No sound from Nobelium

[itchymusic]

Hi,
I just finished my Nobelium build (from Musikding in Germany) yesterday. Unfortunately I'm not getting any sound at all. Neither through the di or the amp out.
Both LEDs light up, I can measure ground all the way through, the connection is fine between input jack and in on the PCB. Both tubes heat up as well - no more than they're easy to touch.
The soldering looks quite fine, but does anyone have some indications as to what and where I could measure, as I'd rather try to narrow it down before aimlessly reflowing all the soldering.
Thanks for your help!
PS - i know there's a 12ax7 in V2. I'm still waiting for a new set of ecc82s in the mail.

 

[vigilante398]

Hi,
I just finished my Nobelium build (from Musikding in Germany) yesterday. Unfortunately I'm not getting any sound at all. Neither through the di or the amp out.
Both LEDs light up, I can measure ground all the way through, the connection is fine between input jack and in on the PCB. Both tubes heat up as well - no more than they're easy to touch.
The soldering looks quite fine, but does anyone have some indications as to what and where I could measure, as I'd rather try to narrow it down before aimlessly reflowing all the soldering.
Thanks for your help!
PS - i know there's a 12ax7 in V2. I'm still waiting for a new set of ecc82s in the mail.

Looks like your signal and ground wires are swapped on the 1/4" output jack.

What power supply are you using with the pedal? Are these known good tubes?

 

[itchymusic]

Looks like your signal and ground wires are swapped on the 1/4" output jack.

What power supply are you using with the pedal? Are these known good tubes?

Thanks for getting back so fast!
The tube in V1 is pulled from a working amp head - ruby tubes ecc82s. The other one I'm less sure of, as it has been in the spare box for years. Power supply is a Cioks DC7.
I'll check the out Jack wiring as soon as I'm back home, but have mainly been looking at the XLR out - as that tube is known to be good.

 

[itchymusic]

Ok, so I actually did invert the wires on the out Jack. Oh my... That'll teach me, being all fancy with a yellow wire for signal.
Well, certain things are clearer here as I just dimed the volume, treble and bass:

There is hiss and hum noise on the jack out. It gets louder when I turn the volume up and almost disappears when I turn it down.
The tone controls affect the sound of the noise as you would expect.
I can introduce louder 50 hz hum by moving my hand around over the board with the backplate off so there's no shielding. If I touch the chassis to ground it the 50 hz disappears.
It was harder to hear on the XLR - probably due to the lower volume - but I can get a good 50 hz hum on that one too by touching the wire coming in to the di board closest to the trafo. And stop it by touching the chassis.
Are there any indicators here?

 

[itchymusic]

Oh and I've seen people talking about the MOSFET heating up. Mine gets warm too, but no more than the tubes, so I can easily touch the metal.

 

[itchymusic]

So since I can amplify the hum with the volume control, the tone controls work and I can create hum on the di out by touching wires, I'm assuming the problem is between the input and V2. Most likely on the V1 daughter board. Does that sound right? And again, are there any good points for measuring voltage or continuity here?

 

[74hc]

Why the 1/2 watt resistor in R5?

All of the resistor footprints are 1/4 watt on my boards which is what the BOM specifies. Check R5 and make sure it was not damaged trying to fit it in. If you are comfortable, check your 250VDC supply.

 

[itchymusic]

Why the 1/2 watt resistor in R5?

All of the resistor footprints are 1/4 watt on my boards which is what the BOM specifies. Check R5 and make sure it was not damaged trying to fit it in. If you are comfortable, check your 250VDC supply.

Thanks for the reply.
I got all the components in a kit from Musikding, so maybe it's just whatever they had at hand. I did notice and wonder why, but took care to pre-bend the legs before installing, so there's no damage or stress there.
What do you mean with check the 250VDC supply? Checking the voltage after the pump?

 

[itchymusic]

Ok,
I have now checked the voltage to be 250V at C1.
I have checked all solder joints on the tube daughter board at V1 - and measured that I have continuity from every socket pin, through the board connectors to where they reach the next component in the circuit. Two socket pins seem connected through a common board pin, but that is the same for both tubes daughter boards, so I assume that's the way it should be.
I've built a bunch of other stuff before, but this is my first time building anything with a PS and tubes in it, so I go about it quite carefully...
Does anyone have any pointers? Anything you would like to have measured or see pictures from?
Thanks