Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: sjeffrey on October 11, 2013, 03:58:56 PM

Title: Tapping sound heard in headphones
Post by: sjeffrey on October 11, 2013, 03:58:56 PM

Hey guys,
so I noticed this week that if I tap on the crack's top plate I can hear it in my right channel.  This is unaffected by the volume and doesn't go away after it being powered on for a while.  I checked all solder joints and reflowed any of them that didn't seem perfect.  The problem was still there.  If I would tap on the input tube lightly I would hear it but not on the output tube.  This was with stock tubes.

Now I was holding off on trying a GEC brown base 6as7g that I had so I figured I would try it now.  I also have and RCA clear top for with both tubes changed I was hoping it would go away.  Well now it's even worse.  I can hear the tapping and if I tap lightly on the output tube it's tapping sound is kind of echo.  Tapping on the input tube is a much lower clunk type sound.  With this setup I can also detect some of the tapping sound on the left channel.

Is all this normal?  The GEC is probably microphonic if I understand correctly what that term means.  Hopefully there's something I can do to make it better.  Even typing on my keyboard I hear it in my headphones with the GEC.

Thanks,
Stephane

Title: Re: Tapping sound heard in headphones
Post by: STURMJ on October 11, 2013, 04:23:18 PM

This is "normal" different tubes will display more or less microphonics. I assume the crack is on the same surface as your keyboard , ( desk or table)  you could find some squishy feet for your crack, or move it off that surface .  I recomend bright star isonodes they are about 3/8" tall and quite squishy.  There are many other options also.

Title: Re: Tapping sound heard in headphones
Post by: Paul Birkeland on October 11, 2013, 07:58:30 PM

This is normal.

The solution is to stop tapping your Crack ;)

Title: Re: Tapping sound heard in headphones
Post by: palmfish on October 12, 2013, 09:08:33 AM

OMG, the puns and double entendres here... I cant stay away...lol

EDIT: And yes, mine does it too. I have found other things to tap.

Title: Re: Tapping sound heard in headphones
Post by: jimiclow on October 12, 2013, 10:22:19 AM

Any microphonics in the Crack is nothing compared to the Quickie.