No Sound and V1 & V2 Tubes don't light up

[JLS]

Hi.  I am new to amp builds as this is my first.  I just completed the 6V6 Plexi 18 but the V1 and V2 tubes don't light up nor do I have sound. I've jotted my troubleshooting steps below but still nothing.  I've attached my pin tests as well.

Im going to get the obvious stuff out of the way.

Lamp lights up
Fuse is good
Tubes are brand new
Yes, amp is plugged in
No stand by switch only on/off
power goes to board (I'm now cause I shock the piss out of myself 3 times on the diodes and capacitors)

"Issue:  V5 - V3 tubes light up but V1 & V2 don’t.  No Sound.  No hum.  Nothing

Troubleshooting:
I measerued the pins with a multimeter by touching each pin with the red lead and grounding the black lead to the chassis

I tested for continuity and all were positive.

I tested the green wires from the PT from the AC side and it was 6.3 v

I jumpered the heater wire from V5 to V1 and both V1 and V2 tubes then lit up"         
         
Measurements
Hoffman 6V6 Plexi 18               
   EH - 12AX7   JJ - 6V6   
Pin   V1   V2   V3   V4   V5
1   431   431   432   372   23
2   0   0   0   3.1   3.1
3   86   102   0   436   437
4   3.1   3.1   3.1   437   436
5   3.1   3.2   3.1   372   24.5
6   430   436   432   437   438
7   0   431   0   3.1   3.2
8   92   140   N/A   422   421
9   3.2   3.1   3.1      

There was a combo of AC & DC measurements.  Is this normal?  I'd assume so with the the PT to V5 being AC and other wires from the board coming from the high voltage phase of the PT.

Any help is greatly appreciated.  I will add I've had a blast building this.

Jarrod

[sluckey]

Look for a bad connection in the filament wires between V3 and V2. If you don't see a broken wire or bad solder joint just replace the wires between V3 and V2.

[JLS]

Thanks for the quick response.  I will take a look and replace the wires.  But since power is measured at V1 & V2 does that indicate a connection between V3 & V2 is good?  Also, I've added some pictures available at the link below for better illustration.  I know its ugly but this is my first build.

https://drive.google.com/drive/folders/0Bzuy0zdU1zb7d2RJbnVWbVNqMWs?usp=sharing

[sluckey]

I measerued the pins with a multimeter by touching each pin with the red lead and grounding the black lead to the chassis

That's not a valid way to check filament voltage. The correct way is to put one meter probe on pin 9 and the other meter probe on pin 4/5.

But since power is measured at V1 & V2 does that indicate a connection between V3 & V2 is good?

If you had power at the tube socket the tube would be lit. The correct way is to put one meter probe on pin 9 and the other meter probe on pin 4/5.

[eleventeen]

It *could* be and *is* an issue that your preamp tubes are not lit up (which means they are not conducting, they are not working, they are not drawing current) and this will likely be fixed by getting them lit up......but the plate voltages on the little tubes should be in the 150-180-200 volt range, not 400+ volts. This would be the case AFTER you get them lit up AND working properly.


So I am looking at your IMG_3364. It looks like you have the keyways on your 6V6 sockets going in opposite directions. In other words, keyway #2 (on the right) is pointing at 2 o'clock (as viewed from under the chassis) and keyway #1 is pointing at 7 o'clock. We NEVER do this, it ends up being visually confusing. We want the wiring to "rhyme" from tube to tube, if possible. I would not change it at this point; taking the socket- flip you did into consideration, they appear to be wired right.


It also results in ONE OF your 6V6 input wires (black, going to pin 1, either 6V6, pin 1 is blank thus it is being used as a tie-point, through 1500 ohm grid stopper resistors to pin 5) running over the 470 screen resistor and one NOT running over the corresponding 470 ohm for the other side. For hum purposes, this kind of defeats the hum-cancelling aspect of a push-pull output stage. (A subtle point)   


You really have to get your soldering and lead trim under control. I don't know what type of soldering iron you are using, but I am going to suggest you go buy a bottle of liquid flux ($7-8) and place a drop of flux on each joint before you solder. Normally it is not needed, but you are clearly overheating your solder joints and/or using not-good wire or have a dirty tip, or some combo of all of those. At least the green; the white looks OK. At the very upper left of IMG_3364 you can see how the heat you've applied to make the solder joint has softened the insulation so much that the conductor has halfway melted out of the insulation. Either learn to apply less heat, or, use a better grade of wire.




Also on 3364, you should not allow excess lead (on the left 470 ohm screen resistor) to poke out past the terminal. This is asking for trouble. There's 400+ volts on that piece of wire and it should be trimmed off.


I am throwing a lot of critique at you, I realize, and this is how a first build looks. But these are all new parts and the solder joints should readily suck up the solder and use less solder, not because we are cheap, but so that you can see the wires inside the joint.


Do you have all the "keyways" on the 9-pin sockets going the same way? I can't tell, but my eyes ain't that great.

[JLS]

Ok.  Thank you for the criticism but feedback is always much more appreciated when it is constructive.  I feel your critique is very useful for someone as myself since I've never delve into an electronic project.  However, solutions to my issue and your criticism is much more effective feedback.  With that said, I've rewired the filament and measuring ~6.4 volts when touching pin 9 to 4/5 so the tubes light up.  But I still do not have sound. 

[John]

Your first build looks a lot like my first build, which I ended up almost re-doing to get it working. This is only what *I personally* would do, *if it were me*. I'd disconnect all wires going to your tube sockets, all of them. Rotate your 8 pin sockets so both keyways are going the same way, as 11teen points out. It will only be confusing to you and anyone else when taking voltages, troubleshooting, etc.


 Make sure all your 9 pin sockets are facing the same way also. If possible, orientate them so that each "side" of the socket is on either "side" of the 4/5 and 9 pins. This helps you keep the 1,2,3 pin wires together and the 6.7.8 pin wires together. Makes it easier for neat wiring and not burning the insulation with your soldering iron.


Then, re-do your heating wiring. Arguably, this is the most important part of wiring the amp. Also, the biggest pain in the ass    I've started using solid core instead of stranded wire for it, in 20 gauge coming off the power tube sockets.I don't bother twisting anymore, just keep the 2 wires paralleled and pay attention to keeping your signal wires (anything going to a grid) away from them. If you want to twist them, that's fine too; twisting once is not going to break 'em.


THEN, re-attach your board wires to the socket. Double check against the schematic for each connection as you make it. Don't make my mistake and try to get it all done in a certain time. I have FINALLY learned to act as if each solder joint is the only thing I'm going to do that evening. And I'm still not close to Sluckey quality (his work is unbelievable) but I'm way better than I used to be. You can use 22 ga. solid core wire for all those connections. Using different color wires for each thing (cathode, plate, grid) helps with trouble shooting too.


I'm only suggesting re-doing the wiring because I really think it's going to be much harder to figure out what's wrong without doing that. Again, this is only my opinion formed by me just having to rip stuff out and re-do it to get it right.


Soldering iron: I've got a Weller cheapie that works great  http://www.all-spec.com/UserFiles/Images/Products/weller-12200_wps18mp_DV_WebXL.jpg
Be sure to always wipe the tip on a damp sponge before each joint, and like 11teen says, a little dab of flux makes it even easier. Should only take a few seconds for the solder to flow into the joint.


Take your time, make every joint count, and have fun! I could have bought quite a few amps with the inventory I've accumulated, but that ain't no fun!!

[HotBluePlates]

... I've rewired the filament and measuring ~6.4 volts when touching pin 9 to 4/5 so the tubes light up.  But I still do not have sound.

All tubes light up now?

If yes, then measure voltage at every tube grid, starting at the output tubes and working back towards the input jack.  Have a speaker hooked up while you do this.  You should hear a pop in the speaker when your meter lead touches a grid.  Do you hear pops at every grid?

[JLS]

Ok.  I re-wired everything.  All tubes light up.  I do get sound now but very faint/fuzzy sound even with volume turned up.  No clean sound at all.  (Hey it's progress) 

Hotblueplate:  I did as you recommended and in fact do hear a popping,scratching sound when I touch the pins but do not get a popping when touching the filament pins (pins 9,4,5 on V1-3 & pins 2 & 7 on V4-5).  Is this normal?  Also, I may be measuring inaccurately.  I assume those pins are DC and the other pins are AC???  If I have this correct I and measuring but putting the (-) probe on 9 and the (+) prob on 4 & 5 -- Voltmeter is set to DC.  For the other pins I am grounding the (-) probe and touching the pins with the (+) probe -- voltmeter set to AC.

I appreciate you help and feedback.

JLS

[sluckey]

The filament pins, 4-5-9, are AC. All other pins are DC. Set your meter accordingly.

[PRR]

Touching heater (filament) pins makes little to NO pop.

But HBP told you to touch GRIDS:

HBP> "measure voltage at every tube grid"

[JLS]

well.  I appreciate the feedback but I give up.  This project bas become more of a pain in the butt and waste of time.  Now the damn thing doesn't even turn on.  Anyone wanna buy this kit from me?

[shooter]

This project bas become more of a pain in the butt and waste of time.  Now the damn thing doesn't even turn on.

but that when the fun starts!

If you want a working one just PM me and we can work out the details!

[HotBluePlates]

Ok.  I re-wired everything.  All tubes light up.  I do get sound now but very faint/fuzzy sound even with volume turned up.  No clean sound at all.  (Hey it's progress) ...

I notice (now that I look at the pics posted in November) that one of your speaker jacks appears to have a wire on the switched lug.  But it's also NOT the jack you're using.  That would short the hot to ground at the speaker output, and result in a weak, fizzy sound you you described.

Simply plugging into the other speaker jack may fix it.

[This has become such a common mistake in new builds that it's among the first things I look at.]

[Shack]

The most common problem ive had in my few builds was filament wires not soldered good enough, and  errors with speaker or input jacks.