Panasonic Tube Console

Dot Heton

Active Member
Some of you might have seen my post of a fuzzy picture with an Elac turntable. I was disappointed that the CL poster wouldn't return my emails. Well out of the blue today I got an email from the guy.
Bottom pic is the crossover.
 

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I really just wanted the TT but was surprised to see it had tubes. Then I was shocked to see the kind of tubes. Then I saw the micro output transformers. This thing sure is a mixed bag.
 

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The Elac is a model 10
The tube amp is a model mw 1717.
The cabinet style is 6011.
I don't know the year yet but I should be able to find some date codes soon.
I didn't pay a whole lot so I'm very happy, even if the tube amp seems a little wimpy.
 
What are the output tubes? Yea, those OPT look very wimpy, although the PT seems to be pretty beefy. Strange amp indeed.

BillWojo
 
25E5, I think the early Sansui 1000 used those. TV sweep tube according to it's data sheet, but thats about all I can say. It doesn't give any audio amp uses.

I hope those aren't actually the output transformers, those things are absolutely tiny. Looks like a nice size power transformer and the speaker crossover looks like they put some actual effort into it. Many consoles had a simple blocking cap in series with the tweeter and thats about it. Interesting that it seems to have an impedance matching transformer as part of it though. Usually you see that sort of thing in a PA system. Wonder if maybe the OPT on the chassis has some strange high output impedance and the trafo on the speaker crossover is the other half of the equation.
 
That thing is just too dang cool! Hope you're not thinking of gutting it...although if you're space-constrained I'd certainly understand.
 
That's a nice looking console there, seems to be in nice shape too. I wouldn't mind having one like that in my home. I have an Elac TT also, I like it a lot.
 
I guess to function properly, you need to keep it intact as the speakers are specific to the circuit.
 
25E5, I think the early Sansui 1000 used those. TV sweep tube according to it's data sheet, but thats about all I can say. It doesn't give any audio amp uses.

I hope those aren't actually the output transformers, those things are absolutely tiny. .
I have a single output trans from a Sansui 1000 and it a proper sized unit. The caps are connected directly to the opt leads. Supposedly the tubes are excellent sounding but are getting rare now. Telefunken also made that tube but that is a very rare bird to find.
The Fisher 460 console amp has tiny transformers too and it sounds good. If they are the outputs they definitely are not high output ones.
 
Gadget is correct with regard to the Sansui 1000 (not the 1000a) using the 25E5's. Watch the heaters on those. They might be in series directly from the line voltage. if you can get a schematic, it would help with troubleshooting it.

44w music power is total peak watts (both channels). That equate to about 7-10 watts RMS. With highly efficient speakers it would sound larger than you think.
 
It is conceivable that the 25E5s are configured in single-ended push-pull (SEPP), which would make sense with a speaker line matching transformer. I would love to see the schematic drawing for this model.
 
National/Panasonic made some interesting stuff back in the '60's. It's too bad they didn't sell much tube stuff on the US market. The only thing I have is a clock radio from 1964.
 
SEPP, hm, looks rather like what Phillips was doing on their OTL designs in the late 50s. They used an EL84 paired with an EL86, with the output coming from the EL86 cathode into an 800 ohm speaker via a capacitor to block the DC. No output transformer. I have one, and unfortunately the 800 ohm speaker died. Its married up with a matching transformer from a PA speaker to allow use of a conventional 8 ohm speaker.
 
Here's a better shot of the crossover with the transformer and the speakers.
300 ohm woofer, 16 ohm tweet, unknown mid.
 

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hm, SEPP sounds increasingly likely with a high impedance woofer. Definitely not your typical output stage at any rate.
 
So far I'm trying to get both channels to work I'm not getting the left channel out of the tuner, the amp is working good. AFX doesn't work. I'm checking all the obvious stuff. All tubes are lit up, I've swapped some of the RCA's, I need to call in a pro. The sound is nice though out of one side.
 
I should clarify about the AFX statement. I should have said that I get sound with the dial on mono and no sound when I turn it to stereo. Also the stereo light doesn't work. The manual says it's a neon bulb, if that makes a difference to anyone. I just ordered a booklet online that has the schematic.

No matter what I try I can't get sound out of both speakers.
 
SEPP, hm, looks rather like what Phillips was doing on their OTL designs in the late 50s. They used an EL84 paired with an EL86, with the output coming from the EL86 cathode into an 800 ohm speaker via a capacitor to block the DC. No output transformer. I have one, and unfortunately the 800 ohm speaker died. Its married up with a matching transformer from a PA speaker to allow use of a conventional 8 ohm speaker.

What is OTL?
 
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