[felixscerri]

G'day all, I've been assembling one of the Universal Preamplifier kits configured for phono and I finished it yesterday and guess what it didn't really work well at all. 

As it turned out there were two separate assembly faults, one was an intermittent fault in the RCA socket assembly and the other fault was on the circuit board.  I had somehow managed to install two incorrect value resistors in the RIAA equalisation network, (the same), on both stereo channels. 

I spent a couple of hours fault finding the board yesterday evening without success, and only found the fault in the clear light of day this morning.  Doh!  Regards, Felix. 

[TomS]

Stuff happens, but at least you found it 

I've made it a habit now to pre-measure every single resistor before installing it. It takes a little more time up front, but saves me a lot of aggravation. Yes, I learned this the hard way.

[richidoo]

I've made it a habit now to pre-measure every single resistor before installing it.

+1.  I once found some expensive, high precision, quality name brand resistors that were wrong value. I notified the kit seller and Mouser. The seller said impossible. Mouser confirmed the batch was mislabeled.

Similar to your discovering the problem in the clear light (and clear head) of morning, I learned the hard way to avoid building stuff when I'm tired - all kinds of mistakes will happen. But the recovery from mistakes improves our skills.

[S Clark]

I learned the hard way to avoid building stuff when I'm tired -

+1.   And it takes more time to find a mistake than to go slowly and avoid them in the first place. 
On the last point to point amp I cloned, on card stock I drew out each tube socket and each component back to ground or to another tube.  Then built the amp card by card.  It let me focus on a smaller area and double/triple check until sure I could go on to the next card. 

[HAL]

I have let the magic smoke out on more than one occasion from a DIY project.  You learn from the mistakes and get better each time.

Time and patience are on your side to do it correctly.

[mlundy57]

It happened to all of us. I wired up and MTM OB speaker with pigtails on the drivers just to check out the networks. They sounded horrible and one channel was a good 5dB below the other. Turns out I got some wires crossed and had one of the woofers wired to the tweeter circuit and the tweeter to the other woofer.  Once I switched the wires around they sounded a whole lot better.

I'll keep the stories about my days as a factory line mechanic to myself   

Mike

[Armaegis]

The thing I still screw up after all these years... when making cables, forgetting to slide the jacket/barrel/etc on the wire before soldering the ends 

[Speedskater]

The thing I still screw up after all these years... when making cables, forgetting to slide the jacket/barrel/etc on the wire before soldering the ends 

Don't feel bad, decades ago my brother told the story, at the TV studio one of the engineers made a camera cable (88 contacts) it took hours to make one cable only to discover that  he forgot the locking ring.

[mcgsxr]

I have a Yamaha P2100 power amp in my basement with a burnt channel.  Managed to forget to turn off the amp and short the speaker cables which making some changes one afternoon.  Dumbass!   

[Armaegis]

I have a Yamaha P2100 power amp in my basement with a burnt channel.  Managed to forget to turn off the amp and short the speaker cables which making some changes one afternoon.  Dumbass!   

Oh I can one-up that. One time I was replacing an old wall receptacle, for some reason my brain thought flipping the light switch was the same as flipping the circuit breaker. So... ever seen the tip of a screwdriver vaporize?

[thunderbrick]

Oh I can one-up that. One time I was replacing an old wall receptacle, for some reason my brain thought flipping the light switch was the same as flipping the circuit breaker. So... ever seen the tip of a screwdriver vaporize?

I got a whole drawer full of screwdrivers like that.....

[Armaegis]

You mean a drawer full of trophies right? 

[ACHiPo]

I got a whole drawer full of screwdrivers like that.....