New Build Squeal

[chunkitup]

I just finished my first amp in almost 2 years. Life and separation took its toll on me. But I'm back and feel really happy to be building amps again. Creating something from nothing is very enriching. Anyway, the build went well. I only forgot a few things during fabing up the turret board. The main thing was the rectifier!! Duh!!

Here's my problem and I attached a pic of where I think the problem lies. I am getting a squeal which get louder when I turn on my DMM's. V1 removed it still squeals. V2 removed it still squeals. V3 removed and the squeal goes away. My thinking takes me to grounding of the speaker jack which in the pic you can see the black wire coming from under the board to the bottom of the long tail PI. I always do this and never had a problem so I was thinking its the polarity of the output tranny but it's a squeal and not a motorboating like I've heard before. I also tried 3 different PI tubes and they all squeal.

What am I missing?

[g1]

I was thinking its the polarity of the output tranny but it's a squeal and not a motorboating like I've heard before.

Try flipping the polarity anyway. The audible symptom can be many different things, sometimes motorboating, sometimes squeal, sometimes other effects.

[chunkitup]

g1 you da man! I learned something today. As long as I learn something everyday its all good. It sounded nothing like what I experienced before with the polarity reversed. It was just a simple squeal like too much gain and poor lead dress and the last time I had the reverse polarity issue the motorboating was really loud and out of control. Now the amp is dead quiet.
If I may pose this to anyone who cares. I have built probably upwards of 20 amps and I get this anxiety whenever it comes to firing it up for the first time. When building an amp I map everything out down to the smallest detail. I draw by hand the complete schematic then work up the turret board. I double, triple, quadruple check everything. But when it comes to energizing for the first time I get this anxiety like if something explodes or bursts into flames I would be devastated. I also fear the amount of voltage in these amps. I have waited 2 to 3 days after completing an amp before I plug it in. Do I have a problem? I am not one for therapists but am I out of my mind? I have never had a catastrophic event but I still get almost panicky. Every one of my amps has been right on. I am not an engineer or guru who will set the world on fire with my amps but I just love building amps and fabricating the entire amp. Blank chassis to complete amp with a crazy headshell is what I love to do in my garage. But I freaking get a panic attack just when it comes to firing it up for the first time. Anyway, sorry for rambling. Im happy my marriage is working out and I am able to do what I love, building one-off, something nobody else has type amps!!!!

[Justin Thomas]

Hey chunk,

No, I don't think you're out of your mind. When I finish a build, I'm usually either tired or distracted, so I too will wait a few days. I prefer to be well-rested and sober and alert, so that if anything DOES go wrong, I'm completely aware of my surroundings. It also affords me the chance to clean a testing space, etc.

If you were genuinely afraid, you wouldn't be doing this. There is a big difference between being afraid of something, and having a healthy respect for that which may harm or KILL you. There's a reason I charge more for amp work than my regular occupations...

Justin

[DrGonz78]

I have felt that anxiety too and I am sure many techs (amp builders) have felt that way. However, that anxiety grows on you if you let it. Similar to the thought growing up that I was going to get a shot at the doctor's office. I feared it and then when it came time for the shot it was over before I knew it happened. Also, similar to when you get an IV going into surgery. Or waiting and worrying every day up to the day of a surgery only to realize it was not worth worrying. Perhaps some people feed off that anxiety in different ways and no doubt we all have to deal with it. Most people I know don't want to be tinkering with a circuit that supplies 400+ volts of electricity or more. We choose to do these things because it is worth risking our lives to build & tame a beast. Personally there better be a bit of panic in the back our minds the first time we power up these home made amp builds. Our past experiences of working safely with electricity should overcome the anxiety but feeling too confident is just asking for an accident.

[nsubulysses]

Of course it is very, very important to be thorough and safe, but can't you just turn it on with a light bulb limiter in series or variac or better yet both, monitor a few power supply voltages and bias supply voltage, and fear not? Nothing can explode if you are in control.

[Enzo]

I tell you what, I have been soldering this stuff over 60 years now. I build stuff, but mostly repair stuff. Often stuff I have never seen before. When I build an amp, I assume to myself that I have paid attention, and I honestly expect it will work when I plug it in, so I do. And yet, underneath that is ALWAYS that nagging doubt. Is this going to dog me or work? And when it DOES work right off the bat, I pat myself on the back and tell myself I did another successful build. But every time I lift a soldering iron to another unit, I have a pang. Will THIS be the one I screw up?

I have made some real bone head errors over the years. I try to report them here as they occur, just for educational value. It can happen to any of us, all of us, and at any time. But like falling off a horse or a bicycle, you have to just pick up and dust yourself off, and hop right back on. No one is immune to making mistakes.

I have said stupid things to women, and yet the wife and I have been together over 30 years. You have to be aware of your limitations and faults. My wife points mine out to me every day. But when the morning comes, I will still take her to breakfast at the Big Boy like I do every sunday.

So when your next amp blows up right out of the gate. So be it. Find out what went wrong, fix it, and drive off to breakfast anyway.

[chunkitup]

Sheww!! Not that I want everyone to have anxiety but I am glad its natural to feel that way. It is so rewarding to stand over a newly built amp and say I built that. Thanks guys!!!