Design & fabrication of highly acclaimed guitar/bass amplifiers and electronic audio equipment that offers superior musical context for the discerning musician, audiophile, and music lover.
“It’s like your favorite amp, only better”
www.dumblekiller.com
JCA Circuits “Vibe” Amplifier
“This strikes us as an unreal studio amp, or something that would be amazing for around home sitting right in front of it and pouring your heart out to after midnight. What a perfect little amp that can do it all. Hot damn…” Tone Quest Report
“For life, is all about the sweet spot, isn’t it? You know it when you find it. The amp has a beautiful and absolutely WIDE GLIDE, pure Fender tone, all while cranking out far more clean headroom than we thought possible from a small amp, and the use of the Jupiter ceramic 8-inch speaker was superb. It was definitively surprising how much sweet and stout low end each note has, and the clarity of the top and mids are also pristine.” Tone Quest Report
“Once we cranked it past about 8 it really sang, but still, maintained a gorgeous fidelity of signal with zero graininess or harsh frequencies. It loved Strats, Les Pauls, and the Junior, and we even put a Gibson J-200 through it to hear it acoustically. This amp is all about the pristine and stunning clean tones, and what you do from there is up to each player.” Tone Quest Report
JCA Circuits GR1.6 “Golden Ratio” Amplifier
“To us, it is among the best 1X12 20 Watt amplifiers we have ever reviewed” Tone Quest Report
“Well, I finally cranked this baby up…OMG! Like Riding a Wild Horse, WOW…Woman Tone X5, Yikes….I think a 100 Watt version would be a useful military weapon (:” Huey Redwine
“JCA GR1.6 Golden Ratio Amp. “Dumble Killer”. Best 1×12 boutique combo ever built.” The Black Lodge
“If a Trainwreck was the sound of the 90’s, then this amp is the sound of the future” Harmony Central Review
“Purring look, roaring sound!” Vintage Guitar Magazine
“A buddy said the Golden Ratio is an amalgamation of many classic medium/small amps, with a level of refinement similar to what the Trainwreck Rocket was to the AC30. I’m paraphrasing and I hope it makes sense but it’s quite the compliment. Your amps are remembered as being at that level.” Elijah Robinson
“I was fortunate enough to make JCA’s acquaintance, and he invited me over to the shop to have a look at his gear. I got a sneak peak of what he was building for you, the Dumble Killer. It’s not only going to sound great, it’s going to look great too. Exquisite attention to detail through and through.” Jae H.
“Jason, Just letting you know how completely thrilled I am with your fantastic amp! With the right pedal, I can finally accurately recreate Alex Lifeson’s unique and elusive tone on Limelight. I don’t know whether or not your amp has any similarities to the Marshall Club and Country (different tubes and power rating of course), but I am so happy with it, all around. It can do almost anything. My tech noted the high build quality and he’s not easily impressed.. Thanks so much!” J.H.
“Okay, Jason, I got the amp home and unpacked it…I’ve got one word for you. RIDICULOUS. Holy shit, man this thing sounds GREAT! It sound EXACTLY how you described it which, to be honest, is usually not the case. I mean I obviously expected it to sound really good or I wouldn’t have sold stuff at a loss and scrambled to buy it. But WOW. Super great cleans, Marshall roar, and that Trainwreck feedback hanging on the ends of the notes when it’s cranked up. And it cleans up with my guitar volume. I still haven’t touched the EQ, cut or trim, just the switches and volume knob. Thank you. THANK YOU.” J.P.
“I just got a JCA Circuits GR (Golden Ratio) 1.6. It’s the best low wattage combo amp I have ever had, played or heard! A truly magical piece of gear!” N. Bessie
“If you relish the prospect of jumping from the sound of a blackface Deluxe (without reverb) to a high gain Marshall short stack with all the dimensional bloom and harmonic character of a hand-wired tube amplifier, the GR 1.6 performs this nifty trick better than just about any amp we have reviewed. A Marshall PA20 can’t do it… the reissue 1974X 1×12 combo can’t do it… and the AC15 won’t do it. The DR. Z MAZ18 comes close, as does the Balls M18, but both lack a bit of the Fender DNA we hear in the GR 1.6. This is an extraordinarily toneful amplifier, created with an equally extraordinary voice, feel and attitude.” Tone Quest Report
“Given its laid-back appearance, we were expecting the amp to purr like kitten, but what we got was a roar! The 6V6s didn’t produce that sedate, scooped Fender-like clean tone; rather it more closely resembled a blackface or tweed on steroids, with an abundance of natural overtones and overdrive and very present upper midrange.” Vintage Guitar Magazine
“The elusive and very rare “Golden Ratio” reviewed by Tone Quest Report and Vintage Guitar both touting “best 1×12 combo we have ever reviewed”. Very few were made, around 20 from what I have read. Super high quality Dumble style boutique build!!!” Mountain Cat Guitars
“Up for consideration is an incredible combo amp. The amp that garnered the glowing review in the Tone Quest report, linked to below. Jason Arthur (JCA) studied with Ken Fischer and his amazing design makes this obvious. This amp has been played by folks with some incredible ears and chops, who had input in the final design as available here, including making the recommendation to have the Celestion Blue re-coned with hemp by A Broun Soun in San Rafael. CA. A Review of this particular amp is available here. Very few in existence – dual 6v6. flavors of Trainwreck Rocket and Tweed Deluxe, Fender Blackface Deluxe. Highly touch sensitive, truly amazing clean sustain and bloom. very touch sensitive. Chimey clean to mean all controlled via guitar volume.” Guitars Electric
“Jason C Arthur (JCA) was a protégée of Ken Fischer (Trainwreck) in the 1990s. He built 12-14 of these amps back in the mid-’00s that are unlike anything else I’ve ever played. The MOST touch sensitive amps you can imagine. 9-10 years ago, I was able to buy the #1 Golden Ratio 1.6 from the builder who’d kept it as his personal amp since it was built. That was the actual amp that was sent to the ToneQuest Report and garnered a glowing review. I later was able to acquire this one as well, the only difference being the speaker and faceplate color. The #1 amp now lives with a good friend of mine, and I’ve babied this one for awhile now.
Being so few of these in the world, and owing to the fact that they came out prior to the days of YouTube gear reviews, there are virtually no clips online. But there are plenty of glowing reviews, from the aforementioned 2008 ToneQuest Report to a handful of folks of this forum who have tried one. The vibe of this amp is influenced by Trainwreck, as it’s got plenty of gain on tap and cleans up better than anything else with the volume knob. But it reminds me very much of a Jim Kelley in the way it sustains and has lots of tweakability with the switches, trim knob and EQ. It’s been referred to as a “Dumble Killer”, although I don’t think that’s accurate, unless you’re talking about an Ultraphonix Dumble. The trim knob let’s you tighten it up like a proper hotrodded Marshall or get a bit looser and fatter like a tweed (switched to Hi Tilt and Plush) or a Vox (when switched to Lo Tilt and Lean). Being a 6V6 amp, the cleans are pretty Fender-y but with slightly more prominent midrange. It’s a room-filling 20 watts, with a very full low end…” SCMAVL @ The Gear Page
“This amp is very unique. I’d be hard pressed to label it as a clone of anything. It’s got the Blackface Fender in there. Marshall crunch. TW / Dumble sustain (I’ve only played clones admittedly). And it seems like it can do all that at the same time if asked. It can also be a nearly transparent voice for your guitar. I’ve played an ES-175 through it with haunting clean jazz tones.
It’s a GREAT pedal platform amp. Driving the input can get you thick tones at modest volume. It will throw some sound waves at you as well if you crank it up along with those pedals. I tried 90 watt Celestron Cream in there and it was phenomenal. Loud, full 3d tone. I’m running a Vintage 30 in it atm.
And then it surprises you with juicy distortion with a voice all it’s own. LP’s sustain like crazy as one would hope. Strat’s chime and snarl like they should, and Tele’s give all the twang and spank you could ask for. Can be touch sensitive and also creamy and full using your touch or volume knob. The settings are very interactive. It works great with attenuators as well.
It’s really an amazing amp that should have an IR done on it if that was at all possible.” AJLo @ The Gear Page
Jason C. Arthur/Designer
484-942-6004