Hum, Grounding, Torture and Agony

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stvnharr

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Re: Hum, Grounding, Torture and Agony
« Reply #20 on: 14 Mar 2011, 05:07 pm »
This is very interesting. Initially, I had huge hum problems with my GK-1R, but these are now more or less solved, involving various measures like shielding all signal wires within the enclosure etc. etc.

However, I am wondering if I may benefit from shorting the R2s (I believe those were the ones) on the GK-1 main board as well.

Cheers,

Jens

Jens,
By all means, replace the R2's, the 10 ohms ones between the 2 ground tracks, with a wire link. This will connect all the grounds together and should remove any and all hum.
Steve

AKSA

Re: Hum, Grounding, Torture and Agony
« Reply #21 on: 14 Mar 2011, 10:39 pm »
Jens,

I agree with Steve.  I'm beginning to think I may have been in error using ground lifting on the preamp;  only for the power amp is this approach useful I believe.

I have been doing a new preamp design, as you know, and have come to Steve's conclusion, no ground lifting works better.....  and it appears that preamps are far more susceptible to hum than power amps.

Thanks Steve!

Hugh

Jens

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Re: Hum, Grounding, Torture and Agony
« Reply #22 on: 15 Mar 2011, 03:19 pm »
Steve and Hugh, thanks :D

I will get this done next time I open my GK-1R. First task for my system right now is to get the true earth connection finalised.

Hugh, still quite curious about that new preamp - could you leak a bit?

Not that I see how it would be possible to create something that could better the GK-1, which is fabulous (once you get the hum killed). I've never heard a more musical preamp :green:

Cheers,

Jens

AKSA

Re: Hum, Grounding, Torture and Agony
« Reply #23 on: 15 Mar 2011, 09:57 pm »
Thanks Jens, high praise indeed!!

The new preamp combines the best elements of the GK1 with revisions to the input stage designed to heighten resolution and create a truly monotonic distortion profile which is even more musical.

The idea has been to make it even simpler than the GK1, and remove a cap from the signal chain near the level control.  The tube is direct coupled to the input stage.

I am yet to hear it but I know all the elements work individually as I've tested them thoroughly.  The integrated design is the acid test however.

I hope to offer the Swift again when this is complete.

I admit the hum had me very worried, but Steve has saved my bacon.  I'm extremely grateful to him for this!


Cheers,

Hugh