ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Recent Posts
Mini Split voltage
by Garemaret - 06/21/24 04:53 AM
Strobing LEDs
by Anovalight - 06/20/24 03:16 AM
Stuff that happens after we leave
by HotLine1 - 06/17/24 03:53 PM
photocell requirement for metal halide ballasts
by gfretwell - 06/17/24 01:44 PM
Commercial lift stations
by triple - 06/09/24 05:23 PM
New in the Gallery:
This is a new one
This is a new one
by timmp, September 24
Few pics I found
Few pics I found
by timmp, August 15
Who's Online Now
0 members (), 154 guests, and 9 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
#152497 04/29/05 05:11 PM
Joined: Aug 2001
Posts: 7,520
pauluk Offline OP
Thanks to Jooles for the following:

I wondered if anyone might be interested in this.

It is a very poor picture of my old SABA valve radio. I think, dated 1965, it must have been one of the last valve radios in production -- alongside those *superb* old Philips sets. As far as I know, the last Philips valve set came off the market in 1966.

I bought it in Luxembourg about six years ago.

The reason why I refer to it now is the East German connexion. On BBC Radio 4 the other day there was a super documentary about number stations. The SW on the SABA is limited, so that one on that cannot get much leeway into SW bands where number stations broadcast, although I can still get plenty of "official" SW stations like Bucarest. When one looks into the innards, one almost suspects it was done on purpose. I remember hearing the scary gongs in about 1978, on an old AIWA set.

The SABA's output stage is a masterpiece.

It uses a pair of ECLL801 valves. And very good speakers.

The FM detection modules in it are semiconductor.

It is the most interesting radio I have ever restored.

Now it is back in good health, it is also the *best sound quality* radio for the whole street, and on MW/LW, also it is the most selective, even though there is no external antenna. A couple of friends of mine cannot tell the difference between the SABA and the proper HIFI with all the 1975 Celestion loudspeakers, 1977 Boothroyd Stewart amplifiers, and proper Marantz source equipment.

[Linked Image]

[This message has been edited by pauluk (edited 04-29-2005).]

#152498 05/08/05 05:27 PM
Joined: Aug 2001
Posts: 7,520
pauluk Offline OP
That's an interesting hybrid set with both thermionic and semiconductor stages.

What's the rest of the tube/valve lineup in this radio? Looks like this set has the "magic eye" tuning indicator as well. The most common horizontal-bar type on British sets toward the end of the valve era was the EM84, also common on tape-recorders as the recording level indicator.

#152499 05/17/05 08:07 PM
Joined: Sep 2004
Posts: 93
Sorry for not replying more quickly. I've had the back off it again [Linked Image]

It has been a bit berzerk here lately: We've been doing a new release, plus all my voluntary stuff.

I replaced a lot of old capacitors that looked a bit heat-worn and aged. The whole right channel of the stereo FM facility was not working, and it was down to dry joints, probably exacerbated by the train ride from Luxembourg to Brussels. The resistors are all still the originals. I am a bit reluctant to replace them, as I like the equipment to be as original as can be.

The EM series valve (magic eye) is a bit of a special one [Linked Image] Because it was tuned into a SW station at the moment I took the photo, the extra bit at the side is not lit, but it can, though. It has an extra anode to display when FM stereo tuning is correct, so it not an EM84; is a EMM803. A very lovely valve. My old Telefunkens use EM84s and I have five, but I can't find a replacement EMM803, so that's a bit of a worry.

The output stage amplifier valves to me repersent the pinnacle of thermionics.

ECLL801 is the code, so if you are not familiar with the Philips/Mallard style code, here we go.

E = heater voltage of 6.3vdc, in parallel

C = there is a triode in there.

L = there is a pentode in there.

L = there is another pentode!!

So, we can make a lovely push/pull output stage amp with no real effort. The only other time I came across such a neat and effortless design was the 6809 CPU.

Now: one Saturday, I went up to Eindhoven where next to the Philips works there exists a bit of a bourse of old valves. To my delight, I was able to buy four ECLL801s, never used, and they cost only EUR40.

The other valves are plain enough. ECC85, ECH81, EAF801, ECC83

The power supply is 220V only, and is the nastiest part of the whole set. In fact it once gave me a bit of a jab, so I am probably not being completely fair when I say it is vile. But while I am repairing them, I always run radios in series with a 60w lamp bulb, to try to limit the current, so it was not as bad as it sounds. Now we are on 230V here I have added a resistor to the circuit so the filaments are not going to get burnt out.

As you say, it's a hybrid set. The semiconductors are these: an AF121 and several AF126S, and some odd diodes that I have never tracked down to my satisfaction. They are all shielded, and are in a beautifully chunky sardine-tin style module.

The more I look at it, the more I think they are not at all FM detection. I think they are the IF stage. They are the wrong components for detection, and it makes me wonder even less about those valves.

The thing at the front that looks like a clockface is connected to the rightmost knob, and it is a rotation mechanism for the ferrite antenne for LW and MW, insidethe set.

There are jack sockets behind for an antenna for SW (I run a thin wire over to the neighbour's chimneystack) and an earth (the gutter drain provides only an ohm or so, now I've scratched off the enamel and put a nice clamp on the bare metal). There is also an input for an old-style piezo-type record player, but it is not a 5-pin DIN.

The controls: the "piano keys" are: On/off, LW, MW, SW, FM, phono, and a defeat key for FM stereo in case of a distant station where tuning in with good sound quality proves to be difficult.

The knobs: Bass and Treble are the first two, and they appear to run a standard eq-type circuit, except there is a reed switch in the treble control whose purpose I have not yet discerned.

Middle knob of the five is volume, but there is a probably-invisible perspex balance-control knob behind it.

Tuning on AM and FM are controlled independently by the last two knobs of the five, but behind the FM one is another perspex knob with two positions for AFC on or off.

In all, it is the most extraordianry radio I have ever met.

Except the 1957 philips set that is on my workbench right now; it appears to have been made out of parts for the American market but produced and sold to Europe: it is utterly mad.

#152500 06/01/05 12:04 AM
Joined: Jul 2002
Posts: 8,443
Likes: 3
That's a beauty Jooles!. [Linked Image]
By the looks of the cabinet, it's brand new. [Linked Image]
Replacing the old paper capacitors in a radio like this is often the best thing you can do, paper capacitors become noisy after a length of time.
Ahh, the magic eye, I never thought I would see one of them again.
Testing a radio or any other bit of gear through a series resistance is a good idea, but can also give you a false sense of security too.
I'd personally use an isolating transformer.

#152501 06/01/05 09:31 PM
Joined: Sep 2004
Posts: 93
Well, I added the lamp in series more in case of hurting the radio than me, but I see what you mean [Linked Image]

I like EM valves too. I have PDFs about them. I need to check with the author first, but I wish it would be OK to reproduce the chapter-and-verse about them here too. Those old ones with the V-shaped beams that converged as the tape bias approached the right point used to facinate me, on my Uncle's old Grundig tape recorder (open reel tape) when I was a kid.

The old Philips I mentioned is now picking up BBC Radio 4 on LW198 and a good number of MW stations, but there are still a lot of overheated, badly specified parts in it. It has a beauty of a case and looks cool. Once it is working nicely again I'll stick a photo of it up here.

And now, somebody's given me an old 1950s Bush set, and I can immediately see three reasons why it can't work before even plugging it in! Two dud joints and a definitely dud capacitor all from some repair job I reckon to have been done 20 years or so ago. I reckon there's basically nothing wrong with it, but it could do with a bit of a cleaning-up though. Tested them, and all the valves still work. I remember an old lady who was next-door-but-one until about 1974; she had the same model, and I clearly remember it had a lovely sound, even though I was only 7. I remember tuning it to listen to ABBA :-)

#152502 06/02/05 06:31 AM
Joined: Aug 2001
Posts: 7,520
pauluk Offline OP
That EMM803 is certainly a strange one. When I was a kid in the seventies, most people were tipping out 15 to 20-year-old equipment for jumble sales or whoever would take them. I had lots of older equipment donated for my hobby, including several of the Grundig TK series tape-recorders, and a very heavy old Telefunken deck. The Grundigs all used the EM84 as I recall, but the Telefunken was the round type.

I still have an old resistance-capacitance bridge with an octal-based magic eye as the balance indicator (can't remember the number off-hand).

I don't recall ever coming across a domestic radio with the ECLL801. Most sets at the cheaper end used a single-ended class A output stage, and the more upmarket push-pull types generally used something like a pair of EL84 tubes, or the P or U-series equivalent for series-connected heater chains.

And now, somebody's given me an old 1950s Bush set,

Do you have a service sheet for it? If not, what's the model number? I may have a PDF of one of the old Electrical & Radio Trader service sheets for it.

[This message has been edited by pauluk (edited 06-02-2005).]

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.5