Acoustic guitar amps have more in common with stereo systems than traditional electric guitar amps. What's the difference? Acoustic amps are designed for a neutral full-range sound rather than a colored electric guitar tone (e.g., crunch and distortion). In other words, a dedicated acoustic amp should faithfully render natural tone rather than color and process it. Thus, these amps have high power ratings so tone is clean, a full range speaker system with woofer and tweeter and ultra sensitive preamp inputs optimized for the low output of piezo pickups.
Unfortunately, acoustic amps tend to be optimized for steel-strings and often don't get classical guitar tone right, even with buku dial diddling. Is the CPK-8T the holy grail of classical guitar amps?
Genz Benz Shenandoah SHEN-CPK-8T
Genz Benz SHEN-CPK-8T
I jacked in my Hirade TH8SS, TH90 and Takamine LTD 2012C Michi (high end classicals with Cool Tubes preamps) and was greeted with thin tone. Amp tone controls were set flat and such was expected. I diddled the controls, hoping to fatten the mids and reduce lower highs. And, yes, the heavens opened and out came fat and sweet tone. Basically 2 notches added to mids (at 250Hz), 2 notches treble cut, bass flat and tweeter set to -6Db and I was good to go. Not a hint of harshness or piezo quack to be found. Guitar on-board preamps were set flat.
The CPK-T8 sounded great in my small living room but that's not a good test. I also auditioned the CPK-T8 in a symphonic band rehearsal room where I teach, a mammoth space with sound treatment to deaden resonance. What a different response! The room ate the bass and highs, requiring a lot more EQ boost than needed at home. Oddly, my Trace Acoustic amps hardly need any EQ changes in these two environments (only slight high boost in band room).
In terms of tone quality, the CPK-T8 just trails my Trace Acoustic TA50R and wipes the floor with the Loudbox Mini. However, the CPK-T8 is more complicated to dial in the tone I like, needing more and larger EQ tweaks than the Trace when I change venues. I suspect the CPK-T8 interacts with room acoustics more than the Trace. Trace projection is more dispersed and omnidirectional whereas the Genz Benz is more directional, shooting straight forward. For dinner and wedding gigs I prefer omnidirectional projection due to the better coverage.
Genz Benz specs the frequency range of this amp at 65Hz to 20,000. Indeed the 8-inch speaker delivered rich and balanced bass tones from my Hirades, even in drop-D tuning. I found timbre a little too bright with the tweeter engaged and prefer it disabled or cut -6 Db depending on the room (via rear switch). I'm guessing steel-string players would like the extra chime of the tweeter.
And, yes, this little amp cranks, blowing my Trace Acoustic TA50R out of the water in sheer volume. I mainly play solo dinner and wedding gigs so I never need to play this loud, but an acoustic rocker would be happy, especially with the extra crank of the matched extension speaker.
Digital Effects
The on-board digital effects are so-so and my main disappointment with this amp. I'm looking for natural tone and found most of the 15 patches bright, thin and gimmicky. The chorus and rotating speaker effects are horrid. I had great hopes for the two hall patches but they made the amp tone thin when mixed only 25% (9:00). At 50:50 (12:00) I sounded like the tin-man! Even a budget standalone unit like the Microverb beat these 15 patches senseless. In contrast the Alesis effects in my 1990s Trace Acoustic TA50R sound a lot better: warm, sweet and complex.
The good news is the CPK-8T has an effects loop and you can easily mix in your favorite effects. But just one decent built-in hall reverb would have been nice for gigs.
Mic Input
My Shure 849 condenser mic sounds rich and natural jacked into my Fishman Loudbox but is bright, boxy and prone to feedback with the CPK-T8. No matter how I diddled the tone controls I could not dial in a natural tone. I could improve it but not enough to suit my ears. My Neumann KM184 fared better but still didn't make the cut. I don't own a dynamic mic so a different mic might make a better sonic match. In fairness, the Shure 849 isn't any good through my TA50R either. I bought the amp to use with piezo pickups so no biggie but if mics are your main thing you may not be happy.
CPK-8T Rear Panel: XLR outputs, effect loop, line level input and output for an extension speaker. The head is easily removable if you need to travel light and jack into a larger system. Without the cab the head becomes a deluxe preamp/direct box.
The diminutive CPK-8T has an attractive vintage vibe and is more handsome than the product pictures. Due to the small size, the this micro amp almost disappears on stage. I prefer black vinyl over the stock reddish brown exterior but Genz Benz doesn't offer color choices.
The knurled metal knobs, rather than plastic, are a nice touch and lend a precision feel to knob twisting. One gotcha: the blue LED pilot light is really bright and can be distracting in dimmer venues. In my lamp lit living room I find the panel difficult to see due to the glare from the LED. Of course, no problem in bright sunlight.
The cabinet has one unusual feature: a built-in kickstand. Give it a good tug and two rubber tipped legs drop down, allowing about a 15 degree tilt. The kickstand is reasonably beefy and certainly better than the one used on Roland acoustic amps. Use of the kickstand reduces bass response in some rooms—you lose coupling to the floor—so it may not be desirable in all venues.
The Genz Benz Shenandoah SHEN-CPK-8T is Peter's pick for the ultimate acoustic guitarist gig amp: warm natural tone, powerful output, ample tone shaping controls and small enough to hump three blocks from cheap parking to your next wedding or coffeehouse gig.
For under saddle pickup classical guitar amplification the CPK-T8 does exceedingly well: excellent dynamics and tone, even response up and down the neck, nixes RFI and resists feedback with a little care. For value and use as an acoustic guitar amp, I award it an "A". For the weak on-board digital effects and mic performance I have to downgrade the overall grade to B.
The CPK-T8 packs a lot of punch and tone for under a grand ($900 street price) and is among the best sounding small amps for acoustic guitarists gigging in small venues. Yes, there are compromises in the effects and mic section, but it gets the most important thing right—piezo tone—and is overall a great micro amp. Genz Benz is one of the many companies swallowed up by Fender and is listed as a KMC company. Hopefully Fender keeps the Genz Benz design team stateside as they're doing a great job.
July 2022 Update: My Genz Benz Shenandoah SHEN-CPK-8T is still going strong after enduring over 10 years of gigs and classroom use. Sadly the entire Genz Benz product line disappeared in 2013 after being acquired by Fender. Once again a promising small company is reduced to another notch on Leo's belt...
Major Features
• 175W (combo) 300W (extension speaker)
• Lightweight Class D Power Amp Technology
• 2 Channel Preamp Design w/XLR and ¼” Inputs
• All Channel Inputs Mix Together
• Active 3 Band EQ with Sweepable Midrange
• DSP w/15 Preset Programs
• Phantom Power for Condenser Mics
• 3 Separate Direct Outputs
• Auxiliary Input
• Headphone Jack
• Strap Handle
• Lightweight Plywood Construction
• Bottom-mounted Tilt Foot
• 16.5 lbs
• 13 1/4" x 11 1/4" x 11 3/8"
10/15/2012 | Revised 10/13/2015
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