New to me 500B

ZR9B

Well-Known Member
Like it says....new to me. This thing is very clean, I can't find much of a scratch on it. I'm sure it needs a total overhaul or a good oncenover. The guy said it has been sitting for years so I bought it with out trying it. The 4 main tubes are not original 3 say Harman Karmin 7581 and the 3rd says GE 7581. The rest that I looked at say the Fisher made in Germany and match the paper. I probably paid a bit more than I should have but damn is it clean! I need to find someone in South East mi to help me. I prefer someone that will let me see what's going on and explain things (for a fee of course) . I know northren vacuum is well know and only a few miles from my house but....I want to learn...... anyway here it is.
 

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I don't know of any Fishers using 7581 tubes.
I think they should be 7591s. You may want to double check that.
 
Ya...I know there wrong....he pulled them I'm sure... Played like he knew nothing...but sure gave me some info!! People that are overly nice make me wonder.....That wasn't make or break considering I was taking a big chance anyhow.
 
500Bs sure are purdy, really nice example you grabbed there. And with complete paperwork, I thought having original owner's and service manuals with my 500C was a find.
 
That's a beauty, not sure about those power tubes as far as being similar to 7591's., hope they didn't rewire the sockets for them.
 
7581 and 7591 wiring are not mutually compatible. I'd verify the wiring for 7591, and put a quad of Tung-Sol Re-ISSUE's in them. Take some close up pictures from the bottom of the output tube sockets, clear and plenty of lighting without glare, please.

7581's are perceived as the US variant of the KT-66. A 6l6GB is equivalent to a 7581. a 6l6GC will push 25 or 26W vs. 19 for the 7581.
 
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Very nice 500B!

The 7581's are in the 6L6 class. I had bought a 800C receiver that was converted to take 6L6GC's. It sounded nice but I converted it back to 7591's as I wanted it original. The guy did a very professional job and had installed a separate bias supply as they are biased differently than 7591's. They needed more bias voltage than the 800C's power supply offered. Different pinout as well. I have a Scott 296 integrated amplifier that uses 7581's. They are noted as having a slightly higher plate dissipation than the 6L6GC, and are rated for 5 or so more watts, but they really seem to be the same as a quality 6L6GC.

The 7581's are scarce tubes and expensive if they test good. If you do convert it back you can sell the 7581's and buy whatever 7591's you want :D
 
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Now that I think about it, as Larry mentioned, just post a photo of the tube sockets from underneath. Someone may have just put 7581's in there thinking they were 7591's.
 
I got a integrated the other day with a bunch of random 12ax7 look-a-likes in the preamp section. The description was sculpted to avoid saying what the tubes were. So it goes.
 
I really think the guy pulled and kept them he is also selling a broken citation h k ....I'll get a pic under tomorrow....I cant wait till she sings!!!!
 
Under pic
 

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Thanks....I'm sure he pulled the good tubes.... If it wasn't so clean I would have passed.
 
Thanks....I'm sure he pulled the good tubes.... If it wasn't so clean I would have passed.

It looks very clean underneath too, and untouched which is very helpful. And with the face as nice as this it would look exceptional in a Fisher wood cabinet. Receivers this nice usually come out of a console where they were well protected.
 
Hey, you stole my thread title!


I was drinking when I made the post and forgot "the Fisher" but i left it because it sounded good......IOU one
 
And with the face as nice as this itwould look exceptionalin a Fisher wood cabinet.

I'm looking for a case .... maybe even make one...I prefer factory tho.
 
Looks like a VIRGIN 500B underneath. The output sockets are unmolested so 7591's are the correct tubes. sell the 7581's
 
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