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Old 30th Aug 2018, 5:34 pm   #21
1100 man
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Default Re: Volksempfanger VE301W People's set

Hi Graham,
Many thanks for the link. Bulgaria seems even more remote than Germany in terms of ordering! I will probably have to bite the bullet and just order one and trust that it will get here in one piece. I guess valves are not the best travellers!
I had hoped that a forum member might be willing to part with one so that it would not have to come that far.
Are there any valve dealers/ suppliers in the UK that would be worth trying? I think the L416 is an equivalent made by Valvo.

Also do you think the 0.15ma heater current is reasonable for the RES164 or is that a misprint?
The PM24M looked great until saw it had a 1A heater current.

In parallel with sourcing a valve, I have now ordered all the parts to build a (in fact three) Minimod AM modulator as this is what the set is most likely to be used with. I like the design, especially as there are no coils to wind!! It seems to have had very good reviews.

All the best
Nick

Last edited by 1100 man; 30th Aug 2018 at 5:36 pm. Reason: extra text
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Old 30th Aug 2018, 5:49 pm   #22
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Default Re: Volksempfanger VE301W People's set

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Originally Posted by 1100 man View Post
Thanks for the suggestion of a PM24M. The problem is the heater current listed at 1A. The RES164 is only 0.15A! Can that really be right: it's very low. How can it do anything useful with only 0.6W heater?
Apart from that, it looks an ideal substitute. The mains transformer is quite small and I doubt it would appreciate the extra loading!

So is there anything else that's actually available, even with a different base that would do?

Cheers
Nick
Whats the HT? The PM24 is 0.15A but only 150V anode volts. It is a much older generation valve so not sure about gain.
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Old 1st Sep 2018, 7:52 am   #23
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Default Re: Volksempfanger VE301W People's set

The 0,15A heater current for the RES164 is definetely NOT a misprint. The RES164 and it's predecessor, B443 (first pentode in the world, introduced 1927) was developed as a replacement for older power output valves in battery radios, for example the triode RE134 - as such, it is meant for 4V heater by battery.
Radiomuseum.org lists a number of equivalents:
https://www.radiomuseum.org/tubes/tube_res164.html


By the way, my first post in the forums in many years, I mostly read nowadays
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Old 1st Sep 2018, 7:44 pm   #24
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Default Re: Volksempfanger VE301W People's set

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Originally Posted by 1100 man View Post
I had wondered about grafting a different valve onto the old RES164 base but what to use?
There's an article about that here:
http://www.jogis-roehrenbude.de/Roehren/Umsockeln.htm

A Russian 4P1L for example.
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Old 1st Sep 2018, 9:04 pm   #25
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Default Re: Volksempfanger VE301W People's set

Had cause to do this a few years back,the ersatz RES164 constructed using Soviet era 4P1L worked out very well indeed.
Fil 0.325A @ 4.2V or can be 0.65A @ 2.1V as desired.

A restorer in the U.S adapted a 3V4 (DL94) I.S.T.R. for the O/P valve in his.

From memory,female D connector will yield appropriate connections for the pins and to which wires can be soldered and routed to the donor valve pins once the old base has been cleared of glass etc.

Had a look and there is an Orphan 4P1L valve sat here doing nothing, if you feel like giving it a try, PM me if you would like it F.O.C.

P.S Bulgaria has been fine when ordering eBay items- be sure to opt for standard tracked shipping and not the commonly offered economy shipping which is slOw and is not tracked.

Last edited by VT FUSE; 1st Sep 2018 at 9:20 pm. Reason: Add a p.s to message
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Old 4th Sep 2018, 2:30 pm   #26
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Default Re: Volksempfanger VE301W People's set

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Originally Posted by Oskar.B View Post
The 0,15A heater current for the RES164 is definetely NOT a misprint.

By the way, my first post in the forums in many years, I mostly read nowadays
Hi Oskar.B,
Glad you have been inspired to post after several years and thanks for the information. I've not had much to do with directly heated valves but I assume they can get away with a lower powered heater as there is no cathode to heat up.

Stuart,
Many thanks for the link which provides interesting information. Google's translation adds a certain entertainment value as well!
I had glanced at it before but a 4P1L seemed almost as difficult to come by as the RES164 but then....

VT.Fuse very kindly offered me one to experiment with
Looking through the 'Umsockein' link, the author very cleverly cuts the old RES164 glass bulb off at the base and uses this to cover the new valve. Like re-stuffing capacitors but for valves!
I imagine the mains transformer will be able to cope with the extra 200ma of heater current:-I'll keep my eye (and my finger) on it to make sure it doesn't run too hot.

The idea of using a DL94 battery valve is interesting although it will need some circuit modifications to work correctly (1.4V heater among other things). Seems a bit too new a valve though as it didn't appear until the early '50's.

VT.Fuse, your offer is most appreciated and I will send you a PM.

All the best
Nick
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Old 12th Sep 2018, 12:14 am   #27
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Default Re: Volksempfanger VE301W People's set

Well, thanks to the wonder of the internet and this forum and more specifically to Mr VT.Fuse, I now have a 4P1L to play with. Not just any old one, but a brand new one and a base to go with it no less!!
Radiomuseum states that this Russian valve was introduced in 1938. It's a directly heated output pentode designed primarily for battery operation. I don't know how long they made it for, but this one looks just like a PL508 from the 1970's!! I can't believe it dates from before the war!
It would seem people have had good success using this as a substitute for the RES164 output valve. The plan is to remove the remains of the old valve from its base and mount the new valve base & valve on top of the old one. Thus no alterations need to be done to the set and if the correct valve turns up it will just plug straight in.
So now I have a functional modulator, I can turn my attention to doing this over the next few evenings. Watch this space....

All the best
Nick
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Old 15th Sep 2018, 11:51 pm   #28
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Default Re: Volksempfanger VE301W People's set

I've been playing with this 4P1L output valve and the problem is it works rather too well! It has way too much gain.

The output stage is designed to work 'flat out': the volume being controlled by the reaction control and by the aerial tapping coil.
I'm having to run the RF stage at a very low gain or else the volume in the speaker is deafening! This also means that the signal to noise ratio is poor and the output stage generates more hum than I would like.

I know the 4P1L has a greater amplification factor than the RES164, (I don't have actual data for either valve) but can anyone suggest ways of modifying the circuit to reduce the gain of the output stage?

I'm using the ' Minimod' modulator to drive the set fed with a 1Khz tone for testing purposes. With the output valve removed (so I don't go deaf), I can receive a decent amplitude, undistorted sine wave at the secondary of the coupling transformer by using the reaction control & aerial tapping coil.
If I could reduce the gain of the output stage, it would hopefully generate less amplified hum and the RF stage could then be run at much higher gain.

The circuit is here: http://www.jogis-roehrenbude.de/VE-DKE/Ve301w.jpg

Many thanks
Nick
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Old 17th Sep 2018, 10:20 am   #29
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Default Re: Volksempfanger VE301W People's set

According to Jogi, the 4P1L has a slope of 6mA/V and the original valve 1.4mA/V but he seems to think you don't need to make any modifications.

Quote:
Originally Posted by 1100 man View Post
This also means that the signal to noise ratio is poor and the output stage generates more hum than I would like.
Did you note the error on the "Umsockeln" page? It's described as such (see "Wichtiger Hinweis"). Pin 4 of the 4P1L should be connected to the mid-point of the heater (pin 8) rather that one end, otherwise you get a lot of hum.
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Old 17th Sep 2018, 6:10 pm   #30
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Default Re: Volksempfanger VE301W People's set

Nick,

The 4P1L valve as you have found, has a significant slope when compared to the more normally fitted type. When I did this sub several years back I think that the valve required taming somewhat-the HT and filament voltage are worth checking and one suggestion may be to experiment with Voltage supplied to the Fil as was done on the old RCA Radiola regen radios.

If you try this approach then a wet finger in the air guesstimate would be to try a series 1/2W 3R-4R assuming your measured fil Voltage is at 4.2V. I am sure that other schemes of introducing degeneration of a directly heated valve would be forthcoming from the forum Gurus.

References to the introduction of the 4P1L being in 1938 are incorrect and relate to the Loctal (B8G) base/socket type, the 4P1L was a post war copy of WW2 German origins rebased for use in Farm radios and Collective factory welfare radios in the main and also a few Military Transceivers for loudspeaker output.
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Old 17th Sep 2018, 6:35 pm   #31
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Default Re: Volksempfanger VE301W People's set

Something else has entered what passes for my mind these days-you have not said what you have done on the ancient and low value smoothing capacitor?

I see that you have scoped the interstage transformer but did wonder if the indirectly heated REN904 detector valve may have some excessive heater cathode leakage?

If the smoothing capacitor has been replaced/rebuilt then a LITTLE more capacity may be of help here,ie another 2uF maybe....

Special note: the mains transformer is for the old European 220V mains thus the set will be seeing at least 10V over its intended voltage on today's UK 230V supply unless running via a Variac to lower this.
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Old 18th Sep 2018, 12:56 am   #32
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Default Re: Volksempfanger VE301W People's set

Thank you both for your comments and suggestions.

I did connect the suppressor grid to the centre point of the heater. Don't get me wrong, it's more of a buzz that a mains hum and not excessively loud: it's just that I know I can make it better!!
The 'humdinger' pot across the heater circuit has a significant effect and has a distinct 'null' point near the centre where the hum is much reduced.

The capacitor block was checked for leakage at 300 odd volts (see earlier in the thread) and tested amazingly well both for leakage and capacity. The ripple present on the HT rail is reasonable (sorry, I'm using the worlds worst scope here: the y axis is calibrated in fractions so can't get meaningful results from it!).
I tried extra capacity on the 4mfd resevoir cap and that made no difference at all. Same on the 2mfd.
The speaker is in amazing condition and could be 8 rather than 80 years old!

With careful adjustments, I had Tom Petty thumping out in good quality- it was just a bit too loud to be comfortable. Its like running your Hi-Fi amp with the volume turned up full and the source volume kept to a low level. The background hum/ buzz is louder than it needs to be. Reducing the gain of the RF stage to reduce the volume, makes the background noise more noticeable.

That's interesting about reducing the heater voltage to reduce the gain: I hadn't thought of that, never having played with directly heated valves before.

The set is being supplied with 220V from a variac for testing.

So I need to do some more experiments.

VT Fuse, Thanks for your message which I will respond to over the next day or so- for now, I really need to call it a day!!

All the best
Nick

Last edited by 1100 man; 18th Sep 2018 at 1:26 am.
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Old 12th Oct 2018, 12:49 am   #33
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Default Re: Volksempfanger VE301W People's set

Well, I must confess, after an extended period of experimentation, this radio is now working remarkably well!! Certainly I've got it to a point where I am very happy with how it sounds!

I've been experimenting with a Russian 4P1L output valve (kindly given to me by VT Fuse) to replace the broken RES164.
The problem was way too much gain and too much hum/ buzz.
I've tried everything I can think of to reduce the gain of the valve but nothing has the least effect!

Running the filament at 1.8V instead of 4.2V. Inserting an 8k2 series resistor in the HT feed to the anode (in series with the 2k0 speaker). Altering the grid bias voltage both more positive and more negative. Decreasing the screen grid voltage. None of this had any effect on the volume, but, and it's a big but, inserting a 4R7 in each leg of the filament drastically reduced the hum. I'm surprised the valve even works from 1.8V!

So with the REN 904 RF valve removed, so there was no input to the 4P1L, the background hum was very quiet- no worse than most valve radio's. Earthing the chassis to mains earth further improved matters.
Inserting the REN 904, generated lots of hum once it had warmed up. Going near it made it worse. The gold metallic shielding was not being earthed properly. Temporarily covering the valve in tin foil cured the problem!

As the background noise is now acceptable, signals can be fed in from the modulator at a lower level. Using a combination of aerial tapping and reaction control, combined with careful tuning, volume can be adjusted from very quiet to very loud indeed!

AM really isn't any good for music (I really notice the gap between 4.5KHz to 11.5KHz where my hearing stops!) but this radio sounds as OK as it can.
Feeding in some speech, in this case some vintage 'Paul Temple' recorded in the '40's, actually it sounds rather good. Certainly comfortable to listen to with no noticeable background noise. The large speaker, even though rather crude in design, sounds good.

I've been running the set from 220V, as that's the highest tapping on the mains transformer. The current drawn by the primary was 83ma. The mains measured 248V. This resulted in a series resistor of 360 Ohm at 2W, so I will incorporate a 5W one in the mains input circuitry. I will also consider attaching a thermal fuse to the mains transformer just in case. At the moment it runs almost cold.
I've also purchased some braided 3 core flex in brown which looks almost identical to the original rubber stuff.

So now its a case of tidying it all up and finishing it all off. I also need to fit some form of auto level control to the Minimod modulator so it can be used from any source without having to adjust the audio level. I'm well impressed with that too!

So a very satisfactory result and I'm well pleased with it and I'm sure my friend, who I'm doing it for will be amazed !!

All the best
Nick
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Old 13th Oct 2018, 5:43 pm   #34
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Default Re: Volksempfanger VE301W People's set

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You lucky XXXXX getting to work on one of these! I've been looking for one for ages but they've either been wrecked or have eye-watering prices. I shall be following with interest.
I also have a VE301Wn and they are very common, the lowest prices, very easy to get parts for including many reproduced parts including NOS parts. An exact speaker cloth is readily available and prices all around are reasonable unless you run into a seller who thinks they are rare and worth more than they are. The DKE38 and VE301DYN are the ones that fetch the high money if they have the Reich emblems intact. Tubes are always for sale and vary greatly in price. I actually find it much easier to get these and parts than what it was for my Philco 444
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Old 13th Oct 2018, 8:37 pm   #35
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And if need be? Actual service manuals in various forms two of which are NOT reprints but the small service handbook is.
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Old 13th Oct 2018, 10:41 pm   #36
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Default Re: Volksempfanger VE301W People's set

Hi Don,
Thanks for your comments. I suppose it depends where in the world you are as to whether these radio's are common or not! Although Ebay makes the world much smaller!
My friend had been after one of these for a while and went all the way to a military fair in Belgium to buy it.

At the BVWS auction at Harpenden recently, there were two of these. The VE301Wh sold for £170 (I think from memory) and the other for £140. They were by far the most expensive things on the day! Average radio's sell for a fiver.
So I think by UK standards they are not that common and are desirable so fetch high prices.

This has been an interesting project for many reasons, but the excellent quality of the components has been one of them. All 5 capacitors in the big block measured perfectly for leakage (at working voltage) and capacitance. The resistors are very well made and are all spot on for value. Amazing for 80 year old parts!

All the best
Nick
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Old 14th Oct 2018, 1:32 am   #37
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And all the best to you as well Nick!
As mentioned for prices etc. it is most certainly harder for me as I live across the pond not the English Channel! This is also why I find "collection in person" as a personal irritant because what I have been bidding on in the land of my ancestors is just as or more so delicate and rare but shipping is easy to discuss (using a translator of course for both sides) and as mentioned earlier MANY parts are available as these seem to be coveted despite their dark history. The W, Wn, and other flavors of the one I have are the most common, cheapest, civilized and or politically correct but are also the least in value and lord help you if you post one for sale with the "verboten Emblems" displayed on our typical web auction as they will be pulled and the auction will pull the plug on the item!! The VE301G is so so for common but are fewer and have a nicer wooden cabinet but the downside is they are DC sets and by DC we are referring to DC mains not battery but there are variations of the "G" that are battery as well as some of the DKE and DYN if memory serves me correctly. I'm not at all worried or concerned about DC as a set of rectifiers and a good electrolytic solves this problem. This is a much easier problem compared to the "Englander" as the Germans refered sets as you will notice voltages are fully adjustable from 110-220/240 and looking at my Philco 444 right now I see 225-260 volts with my line voltage being 110/120 and Drier/Stove 220/240 forced me to purchase a Variac with 110 in and 240 out to boost the voltage! A PITA with no pill to cure. I dragged my Philco out of temp. mothballs to examine the capacitors with the concern of where to get .00011,.00025,.0005 capacitors but these are mica and not Hunts but Dubilier capacitors so even though they are British made I hope they have a better reputation than the British made Hunts flavor David warned me about. The only concern is the pair of .00011 which are located in the infamous block capacitors but I have Canadian and American made Mica from before my time that I can use IF the mystery caps in the blocks fail the test. Values like those are probably Mica. I'm placing an order with Sal's in the States and this was a concern. His prices are lower with free shipping to me as well with a large order so I went this rout as I thought why should a Canadian pay US$ to a Canadian charging US to a Canadian. A bit off topic but this is MHO but anyway back to the Sieg Heils,
I will venture on and add a VE301G to my collection and if possible a DKE38 or Kleinempfanger and a VE301DYN but they must have the "verboten emblem of das Reich" because if these are on is where they are worth the most even in the United States of all places. Fritz Kuene must have left a lasting impression? Anyway I will need one for my Fuhrerbunker, Wolf's Lair, and Eagles Nest lol! If it isn't these I was bidding on a fine Loewe Opta EB100G but got "Blitzkrieged" as it went for £235 and most certainly would have gone higher if I continued to bid. The OE333 are too rich for my blood as fascinating as they are. They talk about a PEN DD61 being rare, find a 3NF, 3NFW etc. because I found the PENDD61 and substitute easy and inexpensive to find and purchase. These Loewe Opta Gotland W,WL must have been high end sets back in the early 30's and would choose one as much as an Ekco.
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Old 15th Oct 2018, 5:54 pm   #38
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Your prices are lower than mine! The DKE38 and VE301DYN I have seen for 350£-500£ translated for myself is $450-$650 US dollars for sale in the US 35%+ higher than my worthless Canadian dollar and they didn't stay around for long. As I get sick and tired of the beurocracy of the usual online auction I have also discovered the German version of Kijiji is a good source as well! It most certainly doesn't matter how they are posted without "others snouts" peering in and pulling their items due to a logo or emblem of an elected government that existed over 70 years ago. Perhaps they have forgotten the words mentioned at Rememberance Day or Memorial Day to honor those who served in both World Wars "Lest we forget"!! If you sell a radio with a communist star or emblem well that is okay. Anyway prices vary and condition is always an issue, not much for the ones you and I have but the DKE Kleinempfanger or the VE301DYN as many have the Reich emblems ground off or drilled out. Also there are post war models of these but that is blank or has a manufacturers logo instead. One seller was reproducing the cabinets but they were very poor quality fiberglass Repro instead of like some of the Ekco cabinets reproduced at much better quality.
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