Known history with this , from its purchase in Germany onwards, including its original set of valves (not in there and used now, but will test out of curiosity). What are the main potential safety/reliability issues with an amp of this age? All the cotton covered wiring looks good but is there some test/procedure more convincing as to insualting value? Bakelite brittleness in the valve bases? metallurgical failure of springiness of valve contacts? Someone modified to 3 core mains cable and made an earth point, for 240V land, at some point in its history. Numerous caps replaced in 1991 and 1997 and some carbon R replaced with MO at some point. I've not checked the main caps yet.
No known safety issues other than mains wiring. These were pretty reliable amps. I own a 1970 Showman USA model. Someone tried to turn it into a 100 watt model by replacing the iron and adding two octals to the already blanked out chassis. I ripped all that stuff out and put new output iron in it. It's not worth much but it does sound sweet.
Closer look and the cotton covering to the wiring between the output heaters is "perished", crumbling to dust, and needs replacing. Strange having a load of Mullard, Brimar and Z&I Aero valves to test
Since the heater wiring is twisted it would be a good idea to replace if it is that poor of a state. I don't recall ever seeing the LV wiring in any Fender of that era in that state and the state of all the wiring is what I usually inspect first on any P2P wired vintage amp.
Z&I Aero!!! I haven't heard that name for over 40 years. That was when their shop in Tottenham Court Road was worth visiting, followed by a stroll to Proops, and then onto Lisle Street. Are there any surplus places worth visiting today?
I still have a Z&I Aero (Zaerix) glossy covered catalogue / data book in near pristine condition. It has data on lovely old things like VCR97 'scope tubes, and has all the prices in pounds, shillings and pence ! Oh those lovely old days of skiving off school for the day and jumping on the train to London to go to Tottenham Court Road and Lisle Street. Into Henry's Radio ... I bought my first 'hifi' amplifier in Proops. It's a Teleton SAQ-307. It's here in the computer room with me, and I'm looking at it right now. Still works as good as the day it was bought. Only about 8 watts per channel as I recall, but punched way above that weight. It drives my EMI 13 x 8 cabs with 7 x 5 mids and Eagle dome tweeters. The EMIs came from Henry's and the Eagles from Maplin I think, but might have been Tandy (Radio Shack). I also have the matching Teleton GT-203 tuner, and then the Nikko ND-790 cassette deck. Remember those ? All together, it was the classic "poor man's" hifi rig of the early 70s.
I think most of the wonderful old junk shops have pretty much gone now, but I think that Anchor Supplies up in Nottingham is still going. Remember AH Supplies ? They used to advertise every month in Practically Witless magazine, and I bought a lot of ex WW2 radios like 19 sets and an R1392 and a Wavemeter D from them. I have a feeling that they might still be going in one form or another. I'm also pretty sure that Birketts over in Lincoln somewhere are still going too. Then there was John's Radio, and Bull Electrical. Happy days ... Blimey. I've just looked up John's Radio, and they are still going !
The conductor size, under the insulation, is only 0.7mm presumably not enough for the current plus localised heating. Will replace with silicon sleeved wire with "Refrasil" glass sleeving over that , dulled down with dark green permanent ink felt tip pen, gives a very convincing contemporary look, and surprisingly does not wipe off the glass
Teleton SAQ-307! yes I had one o them. Marvelous amplifier, didn't it have some unusual feature for it's day, slider control or something? I had mine in my shop driving a stack consiting of a 15" Gauss in a home made Altec Voice of the Theatre copy, a 12" Gauss VotT copy and a whopping great Vitavox multicell horn (courtesy of the recently closed local ODEON). No electronic crossovers in those days! Even tho it was only a few watts, it could visibly make the shop window shake in time to the music (Dark Side of the Moon - Most impressive)
Ron(UK)
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At least not best wiring practise, wires not looped thru tags (2 passes) before soldering. Although original wiring , a 6L6 socket has been replaced at some time. Did he swap around the wires and so the heater pinning is different? . The original "push" pair have opposite polarity pinning for the heaters of each but the "pull" pair, with the replaced socket, are same "polarity". I'm inclined to replace the wiring with both pairs having alternate polarity
I used to visit GWM in Worthing till they closed down in 2003. But I didn't know they had simply moved. Some interesting stuff here:
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With regard to Z&IAero, in the early 70s I worked at a company where the electronics guy was Polish. Somehow the subject of Z&I came up. He said that Z&I were a front for a communist spy group! I Suppose anything is possible, but how they made much money out of pile of dusty and dirty ex-WWII (and earlier!) crap I don't know I actually bought an ancient Cossor 3339 from them. It didn't work and I never got it working. No doubt every capacitor was suspect as they would have been
30 or 40 years old by then, and heaven knows where it had been stored.
I'm surprised you didn't build the "Texan amplifier" sold by Henry's,
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I must have built 10 of those for me and my mates, then spent many happy hours replacing the unprotected output transistors! They did sound good cranked up (with a good heatsink)!
The treble and bass controls are sliders, Ron. I was always told that this amp was designed in Germany, and built in Japan. You can't get above about number 4 on the volume knob before it's blowing the glass out of the windows. As you say, a marvelous amp for its day, and based on the crap I see now on a daily basis, still up there in terms of performance. There were actually several versions of it, as I recall. The name Solatron or Solarton maybe, comes to mind as another version ??
Oh, I did. I built probably three all told, and then a Mark 2 for a friend. He's still got it I think. I'll ask next time I see him. That was a Practically Witless project, designed by a couple of lads from Texas Instruments just up the road from me in Bedford. I went to college with a lad from the same department, but not directly involved in the design.
I used to build lots of projects from that mag. Like 'The Clubman' transistorised HF receiver. Jackson Bros tuning gang with 6:1 epicyclic ball reduction drive. Repanco and Denco coils. Remember those ? Different colour plastic former for each function, and they plugged into B9A valve holders. I also built an audio amp that used those output transistors that looked like TO3s that had shrunk in the wash. Can't remember the type numbers of them now. I still have that amp under the bench in the workshop, and it still worked last time I put it on. I also built the famous PW frequency counter that used those seven segment filament displays, and a cartload of 74 series TTL. Don't build too much any more, except bits of special purpose test equipment to make my life easier.
I hve a non-worker Texan on a shelf. Wood cased , slimline due to the transformer form-factor. Unprotected from high dV/dt I remember, first time I came across fridges blowing amps
Not very convincing , some sort of legacy site? "Page info " dates like 24 October 2003 13:55:48, and 24 October 2003
15:07:28, even for "New In" page info date 24 October 2003 14:43:53 I will try phoning to confirm -( isn't high tech marvelous) but GWM Radio, 63 Victoria Road, Worthing is indeed different to the Portland something address. I used to drop in, going to Brighton
phone number is defunct. Looks like they moved in 2003 and closed in 2008. I keep seeing ref to the Freidrikshaven radio rally on the RSGB rallies page.
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