The new Coda S5.5 amplifier: It's a "Petite Beast"!

I have in-house the New Coda Technologies S5.5 amplifier for review for Stereo Times website. It will be awhile before I write the review. However, I'm so impressed by the performance of this petite amplifier, it only weights 45 pounds, that I wanted to give a heads up to you GON members if you are in the market for a balanced pure class A amplifier, delivers 50 watts @ 8 Ohms, and can drop 100 Amperes of current on a peak!

The world class build quality of Coda amplifiers is on display with the S5.5, along with the most beautiful purity of tonality, precise sound-staging, complete liquidity offered by pure class A design, and what might be the best top end regarding details, decays, and a natural shimmering without brightness or any edge at all.

The S5.5 uses extremely wide bandwidth output transistors instead of the usual TO3 devices used in most transistor designs. I own the Coda #16, which is great, but the midrange/high end is taken to another level of musical enjoyment with the S5.5. The S5.5 has a sense of speed/aliveness that is exciting to listen to that you experience in live music. The amp is dynamic as hell, has driven with ease any speaker I have tried it with, hence my nickname of the "Petite Beast". Remember, 50 watts pure class A, can drop 100 amperes of current and only weights 45 pounds.

Teajay (Terry London)



My only experience with Klipsch speakers is in other people's systems, and I've mostly been unimpressed.....but that may very well be the accompanying electronics. Twice they were being driven by a "mainstream" amp (can't remember but Technics/Onkyo/Sony/or the like). The one time I was impressed, my friend was driving a pair of Cornwall IIIs with a Tubes4hifi VTA ST-120 tube amp......which I later purchased and still own. But I don't own Klipsch and certainly have no extended experience with them.


The information about the maximum current capability of all AGD amps is available on the AGD website under each product description.

Audion, Vivace and Tempo : 30Apk

AGD Gran Vivace and DUET :  50Apk

AGD Solo >70Apk


Im currently using a Coda CB preamp with the No.8. It sounds good but its very neutral in my opinion.

My goal was to get a neutral power amp and let the speakers do their thing and tweek the sound via preamp. My goal was to find a truly balanced tube preamp preamp to pair with the No.8. But with the No.8 having only 10k input impedance balanced. I’ve been having a really hard time finding something to match. I recently came across another low key brand. Backert Labs Rhumba. Made in USA. He has three preamps.. balanced and all three have an output impedance of <75.

. I believe the price ranges from 4000-12000. But you’d have to check his site. Either way.. if you already have a tube preamp that you want to try with whichever amp you decide can’t hurt to try. Doug did say he builds his amps with balanced in mind.. but I’m sure using the single ended is just as good.

Im curious to know why Doug’s amps have such a low input impedance..when using balanced. I guess it doesn’t matter when using a solid state pre amp.. But I’d still be curious to know why. I just don’t see it on other amplifiers.

Sounds like you can’t go wrong with either amp. I’d trust his judgment..I’m wondering why Doug is steering you to the No.8 though. 

As far as I have been able to discern, the general rule of thumb for proper impedance component matching is that the input impedance should be at least 10x higher than the output impedance. Given that the input impedance of the Coda S5.5 is 10K ohms, then one could at least theoretically have a preamp with an output impedance of up to 1K ohms and still be okay. Have people found this to be true or should one strive for even lower output impedances, like 20x or more?

As an example, I noticed that the Atmas-Sphere Class D amps have an input impedance of 100K ohms while their tube preamps have an output impedance of 250 ohms. That's quite a "cushion"!

@vthokie83  I too am interested in your comments on the Caladan / s5.5 pairing. I have Caladans. Currently a pair of AGD Tempo’s as mono blocks, using one channel of each amp - not bridged (don’t ask ;-). 

Regarding tube preamps, I have a Backert Labs Rhythm 1.3 which has an output impedance of < 80 per their specs. Doug at Coda said they would play well together.

There is absolutely nothing wrong with the AGD / Caladan pairing, but sometimes you don’t know what you are missing until you aren’t. Call it curiosity on my part. Or neurosis if you wish.