Uh oh???

[shelby1420]

Ok, finished my second amp and had one little problem, one black wire from Terminal 18 was touching b1 or 2, can't remember now.....  anyway, I simply moved that wire over and presto, listened to some music that night and then yesterday had the amp on most of the day........  went to turn on the amplifers today and the one in question gives a pop, all LED'S are on and the tubes are lighting up as well so I put on an album, very little sound almost none--other side is working fine.  I turned the amp off and looked to see if something else was touching, couple of things looked suspiciosus so I moved them to a clear position (including the .1 cap on the board, I put a Mundorf silver and gold and I think the leads had melted through to the casing, although not sure)..............  turn it back on, no pop so I think all is ok, alas..........no sound again, very little sound turning it up I can her just a wee bit from that speaker.............  I have swapped cables from side to side and checked my seduction, all is well, it is for sure in my left amp..... gonna do some measurments, question is what the heck am I looking for, is it possibble I fried something with this wires touching????

 

[Doc B]

Yes it is possible that the shorted wire took something out. Best bet is to start with voltage measurements and report any deviations here. Then we can begin to narrow down the problem.

 

[shelby1420]

Merde!!! Will do Dan.

 

[shelby1420]

Ok, here they are as follows:

terminals      (10-0v)          15-22.9v
                                      16-471v
1-459v        (11-231.8v)    17-0v
(5-179.2v)    (12-161v)        18-0v
(6-178v)      (13-0v)          19-146.4v
9-149v          15-22.9v

Four pin socket A1 181.8v
                    A2  451v
                    A3  146.8v
                    A4  179v

Nine pin socket B1  3.1 VAC
                    B2  2.8v
                    B3  0v
                    B4  147.2v
                    B5  0v
                    B6  300v

Workin on the last three, as you can see by the brackets lots are off, what does it all mean????
                   

 

[shelby1420]

Thoughts??  Weird thing is all my LED's are lit and both tubes are heatin up fine, what the heck have I done???

9.43am......I decide to zip home quick and do something that until now I had not.... I swap the EH 2A3 power tubes from side to side and presto, the lack of sound follows the tube!! I figure awesome its the tubes so I run to the living room and pluck the Sovtek 2A3's from my Stereomour to put in my Paramounts , wait my 20 minutes and fire them up--YEAH music, glorious music from both channels......  so for shits and giggles I decide to try the EH 2A3's from my Paramounts( yeah the ones that one tube is bad cuz it followed the tubes..............)  and presto, music out of both channels in my Stereomour..........  I have not been drinking this morning, just to be clear, LOL!!!  Freaky chit tho, no??  Should I just be happy they are working or should I still be concerned??

 

[Doc B]

Don't worry, be happy. Maybe just recheck those voltages that were off for peace of mind and let us know if any are still way off.

 

[shelby1420]

Will do Dan, been listening for about 2 1/2 hours and it sounds lovely, I've invited Frank over as well as Ella...............................

 

[jrebman]

Rick,

Unfortunately, this also sounds like it may be a tube socket problem -- and I only say that because I've had a number of experiences with suh things.  Hopefully it will be all fine, but I'd suggest taking a closer look at tube sockets just to make sure.

Once a bad tube socket in a SE pentode amp cost me a very nice output tube and half a driver tube all because f a bad connection to a screen grid pin.  I was very lucky that it didn't take out the transformer too, but that shouldn't be the case with a SET amp, at least the way the BH mps appear to be designed.

Glad it's making music, but if it were me, I'd want to know what happened and if it's going to happen again.

-- Jim