I have made a short clip with 4 paired 6L6's, in this order:

New JJ

4 year old Groove Tubes

3 year old JJ

Bad new(s) JJ

Used clean and distorted channels, with almost every knob at noon

Both of them went to see the doctor today http://www.orangeamps.com/products/accessories/amplifier-management/vt1000/

And they are both working, but 3 of 4 grades apart. Not paired at all.

Bought 2 new tubes at the store. JJ 6l6GC, same thing. I'm doing a shootout with them

I couldnt even set a stable voltage for power tubes. They kept rising from 20mv to 50mv, and more, in less than 2 minutes...  Even though on Conford they were very silent, they got very hot in less than 5min.

These were identical to those i have on Cornford, they fitted the same way... Tube sockets don't seem to be the problem

I Have a Fender Super Sonic, gonna try those 6l6's there.

I think i have the problem solved 

I would like to thank you wyatt, for patience, help and support! Without your feedback, i would have take it to a tech long ago...

.... Inspected, reviewed and rechecked most solder joints and ground connections. Everything was ok... The last thing before i take to a tech, was replacing power tubes.

Amp came out alive and well no noise, wonderful sound, everything 100%. Biased the used 6l6's (32mV-V4 39mv-V5), tuned PI trimmer to 6VDC difference and FET board trimmer as well, everything ok. Played for an hour or so. Stable voltage readings everywhere, no noise.

Then replaced the tubes with the new ones again. Noise again. So, i think i have solved the problem.

Now, one thing puzzles me : Tried the new 6l6's in my Cornford Roadhouse 30 (from where the used ones came). No noise, even in high volume.... Only blue light and extra heat was noticeable.
The new tubes look good and new from the outside.... How can i test/make sure that these tubes are faulty? A tube tester is the only way to go?

As for the OTS, i'll try to describe it in another post maybe.... I've played several amp models of brands like Fender, Marshall, Vox, Mesa, Soldano, Cornford, Orange, Bogner, Egnater... The OTS doesn't have all the best or signature sounds from the previous, but it's far superior IMO !!! Versatile, flexible, dinamic, transparent, powerful, detailed. And topping that, it has all the features for Gig and Studio work!

Thanks Wyatt for all the help

Mr. Nick too, for a huge contribution to the guitar world!!!

In fact i didn't grind any ground connection to the chassis.... how noob is that? The chassis has no paint finish, showed continuity, so i didn't bother.

Instead of taking out screws and grind, i filed the chassis right beside the screw and solder a jumper to it. Did all the ground connections, plus the bias pot cover and Od Trim (this pot has lug 3 connected to ground, but i assume it's no problem).

The result was a very silent powerup but in less than 1 minute, the noise started to volume up; had a multimeter connected to bias probe V5. during this minute value raised from 20mV to 40mv....

Should i ground V4 and 5 Sockets to ground too?

Thanks again

The volume or any other pot doesn't interact with the noise. It's always there

 Checked most solder joints, reflowed some just to make sure... no difference.

The Bias pot all the way down reads more than 50mV on V5 and more than 40mV on V4 !!  I always keep it on for less than 3 minutes


I'm going to try chop suey test, and if no result i'll resolder V4 and V5

Thanks again waytt!
 
If any thing comes to mind, let me know

I have sound also noise    

Should i start to diagnose with an audio probe? where should i start?


I made a short audio with the noise... can you tell by what it sounds what it might be? Is it safe to keep running longer time?

... comparing with the voltage chart, it seems all High Tension Pins are colder in my build....


On V4 and V5, the negative voltage is also lower, but 1 and 8 are almost double!

Thanks Wyatt!!!

Here are my readings, tubes loaded, speaker load in "operate" mode:

V1
1- 163   VDC
2- 0
3- 1.7   VDC
4- 3.15   VAC
5- 3.15   VAC
6- 185   VDC
7- 0
8 -1.65   VDC
9 - 3.15   VAC

V2
1- 174   VDC
2- 0
3- 1.7   VDC
4- 3.15   VAC
5- 3.15   VAC
6- 186   VDC
7- 0
8- 1.54   VDC
9- 3.15   VAC

V3
1- 270   VDC
2- 0
3- 57   VDC
4- 3.15   VAC
5- 3.15   VAC
6- 260   VDC
7- 0
8- 57   VDC
9- 3.15   VAC

V4
1- 55.2   mVDC
2- 3.15   VAC
3- 424   VDC
4- 422   VDC
5-   -33   VDC
6- 422   VDC
7- 3.15   VAC
8- 55.2   mVDC

V5
1- 54.7   mVDC
2- 3.15   VAC
3- 423   VDC
4- 425   VDC
5-   -33   VDC
6- 423   VDC
7- 3.15   VAC
8- 54.7   mVDC


After speed-reading the OTS topics, i tried swapping the Output transformes Primary wires on V4 and 5, Pins 3, and it got lot more quiet!!!     

I mean silent, with sporadic noise..... the noise is very close to the interference that the probe does while touching some of the tube's pins.... i haven't tried plugin my guitar, but i'lll eat something first.....

Is there anything to worry on these readings, wyatt?

So, figured out wich Pins are AC/DC  that's why i had bad readings the first time....

values without tubes:

V1
1 - 334 DC
2 - 0
3 - 0
4 - 3.2 AC
5 - 3.2 AC
6 - 350 DC
7 - 0
8 - 0
9 - 3.2 AC

V2
1 - 340 DC
2 - 0
3 - 0
4 - 3.2 AC
5 - 3.2 AC
6 - 350 DC
7 - 0
8 - 0
9 - 3.2 AC

V3
1 - 434 DC
2 - 0
3 - 0
4 - 3.2 AC
5 - 3.2 AC
6 - 430 DC
7 - 0
8 - 0
9 - 3.2 AC

V4 and V5 measure pretty much the same, so:
1 - 0
2 - 3.2 AC
3 - 490 DC
4 - 490 DC
5    -37 DC
6 - 490 DC
7 - 3.2 AC
8 - 0

Comparing with the voltage chart ( www.ceriatone.com/voltage/VoltageChart.xls ), i have "expected" higher voltages on DC Pins.

Exceptions are
V4&5   Pins 1 and 8 are 0V instead of 37mV

V1 & 2 Pins 3 and 8 are 0V instead of ~1,5V

V3       Pins 3 and 8 are 0V instead of 54V

are these readings tolerable? What would be the next step? Still no burning smell, hope i'm on the right track

Hi, i resoldered the two green wires. Heaters ground to ground and 340v center to fuse. My written english is not the best.... Hope the picture clarifies...

The pins 4,5 & 9 from v1, v2 and v3 read 3,4v now.

Im Göing to measure all v pins without tubes next... Or is there something else to test before?

...The diode (rectifier?) board reads 340v on each Red wire from PT secondary.
55v from another PT secondary wire to this board.
 The wire out from this board reads 507VDC.

Thanks for support onde again Wyatt !!

So i've checked the 3.15V (3.4V in my DMM) taps: the pilot light comes on, heaters on V5 and V4 (pins 2 and 7) all see 3.15V.



.....  About the center tap, there is a sticker in the PT. reads as follows
- 2 x yellow = 6 V
- black 2,5 mm2 = 3,15
- green 2,5 mm2 = 0 V
- red 2,5 mm2 = 3,15 V
- 2 x red 1,5mm2 = 340 V
- green 1,5 mm2 = 0 V
- orange 1,5 mm2 = 60 V

 wich means i don't have it well connected in the picture, right? The thickest green wire on the bottom(3.15V center tap) goes to fuse instead of direct ground. I'll correct it tomorrow....

this is what i've got without tubes:

PT secondary taps:
55VAC
374VAC x2
3,4VAC x2
15VAC x2
0V x2

OT Primary taps:
507VDC x3

I've re-checked the connections from these taps on my build, and they seem to be according to the layout...

Measured some connections :  3,4V at pilot light wires and heaters, 6L6's pin3 with 507VDC; 30V to voltage regulator and 25,6V out...
Maybe i just misread the DMM  at the first time    im going to measure again with the tubes tomorrow and compare them with the chart.

Just receveid your reply, ill answer after....

Thanks wyatt, i'll try your advice before taking it to a tech...

Already turned it on for a minute, the only sound i get is static....

I have it working with tubes and on standby, it measures the following:

V1

1 - 380mv
2 - 400mv
3 - 60mv
4 - 0
5 - 0
6 - 390mv
7 - 610mv
8 - 10mv
9 - 0

V2

1 - 490mv
2 - 550mv
3 - 30mv
4 - 0
5 - 0
6 - 430mv
7 - 630
8 - 1
9 - 0

V3

1 - 290mv
6 - 290mv
all other pins read 0


should i take the tubes and measure every pin?