Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Quicksand => Topic started by: 2Bornot2B on August 11, 2014, 09:18:03 AM

Title: It worked for a day
Post by: 2Bornot2B on August 11, 2014, 09:18:03 AM

I was amazed at myself, my Quicksand and Quickie worked. http://bottlehead.com/smf/Smileys/default/smiley.gif After 40 years of not soldering, it was reasonably easy to get back into the process. My Q&Q developed turn-on/turn-off thumps and now it hums when the volume is increased. http://bottlehead.com/smf/Smileys/default/angry.gifAny suggestions on where to look? I have re-flowed all the joints and the resistance and voltages on the Quickie were spot on.
Thanks

Title: Re: It worked for a day
Post by: Paul Birkeland on August 11, 2014, 10:06:26 AM

Quote from: 2Bornot2B on August 11, 2014, 09:18:03 AM

My Q&Q developed turn-on/turn-off thumps

The Quickie and Quicksand will make a little noise when turned on and off.  We suggest turning the Quicksand on last and off first.

Quote from: 2Bornot2B on August 11, 2014, 09:18:03 AM

and now it hums when the volume is increased. Any suggestions on where to look?

I would get more specific on what "it" is.  Does the Quicksand hum if you stream music into it through your phone?  Does the hum come in with the Quickie? 

Neither of these pieces has a conventional power supply, so my guess to your answer to these questions would be that you plugged in an AC powered source and began having issues, in which case a wire from the metal case of said component to the ground buss of either the Quickie or the Quicksand will get you back on your feet.

-PB

Title: Re: It worked for a day
Post by: Grainger49 on August 11, 2014, 10:22:05 AM

Just an educated guess, it sounds like a hot or ground wire in the signal path had a questionable connection.  Try touching up all signal solder joints.

Touching up solder joints is always Dan's first suggestion.

Title: Re: It worked for a day
Post by: 2Bornot2B on August 11, 2014, 10:38:30 AM

Thanks for the responses, I was connected to an AC device so, wired on grounds for both Q&Q and the hum stopped. Still has a turn-out thump. Any suggestions?
Neat to think twelve batteries are driving my Cornwalls!
Bob

Title: Re: It worked for a day
Post by: fullheadofnothing on August 11, 2014, 10:46:52 AM

The turn on transient is known, and mentioned in the manual on page 29.

Title: Re: It worked for a day
Post by: Grainger49 on August 11, 2014, 10:56:27 AM

The turn on thump can be avoided by a number of things. 

1) Turn on the preamp 10s before the power amp.

2) Short the output of the preamp for 10s (my Counterpoint and ARC tubed preamps did this with a relay).

3) Unplug the speakers before you turn off the Q&Q, plug them in after the Q&Q are on for 10s.