My Slantmaster 50 Story

Back in the early 2000s, I was happily working as a college instructor for a music school in St. Paul. I was the school’s Student AES Club faculty advisor and I was having the time of my life working with brilliant, inspiring, energetic young people who were fascinated with all things audio. Back in my early-QSC Audio days, I’d built a pretty cool ABX tester and, later (after I’d left California and the pro audio business), QSC decided to build a much more sophisticated ABX tester and use it to promote the company’s products. That didn’t work out well and the ABX testers were recalled from the company’s sales force and, I’d been told, crushed to bury the evidence that someone at QSC once thought professional audio people gave a crap about audio fidelity and honest listening tests. I’d been that same dumbasss a decade earlier, so they had my sympathy. Because I’m lazy and that wheel had already been built, I’d bothered Pat Quilter often to see if he could find an unwanted ABX test box that hadn’t died in the garbage compactor.

So, in late 2008 when Pat sent me an email warning me that there was a package coming my way, I thought I knew what would be in it. When it arrived, it seemed almost Amazon-oversized for what I thought would be a 1 rack-space piece. The box was also a lot lighter than I’d expected. I cracked the tape at the top of the box and saw the beige tolex, the leather handle, and the black dust cover and I was confused. I knew Pat was retiring from QSC Audio, so I assumed he’d built a model amp as a memento. When I pulled the amp from the box and saw the Celestion Century 12” I suspected it was more than an empty box demo. I plugged it in, turned it on, and (like everyone I’ve ever show the amp to) said, “Wow!” There is a cool, brief light show from the backlit front panel as the amp powers up that blows everyone away. I spent the rest of the day playing with the amp, which was more guitar playing than I’d done in the past 20-some years.

I brought it to school the next day to show it off to students, employees and instructors, and anyone who was interested. We used it several times in recording sessions over the next couple of weeks. One to-be-unnamed guitar instructor tried to buy it from me, tried to get me to have Pat build one for him, and coveted it so blatantly that I started storing it in the secured record lab area so that it wouldn’t disappear. Over the next year, I used the Slantmaster dozens of times with all sorts of guitars and guitarists and it was universally loved by everyone who heard it. It is kind of sad to admit that the amp has never been used outside of McNally Smith College or my home studio. It has never seen a live gig other than the MSCM’s auditorium stage a couple of times by players who I trusted not to abuse it.

This is what the Quilter Labs website has to say about the Slantmaster 50, “Built to celebrate QSC’s 40th anniversary, the Slantmaster 50 used a linear amplifier to deliver 50 ‘hot watts’ to a simply awesome Celestion ‘Century’ neodymium speaker.

“This was the precursor to Quilter Labs foundation.

“Only one hundred were made and featured a spring reverb! These are very limited, so if you have one you are lucky!”

I have one (#72 of 100) and I am well aware of the fact that I am lucky to do so. I have meant to write something about this amazing gift for nearly 15 years, but a conversation about the Slantmaster in the Facebook “Quilter Musical Equipment Owners Group” about the Slantmaster moved me to finally do the work.

The day I started work at QSC Audio Products in Costa Mesa in early 1983 was the day Pat took his first vacation in a decade. Pat and his mother had booked a tour of Europe on the Orient Express and he’d entrusted me with overseeing the initial production of the first Series One amp, the 1400, without a single unit having yet passed through production. There were . . . problems, but the QSC team of that day pulled together and by Monday afternoon we were cranking out 1400s at a pretty decent pace. The Series One and Three amps were the breakthrough products that put QSC on the pro equipment map and for the next 9 years I was a product engineer, test engineer, manufacturing engineer, manufacturing engineering manager, and tech services manager: 5 different jobs, with a couple that lapped-over each other a bit, in 9 years. Pat and I became friends, partially because I was the interface between his working hours (noon to whenever in the evening) and everyone else and me (7AM to 5-or-whenever-PM). We shared an interest in audio electronics, psychoacoustics, music, guitars and guitar amplifiers, electric vehicles, science fiction and fantasy, literature, and the people we worked with. I quit QSC and left California, after giving notice almost 3 years earlier that I would be leaving when I graduated from Cal State Long Beach, because I could never see myself breaking even economically in southern California and for personal reasons. Pat and I have continued to communicate through email for the past 30 years. I keep his Xmas letters in the same envelope as the letter that came with the Slantmaster.

Product Review: Positive Grid Spark Go

About a year ago, I reviewed the Positive Grid Spark Mini and didn’t find it worth keeping. There were a lot of things to like about it, but it seemed like a larger-than-necessary package for such a low volume device. I was looking for an electric guitar amp that could be used in small acoustic guitar jam situations, for home practice sessions, and anything beyond that would be gravy. Positive Grid must have read my mind with the Ultra-portable Smart Guitar Amp & Bluetooth® Speaker because it meets all of those requirements and adds a bunch of extras. To be honest and clear, there is nothing in the Go firmware or software that is different from the Mini. The difference is that the Go fits in a pocket of my guitar’s gig bag and does everything the Mini does, maybe better.

I, sadly, didn’t figure this out on my own. I was down enough on the Mini that it wouldn’t have occurred to me to try an even smaller Positive Grid amp. Lucky for me, a much smarter friend brought a Go to my home to show off a couple of weeks ago and I was almost instantly sold. After playing with his for an hour or so, I ordered one from Sweetwater and it arrived a few days later.

The controls to the Spark Go are incredibly basic. The top of the amp contains the 1/4” guitar input jack, the guitar volume control (the ring around the input jack), a 3/5mm headphone/aux out/Line out 1/8” jack (using this connector disables the Go’s speaker), Music +/- volume buttons (Bluetooth is the Music input), a Preset select switch and LEDs to indicate which preset you’ve selected (4 are available).

The right side of the amp hosts the remaining USB3 port, a power switch and power LED, and the Bluetooth indicator. The power switch is a little hard to find in good light and almost impossible to find without good lighting. I’m going to paint a white dot on mine. There is a strap button on the left side of the amp.

There is a rudimentary guitar tuner bult into the preset/Select button setup. Bluetooth setup is pretty obvious and basic. I love the guitar volume control and, since it is an infinite rotary control, it beeps at you when you’re at max volume. The chassis is wrapped in a removeable black rubber-like sleeve that is easy to grip, but does disguise some of the buttons in poor lighting. The back of the amp is brilliantly covered in an even more rubbery base which nicely couples the amp to a floor or table, restricting the speaker disbursement by half (hemispheric) and providing a theoretical 3dB boost over leaving the amp suspended or even on edge. I like to put the amp at my feet when I’m playing with friends (who are mostly on acoustic guitars) and full-up the amp is pretty much a perfect match, volume-wise, with the other instruments in the room.   

Positive Grid has been fairly aggressive about firmware updates, including the one I downloaded and installed today (10/15/2023, the 2nd update in the month I’ve owned the amp). Updates are installed through the USB3 port via either Windows or Mac OS. So far, all of the updates have been seamless and none have caused problems (imagine that Microsoft and Apple?). The software, either on Android or iOS, is excellent and easy-to-use (essentially Bias 2). As I demonstrated in the Mini review, is insanely flexible, although you can only load 4 presets at a time you can load a lot more than that through “favorites” on the app while playing. You have 33 different amps and 43 different effects to play with and the effects range from (in this order of signal flow and grouped as described): noise gates, compressors (5) and wah (J.J Legendary), drive and overdrive (14), amplifiers (40), modulation (11) and EQ (2), delay (6), and reverb (9).

The part of any amplifier review that matters is “how does it sound?” Obviously, there isn’t a lot of bass from a tiny speaker and a passive radiator, but there is enough to create pleasant, musical guitar tones if you aren’t greedy. I wasn’t impressed with the default sounds, but it didn’t take long for me to come up with 4 that I like a lot and at least a couple dozen in my favorites pile to fall back on for other situations. As a direct-to-recording interface, the latency is close to zero and while I usually need to brighten-up the output (especially distorted amp setups) I’m pretty happy with the Go as my recording electric guitar interface, too. For $120, that is a lot of function for the buck and I’ve really upped my guitar practice time as a result. 

Postscript: This past week I tried using the Go as a guitar interface for recording and online music (Sonobus) and it was terrific. I'd read some complaints that the sound was dull or artificial, but I didn't find that to be true at all. I have a couple of emulation pedals and I think the Go is at least as good and a lot more flexible. 

Ego Noise

This has been a week where two of my blogging interests, motorcycling and blogging, have unfortunately grown together into one large irritation. Last Monday, a parade of nitwit of bikers blubbered past our home at their usual barely-above-a-crawl speed and well-above-a-thunderstorm noise level, proving that there are more than enough reasons to defund the lazy, cowardly couch-potatoes who inhabit our local police and sheriff's departments. If you can’t identify a national, state, and local crime that produces enough noise to drown out a freight train, you are too dumb to be carrying a gun and badge and do not deserve to be wasting public funds pretending to be “law enforcement.” 

A few days later, I went to a downtown outdoor concert and was assaulted by another of the many painful, anti-musical sound systems I’ve suffered in my lifetime. I have an stock of ear plugs in the car, but I shouldn’t have to use them to protect myself in an outdoor concert that drew 75 people max. It took me a few moments to realize that it would only get worse and, as a result, my ears rang all through the next day.

A few days after that, we went to a graduation party for a friend who had been workingm part-time and nights, on her Master’s degree for the last 25 years. Her husband made the event into a “look at me” episode by playing in 3 different bands that were all so loud that nobody could carry on a conversation anywhere in the building. His wife’s celebration was turned into a “I can do stuff too” event for her husband. We all only have a wild hope that she heard, or recognized, at least a few of the many congratulations that were mimed her way.

At the first event, I got into a discussion with a self-admitted deaf guy who argued that the sound system wasn’t as bad as I alleged because he could pick out the three instruments and two voices with some effort. We’re talking about a male and female vocal, acoustic guitar, mandolin, and cajon. If you couldn’t at least make out the existence of those “voices,” the sound would amount to pure cacophony. That is a massively low bar for a sound goober to achieve. At the second event, a musician friend and I decided that an upside to this nonsense is that as long as live sound is this bad, there is no point in wasting a lot of energy on learning lyrics. As Ms. Day said, “Every song is ‘Louie, Louie’ so why bother learning any other song?” Honestly, as long as the vocals were sorta in the general territory of the key, even the melody was obscured by the noise, the dominating mediocre bass and guitars.

A few nights ago, an old friend and his daughter went to a Bastille, Nile Rodgers & CHIC, Duran Duran concert at the Atlanta State Farm Arena. His comment on the show was, "The bands were good. The sound was fairly unintelligible due to extreme loudness. But, I didn't let the sound people steal my joy!" He has been nearly a life-long fan of Rodgers and CHIC and “I didn't let the sound people steal my joy” was the best he could say for his outlay of several hundred dollars for the tickets, the cost of the trip and an overnight stay, and the experience. He also spent a good bit of his life working backstage and FOH with professional sound systems and touring companies. That is how low the bar for live, amplified music has become, at best, we hope the sound system doesn’t ruin the experience for us.

Talent, Technique, and Tone: How to Hide Them All

Back in the mid-70s (as an old friend would say, “When the sun was little-tiny and the moon wasn’t born yet.”), I was a wannabe rock lead guitarist with a lot more confidence than talent and had just moved from rural Nebraska to a city within easy striking and gigging distance from the “Big City”: Omaha, Nebraska and, almost as often, Lincoln, Nebraska and, occasionally, Kansas City and Des Moines. It didn’t take long for me to learn that all of the hot players in town got together fairly regularly at the Saddle Creek Bar for an open mic/jam session and as soon as I figured out where Saddle Creek was I geared up to go into battle.

My amp and gear, at the time, was a 1970s Peavey Artist 100W combo with a Peavey 12” speaker. It was more than enough amp for any gig my band ever did and with an assortment of pedals screwed to a board and a Morley wah, I could handle almost anything on the pop charts at the time. That was considered a “tiny” rig at the time for a rock band guitar player. The Artist was the first amp I ever owned that had a “switched” input setup where I could go from a clean channel to a distorted one with a footswitch. The distortion that amp provided was pretty much fuzz-box quality and, at the time, my tone roll model was probably Carlos Santana.

The Saddle Creek jam session was a different setup than I’d expected. The stage backline was a permanent setup. As I remember there were a couple of Fender Twin Reverbs for the guitars, a Rhodes, a drum kit, an Ampeg bass amp of some sort, and 3 or 4 vocal mics; all set up and ready to go. This was 40 years ago, so my memory of the equipment is open to question, but I won’t be far from wrong. As a guitar player, I was “allowed” to bring myself and my guitar, but no pedals and sure-as-hell no amp. What I learned about myself that first time at Saddle Creek was that I sucked. Without the crutch of distortion and sustain to cover up my mediocre right and left hand technique, I sounded embarrassingly mediocre and having to pick every note or cleanly hammer-on or off slowed me down to 1970s country and western music territory. I went home with my tail between my legs, my ego squashed, and my confidence turned into brutal humiliation. Not that anyone I was on stage with or who heard me said anything. They didn’t need to, I said it all to myself.

After getting my ass handed to me, I went home and re-evaluated my equipment choices and my playing technique. There were a lot of terrific musicians at the Saddle Creek jam and I desperately wanted to go back and, even more, I did not want to suck in front of my peers. I started practicing on an acoustic guitar, even with the band. We lowered our practice volume drastically to accommodate my acoustic guitar and to protect our hearing. For performances, I sold the Peavey Artist and lucked into a 1950s Fender Harvard, which I immediately “hot-rodded” with a JKL K120 12” speaker, Marshall-style tone controls, and a foot-switched gain-boost circuit (all tube). [Yeah, I know. I destroyed the “collector value” of the amp. I did that sort of thing to a few hundred amps between 1974 and 1984, so get over yourself.] No more pedal board, no fuzz box sound, just a collection of tones produced by my Moonstone guitar, my amp, occasional contributions from the Morley wah pedal, and my fingers.

A few months and dozens of gigs later, I went back to Saddle Creek and I didn’t suck. I went back often over the next few years and learned more from that experience than I had from practicing and playing in bands in the previous dozen years. In the process, I also learned a lot about live sound systems, acoustics, electronics, and even audiences. Not only did I improve, as a player, enough to feel reasonably happy with my performance among the great players at the Saddle Creek Bar, but my band’s overall sound improved enough that I would often have other musicians walk right by my little Harvard, on it’s folding stand right behind me on stage, They’d often ask, “How do you get that sound from that amp?” And they’d be pointing at the bass player’s SVT, totally ignoring the little Harvard they’d walked past.

And so, sometime around 1976 I discovered “small is better” and I have never found any evidence to the contrary. But I have seen a lot of evidence that big is bad from everyone from the rich and famous to the godawful cacophony produced by wannabe guitar players in cover bands from Texas to Nebraska to California to Colorado to Minnesota and the surrounding territories. When my Nebraska sound company was designing and building sound systems for bands in the late 70s, I’d tell whoever was spending the money “For every 100W Marshall you let on to your stage, you’ll need at least 1,000W of PA system to get the vocals over the guitar.” I haven’t seen any evidence to conflict with that advice, either.

Product Review: Positive Grid Spark Mini

Silly me, I thought the Positive Grid Spark Mini was a fairly new product, but my resident guitar repair guru and guy-who-will-try-to-fix-anything about town, Brian Stewart (Tree Strings Music), has already repaired one in his Red Wing shop. I haven’t yet heard what the fault was in that unit. I ordered a white one from Amazon, thinking it might be a fun practice and outdoor jamming amp. I’ve had it about a week and, sadly, the fun is wearing off fast. The good and bad news is that almost everything about this amp is driven by a phone/tablet app, iPhone or Android. The good is that it has hidden power if you’re willing to climb the usual steep software learning curve. The bad is, like most apps, it’s glitchy, unpredictable and often counter-intuitive, almost completely inflexible, and very dumbed-down while pretending to be a product for the sophisticated, discriminating guitarist (the ultimate oxymoron?). A lot of the positive reviews you will find for this amp begin with something like “I’m new to guitar and have only been playing about a few months . . .” It’s easy to like or even love something if you don’t have anything to compare it to. In my case, it’s hard for me to look at any product with the eyes of a newbie. So prepare to be disappointed if you’re hoping for that kind of bubbly, happy-talk review. At 74 and after 50 years in various areas of pro audio and music, there is nothing new about me except for the crap that keeps popping up every time I have a doctor’s appointment. Having spent 20-some years in test and reliability engineering I tend to find more things wrong with software than right.

 

You can’t beat the Mini’s physical controls for simplicity. On the top of the amp chassis, you get 4-position Preset switch (Rhythm, Lead, Solo, and Custom), a Guitar volume, a Music volume control (Bluetooth or Aux In signals), and a guitar input. The back of the chassis has 3.175mm (aka 1/8”) Line Out and Aux Input jacks, a USB-C port for charging the battery and (sometime in the future) a functioning digital audio interface), a Bluetooth “Pair” switch (the Pair switch also fires up a rudimentary guitar tuner), and a power switch. The amp comes with a cute leatherette strap and a pair of buttons to attach the strap on the side. The amp is a 10W Class-D unit that, supposedly produces 90dBSPL at 1m. The cabinet has two 2” speakers and a bottom-facing passive radiator. The 3Ah battery supposedly provides power for 8 hours (on mid-to-low power output) and charges from empty to full in 3 hours. The firmware contains “33 Amp Models, 43 Effects, (Noise Gate, Compressor, Distortion, Modulation/EQ, Delay, Reverb – fixed in that order) and the USB interface is a 44kHz/16 bit A/D. You also get a a free download of PreSonus Studio One Prime recording software with your original purchase. Registering for your software is the closest thing to registering for warranty with Positive Grid. You can buy (for $110) a Spark Control footswitch to either control the presets, turn on and off various virtual pedals, or a combination of those functions. The amp is 146.5 x 123 x 165 mm (5.76 x 4.84 x 6.49 in) and weighs 1.5 kg (3.3 lb).

As usual, the included paper “Quick Start Guide” is close to useless. Not so typically, Positive Grid hasn’t provided much in the way of useful information on their website, YouTube, or anywhere else. Figuring out the app and the various features of the amp that are only accessed through the app is up to the buyer.

For a beginning guitarist who doesn’t know any other musicians, some of the Mini’s app features are probably fun-to-useful. This “screenshot” is really a compilation of three different screens as typically displayed on a phone. The middle one is an example of a dumbed-down imitation of a fairly common DAW guitar pedal screen; like the one in Logic Pro. A big difference between the DAW pedal boards and the Spark is that you can’t reshuffle the order of the pedals to suit your purposes.

After spending considerable time playing with the various pedals I can say “they work.” The compressors in the Comp/Wah section aren’t up to DAW standards, but they are probably as good as most hardware pedals. The “Wah” function, also included in this group, is “Temporarily Disabled.” As usual, I don’t like the distortion (Drive) pedals much, but I rarely do. About half of the Drive pedals are red-flagged, which means you’ll have to spend $20 or more to enable those pedals on your device. So it goes for the Amp models, too. Most of the red-flagged amp models are variations on the mediocre Marshall models. The Mod/EQ models are predictable and not bad. The Delays are ok, except for the absence of a multi-tap delay. The Reverbs are typically pretty good, since digital reverb plug-ins have been fairly well staked-out territory for at least 20 years. I didn’t find a favorite from the verbs, but I didn’t find anything I hated either.

Irritatingly, with my Samsung tablet and the Samsung Music player, anytime I open the Spark app the music player starts playing something from my current playlist through the Spark Mini. Before you start babbling about some “play on Bluetooth connection” toggle in the player, get a grip on yourself. No other Bluetooth device that I own has this behavior: from consumer buds to Shure in-ears to three different Bluetooth speaker systems. It is a glitch in the Spark app and that has been logged by Positive Grid’s customer service and I wasn’t the first to make the complaint. If everything else was excellent this wouldn’t be a deal-breaker, just unpredictably irritating. (If it does this when I first open up the app, will it spontaneously do the same during a gig?) Yes, I could turn off the Music volume, but if I am using it as a backing track at the time it sort of defeats the purpose of that function.

With that out of the way, my impression of the guitar amp is somewhat positive. I’m not fond of electric guitar distortion in the usual buzz-box fashion, but some of the amp models deliver decent slightly over-driven sounds with the kind of amp EQ and tone you’d expect from what I’m guessing are the amps being modeled. Some of the setups both by other users and Positive Grid are fair-to-decent. I had some high hopes for Pat Metheny style sounds, but the lack of multi-tap delays squashed that. You could just add a pedal delay up front but that would defeat my purpose. I have an old MacBook Pro with MainStage that will do everything this unit does with a ton more effects including my multi-tap delay that I’d rather use with a small wired power speaker than add a pedal that is almost as big as this amp.

And speaking of power, I wouldn’t be surprised if the Mini an produce 10W, but the distortion at that output would be objectionable. That goes for the spec’d 90dBSPL@1m acoustic output, too. At any volume over a moderately loud voice or a strummed full-size acoustic guitar, the bottom end of this amp clips indecently. It is not a pleasant distortion, either. It is the usual splatting sound of digital clipping. That was the straw that broke the back of my interest in the Positive Grid Spark Mini. There were moments when I thought I was about to find the sweet spot for several of the Presets but “almost there” was as close as I got to something useful. When the amp sounded good, it was too quiet to compete with a couple of acoustic guitars. When it was loud enough to cut through a small instrument crowd, it sounded awful.

For a beginning practice amp the Spark Mini isn’t bad. Most beginners, however, will have a terrible time with the mediocre application software that is an absolute necessity for using the amp. Advanced users will be frustrated with the user-hostile programming of the app and disappointed with the little amp’s small performance.