resonance/micro phonic sound when tapping on the unit

[Paul Birkeland]

The next thing to do would be to take voltage measurements. 

[Paul Birkeland]

thanks Jamie ,finally someone that actually trying to help ,yeah Crack seems to be very vulnerable to anything and everything ,just noticed very similar thread here with dead end as well
http://bottlehead.com/smf/index.php/topic,5806.0.html

right channel is barely audible

I'm not sure how this has a dead end?  There was an issue present in this thread that would show up on voltage checks (and probably resistance checks), and once the error was remedied, the amplifier performed to its specifications.

[xcoolhandx]

The next thing to do would be to take voltage measurements.

I have to look in manual since I'm not sure where you take the measurements,also

It took some time, but I found what was causing the buzzing noise in the right channel. I had previously swapped speedball boards left to right, but this had no effect. Eventually I noticed that the red wire coming from the pot was running right beside the heater wires toward the input tube. I rerouted the red (signal) wire to approach the socket terminal from another direction and this completely fixed the problem.

here is my 9 pin socket

[Doc B.]

Did you change the output coupling capacitors?

[xcoolhandx]

yes I did but nothing changed


,here is the weird part ..when I have the unit on it's side everything is nice and even and no noise

[Doc B.]

A change by laying the unit on its side would tend to indicate that gravity is changing the contact of something. The first thing that comes to mind is that the headphone plug might be making better contact inside the jack. That might be supported by your earlier mention of some kind of microphony when tapping near the jack. Perhaps the plug was overheated a bit and distorted a little when soldered.

[xcoolhandx]

I already ordered new phone and RCA jacks from this place
https://www.parts-express.com/ShoppingCart.aspx
and Blue velvet arrived today as well

EDIT; were there any socket complains in the past and what would be good socket replacement ?..just in case 

[Paul Birkeland]

EDIT; were there any socket complains in the past and what would be good socket replacement ?..just in case

Yes, we have had at least one customer remove a teflon upgrade socket because it was defective. 

[xcoolhandx]

little update on this issue..
impedance no more rerouted few wires ,swapped phone jack ,RCA jack and I'm back in the game (the tapping noise is almost gone )

P.S. I recently noticed this thread (probable cause of my dead HE400s ..I think I connected my cans to early -loud pop=only one channel active)
http://bottlehead.com/smf/index.php/topic,2946.0.html