw a fare wack of current. Two D cells in parallel may not be nearly enough. Should I forget this fantasy before I waste money on one of these radios. I am quite shocked at the prices people want for them on eBay. For the general public they would be quite useless.
Regards Jimb


 
 Return to top of page · Post #: 2 · Written at 5:53:38 PM on 11 March 2019.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

I am quite shocked at the prices people want for them on eBay.

eBay sellers are notoriously optimistic. Watch what they end up selling for, if they sell at all.

I've mentioned before that, in my experience, this type of set does not sell well at Sydney HRSA auctions. There is usually little to no interest in them. By way of contrast 32 volt farm sets seem to be popular in VIC, so it seems to be a regional thing.

As for battery drain, it will depend on the lineup (which tends to be fairly similar among the brands) but, going by the popularity of battery eliminators, I figure they chew through batteries if used regularly.


 
 Return to top of page · Post #: 3 · Written at 5:56:20 PM on 11 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Thanks GTC.


 
 Return to top of page · Post #: 4 · Written at 6:08:45 PM on 11 March 2019.
Gandhn's Gravatar
 Location: Windella, NSW
 Member since 5 November 2010
 Member #: 770
 Postcount: 343

A typical 4 valve portable is the AWA 450P using a 1R5, 1T4, 1S5 and a 3S4.

Total filament current is 250 mA and the radio uses 2 X 1.5V D cells in parallel.

Total B+ current, from a 67.5V battery is about 20 mA.

Using a string of 9V batteries for B+ and 2 X 1.5V should certainly give you a few hours operation.

Harold


 
 Return to top of page · Post #: 5 · Written at 6:24:44 PM on 11 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Thank you Harold


 
 Return to top of page · Post #: 6 · Written at 7:50:21 PM on 11 March 2019.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6353

I once had a couple of the AWAs that Harold spoke of. They do indeed only go for a few hours which is a shame because buying enough cells to power them costs a small fortune.

I don't have the AWAs anymore but I do have a similar Breville portable which runs on the same battery compliment. I haven't powered it up since purchasing it though but will one day. This is the model with the lid that looks like a roller shutter.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 7 · Written at 8:52:23 PM on 11 March 2019.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Funny someone mentioned a 32V farm set. An STC 236 landed here a couple of weeks a go & is now in "the line". Bit of a mess. Vibrator box has a snapped mount, paper caps have become ratatouille an hour to actually extract the chassis & dirt. Valves were that filthy I washed them & are still in the oven; TC coming off a couple so binder will not stick to the dirt.

The Guy owns a lighting plant & wants to run it at displays. Something went wrong as there is what I think is R6 in two pieces.

I will resort to portables & fix both transistor & tube. I did have an English "Roberts" feature in SC. I don't know what will happen now Tony Maher (spelling) is gone, as he made PSU's to sub into these.

However, Amp Hours of common batteries is not easy to find but its out there. It rather depends on the valve count as to how hungry it is but depending on the power output & the fact that there are no heaters, the transistor can have the advantage; especially cost per hour

The small 9V batteries link into themselves & 10 make 90V. We always use two "D" cells in parallel for the 1.5V heaters.


 
 Return to top of page · Post #: 8 · Written at 3:22:14 AM on 12 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Thanks Brad and Marcc. I think one reason I was thinking of getting another is they are the missing link between my valve mains radios and the transistor ones they are part of the evolution chain. I never thought of linking the 9 volt batteries that is a good idea. I was thinking of using the snap on battery connectors. If I come across a suitable repairable battery portable at an affordable price I might buy one. I would enjoy repairing it. even if in practical terms it would be too expensive to use. Does anyone know if their sensitivity was better or worse than their transistor cousins. The people on ebay selling these have no idea you just can't go out and buy batteries for them and they are quite useless to most of the population unless they just want them for displaying and it is quite possible those buying them have no understanding either.
Regards Jimb


 
 Return to top of page · Post #: 9 · Written at 5:39:33 AM on 12 March 2019.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1575

I have three hmv portables which I am going to restore one of them. They have the two rd tubes and are very selective. If you email me I can send you photos . You are welcome to one for a small price plus postage. They really are good performers. I have the case of the one my mother gave me and I'm going to use parts from one or two to restore it, but I have three so ones yours if you want.


 
 Return to top of page · Post #: 10 · Written at 8:41:54 AM on 12 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Thanks Carl.
That sounds good.
Regards Jimb


 
 Return to top of page · Post #: 11 · Written at 5:32:11 PM on 12 March 2019.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1381

I have a few battery portables. They mostly have the filaments in series rather than parallel, so 8.4 volts (5 tubes) or 7 volts (4 tubes) is needed rather than 1.5 . I suppose you could try a 9 volt battery for 8.4, but it isn't going to last long.

The HT would be done by a bunch of 9 volt batteries plugged together, as you'd expect.

I never bother with the battery side of things, I just make sure it works off the mains.

The slightest amount of corrosion (even invisible) on the filament pins can bring the entire radio to a halt. Since the filaments can't be seen in daylight, it's very difficult to know if they are at full brightness, or even lit up at all. This is where you need to measure pretty much every voltage to make sure it's all working as it should.


Oh - my personal experience with the 1R5 is that they are quite unreliable. Usually the filament blows, but sometimes they just stop working for no apparent reason.


 
 Return to top of page · Post #: 12 · Written at 7:27:58 PM on 12 March 2019.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

There are a couple of miniature battery valves that are a bit like that & in octals 6SA7 without a separate exciter is another.

A seriously good current insensitive, voltage dropper for DC circuits is a silicon diode.

A lot of reject shops have cheap 9V battery's & rolls of Duct or Gaffer tape to hold them together.


 
 Return to top of page · Post #: 13 · Written at 8:45:10 AM on 13 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Hello Carl Robbbert and Marcc.
Thank you all for your contributions. Carl has kindly offered me one of his battery portables and I will be taking up his offer. Robbbert just a thought, it might be a silly one, with filament votages you have stated have you considered the possibility of using two Lithium 18650 batteries pick good quality ones they have 4000 mAh rating and the chargers are not that dear. Their nominal voltage is 3.7 volts when charged they sit a little over 4 volts they would suit your 8volt filaments.,and as Marcc has mentioned you could put in a series diode or two to drop them back for the 7volt radios. I guess the higher filament series configuration is a mixed blessing lower current but a little more difficult to fault find..
Regards Jimb


 
 Return to top of page · Post #: 14 · Written at 2:15:30 PM on 14 March 2019.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1911

I have quite a few battery valve portables including a couple of AWA 450s. One of these gets occasional use for about half an hour, once or twice a week. The batteries in it are two alkaline D cells and 8 x 216 9v alkalines, snapped together. Fits nicely. Existing batteries were fitted about 4 years back. Alkalines should last about 10 times as long as the original carbon-zincs in this service.

Of course there's always the mains power supply I designed that SC featured a couple of years ago. Designed to fit inside the larger battery portables.

Sensitivity varies. The AWA 450p with its small loop antenna and single IF stage is no ball of fire. I have a Technico cloth covered wooden portable from the late 40s that is quite respectable - it has octal battery valves and an RF stage. However my 1958 vintage Philips transistor (OC44, OC45, OC45, OC70, OC71, 2 x OC72s) outperforms all of them.

Like most transistor radios, some battery valve sets had 2 IF stages, they put up a respectable performance.

Marcc is spot-on about the importance of clean and properly tensioned valve socket contacts, particularly with the all-glass valves. Same goes for battery contacts and on-off switches. Lose 100mV in a filament contact and performance goes south rapidly.

I have quite a few battery sets, both portables and bush radios. I'm also doing a garage cleanup if there is interest!


 
 Return to top of page · Post #: 15 · Written at 1:37:17 PM on 15 March 2019.
Jimb's Gravatar
 Location: Kanahooka, NSW
 Member since 18 November 2016
 Member #: 2012
 Postcount: 662

Hello Ian.
A lot of good information there thank you.
The battery portables maybe of some interest. Carl is possibly selling me one of his.
Space is a problem I do not have a lot of room and recently I also had a clean up. My wife commented on the fact that I am filling up the newly gained space. However what can you do.
Regards Jimb.


 
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