New crack - No sound from right channel [resolved]

[calmiswar]

To add to this, the terminals 6-10 were working properly before. The (bigger) tube doesn't seem to light up now. I also see that it has gotten cloudy white at the top of the tube.
Did I do something to mess it up or was it faulty?

[Paul Birkeland]

If the 6080 is cloudy white at the top, it's lost its vacuum and it needs to be replaced.

The front end (12AU7) is working properly, and with a working 6080 installed in the amplifier, you should get good voltage checks.

[calmiswar]

Here are my voltage readings now:

1 - 93
2 - 230
3 - 0
4 - 230
5 - 93
6 - 0
7 - 93
8 - 0
9- 93
10 - 0

Is this fine? Could you please tell me how 230v at 2 & 4 terminals are normal? Does it depend on the input tube?

Also, do you think I can claim a replacement for the driver tube?

Thanks a lot for you help.

[calmiswar]

And last question.. can I use the amp now??

[calmiswar]

Very sorry to bombard you with questions, but should I check the voltage/current at the headphone jack too or should we be good?

I ask because I'm scared I'll fry more headphones.

Thanks!

[calmiswar]

Sigh.. Turned on the amp today and there was no sound. Flipped it over to check and saw that the LED was not lighting. Just as I was about to turn off the power supply, the LED turned on. When the LED is on, the voltages are bang on.
The LED keeps flickering sometimes, doesn't turn on other times and turns on properly other times.

Did some continuity checks and things seem fine..

I'm going crazy here.

[Natural Sound]

Sounds like an intermittent connection. You could poke around with a chopstick and try to figure it out. Or you could simply reflow all the solder joints.

[calmiswar]

Sounds like an intermittent connection. You could poke around with a chopstick and try to figure it out. Or you could simply reflow all the solder joints.

Thanks for the reply. Tried something similar to the toothpick test, didn't yield anything. Will reflow all joints yet again and hope for the best.

[Paul Birkeland]

Here are my voltage readings now:

1 - 93
2 - 230
3 - 0
4 - 230
5 - 93
6 - 0
7 - 93
8 - 0
9- 93
10 - 0

Is this fine? Could you please tell me how 230v at 2 & 4 terminals are normal? Does it depend on the input tube?

Also, do you think I can claim a replacement for the driver tube?

You still aren't in a position where you should listen to this amp.  Not passing the voltage checks means that your amplifier is not safe for use. 

The 6080 tube draws a lot of current during operation, and this will bring the 230V down closer to the specification in the manual. 

You can contact [email protected] regarding the 6080.

-PB

[calmiswar]

You still aren't in a position where you should listen to this amp.  Not passing the voltage checks means that your amplifier is not safe for use. 

The 6080 tube draws a lot of current during operation, and this will bring the 230V down closer to the specification in the manual. 

You can contact [email protected] regarding the 6080.

-PB

Hey, I had another 6080 tube with me. Popped that in and did the measurements.

And it's weird, when I did the measurements yesterday, terminals 2 & 4 showed 230V. But, today (when the LED actually lit up) it was around 170V.

Would you say all this is because of some shoddy soldering from me?

Thanks.

[Paul Birkeland]

With a working 6080 in the amp, the voltages at terminals 1 and 5 should be lower than the voltages at 7 and 9.  If they are all the same, then there is still something very wrong with the amplifier. 

[calmiswar]

Okay.. Just redid all the solder joints at the 9 pin socket. The (damn) LED lights up now.

Both sockets have tubes in them: BEL 12AU7 & a Russian Winged C 6H13C. Both tubes have 2 glowing rods each when on.

Voltages - They were taken across 3 different startups. They remained largely the same, +/- 1.5V.

1 - 79.8
2 - 178.2
3 - 0
4 - 178.4
5 - 79.8
6 - 0
7 - 103.8
8 - 0
9 - 102.2
10 - 0

Please tell me this is alright.

Are there any other checks that I'd need to perform in order to ensure the safety of human/gear or should these voltages suffice?

EDIT: Latest checks show 2 & 4 voltages at around 172V.

Thanks.

[Paul Birkeland]

Those voltages are perfect.

-PB

[calmiswar]

Thanks a lot PB! You helped me through some frustrating times. Top class service, you have made me a bottlehead customer for life.

Plugged in a pair of HD558 (awaiting another pair of HD700s) and it sounds glorious! So much details and such emotion! The bass is pretty wicked too. I simply cannot get off my couch, I'm hooked. Cannot wait to connect the intended headphones!

Thanks again!

[calmiswar]

Also, to anyone else that reads this who is having similar issues, I had a miswire (connected the led to A9 instead of A8), a bad 6080 tube and finally a bad solder at the center pin of the 9 pin socket.

EDIT: Thought I'd include the consequences to each misstep as well (to the best of my abilities, please correct/remove if anything is wrong here):

Event: Toasted the RCA cup-type jacks.
What happened: No audio. Fails resistance checks.

Event: Connected the led to A9 instead of A8
What happened: High voltage at terminals 1 and 5. No audio from right channel. Fried Headphones.

Event: Bad 6080 tube
What happened: No voltage at terminals 6-10. Tubes turned cloudy white at top.

Event: Bad solder at the center pin of the 9 pin
What happened: No audio. LED doesn't light up. High voltages at all pins.

Hope this helps someone, please remove this if there is some misinformation here.