Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: alan 53 on April 06, 2014, 11:26:39 pm
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HI ,I'm a member here and a long while back I built a tube amp from a kit.I could never get it to work.Could never get the power tubes to light up.I asked questions here as well as other places and although I got lots of helpful tips on how to troubleshoot the amp ,I still could not get it to work.I got back into trying to figure this thing out because I 'm somewhat knowledgeable with electrical circuits.I had ordered two 8 pins sockets a while back so I decided to replace the original ones with them.That's when I finally found the problem.When removing the original sockets I noticed that the KEY in socket was between pins 4 and 5. On the new sockets the key is between pins 1 and 8.I looked at the Weber diagram and compared it to the Triode diagram. The Weber Diagram doesn't show the location of the key in the socket.The Triode diagram does.So even though I had soldered the wires to the correct pins,when I put tubes in the sockets,The tube wasn't positioned properly.I was very happy to finally find the problem .I have a picture of the sockets that I'll try to post here.I had tripled checked all my work on the turret board believing the problem was in my work.I'll try to put a picture up if I can figure out how to for anyone interested Alan
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Key between 4 & 5??
Yeah, that would ruin your day. Almost any mis-insertion of an octal tube that gets high B+ releases the hidden smoke.
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Are there numbers on the tube sockets? Never noticed. The key is ALWAYS between pins 1 and 8, regardless of what may be written on the socket. Looking at the bottom of an octal socket pin 1 is clockwise from the key. Just count pins in a clockwise direction.
Can you post a pic of the socket that is mis-numbered?
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I think sometimes people can get a little confused between looking from the top or bottom?
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Well I'm going to post a picture of the socket I took out.I posted it in AMP GARAGE.Trust me.This is a picture of the SOCKET,the numbers are 180 DEG off. Now I wired the socket correctly but the key being between pin 4 and 5 and not 1 and 8 AIN'T going to work.Funny though I don't think any damage to the transformers or anything else happened.
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Where did you get the sockets? I'd be interested in broadcasting that so others can avoid them.
The key is ALWAYS between pins 1 and 8, regardless of what may be written on the socket.
... the key being between pin 4 and 5 and not 1 and 8 AIN'T going to work ...
What you should take away from this is you have to know what pin is what on a tube.
And what Sluckey is saying is looking at the socket from inside the amp, pin 1 is always the first pin clockwise from the key. That's because pin 1 of the tube is always the first pin clockwise from the key.
Same with 9-pin sockets: pin 1 is always the first pin clockwise from the open space.
I know some sockets have numbers on them, but I always find myself counting pins when I'm wiring up an amp.
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here what I posted on another forum http://ampgarage.com/forum/viewtopic.php?t=24460 (http://ampgarage.com/forum/viewtopic.php?t=24460)
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I'll post the socket pic here since you have to be logged in to see the pic at TAG...
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thanks for moving the picture.I'm not all that good at posting pictures
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It was fortunate the way the socket was mis-numbered that tube damage is unlikely, much less amp damage.
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Yeah, you are right.No damage .But me as a beginner,I was doubting myself.Now all is working.Crazy.Who would have figured :laugh: