strange console phonograph- pictures

[init4fun]

Hi Rob ,

6SJ7-GT most certainly is a tube identification number , and designates that tube as the "pre amp" or "1st audio" , depending on whose terminology you choose to use . The other two numbers are not tube identification numbers and are likely either manufacturer code or date of manufacture code . Those two tubes will likely have numbers 5Y3-GT , which is the rectifier that supplies DC plate voltage for the two audio tubes , and 6V6-GT which will be the "audio output" or "final audio" tube . It's likely that the final could also be one of the cousins of the 6V6 , and there are a few , with such numbers as 6F6 , 6K6 , 6L6 , and the "GT" designation refers to it being a "Glass tube of tubular construction" as opposed to being glass of a bell type shape or all metal .

As to a schematic , you may not find one exactly for the equipment , but just about any 3 tube amp with the same tubes will likely have the same wiring . The schematic will be needed really only if a recap fails to produce a running amplifier . The caps you will replace are all labeled with their ratings , and you simply replace them with new caps of equal ratings . The two ratings are "working voltage" , which is as it sounds , the amount of voltage the cap can be safely asked to endure , and "capacitance" which refers to how much electricity the cap can store till it's needed to be released back into the circuit . Yes , to the casual glance , a capacitor acts similar to a small battery in that it builds up an electrical charge to be used later , the difference being that the cap can charge and discharge many thousands of times each second , instead of the much slower charge/discharge cycle of a common battery . Ripple filtering and AC blocking are two prime uses , as well as interstage coupling . Your likely to find the B+ filtering to be a couple of "40 MFD 450 Volt" electrolytic type capacitors , and these are to be found in a round can made of either metal or cardboard . These caps ARE polarity sensitive , having a defined positive and negative connection that must be observed during instalation . The other caps , the ones taking sound from circuit to circuit will have fractional MFD numbers like ".05 MFD at 450 Volts" and are not polarized , it will work no matter which connection is + or - . The general practice here with the replacements is to come as close as possible to the MFD rating (.047 being a perfect modern day replacement for a .05) and to AT LEAST meet (or better , to slightly go over) the voltage rating (a 600 Volt cap is a perfectly acceptable replacement for a 450 volt one , and a 400 volt one WILL fail in short order) .

I'm happy to hear your willing to give recapping the amp a try , and if you could post pictures of the underside of the amp I'll be more than happy to let you know what's what under there to get you going in the right direction .