Troubleshooting a Champ

Telecaster65 · May 4th, 2004, 05:03 AM

Hi everyone,

After having completed my first amp project, I have these (small I guess) issues:
The situation is this:

The amp turns on nicely i.e. the tubes show a pretty orangish light, the speaker a very low, almost imperceptible buzz... but this buzz doesn't grows as I increase the volume. By plugging a cable and touching the jack edge, you may detect a higher noise, but this too does not increase with the volume. Tried to plug a piezo pick up but no sign of life (low hum apart)...

What could be wrong?

:(

Thanks anyone replies...

Tim Swartz · May 4th, 2004, 11:55 AM

It could be a disruption anywhere. I would start w/ the tube voltages (plates and cathodes), and if voltages are OK, a signal generator and scope would be next. If you don't have a scope it will just take longer as you need to verify the integrity/accuracy of each connection. Luckily it is a Champ, so you are only dealing with a few components.

BrianF · May 4th, 2004, 12:05 PM

every connection. Also check that all the grounds are actually making contact. Check all signal path, power, grounds, filament circuits etc. Look for poorly soldered joints, make sure jacks and switches are connected correctly. Be methodical and check schematic and layout section by section. A tube could be bad too...

Telecaster65 · May 4th, 2004, 12:08 PM

Maybe I've forgot to ground the leftmost volume tang.
This evening I will try to star ground it...

Thanks!

Tim Swartz · May 4th, 2004, 01:36 PM

My suggestion is that you locate/fix the current problem(s) before moving on to a new grounding scheme.

Telecaster65 · May 5th, 2004, 05:47 AM

Quote:

Originally Posted by Tim Swartz

My suggestion is that you locate/fix the current problem(s) before moving on to a new grounding scheme.

Thank you Tim, a couple of grounding was missing. Now it works, even if..... Jeeez! He's noisy!!!

Thanks you all

May 4th, 2004, 05:03 AM	#1 (permalink)
Telecaster65 Tele-Holic Join Date: Jan 2004 Location: Cisano sul Neva (Savona) NW Italy Age: 43 Posts: 840	Troubleshooting a Champ Hi everyone, After having completed my first amp project, I have these (small I guess) issues: The situation is this: The amp turns on nicely i.e. the tubes show a pretty orangish light, the speaker a very low, almost imperceptible buzz... but this buzz doesn't grows as I increase the volume. By plugging a cable and touching the jack edge, you may detect a higher noise, but this too does not increase with the volume. Tried to plug a piezo pick up but no sign of life (low hum apart)... What could be wrong? :( Thanks anyone replies... __________________ Sleep tight, my child, sleep well For I'll be at your side That no shadow, no darkness, no tolling bell, Shall pierce your dreams this night

May 4th, 2004, 12:05 PM	#3 (permalink)
BrianF Friend of Leo's Join Date: Apr 2003 Location: Carlsbad, Ca Posts: 2,179 7 Photos	check and double check every connection. Also check that all the grounds are actually making contact. Check all signal path, power, grounds, filament circuits etc. Look for poorly soldered joints, make sure jacks and switches are connected correctly. Be methodical and check schematic and layout section by section. A tube could be bad too...

May 4th, 2004, 12:08 PM	#4 (permalink)
Telecaster65 Tele-Holic Join Date: Jan 2004 Location: Cisano sul Neva (Savona) NW Italy Age: 43 Posts: 840	Maybe I've forgot to ground the leftmost volume tang. This evening I will try to star ground it... Thanks! __________________ Sleep tight, my child, sleep well For I'll be at your side That no shadow, no darkness, no tolling bell, Shall pierce your dreams this night

May 4th, 2004, 11:55 AM	#2 (permalink)
Tim Swartz Tele-Afflicted Join Date: Mar 2003 Location: Michigan - Tweenst the Great Lakes Posts: 1,904	It could be a disruption anywhere. I would start w/ the tube voltages (plates and cathodes), and if voltages are OK, a signal generator and scope would be next. If you don't have a scope it will just take longer as you need to verify the integrity/accuracy of each connection. Luckily it is a Champ, so you are only dealing with a few components.

May 4th, 2004, 01:36 PM	#5 (permalink)
Tim Swartz Tele-Afflicted Join Date: Mar 2003 Location: Michigan - Tweenst the Great Lakes Posts: 1,904	My suggestion is that you locate/fix the current problem(s) before moving on to a new grounding scheme.