Amp ID?

Its a common tube in Mullard designs. Eico stuff used them. EF86 and a 12AX7 is the front end for a 5-10 (EL84 push-pull) or 5-20 (EL34 push-pull) amp.
 
Tubes came,, Big thanks to RWood!!!

I have to use a jumper between the OPT secondary Common lug to the main metal chassis to eliminate oscillation and hum... I don't quite understand how it worked originally, as the main CT,,cap can, and all other grounds are insulated above the chassis... There is an original ground wire from the OPT Com lug and input jack lug, but both jacks are also insulated from the chassis... I want to try and retrace the original wiring from pics, to see where, if at all, the chassis is grounded to the OPT.... Only place I can think of is the original crystal phono input jack... Stay tuned,,, we'll get to the bottom of this mess!!!
 
Well,,, Its back together,, very quiet, nice sound, excellent face plate, etc... Too bad, as I thought it would be a good source for a guitar amp project! Thanks again for all the input, conversation, help and tubes!!! It would a nice to mate it with a matching amp for a small stereo setup, not for me tho,,, I hope to never open that box again!!! It had to be designed by a guy named Pandora... If I were to keep it, I would rebuild it on a chassis similar to the Mullard amp link in the thread, and offer the face plate and box up for someone's up grade...

Seems the original 6267 had an intermittent short... So, along with a broken ground wire connecting the two input jacks, bolting the chassis back together, and eliminating all the jumpers killed the hum... All the caps and out of spec resistors are replaced... Restuffed the can...

I put the power switch on the front panel,, and rewired the crystal phono jack as a 2nd line input with a switch in the proper hole... Left enough slack in polarized line cord to put an inline fuse holder in it, by just removing the bottom plate... Its running on variac now, so its protected...
 

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Actually,,, Heath plate is part of the box, which is what makes it hard to disassemble and work on the chassis... gotta remove the pots and let em dangle, as the wires are too short to get it apart... Also, the pots have to be bonded together to eliminate hum when they are apart... Face plate looks so good because it was covered by BEA plate since new, never had a screw or pot bolted directly to it...
 
I like the looks of it. Like a tiny console with those legs. I had a similar problem with an E80CC. It has an intermittent short in one half. I thought it was one of my KT77'S at first. Swapped out power tubes and all was good for a few days then the same thing happened again.
 
Yeah,, a lot of those Heaths had legs like that, modern look or something? One was missing, I made a replacement and put it in the back,,, I'm thinking, that tube was intermittently shorted, and with how clumsy it was to work on this amp, I guess I jostled it too much and shorted it sometimes... Saw that happen with an 811,,, that one made fireworks,, I knew it was shorted!!! Don't think I'm a fan of these Exxx tubes! Tester didn't seem to pick it up...
 
I've got a couple of noisy ones. They're also microphonic and they are in a console. Turn it up and it actually starts ringing from feedback. Its not in active service so I haven't been worried about it but at some point that will change, and so will those tubes.
 
I've never run into them before, really surprised at teh low V they run at... I used the TC2 tester settings you sent, maybe they weren't accurate on TC3,,, didn't show a short,,, maybe it was clear when I tried it? who knows... I thought this amp was going to be a parts donor!!!
 
I haven't tried it after I got it working, was tempted, but figure if its shorted when I plug it in, and it causes anything to blow,,, I'll have to disassemble it again!!!! Not up for that!!! If I run into something that uses these, and is easy to access, I'll give it a try...
 
I haven't tried it after I got it working, was tempted, but figure if its shorted when I plug it in, and it causes anything to blow,,, I'll have to disassemble it again!!!! Not up for that!!! If I run into something that uses these, and is easy to access, I'll give it a try...
Chicken. :D
 
YEP!!!! I broke a wire/cap lead/ground connection every time I moved those pots,,, front plate should have been attached to the chassis.... Real bad box design...
 
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