Many years ago when my late father was helping me with an issue involving an electrical outlet in a bathroom of my first house, I asked him if he’d turned off the circuit breaker. A proud chemical engineer, he said there was no need. Moments later, his screwdriver hit a live wire.
Zap! A bright spark. A loud noise. A slight, metallic, ozone-like smell. We both jumped, but survived. After my heartbeat slowed down, I went downstairs and turned off the circuit breaker in the basement myself.
Fast forward to last week. I had half a dozen guests over to observe some A/B comparisons with two pairs of loudspeakers. The first compared my Usher ML-802 tower loudspeakers with a smaller pair of ATC SCM40 loudspeakers in for review, while the second would examine how they played on IsoAcoustic Gaia Speaker Isolation Feet versus on the speaker spikes (atop floor protector discs).
My listening space sports bright seafoam green leather couches, white sherpa fleece accent chairs, an ottoman, and a thick area rug in the front half of a 32’ by 24’ wide, open plan basement room. It features painted exposed joists and rafters above, some light acoustic treatments, and thick blackout curtains covering garden windows; a long dining table occupies the rear section that serves as a formal dining area (you can read more about its construction HERE).
The party began with socializing and noshing on pizza, chicken wings, cheeses, chips, chopped salad, and libations while listening to streamed, ripped, and stored digital content using a Sonore SystemOptique Signature Sonore Rendu SE network player in tandem with an Intel NUC using Roon Labs ROCK (Roon Optimized Core Kit) software in a fanless case, and Schiit Yggdrasil Analog 2 (or Original Gangster (OG)) DAC linked to a Pass Labs XP-12 preamplifier and Pass Labs X150.8 amplifier, which drove the loudspeakers over Straight Wire Crescendo 3 speaker cables (other cabling was also by Straight Wire). I provided the pizza, cheeses, chips, soda and sparkling water, while guests brought chicken wings, chopped salad, wine, and other drinks of their choosing.
Afterwards, we switched to vinyl, alternating playing cuts with the Ushers and ATCs. The vinyl played on a vintage Micro Seiki BL-91 turntable with an Audio Creative GrooveMaster 3 tonearm, a Goldring Ethos SE phono cartridge in a Korf Audio HS-02 ceramic headshell, connected to a Quadratic Audio MC-1 Moving Coil Transformer, linked to a Pass Labs XP-17 phono preamplifier that fed into the Pass Labs XP-12 preamplifier. Guests were pleased with the well-defined and balanced analog sound coming out of the loudspeakers.
The ATC SCM40 loudspeakers at the front of the room.
I found the speaker comparisons enlightening, but reaffirming my earlier observations in numerous private sessions. Almost twice as heavy (at 128 pounds to the ATCs 70), a foot taller, and sporting two eight-inch bass drivers to the ATC’s single woofer, the Ushers dug deeper in the lower frequencies. Moreover, using its magnesium alloy tweeter, it had more extended highs than the ATC, with its handmade soft dome tweeter.
However, using its handmade soft dome midrange driver, the ATCs were a little richer and more natural sounding in those frequencies. Horns, vocals, and pianos, for example, sounded just a little more “right”. Also, as a sealed speaker, the ATCs’ bass was a little faster, making the snare, tom and bass drums sound a touch truer.
Christan Griego of SOTA Turntables, seen here at his factory in Delevan, Wisconsin.
One of the guests, Christan Griego, owner of SOTA Turntables, stated that the Ushers had better highs and lows, while the ATCs were “more midrange forward.”
To help equalize the lower end disparity, one guest insisted that I raise the volume of both subwoofers that I was using (a front-firing Hsu Research ULS-15 Mk2 subwoofer on the left, and the down-firing ATC C-1 Sub on the right). I did, and he asked me to raise it some more to bring it to a closer low-end match with the Ushers.
I’d previously crossed them over at 60 Hz and fine-tuned their volume to voices playing on the TV (we do a lot of HD TV watching); above a certain volume, their vocals took on a bassier quality that I felt sounded unnatural. And when I mentioned that later with a friend, he posed the question, why would I use voices to tune subwoofers? Of course, I should be using heavy bass tracks and white noise to tune them, he asserted, but when I mentioned that an authority in the field whose name escaped me (that would be Jim Smith in his book, Get Better Sound) said that female vocals should be factored in tuning a subwoofer, he said that whoever that was, he had an issue with him!
Raising the subwoofer volume worked nicely, however, it also amplified the weaknesses in my temporary subwoofer setup (I am planning on getting a pair of REL subwoofers in the near future); the left channel, with its front-firing, 15 inch drivered sub stood out more notably than the right channel’s down-firing sub, subtly detracting from image clarity in the listening sweet spot. Griego stood up, walked around, and declared that the imaging was a little crisper sitting in the loveseat to the right of the sweet spot located in the front, center seating position.
Before I switched loudspeakers, as is my habit, I turned off my Pass Labs X150.8 amplifier, removed the cables from one set of speakers, positioned and reconnected the second set, and then turned the amplifier back on.
A friend asked me why I turned off the amplifier, adding that it wasn’t necessary. I said I always do that, as I don’t want to risk positive and negative cable leads to touch one another and short out the amp. Little did I know this very issue would haunt me later.
Gaia-ty and Laughter
There was laughter, musical enjoyment, and a great sense of camaraderie as guests dined, drank, and listened some more. It was getting late for a work night (the party had started at 5:30 PM–minutes after I arrived home from work, and now it was around 8:00 PM), so I thought I’d postpone the A/B speaker spike versus Gaia isolation feet comparisons. However, a guest protested.
“You promised to compare the Gaias with the spikes!” he said loudly. Others concurred.
I turned to my friend, Bob, a retired mechanical engineer, certified technician, and neighbor who’s helped me in setting up loudspeakers in the past and was going to help me with this endeavor. He said, “Why not?”
That’s when things got icky.
I turned off the amplifier, as I had to remove the heavy Straight Wire Crescendo 3 speaker cables while doing this procedure. Then, one at a time, I tilted and supported the ATC SCM40s, while Bob removed their spikes and replaced them with the Gaias. I reconnected the cables to the loudspeakers, but before I powered up the amp, I noticed a strange bubbling on the top of the front speakers wood tabs that the Gaias screwed into. Apparently, the Gaias’ bolts were longer than the spikes’ holes and were pressing upwards under the tabs’ veneers, creating the alarming bubbling! So, I quickly unplugged the power cords, and held the speakers in place while Bob began readjusting the Gaias.
Hello!
Just then, my cell phone rang. My wife, Belle, who had planned on staying overnight with our daughter, Colleen (her husband was out of town and she needed help with her children), was coming home, as Colleen and the kids were coming down with a cold, she said. That meant that she’d be back in 30 minutes, tops, and wanting to get ready for bed after her long day.
Getting off the phone, I felt a little stressed and pressured. Resuming our Gaia adjustment, I held the angled ATCs in place while Bob dialed them in. Perhaps fueled by alcohol, several guests were getting noticeably impatient (nowadays I don’t drink).
“Come on!” several guests bellowed.
Okay, I said, turning on the amp.
There was no sound. I double-checked, clicking the standby button on and off. The blue light on the front of my Pass Labs amp didn’t turn on.
“Oh! The speaker cables aren’t plugged in,” someone noted.
I felt an uneasy ache in my stomach. Reconnecting the cables, I tried again. Nothing. Apparently, positive and negative leads had touched – and that was that.
Bob removed the fuse at the back of the amplifier, and we sought to find a replacement. I thumbed through the owner’s manual and couldn’t find a listing of the proper fuse. However, a Google search yielded an AI (artificial intelligence) result suggesting a 3.5 amp slow blow fuse. Always the handyman, Bob went next door and retrieved a 3 ½ amp slow blow fuse and replaced the factory-issued one with it. It still didn’t work.
We heard footsteps clicking overhead. Belle was home. It was now 8:30 PM and with no amplifier to drive the system, the party was over.
“I’m so sorry,” one friend offered. There were thank yous and pleasantries, and several friends offered to loan me an amplifier if a fuse wouldn’t fix it.
The Day After
I called Pass Labs during lunch break the next day to get the exact fuses to order, as well as clarification on my options if that wasn’t the issue. On the other end of the line, Kent English politely informed me that the proper fuse should be listed on the back of the amp (in all fairness, it was dark where the amp resides, so we never saw that!), but checking with a Pass Labs technician, he said that it probably reads six amps, but I should go with an eight amp slow blow, 5 mm x 20 mm fuse instead. And, if that doesn’t work, I can always ship my X150.8 amp to them and they can flip it around in a few days, he offered.
Relieved but anxious, I ordered a set of eight amp slow blow fuses from Amazon and waited several days.
Deflated, Then Redeemed
Several days later, I reached out to Jam Somasundram, owner and designer at Quadratic Audio that makes the MC-1 Moving Coil Transformer that I use for vinyl playback in tandem with the Pass Labs XP-17 Phono Preamplifier. He also previously designed the Pass Labs HPA-1 Headphone Amplifier that I used this week for a current review of a phono cartridge headshell in tandem with the Dave Clark Audio Stealth closed-back planar headphones. Jam wanted to hear more about the debacle. Being an engineer, he asked a few diagnostic questions about exactly what happened.
“Juan, you always need to unplug the power cord and turn off the amplifier when changing cables,” he cautioned in a professorial tone, adding that a friend of his damaged his amplifier when he plugged in new interconnects while it was powered up. “He ended up paying $600 for repairs,” he added. By following these cautionary steps, such disasters can be avoided.
He was right. The Pass Labs X150.8 owner’s manual read, “Cables should never be connected / disconnected with equipment powered up. Failure to heed this warning may damage or destroy equipment.” I knew better, but in a distracted moment, I blew it. I spent the next several days kicking myself emotionally. Argh!
However, late this Saturday morning, my fuses arrived. I texted Bob, and he came over an hour later to perform the official fuse replacement duties. Several minutes later, Bob pressed the standby switch and presto! That familiar blue LED light with the Class A meter was back on again and, moments later, we had music!
I was relieved, and Belle was ecstatic. Lessons learned and problem fixed, now, we could resume our Saturday matinee NetFlix binge-watching session, and Bob could go home and join his wife to watch theirs!
As he donned his coat to go out the door, Bob turned to me, winked, and said, “I fully expect to hear you playing your music loudly later on tonight!”
Not a problem, neighbor Bob!