Leave it to me to be "that guy" [resolved]

[skeeb234]

I just made a separate post about some voltage check issues.  Thanks to the Doc I got that sorted out quick with a missing wire. 

I just ran through my resistance checks, voltage checks, LED's lit up and the Tubes glowed on both ends.  So...all should be good? 

Well, I plugged in the AMP to my Modius.  I had the volume pot turned all the way down as it was powered on.  Something told me to use my cheap Porta Pro to test out the amp, but I thought if all checks passed then I should be ok.  So I plugged in my ZMF Atriums and immediately heard a pop on the left channel.  The weird part is when I first plugged in the headphone to the jack on the amp, I didnt get a popping or anything. 

So, thinking it was just a fluke I plugged in my Porta Pro's to the amp.  Now this of course has an adapter since the Koss is just normally a 3.5mm connection.  They actually worked fine.  Low volume of course so I didn't blow them but they sounded normal. 

Went back to the Atrium and got the popping type sound when plugging in the cable this time to the amp (with the volume pot all the way down) and my left channel in the Atrium is very quiet.  Right channel volume is fine.  I switched back to my Jotunheim2 with the Atrium and even switched the cables, same result.  I have managed to mess up a driver on a $3k headphone and I'm sick over it.  I'm sure it must be a solder or something somewhere...but to do this to my headphone doesn't exactly make me want to go tinkering around for now.  I don't consider myself a complete novice at electronics either so that is frustrating.

Don't mistake my post here.  I love the idea and function of the BHC and couldn't wait to hear ZMF on tubes.  Everyone here is very helpful too...I just had no way to really know this would happen unfortunately.  Damn. 

[Paul Birkeland]

Popping would often indicate a loose black wire on the headphone jack, and this is extremely common where the two black wires meet.

[skeeb234]

I'll check those for sure.  My question is: could that really short out a driver of a headphone?  Especially since I had the volume turned all the way down.  That is what concerns me so much.  I feel like I'm the unlucky 1% but still.

[Paul Birkeland]

Yes, a loose wire at your headphone jack can damage your headphones.

[skeeb234]

Thank you Paul.  I'll definitely go back through and reflow, especially where those two black wires meet.  Is there a recommended way to retest everything (other then voltage/resistance checks) before plugging in a headphone?  I'm not going to lie, this has me 2nd guessing plugging another HP in without knowing for sure.

[Paul Birkeland]

Plug in a cheap pair of headphones (any will do) and slap your palm against the chassis while listening for pops in the headphones.  If you hear pops, you have a loose connection.

[skeeb234]

Thank you - I'm actually going to order some cheapies off of Amazon for the next retest.  Feel pretty dumb not doing that to start with!

So, before I go back and work on reflow and things, I wanted to ask a couple of more questions. 

1.  When checking the resistance on the RCA jacks I was getting the correct within spec reading when I would touch the black probe to the left jack and the red probe to the right jack.  I know I should use probes with alligator clips, but that is not what I own.  Instead I used a spare alligator clip to attach the black probe to the 12U in order to keep that there during the rest of the tests as to not shock myself or cause harm (1 hand free).  I understood all checks until I got to the RCA part simply because leaving a probe on 12U and then touching the red to either jack did nothing.  It only worked once I did what I mentioned above, just making sure I was correct on that before I go and do the next round of tests!  So if the RCA resistance check can be explained by someone I would appreciate that.

2.  When I reflow soldered joints, is it typically a good idea in this case, with this type of project, to simply reheat the solder already there as I have seen others do?  I don't want to add in more solder if it will just bubble it all up too much.  I also tried using the copper wick for removing and proved to be a bit difficult working with the different parts of the amp (I had just 1 solder during my build that I had to remove some from and redo the joint).  You'll see the capacitor at 14U/15U had to be resoldered as I had originally put it in 13/14U! 

I am posting pictures on my next reply that I just took.  These are much closer in pictures and lit up better so they can be seen well enough.  Beings I am very much a novice, I am hoping some errors could be spotted...or hell maybe I did a decent job and its simply a couple of loose wires as stated!  I'm definitely going to check the left RCA jack but I'm not quite sure how to fix either RCA jack if that is the issue as soldering those were probably my biggest challenge since attaching to the cups was not as simple as the rest.  Perhaps I need to just order new RCA jacks and do that over...though I'd rather not. 

Alright, pictures incoming and again, thank you everyone!

[skeeb234]

Photos!

[Doc B.]

I'd be inclined to carefully reheat all of the connections on the headphone jack. Just enough to get them to flow out, you don't want to damage the plastic. Some of the resistor connections there look a little suspect. If they were not making good contact at startup because of a bad joint they might have made contact as the headphone plug was in and moving around a little, which could cause a pop just like the black wire connection closest to the chassis can. Left channel would be the resistor farthest from the chassis, connected to the white wire.

[Paul Birkeland]

I understood all checks until I got to the RCA part simply because leaving a probe on 12U and then touching the red to either jack did nothing. 

This would be consistent with the missing wire that you had.

Do you have a loose black wire on the headphone jack?  If you wiggle the one that runs across the bottom row of terminals on the jack, is it well captured by solder or does it wiggle around?

[skeeb234]

Thank you Doc and Paul!  I will check that black wire and touch up my soldering tonight on the headphone jack then retest the RCA resistance.  I'm guessing if the resistance still doesn't read, then it could be my wires going into the RCA aren't getting a solid connection.  I did notice last night that left channel RCA had a slight wiggle to it but right RCA was firm. 

Also when doing resistance checks is it normal to have to touch a few places on the prongs to get a reading at times?  I got the correct readings for instance when it should be 2.9 once I hit the right spot.  Guessing also is due to not using alligator clips. 

Sorry for a the questions just trying to be thorough as to not damage anymore HPs.

[Doc B.]

Your probe not getting a consistent reading is most likely an indication that there is some excess flux on top of the solder joint. Try rubbing the probe against the solder joint a bit to scrape thru the flux and see if it makes the reading more consistent.

[skeeb234]

Ok, I reflowed the joints around the headphone jack.  I did add a bit of solder to the black wires that connect as well as the top white wire (I also crimped the bit of wire poking out you see in the pictures).  I also checked the rca posts and reflowed those carefully as to not heat too much.  I do get a little wiggle on the Right RCA (not much) but that was not the channel I had the problem with. 

Then I did all resistance checks again.  All of them passed.  I even tested out the RCA jacks again while having the black probe to the 12U and this time I got readings!  The left jack was a bit higher then the right (should have wrote them down but I believe left was 108 and right was 95.6 ) both still within the specs. 

I turned on the amp and both tubes lit up fine and the LED's as well.

I checked all voltages, and they were again consistent and measured well within spec. 

Now all that is left is to do a listen test.  I will make sure to use your advice to smack the chassis with my palm while I test it to hear for pops.  That will have to wait till my cheap pair of headphones arrive on Friday. 

All of these adjustments took me less then 20 minutes.  Call me crazy...but I can't help but think did I really fix an issue in such short time that shorted out a headphone?  I mean I hope so...but still has me very nervous even if it works ok with a cheap set to go plugging in an expensive one again.  I haven't even done the Speedball upgrade yet which I know I shouldn't do till after I listen a while on the stock Crack. 

Fingers crossed everyone!

[skeeb234]

I am happy to report that I am listening to my BHC right now on my TYGR 300 headphones and no issues.  I did tap on the amp around different areas to listen out for popping and I didn't get any so far.  I do get a bit of a static type noise when plugging in the headphones...but I get that at times on my normal amp so I'm sure that is not something to worry over? 

So my next question is about how long to give this before I feel ready to install the Speedball upgrade?  Also I'm sure I should do some inspections under the hood after listening for a bit to double check connections are solid.  Still dont know how long till I get up the nerve to plug in something expensive to this. 

Very interesting what it has done to the TYGR sound.  I know this is not a high ohm headphone, but its mellowed them out other then a slight sibilance still...after all it is a beyer. 

[skeeb234]

Oh, and a picture!