First Time Crack Builder Need Assistance [solved]

[prtuc2]

On the second time power up I was able get B1 to hit the low 70s voltage.  I noticed I was having a little hard time inserting the RCA cable into the white RCA jack, then as I use my headphone to test out the amplifier something new happen.  At the first 2 minutes of the song everything seems fine, then I start hearing crackling sound then eventually shortly after the right channel of my headphone completely gone.  I re-test the headphone on my other amplifier it is still functional, but now I have a new problem to solve. 

Thanks for any input.

 

[prtuc2]

I check over the resistance values and the voltage values after the crackling sound heard, voltages are closer to the actual values now.  Could it be a bad tube? If the problem is the tube do I need an adapter to use 5998 or other tube like 6SN7 type of tube?

 

[Paul Birkeland]

This is usually a flaky solder joint.

-PB

 

[prtuc2]

It seems the more I do the more problems I am running into. 

The first thing I did was to resolder all the terminals that doesn't have a shiny finish and I redo the RCA center pins area but I might have mess it up.  Inside the center pins there is some solder left over that I can't remove so I just place the white cable into that RCA jack. 

Then I recheck the resistance and voltage values all within range.  Right before I try to turn off the amp and in the process I noticed the led on A3 and A8 both went out.  I proceed connecting to the DAC and headphone in place to check for sound.  No sound at all.

I power down the amp and unplug the power cord, checking the resistance values now show OL in most of the terminals.  So, lost in what is going on.  Not sure if the multimeter playing trick or I am doing something terribly wrong.

Thanks for any input.

 

[Paul Birkeland]

Do the tubes still glow?

 

[prtuc2]

Yes, the tubes seems fine.  The voltage and resistance reading is hit or miss sometimes I got the values all within range, next time I measure it will be different.

 

[Paul Birkeland]

I would recommend reporting any resistance readings that are not correct.

-PB

 

[prtuc2]

This measurement is taken more than 8 hours after I power down my amp and with the tubes inserted.

Resistance
1              >1000K ohms
2              >1000K ohms
3              OL
4              >1000k ohms
5              >1000k ohms
6-10          OL
12            0.2 ohms
13            >800k ohms, but slowly dropping my meter can't get the actual value on this terminal less than 10mins
14            0.5 ohms
20            0.2 ohms
22            OL <---? I didn't solder this on page 19 under revision I connected to 14U instead
B3            OL
B6            OL
RCA ground    OL
Center      OL

 

[Paul Birkeland]

Terminal 3 is connected to the chassis plate.

A wire goes from 12 to the lower set of lugs on the headphone jack, then from there to terminal 3.

Getting OL between 12 and 3 means that this wire is not connected.

 

[prtuc2]

Thanks for the all the help so far, now everything is up and running.  But, on the right channel of my headphone there is a pop sound like every 30 seconds, what could be the problem?

 

[prtuc2]

Also heard noises like blowing wind rushing or blowing into the headphone causing noise like static.

 

[Paul Birkeland]

This sounds a lot like a cold solder joint or a loose wire.

 

[prtuc2]

I got everything up and running for a few days.  Eventually got the speedball upgrade install as well.  The first two days the amplifier sounds great, however today as I turn on the amp I noticed the sounds so weak on the left channel and no sound on the right channel.

I measure the VDC voltages and the reading:

Terminal                      Voltage
1                                2.8
2                                45
3                                0
4                                45
5                                40
6                                0
7                                0?
8                                0
9                                37
10                              0
11                              0
12                              0
13                              44
14                              0
15                              116
20                              0
21                              186

All the values are below the range, the capacitor between terminal 14 and 15 feels much hotter than all the other parts of the amp.  I noticed the heat generate between the two terminals actually melt the solder iron on terminal 15 and the 270k Ohms resistor connecting to terminal 15 is loose in the process.  Also saw a burn mark around terminal 14 and 15, the capacitor

Which is an appropriate step to go from here?

Appreciate any input.

 

[Paul Birkeland]

Something in the circuit is sucking down a crapton of current.

Start by running the amp without the 6080, then remeasure the voltages.

If they are all still low, remove the red wire from terminal 13, then run the amp and measure the voltages on the two 6 lug switches.

If you have a cap that's getting really hot, that generally happens when they are in backwards. 

Do also be aware that without tubes in the amp, the power supply will take an unusually long time to discharge.

I suspect you have a loose part shorting two adjacent terminals, but the tests above will help narrow down where the issue is.

 

[prtuc2]

Here is my reading without the 6080 tube:

Terminal                Voltage
1                            63
2                            224
3                            0
4                            224
5                            64
6                            0
7                            0 <<--- should be around 100 still got no voltage here
8                            0
9                          1.5 <<-- should be 100, voltage very low
10                        0
11                        0
12                        0
13                        224
14                        0
15                        230
20                        0
21                        236

I noticed two thing when I was taken the voltage, there is a big spark when I was taking reading on terminal 3 not sure if I was touching something else is little tight in the area.  There is heat is normal this time on terminal 15 where the soldering iron didn't melt.  The capacitor is facing the right direction, striped side on terminal 14 and non-striped side on terminal 15.

Thanks again for the help.

 

[Paul Birkeland]

OK, these voltages are correct, and indicate that there is an issue present with the 6080 tube installed.

Can you shoot a picture of the octal socket wiring?

-PB

 

[prtuc2]

 

[JamieMcC]

Are both the upper and lower black wires on B7 soldered the lower one is hard to see?

 

[prtuc2]

They are not solder together, sorry I always having trouble taking pictures with my camera not sure if that is skill related or need to get a better camera.  My pictures always come out darker than expected.

 

[Paul Birkeland]

Ah, I had forgotten that you have the Speedball installed.

Can you measure the resistance between the chassis plate and each TIP-50 metal tab?