LA-2A hum and oscillation problems - SOLVED !!!

[Purusha]

I agree, I may have to check this also :thumb:

 

[MrZpliff]

I had some hum-problems too, so I made shure all the parts of the case had proper connection with eachother (and grounded, of course).
That turned out to be the cure.

 

[mcfarlane_audio]

so funny that you started this thread, i have the same problem with my la2a and finally stole it out of my friends hands today ( he was ok with the noise but i of course was not!) Grid stoppers did it for me, i also made sure all parts of my case where properly grounded to each other, good luck, youll love it once you cant hear the radio :grin:

 

[Purusha]

[quote author="mcfarlane_audio"]so funny that you started this thread, i have the same problem with my la2a and finally stole it out of my friends hands today ( he was ok with the noise but i of course was not!) Grid stoppers did it for me, i also made sure all parts of my case where properly grounded to each other, good luck, youll love it once you cant hear the radio :grin:[/quote]

:green: :green: :green:

 

[matta]

For Purusha and other wanting to add the 'Grid Stoppers' to their Drip Electronic LA-2A PCB's (V1, V2 has them onboard) I have posted a photo thread and explanation here: http://www.groupdiy.com/index.php?topic=258781

Cheers

Matt

 

[Purusha]

Thanks Matt :thumb:

 

[Purusha]

PROBLEM SOLVED BY GRID STOPPERS!!!

 

[SaMpLeGoD]

Hey! I'm having hum's problems with my LA-2A... Mat, did you have the explanation for the "Grid Stoppers"? the link is dead!
I have a 50hz hum even with the gain fully off... can anyone help please?!!!

Cheers,

Eddie

 

[volker]

If it's 50Hz, you either have bad heater layout or a bad grounding scheme.
Has nothing to do with the grid stopper in or not.

 

[mushy]

Could be a couple of things. More info please. What layout? What transformers? Pics?

 

[SaMpLeGoD]

Ok, I'll post some photos!
The ground Scheme is ok, and wired as Greg say at his V2 manual!
I realize in the V3's manual there some mods to do, including the DC voltage ref for the heaters...I'll try this first
Cheers,

Eddie