I may be attempting to restore a mid 1960's tuner/amplifier that may have germanium transitors. If that comes to pass and some are faulty, is there a reasonable chance modern substitutes can be obtained?
I accquired the notion a few years ago that such a thing was either impossible or next to impossible.
I accquired the notion a few years ago that such a thing was either impossible or next to impossible.
GE transistors of previous years can be purchased in Russia.
Alloy type PNP P213-P217. Drivers GT402 PNP and GT404 NPN.
There is an idea to use a composite transistor GE PNP together with SI PNP. This will provide high power and reliability and good frequency properties.
Low-power GE transistors can be replaced by SI with a change in bias.
Alloy type PNP P213-P217. Drivers GT402 PNP and GT404 NPN.
There is an idea to use a composite transistor GE PNP together with SI PNP. This will provide high power and reliability and good frequency properties.
Low-power GE transistors can be replaced by SI with a change in bias.
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Do you have schematic for the thing? That would be very useful if you have to convert to Si devices.
Yes, asking the question before having it in front of me is putting the cart before the horse. It is an attempt to determine what might be facing me.
Since it's a console stereo, my thought was it may be more trouble than it's worth. The travel time to get it is considerable which dictates when the trip can be made. Realistically, that is two weeks from now.
Normally I would not be acquiring stereo consoles. But a housemate likes the look of it as a piece of furniture and wants it to be functional.
But, I've become more interested in acquiring it mainly due to the turntable inside. If the electronics portion proves to be difficult and beyond me, I can at least get the table into working order. Which in my opinion, is worth more than the cost of the entire unit. The table is a Dual 1009 and I am somewhat familiar with their disassembly/reassembly having put several to rights.
There were no online schematics I could find for this particular console model. But I found a somewhat local source which lists numerous diagrams for model numbers of this particular brand, available as PDF's. It happens to be a TV & radio repair business.
A possibility, maybe remote, is that a schematic exists inside or underneath the cabinet. There is also a possibility that the owner's manual which will come with the console may contain it. On the back page or something.
If none of that is the case, my thought was then to contact that repair business and ask if any schematics they do have on hand correspond with with this particular one. It may be a reasonable expectation that the same amplifier/tuner devices were used in multiple cabinet designs.
Since it's a console stereo, my thought was it may be more trouble than it's worth. The travel time to get it is considerable which dictates when the trip can be made. Realistically, that is two weeks from now.
Normally I would not be acquiring stereo consoles. But a housemate likes the look of it as a piece of furniture and wants it to be functional.
But, I've become more interested in acquiring it mainly due to the turntable inside. If the electronics portion proves to be difficult and beyond me, I can at least get the table into working order. Which in my opinion, is worth more than the cost of the entire unit. The table is a Dual 1009 and I am somewhat familiar with their disassembly/reassembly having put several to rights.
There were no online schematics I could find for this particular console model. But I found a somewhat local source which lists numerous diagrams for model numbers of this particular brand, available as PDF's. It happens to be a TV & radio repair business.
A possibility, maybe remote, is that a schematic exists inside or underneath the cabinet. There is also a possibility that the owner's manual which will come with the console may contain it. On the back page or something.
If none of that is the case, my thought was then to contact that repair business and ask if any schematics they do have on hand correspond with with this particular one. It may be a reasonable expectation that the same amplifier/tuner devices were used in multiple cabinet designs.
A lot of people keep the typically beautiful cabinet, real polished wood, etc, gut it and install modern electronics and speakers inside.
Keep the cool visual factor but sound 1000 times better.
FWIW I have embedded a killer sounding Kawai electronic piano plus an "invisible" amp and speakers inside a discarded vertical piano housing, without its original sound machine, for a local Symphony Orchestra (actually the reduced 16 member version) because they do shows in different places, it´s easy to trav el with a Cello, A Fagot, a Clarinet, etc. but hard to move a real piano.
The new one was *light* (easily lifted by 2 people using added side handles) and if needed, way louder than an acoustic one.
Nobody was the wiser.
They asked me to do the job because customers were dissappointed when piano player showed up with his tiny Kawai on 4 folding legs and an amplifier besides him, they thought he was cheating.
There are many organizations of people who restore historic equipment, they probably know where to find germanium devices. Here in the Netherlands I would go to Radio Twenthe in the Hague, and if that doesn't work try Nederlands Transistorforum or one of the NVHR fairs, whenever those will be held again (the last two were cancelled because of COVID-19). I haven't a clue about historical equipment in Canada, though.
I will do that but I am literally out in the sticks for a few days and cannot access the model number from this laptop or my phone.
It is contained within a FB Marketplace conversation and for whatever reason, nether device at hand is giving me access to that account. So providing the model number must wait until I'm back home.
My ability with handheld and WiFi devices is pretty much zero and there is no 12 year old anywhere nearby to show me what to do.
EDIT: That's a good point about a 1009 being in a "deluxe" console which is what I thought as well. But the photos I saw of the control panel looks kind of cheesey. Maybe the 1009 is not original? But then the cabinet features doors that cover the speakers. When opened, they can be slid inside so the furniture aspect seems well done.
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Yes, stuffing new amlification inside crossed my mind because I traded with this person a decent system (amp, turntable, speakers) for some furniture. But she now feels the look of a console would be more appropriate for her decor.
I've subbed silicon for germanium directly in organ oscillators and mixers and voltage regulation circuits. Amplifiers may require a resistor change to keep the currents under control. Germanium power transistors were a mistake; by 1966 nobody with a reputation to protect was using them, preferring vacuum tubes for power drivers in the oil exploration business. (parallel 6L6 driving vickers hydraulic valves, for example.) Definitely redesign for silicon power transistors or gain units (boards) if you encounter power germanium transistors. Especially those flying saucer packages.
Output stages that were class B had only moderate crossover distortion in germanium, which was acceptable for 1962. Horrid sounding in silicon and really class B was a nuisance if people weren't wowed enough by the logo "9 transistors" on the front of the product to forget to listen to it.
Output stages that were class B had only moderate crossover distortion in germanium, which was acceptable for 1962. Horrid sounding in silicon and really class B was a nuisance if people weren't wowed enough by the logo "9 transistors" on the front of the product to forget to listen to it.
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Your console is likely a Electrohome or a Clairtone, if Canadian made. Electrohome used mainly Garrard, Clairtone, in later years, often DUALs. Of course it could be a retrofit or a European unit. Nordmende was brought into Canada by Noresco and had a loyal base with the German community Southeastern BC. E
Since the Dual table within it was made from 1964-66, my assumption s that was when the console the console is from.
The brand name is Viking - T. Eaton Co. I have been assuming that the electronics portion was by Electrohome. But maybe the entire affair. The photo of the rear label I was sent does not look to dissimilar to those I've seen online pics of belonging to Electrohome consoles.
The last one of these things I worked on had PNP Ge outputs, but the rest of the electronics was silicon. And it was the Si *driver* transistor that went out - in both power amp boards. The outputs were still good.
Biggest problem with these old consoles is finding replacement speakers. They don’t have much power, so putting in 87dB/W replacements doesn’t go far, and too low a Q results in no bass. Putting in modern speakers in a proper reflex sub-enclosure would sound good, but not on the typical 10 watts output.
Biggest problem with these old consoles is finding replacement speakers. They don’t have much power, so putting in 87dB/W replacements doesn’t go far, and too low a Q results in no bass. Putting in modern speakers in a proper reflex sub-enclosure would sound good, but not on the typical 10 watts output.
Yes, those used thin paper light voice coil inherently efficient speakers.
Call it "easy to drive", same thing.
High Q so boomy bass which way back then passed as "Bass", no qualification.
Somewhat tamed by aperiodic cases, any size you get in that piece of furniture (can´t call it "acoustic cabinet") , with back closed by a multiperforated piece of hardboard which resistively damped Q and somewhat flattened response.
Completely different from any modern speaker.
Call it "easy to drive", same thing.
High Q so boomy bass which way back then passed as "Bass", no qualification.
Somewhat tamed by aperiodic cases, any size you get in that piece of furniture (can´t call it "acoustic cabinet") , with back closed by a multiperforated piece of hardboard which resistively damped Q and somewhat flattened response.
Completely different from any modern speaker.
It's still two weeks away before I have the thing in front of me to see what it's got inside, Speakers included. I am not inclined to replace those unles there is something bad wrong with them.
For the purpose it will serve, the console's original drivers will do provided they are still functioning. Mainly the project will be ensure things work and to bring the cabinet as up to snuff as I can manage.
That. Original speakers were matched to original amp and viceversa by definition.
designers used what they had available (modern ones do the same, I bet prized 2020 systems will be quite despised in 2050
)
Modern 85/88dB speakers will be weak sounding with old 5/10W power amps, old speakers will "lose Bass and some Treble" when driven by modern high damping factor amps and so on.
And will be destroyed by >25W amps while they were perfectly adequate to single 6BQ5 outputs or equivalent.
A pair 6BQ5 push pull per channel would have been fitted tothe highest power and quality home consoles, very rare indeed.
I still keep, for sentimental reasons, an old 1963 Grundig console, wih a record player, multiband radio, including FM, 1 6BQ5 per channel, and sporting 2 x 10" speakers + .... Tweeters! ..... in unstuffed integral enclosures with back panels made out of multiperforated hardboard.
As crude as it was (by modern standards) it was the best of the neighbourhood and friends brought their Beatles, Stones, Tremeloes, Sinatra records to my home to "listen to them properly" , go figure.
So I suggest you keep original speakers, if at all possible.
ZERO specs on them, of course, but they will be roughly similar to these modern made speakers:
C10R | Jensen Loudspeakers
or
C12R | Jensen Loudspeakers
currently sold "for Guitar use" but really they were "all the same" way back then.
Famous G12 Celestion speakers started their life in 1956 or so as highest quality "Console speakers", go figure; same with 40s and 50s Jensen speakers, only later both genetic lines split, specially after Acoustic Suspension speakers were invented.
designers used what they had available (modern ones do the same, I bet prized 2020 systems will be quite despised in 2050
)Modern 85/88dB speakers will be weak sounding with old 5/10W power amps, old speakers will "lose Bass and some Treble" when driven by modern high damping factor amps and so on.
And will be destroyed by >25W amps while they were perfectly adequate to single 6BQ5 outputs or equivalent.
A pair 6BQ5 push pull per channel would have been fitted tothe highest power and quality home consoles, very rare indeed.
I still keep, for sentimental reasons, an old 1963 Grundig console, wih a record player, multiband radio, including FM, 1 6BQ5 per channel, and sporting 2 x 10" speakers + .... Tweeters! ..... in unstuffed integral enclosures with back panels made out of multiperforated hardboard.
As crude as it was (by modern standards) it was the best of the neighbourhood and friends brought their Beatles, Stones, Tremeloes, Sinatra records to my home to "listen to them properly" , go figure.
So I suggest you keep original speakers, if at all possible.
ZERO specs on them, of course, but they will be roughly similar to these modern made speakers:
C10R | Jensen Loudspeakers
or
C12R | Jensen Loudspeakers
currently sold "for Guitar use" but really they were "all the same" way back then.
Famous G12 Celestion speakers started their life in 1956 or so as highest quality "Console speakers", go figure; same with 40s and 50s Jensen speakers, only later both genetic lines split, specially after Acoustic Suspension speakers were invented.
It is not advisable to replace Ge transistors by Si ones especially in the AM/FM frontends of IF strips. This unevitably leads to the need of a complete realignment, if you manage to get these stages working at all. And for the AF amplifiers: It has been said yet that Ge power devices are not that reliable at all. But if the amps are still working, leave them alone. Otherwise get a pair of relatively cheap chipamp boards, mount them to the heatsink(s) and replace the complete power amplifiers besides the tone control section.
Best regards!
Best regards!
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