I was a little hesitant about buying this radio, because I wondered if it may have been a bit of a mongrel. It had what I thought looked like the wrong dial and various things missing including the handle, battery cover, and a very obviously wrong tuning knob, but in the end I put a small bid on and got it for £5.50 plus a reasonable postage of £6.99.
This is a substantial portable transistor radio measuring 13 x 9.5 inches, the circuit has 15 transistors and it is powered by 6 D cells, with a socket for an external 9v DC supply. It seems it originates from about 1968/9 and probably made in Germany before manufacturing of many sets was moved outside Europe to the Far East. The majority of the transistors are branded ITT.
The radio had previously been taken apart and tampered with as many screws for the casing were missing, the tuning cords , both of them, were intact but unattached.
The tuning cord lacing is not complicated, if you have the service information, but in this case was made extremely difficult because for some reason the existing cords were about 1 cm too short of being a sensible tight fit. During the process of trying to lace the cords 3 guide pulleys snapped their mountings at different attempts because of the excessive strain. There were signs that 2 of them had previously been repaired. It took me 2 days to get the cords back on and working, and required a 3rd hand to get the springs over the clip on the tuning drums. In the end I cut additional entry slots in the tuning drum rim to shorten the path of the cord. (on one attempt the spring slipped off the clip and imbedded its end in my thumb, ouch! I said)
Another mishap happened in the process of fitting the FM cord, the tuning mechanism end stop was damaged by over turning the drum causing a very small plastic lug inside the FM tuner module to break.
I had 3 attempts at repairing the end stop on the FM tuner.
2 of the attempts failed when the super glue I used gave way again in the lacing process. I then used SPX epoxy glue. This held quite well but finally the repair broke when the cord lacing was finished and I turned the dial to test the end stops, there was so much gearing, I could not feel the end stop.
Oh well! never mind, the tuning still worked but the FM pointer tended to wind off the end of the guide and there was a risk of the reactive tuning core moving too far and the teeth on the drive becoming un-meshed.
I could not see a way to rig any other kind of stop on the tuning drum because it made a total of 1.5 turns.
Something had to be done, so after realigning the pointer and marking the 87.5 and 108 Mhz limits I glued 2 small brackets to engage with the pointer and act as stops. This required reinforcing the glue fixing the pointer on the cord with super glue. It is all working reliably now and the drive spindle capstan slips on the cord at each end of travel with out straining anything too much.
There were 2 case fixing lugs broken off and missing from the back and it is probably because these were broken that the dial was cracked when the 2 screws were tightened on the dial. I made and fitted 2 new mounting lugs which fill the gap in between the acrylic dial and a threaded socket in the case.
I searched around and found enough screws to securely fix the case back together. There is only the battery cover which forms the entire base of the radio to do now.
The radio has a number of features I have not come across before in a portable transistor set.
The separate FM & AM tuning devices are operated by an interesting arrangement of clutches operated by a leaver attached to the FM push button. This enables both of the AM and FM tuning pointers to be operated by a single knob. It also enables me to switch from Gold on AM and the misses can switch to Radio 2 on FM with out re-tuning.
Although the case is all black plastic it is covered with a plastic sheet fitted around the 2 case halves.
There is an additional small treble speaker to supplement the large elliptical speaker.
It has what I call “proper” power output transistors, not the usual OC or AC types held in copper clips. These ones are of the TO37 style, AD161 and AD162 and bolted to a substantial aluminium plate.
The tuning dial has a luminous backing plate which gives off a green glow in the dark.
There is also a dial light but I don’t think this is fitted with the correct bulbs because the radio dies when the light is switched on and the current limit on my bench supply is reached, the bulbs glow but only dull orange. (I tested and this also happens on battery)
Switching between the 8 wave bands is done using 6 individual band push buttons and the AFC button.
Up until now I had thought of my Hacker Sovereign II as my best sounding transistor radio. However following comparison tests on FM with the Hacker and the ITT KB Touring International, I found that in a piece of classical music the ITT KB brings out more of the individual instruments with crisp highs and clearer low tones, on speech the ITT KB set also seems to be clearer. On pop music the radio has what I consider to be the best quality audio of any other transistor radio, with a good punchy sound, and extremely clear vocals and sounds better than the majority of the FM valve sets I have.
On AM however it has a little too much bass and the base control needs to be turned down fully, and the treble turned up a just a little, but the audio is still beautiful to listen to.
Mike
I am not surprised about the sound quality, ITT sets always perform very well, even my ITT tiny outperforms sets twice the size!
I also have an ITT 'Weekend', this is very impressive on FM, if a little on the bassy side.
I admire your patience with the dial cords, not my favourite job, glad you have sorted it.
I have never seen this model, but I will certainly get one, if I ever see it.
I hope you manage to sort out the battery cover
Yes some of the models in the "Touring" series and the "weekend" series are lovely. There is a Schaub Lorenz valve battery "Weekend" I'd like. Is the Weekend T30 the earliest transistor version in the series?
Does this model have a BFO? I think some models do.
Can you look at the German model info to see what the bulbs should be? Also I was thinking of this family on the Scale Lamp thread of the few transistor portables with Scale lamps and how few Battery valve sets after 1949 had scale lamps. The Kolster Brandes GR13T I think ought to be 2 x 150mA or less rather than the 2 x 300mA bulbs fitted which seems crazy on a battery set, esp. when they are not button actuated like early Ever Ready Model T, this model or the Valve Zenith T.O. models.
Full marks for patience and persistence, seems like an excellent and rewarding result. I haven't come across many ITT transistor portables but they impressed me with their no-nonsense practicality and quality. Another quality name sadly missed,
Colin.
I have looked over the details for the other radios in this family and the only information I can see is for the Touring International 103 which has 2 x 6v 1.2w bulbs in series. On the 103 it looks like when the set is working on mains the lamps are on continuous when on battery you have to operate the push button.
There is no BFO facility on the model I have.
Mike
Try 2 x 6.5V 150mA bulbs?
Or these
http://www.ebay.ie/itm/2-12v-80ma-White ... 0603410648
or
http://www.ebay.ie/itm/50-pcs-3mm-9V-80 ... 0782679801
I had a think and came up with a method of making a battery cover. My first thoughts were to make them out of thin ply, but then remembered I had some odd bits of acrylic sheet laying around.
Hopefully the photos will explain and show the process.
Tomorrow the final coat of black paint and then sit back and enjoy.
Mike
Fantastic result Mike and good write up.
I think the AD161/162 combination were unlikely to give up the ghost in this application, what are the driver transistors?
Eddie
Hi Eddie
The transistors are BF125 BF125 BF125 BF125 BF121 BF121 BF125 BC172 BC252 BC252 BC252 BC108 AD161 AD162 BC252
More details are on the Radio Museum site.
What is the function of T305, is this a stabilised supply for the RF stages?
Mike
It's certainly a regulator.
What is the function of T305, is this a stabilised supply for the RF stages?
Looks like it. Fairly common by this stage - certainly Hacker introduced it with the RP25B...
Nice sets when working, but in common with all German sets I've known, they are a total pig to work on. You've discovered this with the mechanics, but electrical faults are even worse. I have 2 here awaiting repair, but both have issues on AM and the service data isn't very helpful. I've fixed a problem with intermittent audio with one, which was a faulty "via", hidden under one of the larger capacitors in the audio section. I've no idea if I'll ever fix the AM faults
They also sound like a typical German set - sorry to stereotype, but I've seen/heard a lot (a local friend collects them, and I have to fix them for him). Very bass/treble heavy - just look at the amount of response shaping around the volume control. Plastic cabinets that rattle (you get handy with the self-adhesive foam strips with German sets!). At least this one has a reasonable amount of output power when running on mains, so isn't driven into clipping quite as quickly as a Yacht Boy.
I note that you mention the Hacker Sovereign II - are you aware that they used different loudspeakers over the years, and they all sound quite different to each other? The later sets used a Celestion, which does sound a lot better than the earlier Goodmans, but this Celestion can suffer from rubbing voice coils. When good, they are very good. The Hunter RP38A with an Elac loudspeaker has the edge in quality terms, but it isn't as good in RF terms, so might not be so useful in a fringe area. The VHF Herald was sometimes fitted with another Elac (with a large ceramic magnet) and this is also excellent - perhaps the best. Shame that magnet precludes it being fitted to a Sovereign II.
Very impressed with the repair work - I'm not sure I would have stuck at it!
If you haven't already seen it, here is a very positive review: http://radiojayallen.com/itt-schaub-lorenz-touring-103/ - I know Jay a bit, and while I'm not quite as positive about the audio quality as he is, it's a generally accurate review.
Hi Mark,
Hmm, my Hacker has a Goodmans loudspeaker, it does sound good but you say it could sound better?
You are right about the shaping of the audio to give the ITT set enhanced low and high tones, but the mid tones (vocals) also sound excellent on the ITT. I do like the ability to have plenty of adjustment to shape the audio, especially as my hearing rolls off rapidly from 10kHz.
I dont believe this radio!!, it certainly has had a fiddler looking at it.
I had already discovered the tweeter sounded a bit ineffective, following Eddie's comment about the driver transistors I had a further study of the OP stages and I noticed the capacitor feeding the tweeter on the circuit was 5uf but in the radio it is 2.5uf (which I changed for a 1.8 and 0.5 uf capacitors in parallel because it had yellow crumbly stuff all round the + end. I thought I would experiment and swap this for a 4.7uf, and then I discovered there is no signal getting to the tweeter at all because the wipers have fled the little slide switch which controls the tweeter. Luckily I have found a matching, well almost matching, switch and have just finished fitting it.
Distinct change and further improvement in the sound with just the 2.3uf cap.
I cant work out what the other connection to the tweeter switch (S301 just below the LT2) does. It connects via a 10nf cap to the emitter of T306. I can hear no difference when I change the switch other than the loss of the tweeter. Should it make any other difference. I was expecting it to shape the sound a bit and cut the base so it is more suited to SW listening.
Mike
If the crossover capacitor is 2.5uF, I'd leave it at that. Increasing it might cause an upper mid-range bump - perhaps the change was made for that reason, or perhaps the loudspeakers changed slightly over the years.
It looks like switching off the tweeter also applies treble cut to the amplifier - perhaps to give the impression the tweeter is doing more than it really is, or perhaps to improve matters on AM, as you suggest?
Yes, your Hacker might be good, but there is better to be heard. I'd recommend a Hunter RP38A - you'll be impressed by the extruded aluminium grille if you get one of the later ones too. Earlier ones used punched aluminium sheet, which picks up dents far too easily. But I won't take this OT 
Hi
Please can someone confirm if the attached diagram I have marked up with speaker polarities, is correct for the tweeter phasing.
At the moment it is wired with the tweeter the same phase as the woofer, but I thought with this simple type of capacitor filter it had the effect of reversing the phasing.
Thanks
Mike
A single capacitor causes just 90 degrees of phase shift.
I could take a look inside one of the ones I'm meant to be fixing if you like. But honestly, I doubt it makes much difference - when you measure the frequency response of old paper-cone transistor radio loudspeakers, they are so ragged that subtleties like phase tracking via the crossover region hardly matter. I doubt ITT paid any attention to it - the tweeter is just there to add "sparkle" and marketability.
Nice sets when working, but in common with all German sets I've known, they are a total pig to work on. You've discovered this with the mechanics, but electrical faults are even worse. I have 2 here awaiting repair, but both have issues on AM and the service data isn't very helpful. I've fixed a problem with intermittent audio with one, which was a faulty "via", hidden under one of the larger capacitors in the audio section. I've no idea if I'll ever fix the AM faults
Mark, this is so true! I'd come to respect Grundigs for their performance but there have been times when I've thought , how on earth was this ever put together?!! There almost seems to be a delight in un-necessarily complex mouldings and assemblies. I'm sure that some of the circuitry is "elegant" and "ingenious" but "infuriating" might more readily come to the mender's mind. I have what used to be a Yacht Boy in lots of bits in a shoe-box for "one day" attention but there's a lot of "dropped plastic" syndrome to sort out...
Mind you, they might have a few things to say about "THAT" module in the R707!,
Colin.
Yes, good performance - especially on FM - but not built to be serviced! I suppose some might call that "industrial design", where it was designed to go together on a production line as easily as possible, and the assumption was that it would never go wrong...
I'm no fan of the Mullard modules, but to be fair to Mullard, it was Roberts who decided to mount the switchboard directly beneath it with ~25 hard-wired connections. I've got one of these damn things on the bench right now, and am trying to summon up the energy to dive in there (it also means going in the attic to fish out a spare chassis because you can take all the digital photos you like, but there will still be a connection left over with nowhere to go that somehow managed to hide from the camera!).
But serviceability is why I'm so fond of Hacker. Proper engineering, excellent service manuals, and decent performance as well.
In the context of the early 70's where FM was pretty sparse, I reckon the ITT would have been quite some radio.
I remember FM starting up in Nottingham, programme material was a bit lame for a teenager and something your parents might listen to.
I can't help but feel that the quality of the Grundig Yacht Boys & co meant they were owned by the same people who could easily afford a colour television, because a transistor radio that ran off the mains was a luxury.
I'm not sure how the ITT compared but it looks as though it would have been right up there.
I did wonder about that series pass regulator Mike I got the impression it would only work when it is supplied with an external supply. The zener on the base is 10V so with Vbe say 0.6 v there will be just over 9V out.
Eddie
I can't help but feel that the quality of the Grundig Yacht Boys & co meant they were owned by the same people who could easily afford a colour television, because a transistor radio that ran off the mains was a luxury.
I'm not sure how the ITT compared but it looks as though it would have been right up there...
Eddie
Around 1970 the Touring International sold at £56: that compares with just under £40 for a Yacht Boy, just over £40 for a Hacker Sovereign II, £59 for a Tandberg TP41. Not nearly so prohibitive as a colour TV as all but small-screen models I think would still have been in the £300 region to say nothing of the licence, but with the relative importance most folks gave to television many of the buyers of those radios probably will have been early adopters of colour too. Only elaborate world band portable radios were in another league as regards cost, with the then current Grundig Satellit, Zenith Transoceanic and Braun offerings each selling at around £180 and Sony's CRF230 twice that.
Superb work by Mike to have this set rejoin the living. My only related model is a Touring International 103, whose dial lamps are indeed permanently on (and unusually bright!) when used on mains power. It does seem a lot less boomy than a Yacht Boy to me, but I'm relying on distant memory for what those are like.
Paul
ALL done!
A fully functional portable radio again, or at least the batteries dont drop out anymore. 
A replacement handle would be useful as it is a bit of a handful when it has 6 D cells in it.
You never know I may find somthing yet to turn into a handle. 
I dont know what the dial bulbs were in this radio, they glowed about as much as a 40 watt lamp limiter with a batery set connected. 
I connected one of them to the bench supply and cranked it up to see what voltage they looked about right at.
It glowed a brighter orange at 20 volts and blew at 24v, I dont understand why they did not glow white. 
I have fitted a couple of 12v 0.04A grain of wheat bulbs and these give a useful nice orange glow.
Mike
