Speedball Passed final voltage test but Problem at TRS

[xjab]

Hi Guys-
I installed my speedball upgrade after 2 years of perfectly functioning Crack. My voltages all read within spec then when I got to the TRS tip I got a reading of 0 when I turned on the power and stayed at 0. I decided to go through with a soundcheck using old headphones. there was no sound but within seconds there was a really loud pop coming from the headphones (Luckily they weren't on my head! headphones weren't destroyed BTW)
I haven't done any mods or anything out of the ordinary.
My question is if the voltages were all correct does this eliminate some areas from suspicion?
I've checked the wiring carefully everything seems to hooked up correctly so I assume I should re-flow solder joints but I don't want to re-flow every joint if I don't have to for fear of screwing something else up!
I've dug through the postings for over an hour today and have come across bits and pieces of info but haven't been able to put it all together into a plan of attack. If anyone could steer me in the right direction as a novice I would be most appreciative.
Thanks,
James

 

[Paul Birkeland]

I would start by rechecking your voltages.

-PB

 

[xjab]

Paul I went through and re-flowed the connections at 1-10, i checked every transistor and led for correct placement and looked at all my connections with a magnifying loupe. I re-checked the voltages and get the same results as before below:
1-71
2-177
3-0
4-177
5-69
6-0
7-98
8-0
9-94
10-0
11-0
12-0
13-177
14-0
15-197
20-0
21-218

Also the led's were all lit up and i did check the resistors with an ohm meter. I looked carefully with magnification and didn't see any solder bridges. I was able to duplicate the same results 2 more times: no voltage at the trs jack then a loud pop from the headphones after about 4 seconds.
Is there any other testing I can do or should I resolder every connection on the PCB's? I assume that the old solder connections that weren't touched for this upgrade would still be good.
Thanks

 

[Paul Birkeland]

If it's just a pop when things are warming up, it might be the 6080 making some noise while it's warming up.  You may just want to let that tube cook for 30 seconds or so before plugging headphones in.

-PB

 

[xjab]

Thanks so much for responding Paul did just what you said- turned it on waited 30 secs and then plugged in the ipod earbuds - I definitely hear music so switched to the hd650's and there was my Led Zeppelin remaster in all its punchy bass glory! This amp sounds so great now can't wait to re- listen to everything I'm tired of.
BUT that loud pop is still there - I let it cool down and turned it on again  sure enough about 5 secs in there it was. It concerns me because it's  hearing loss loud and that never happened in 2 years before the upgrade. I'll check it out again tomorrow and see if it's coming from one or both channels and report back. If I have to try new tubes I will.
Thanks again-
James

 

[Grainger49]

As a tube warms up the DC voltage seeps through the coupling caps.  That is the 100uF caps in the middle of the chassis.  More expensive equipment have timers and a relay to short the outputs for the first 10 seconds. 

In the Bottlehead world we turn things on in a given sequence.  I turn on my Eros, wait 10s, turn on my FP 2, wait 10s and then turn on my Paramours.  This eliminated turn on thumps.

In the case of a self contained "system" like the Crack you just don't plug in your headsets till the thump has passed.  It is a small cost for getting the quality of sound you get at an unusually low price.

 

[xjab]

Thanks Grainger-I read your FAQ regarding the loud pop. I guess I thought my problems were bigger than they were. Lucky for me I get to just listen to music when I thought I was going to be flowing more solder connections!