Help, voltage problem!

[smallmany]

Resistance
1 0
2 0
4 0
5 0

VDC
1 0
2 0
4 0
5 0
7 65
9 62
13 198
15 210
A1 0.1
A3 0.6
A6 0.1
B1 0.1
B3 64.3
B4 0.1
B6 61.4

Off my multimeter, the 9pin socket should have zero voltage but both my tubes filaments glow. The sound comes out but is really quiet. There is a loud constant hum at any volume.  Both the LEDs are not glowing.
Any ideas? Help


tl;dr No voltage at 9 pin socket. Low voltage at 8 pin socket. But there is sound just not very audible/distorted + constant hum

 

[Paul Birkeland]

Having 0 Ohms at 1-5 means don't turn the amplifier on....

Since terminals at 1-5 are directly wired to other terminals, you should have other resistances that are off.

Can you post a full list of these?

Is there any way you can upload pics of your build?

 

[smallmany]

Welp, I was missing the wire from B2 to 2L.

So I solved the resistance problem but the LED connected to A8 is not lighting up.
I can't remember all but terminal 1 had voltage of around 150v

 

[smallmany]

is the LED important or is it just a indictation that voltage is running through

 

[Paul Birkeland]

Again, please post your resistances and do not turn the amp on...

 

[smallmany]

Is mis-wiring the culprit for my blown LED at A8? If not, what may be the reason? The other LED was functioning

Thanks

 

[Paul Birkeland]

How is the LED blown?  Did you hear it snap, did the leads break off, etc?

 

[Grainger49]

smallmany,

Paul, Caucasian Blackplate, knows this amp as well as anyone alive.  You should be answering his questions rather than asking new questions.  Paul can walk you through fixing this.

 

[smallmany]

The LED at A8 would not light up. Thinking that it was a cold joint, I reheated the solder, and the lead melted out of the LED.

 

[Paul Birkeland]

You can e-mail [email protected] and we can send you some additional LED's.

I would encourage you, however, to post all your resistances before turning this amp on again. 

If the resistance check is good, then move on to powering up the amp. 

For an issue like an LED not lighting, that is certainly what we are here for.  More often than not, this actually has nothing to do with the LED itself, but manifests from elsewhere in the circuit. 

-PB

 

[smallmany]

Once the replacement arrives, I'll be sure to give you an update of the readings

Thanks

 

[smallmany]

After soldering the new LED, everything checked out almost perfect. The center seems a bit off when i listen to it, i feel like the center is a bit off to the right. Hoping it is just the tubes burning in.

 

[smallmany]

Also, the tube next to the transformer gets so hot I could cook my eggs on it.

 

[Doc B]

Also, the tube next to the transformer gets so hot I could cook my eggs on it.

That's good, it is working exactly the way it is supposed to.

 

[smallmany]

I noticed that when i increase the volume, the right side is louder than the left , but is fine at low-medium volume.

 

[smallmany]

resistance of 600k ohm on terminal 13 , it is above the 270k but it varies with ohmmeters right?

 

[Doc B]

The difference may be due to the fact that the tubes haven't burned in yet. Just enjoy some music for a while and see if the imbalance gets better as the tubes break in.

 

[Paul Birkeland]

resistance of 600k ohm on terminal 13 , it is above the 270k but it varies with ohmmeters right?

Yes indeed.

 

[smallmany]

Since tubes degrade faster the hotter it gets, is it possible to add a heat sink to deviate the heat away?

 

[Paul Birkeland]

Since tubes degrade faster the hotter it gets, is it possible to add a heat sink to deviate the heat away?

There is a range where a given tube will operate well.  If you go too high, you will indeed shorten the life of the tube, if you go too low, you get poor performance out of the tube.  We are running the 6080 at about 25% of its maximum dissipation rating, so there is nothing to be concerned about here.