With many thanks to Alan Exley of Project Guitar Parts.
In the UK during the 1950's and into the early 1960's, guitar amplifiers were not that common. Yes, they were available, particularly from the Selmer London company who were soon to be joined by Elpico, Watkins, and Vox etc. The basic problem was that the majority of amateur guitarists couldn't afford a dedicated and properly designed guitar amplifier after having paid out the best part of a week's wages for a screw-on pickup for their guitar.
What was available however in the corner of almost every sitting room in the land were large valve-powered radio receivers, and even radiograms or tape recorders in the more wealthy households. These items of post-war domesticity usually had two small sockets in their rear, marked "pick up". This label did not refer however to the pickup on one's guitar, but in general to the pickup of a record player which could thus be provided with the facility of being played through the radio's amplifier and speaker. It was unfortunate that very few people in those days could afford a record player deck, and hence the sockets in the back of the radios usually remained idle.
With an increase in popularity of the guitar during the 1950's in Britain, and also with the advertising of add-on pickups as guitar accessories from around the mid-1950's, guitarists soon realised that some sort of an amplified sound could be obtained by plugging into the back of the family radio set. Because the impedance of a guitar is different to that of a record player stylus, the resulting volume was very low and the tone rather muddy. Most however persisted with this form of amplification until sufficient funds were available, or until a guarantor had been talked into signing a hire purchase agreement, for the purchase of a proper guitar amplifier. One thing that all were blissfully unaware of however were the dangers of electrocution which could result if the chassis inside the old radio was live!
A little while ago, Alan Exley of Project Guitar Parts came across the small piece of electrical equipment shown above, which was still in its original box. On the box was the name "Hofner", together with a description that explained that the equipment's purpose was to act as a pre-amplifier in order that "your radio set, radiogram, tape recorder (could be) converted to an amplifier....." Alan purchased this, and set about investigating its use and purpose.
The basic explanation of the pre-amp's function is given on the back of the packaging:
As far as setting things up were concerned, this was simple..........plug in the two banana plugs from the unit into the pick-up sockets in the back of the radio; plug in the �" jack plug from the guitar pickup into the top of the unit; turn on the radio; flick the switch on the top of the pre-amp unit, and that was it....just play the guitar will you! Probably best to make sure that there was a battery in the pre-amp unit though.
The "specially isolated circuit" feature was described on the box. Really this was very simple, consisting of a capacitor in the earth line in order to offer a degree of protection to the player. Alan has very kindly supplied a circuit diagram of the unit, which is reproduced below, together with a photo of the unit's inside. It would appear to be similar to the circuit of the later Dallas Rangemaster, with a few values changed.
So that's it; a neat solution to one's guitar amplification needs during the 1950's. Just one or two little mysteries though........
Why did Hofner make such a piece of equipment in England, rather than use one of their several electronics suppliers in Germany? It could of course have been Selmer who developed the unit, and used Hofner's name for credibility reasons. However, knowing Selmer, it would have been very unusual for them to have refrained from having their name somewhere on the packaging.
Why can't the unit be found in any Hofner catalogue or price list?
It can be found in just one Selmer Electronics catalogue however; the September 1964 edition. This seems rather odd as, by that time with the increase in personal afluence just about all guitarists in the UK had moved on from using domestic radios to proper guitar amplifiers. Was Selmer too late in coming up with this life-saving piece of equipment, or had it actually been for sale from the 1950's but never properly promoted? I suspect that we would have seen a lot more of these pre-amps about if that had been the case. I think this is one of those rare examples of Ben Davies (who ran the Selmer London Company) "missing the boat"!
....and as final proof of the introduction date of this little gadget, below is a scan from Beat Instrumental of October 1964:
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Note the reference also a small transistor amp with a one watt output, introduced by Selmer at the same time as the Selmer/Hofner pre-amp.
Many thanks again to Alan Exley