Review: Job 225 stereo amplifier ..
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Review: Job 225 stereo amplifier
A tiny amp with decades-old tech delivers a stunning sound.
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Photo: Brent Butterworth
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Back panel of the Job 225 stereo amplifier. Nuthin' but amplifier.
Photo: Brent Butterworth
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Job 225 stereo power amp ($1,495)
+ 2 x 125 watts RMS into 8 ohms
+ five-way speaker cable binding posts
+ stereo RCA line-level input
+ Dimensions: 3.2 x 14.1 x 9.6 in (hwd)
+ Weight: 15.4 lb
jobsys.com
“You test … amplifiers?” the lovely brunette MBA said to me from across the couch in the lobby of a hipster L.A. hotel. Sadly, my reply — “There are people who care about this stuff!” — didn’t convince her of the value of my work. On some level, though, I’m in sympathy with her sentiment. While I do, on occasion, test amplifiers, I’m really a speaker and headphone reviewer.
With those products, I understand how the design decisions of engineers affect the sound. But while I understand quite well how amplifiers work, the sonic differences among amplifiers are relatively subtle, and plausible explanations for these differences are rare.
So why am I reviewing an amplifier? Because I couldn’t resist a good backstory.
A couple of months ago, I was discussing the state of the audio industryhttp://images.intellitxt.com/ast/adTypes/icon1.png with Michel Reverchon, CEO of Goldmund, a super-high-end audio company based in Geneva, Switzerland. Goldmund’s products are sold exclusively through a small corps of dealers who are trained in installing the company’s ultra-advanced, cost-no-object systems. When I asked Reverchon if he thought his company would ever distribute products through the Internet, he shocked me by saying, “We already do, on Amazon.”
The product he was talking about isn’t a Goldmund product per se, but it was designed by Goldmund engineers and manufactured in the company’s Geneva factory. It’s the Job 225, a stereo amp rated at 125 watts per channel into 8 ohms. On Amazon, the 225 sells for $1,499. Considering that Goldmund’s amps typically sell for tens of thousands of dollars, its move to sell a relatively affordable amp through the Internet is sort of like Rolls-Royce coming out with a sub-branded hatchback for $40K.
As Reverchon told me more about the 225, I realized it was interesting not only from a businesshttp://images.intellitxt.com/ast/adTypes/icon1.png standpoint, but from an engineering standpoint, too. According to Reverchon, the amplifier’s Class AB design was taken from an amplification circuit originally used in a Tektronics oscilloscope in the late 1960s.
Weird as this source might seem, it makes sense. Oscilloscopes are used to measure radio-frequency signals as well as audio signals, so the amps used to drive the old cathode-ray tube oscilloscopes had to have high bandwidth. Reverchon told me that the circuit has since been refined by nine generations of Goldmund engineers, and variations of it are used on all of the company’s amplifiers.
The 225’s rated ±0.5 dBhttp://images.intellitxt.com/ast/adTypes/lb_icon1.png bandwidth is 10 Hz to 100 kHz, about double that of a typical high-end Class AB amp and five times what you need to cover the audio band. Its rated -3 dB high-frequency response extends to 900 MHz. Why put such a premium on high bandwidth when it’s out of the audible range? Reverchon says while the magnitude of the treble roll-off isn’t audible, the phase (i.e., timing) effects of the roll-off are. In other words, the filtering effect of an amplifier’s treble roll-off shifts the phase of high-frequency signals relative to low frequency signals.
Can you hear those effects? I don’t know. I’m not a psychoacoustics researcher. But other manufacturers, including Krell and Constellation Audio, have recently won acclaim for their new ultra-high-bandwidth designs, so maybe there’s something to it.
Anyway, I was hooked enough to ask Reverchon if he had a Job 225 he could loan me, so I could hear what this decades-old circuit could do.
Setup
I used the 225 with several different speakers, everything from the $378/pair Hsu Research HB-1 Mk2 to the $3,999/pair Thiel CS1.7 to the $20,000/pair Krell Resolution One. In most cases, I fed the 225 signals from the preamp output of my Krell S-300i integrated amp; I also used my Bottlehead Quickie tube preamp. Sources included a Firestone Audio ILTW USB digital-to-analog converter connected to a laptop computer, and my ProJect RM-1.3 turntable feeding an NAD PP-3 phono preamp. I also did comparisons between the Job 225 and the Krell S-300i’s internal amplifier, with levels matched to 0.1 dB.
The 225 is a totally straightforward amp, with nothing but a pair of RCA line inputs, a pair of five-way binding posts for speaker connection, an IEC-style socket for an AC cord, and a power switch on the front. There is one interesting thing about installing the 225, though: At just 14.1 inches wide and 9.5 inches deep, it’s surprisingly compact, small enough that you could probably slip a couple of them into your rack. Too bad there’s no cute little Job preamp to go with it.
I used a standard AC power cord with the 225. Reverchon supplied me with a Job Sweetcord power cord, a high-end model that costs $300, but I decided that for a fairer comparison with the Krell amp I’d use the same power cord for both. (And I have to confess, I wasn’t excited about doing A/B comparisons of power cords — which I’ve done before — and that’s why I’m not excited about doing it.)
Review: Job 225 stereo amplifier
A tiny amp with decades-old tech delivers a stunning sound.
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Frequency response of the Job 225 amplifier at 2.83 volts (1 watt) into 8 ohms
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Total harmonic distortion (THD) vs. output in watts of the Job 225 amplifier, at 8 ohms (blue trace) and 4 ohms (red trace), one channel driven
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Performance
Connected to the pair of Thiel CS1.7s, the 225 sounded … well, just fine. Putting it into the system didn’t produce any immediate sonic revelations to speak of. I did note that the 225 did a superb job of controlling the Thiel’s woofer, keeping the bass maybe even a shade tighter than the Krell amp did, and easily driving the CS1.7’s woofer to the point of pain when I cranked up ZZ Top’s La Futura. Considering that the CS1.7 has a 4-ohm nominal impedance and a 2.6-ohm minimum impedance, that’s fairly impressive. Still, though, the difference I heard in casual use wasn’t dramatic.
It wasn’t until I started to do direct A/B comparisons with the Krell’s internal amp that I got a real sense of what the 225 could do.
For sussing out subtle differences between two pieces of audio gear, I often rely onhttp://images.intellitxt.com/ast/adTypes/icon1.png L.A. saxophonist Terry Landry’s Amazonas (hear a few cuts here). Amazonas was recorded in Direct Stream Digital (DSD) by audiophile producer Joe Harley and tweaked up by mastering guru Bernie Grundman—and best of all, I was there for the recording and mastering sessions so I have some inkling of the way it’s supposed to sound.
With the Job 225 replacing the Krell’s internal amp, Amazonas simply sounded more lifelike, more like what I remember hearing in the studio. Instruments were spread smoothly across the stereo soundstage, sounding more like real instruments in a room instead of like a bunch of instruments steered around the soundstage with pan knobs. Amazonas used a combination of direct and ambient miking, so some of the “pan-pot” effect is inevitable, but still, the 225 gave a more realistic sense of ambience. This happened with the instruments, too—the muted trumpet in the background of the title track sounded more fully embodied, more like a live instrument. The cymbals had a lot more of that natural, airy, unmistakable sound you hear when you’re in the room as the stick hits the brass.
“Words We Never Use” from singer/songwriter Ron Sexsmith’s debut album also dazzled through the 225. Sexsmith’s voice still showed its trademark coarseness, but it sounded a little clearer and less “electronic.” I also heard more detail in the soundstage, i.e., a more complex rendering of the way the sound of the percussion instruments bounced off the studio walls or flowed through the reverb processor or both. I think this is what audio reviewers are referring to when they talk about “inner detail”—which I’ve always thought could be expressed just as well, and less confusingly, as simply “detail.”
The 225’s amped-up ambience inspired me to play Toto’s “Rosanna,” the best choice I’ve found to “light up” every part of the audio spectrum. This dense recording gave the 225 plenty of chance to work its magic. The soundstage was wider and more detailed. The piano lost some of its electronic edge and started to sound more like the real thing. The bass and kick drum sounded just a bit tighter.
In short, I was hearing a really good amp.
Measurements
Like I said, I don't review amps on a regular basis, but I do own two audio analyzers that can perform amp measurements. So I thought I'd run a couple of quick sweeps on the 225 to get an idea of whether or not it lives up to Goldmund's claims. I used a Clio FW analyzer for these tests. You can see the results in the charts on this page. Note that the powerhttp://images.intellitxt.com/ast/adTypes/icon1.png measurements are with just one channel driven; I didn't have enough load resistors on hand to do both channels.
The frequency response measurement suggests even greater bandwidth than the manufacturer claims. The official spec is ±0.5 dB from 10 Hz to 100 kHz. My measurement indicated +0.05 dB/-0.11 dB from 10 Hz to 88 kHz (Clio's measurement limit), down just -0.05 at 80 kHz.
Output at 8 ohms is far beyond the 125-watt spec: 194 watts at 0.5% THD, 201 watts at 1.0% THD. Into 4 ohms, it's not as impressive. While the manufacturer doesn't specify power at 4 ohms, we typically expect a high-end amplifier to double its power (or come close) into 4 ohms. The 4-ohm numbers I got with the 225 are 218 watts at 0.5% THD, 227 watts at 1.0% THD.
Bottom Line
The Job 225 seems to break beyond the limits of the “affordablehttp://images.intellitxt.com/ast/adTypes/icon1.png high-end amp” to deliver a sound quality more like that of the $5,000-and-up amps I’ve tried. No, it’s nothing to look at, nothing you can brag about, but it does deliver superbly smooth sound from a chassis that seems almost impossibly small. So should you get a Job? If you’re looking for a compact, reasonably affordable, high-end amp, then yeah.
Re: Review: Job 225 stereo amplifier ..
Nice review. Those sound like awesome nicely priced amps.
I'm noticing alot of quality in alot more affordable electronics nowadays,
Which is great for me, I can put together a nice system and still eat!!
Thanks for a good read!
Re: Review: Job 225 stereo amplifier ..
It really is an amazing amp for the money.
Quote:
Originally Posted by
Petro85
Nice review. Those sound like awesome nicely priced amps.
I'm noticing alot of quality in alot more affordable electronics nowadays,
Which is great for me, I can put together a nice system and still eat!!
Thanks for a good read!
Re: Review: Job 225 stereo amplifier ..
Quote:
Originally Posted by
joeinid
It really is an amazing amp for the money.
This should be a standard field for US reviews: Will it drive Maggies? 4 ohm is such a drag on small amp power supplies.
Re: Review: Job 225 stereo amplifier ..
Welcome to the forum sandifop.
I think the Job will work on the Maggies but getting sufficient volume for some will be difficult to achieve. I felt it was more than enough on my Studio2 which are as follows:
| Sensitivity (2.83V @ 1m) |
87.7 dB SPL with 2.83 V @ 1m (4 pi anechoic) |
Re: Review: Job 225 stereo amplifier ..
Thank-you Joe. The good part of condo living is "loud" happens only in the headroom. I look forward to plugging a Jobs in my 12s and hope I don't go "oh cwap."
Re: Review: Job 225 stereo amplifier ..
Quote:
Originally Posted by
sandifop
Thank-you Joe. The good part of condo living is "loud" happen only in the headroom. I look forward to plugging a Jobs in my 12s and hope I don't go "oh cwap."
I think you will be quite surprised by this little gem of an amp. I love mine and can not believe the level of sound for the asking price. They do offer a return policy but I think the restock fee can be 20%. I feel it is well worth the cost at $1500 and think you will be able to sell it here or on audiogon for not much of a loss if you fell the need. I could easily live with mine as my only amp. Please let us (me) know what you think of it.
Re: Review: Job 225 stereo amplifier ..
Quote:
Originally Posted by
joeinid
I think you will be quite surprised by this little gem of an amp. I love mine and can not believe the level of sound for the asking price. They do offer a return policy but I think the restock fee can be 20%. I feel it is well worth the cost at $1500 and think you will be able to sell it here or on audiogon for not much of a loss if you fell the need. I could easily live with mine as my only amp. Please let us (me) know what you think of it.
Nice avatar Joe !! You better be able to afford the MIT cables though !!
Ha !
Re: Review: Job 225 stereo amplifier ..
Quote:
Originally Posted by
MDP
Nice avatar Joe !! You better be able to afford the MIT cables though !!
Ha !
We know the rules ...
