Toshiba Amp and Tuner

[Wolfe64]

Picked up a Toshiba SB-620 amp and a ST-420 tuner at a garage sale today along with 2 albums and 18 78 rpm records.
I cleaned up the units and plugged the amp in but I don't get any sound out of it.
Another project LOL

Mark

 

[Unican_Eric]

By the look of things the pre amp jumpers are missing. Run some rca's in there and it might solve your problem.

 

[Wolfe64]

Thanks for the tip Eric.
I will try that tomorrow and see what happens.

Mark

 

[Wolfe64]

Installed the pre amp jumpers and now everything works as it should.
Thanks Eric :thmbsp:

Mark

 

[superdog]

That's a nice find.Toshiba stuff from the 70 s is good and not too common..

 

[Wolfe64]

Thanks superdog.
The only issue I found now is there is a significant hum on the turntable channel.
I tried 4 different turntables, turned the plugs around on each one and on the amp, had ground wires tooked to the amp chassis and no difference
It's just on the turntable channel.

Mark

 

[Binkman]

can't see the inputs really well with your pics. Take a look at the rca phono input mounting if any screws make sure it's aligned. Ya gotta open the box and take a look.. cable?.. loose connections around the rca hardware. Most metal chassis and negs of the rca's are usually on one neg. branch aside from the phono input. but I'm certain it's ground related. Look at chassis mounting if it's a sep phono board, again wires cables.

 

[Wolfe64]

Thanks Binkman
I took the cover off and checked around inside the RCA jacks and everything looked good.
Sprayed and cleaned the jacks and also the phono selector switch with Deoxit and now the hum is gone.

Mark

 

[Wolfe64]

Now a question about the tuner.
There are 2 outputs on the tuner, one says fixed and one says variable.
Why these 2 outputs ?

Mark

 

[Valveglow]

Now a question about the tuner.
There are 2 outputs on the tuner, one says fixed and one says variable.
Why these 2 outputs ?

Mark

See the output level knob on your tuner? When "variable outputs" are attached to the amp, the output level knob works on your tuner. It will not work if you use the fixed outputs.

 

[Wolfe64]

Thanks for the info Valveglow.
So, in other words it is a volume control for the tuner?
I'll have to experiment with that tomorrow.

Mark

 

[Valveglow]

Thanks for the info Valveglow.
So, in other words it is a volume control for the tuner?
I'll have to experiment with that tomorrow.

Mark

Sort of. I think it's more like an attenuator. If your tuner did not have this knob, it would always play at full output. This way, it is handy, especially if the tuner and amp are more than an arms length away and reaching the amp's volume control is difficult. Sometimes as you move across the dial, some stations are too loud or too quiet. Also, it can function as sort of a muting aid to temporarily quiet interstation noise as you move across the dial.

 

[Wolfe64]

Ok I understand

Thanks again

Mark

 

[Beatnik]

That's so ugly it's cool, especially the upside down tuner.

 

[superdog]

The upside down tuner is an odd feature.

 

[Wolfe64]

I never thought of it as an upside down tuner and I had to go back to the picture and, well, it's an upside down tuner !!! :lmao:

Mark

 

[Valveglow]

I never thought of it as an upside down tuner and I had to go back to the picture and, well, it's an upside down tuner !!! :lmao:

Mark

Just a few arguably "upside down" tuners:

http://www.fmtunerinfo.com/L-07TII.jpg

http://www.fmtunerinfo.com/L-07T.jpg

http://www.fmtunerinfo.com/ST-2950SD.jpg

http://www.fmtunerinfo.com/ST-4950.jpg

http://www.fmtunerinfo.com/ST-5950SD.jpg

http://www.fmtunerinfo.com/ST-A6B.jpg

 

[Oilmaster]

naahhh, for true upside-down tuners the dial knob should be on the left side. Haven't seen one of those so far :tongue:

 

[janikphoto]

That's so ugly it's cool, especially the upside down tuner.

That's what I thought. I had to take a second look, because I thought the piece was just sitting upside down!

 

[Wolfe64]

You guys are giving my tuner a complex !!!!! :lmao:

Mark