The Short Answer
- Choose the Schiit Magni Heresy — if you want a US-made, warmer-voiced amp with a preamp output for powered speakers and easy local support
- Choose the JDS Labs Atom Amp+ — if you want the lowest possible measured distortion at this price and transparent, neutral amplification
Both are among the best-measuring amplifiers under $150. The differences are small. Your system context matters more than which you choose.
Side by Side
| Schiit Magni Heresy | JDS Labs Atom Amp+ | |
|---|---|---|
| Price | $109 | $99 |
| Output Power (32Ω) | ~1,000mW | ~1,000mW |
| THD+N | <0.003% | <0.001% |
| Noise Floor | -108dBu | -113dBu |
| Preamp Output | Yes | Yes |
| Headphone Output | 6.35mm | 6.35mm |
| Gain | Low/High switch | Low/High switch |
| Origin | Made in USA | Made in USA |
| DAC required | Yes (separate) | Yes (separate) |
Measurements: Both Are Excellent
Both the Magni Heresy and Atom Amp+ have been measured extensively by Audio Science Review and other independent labs. Both measure better than amplifiers costing 5-10x their price. At normal listening volumes and with typical headphone loads, the difference between their distortion figures is inaudible to any human listener.
The Atom Amp+ measures slightly lower THD+N and noise floor. Whether this translates to any audible benefit is debated. The honest answer is: at these measurement levels, the difference is academic. You will not hear -108dBu vs -113dBu noise floor in any real listening environment.
The practical takeaway: both amps are transparently clean. They will not add character or colouration to your signal. What you hear is determined by your DAC and headphones, not by these amplifiers.
Sound Character
Describing the “sound” of amplifiers this clean is difficult — both are designed to be neutral, not to have a sound. That said, listeners who have compared them directly (primarily on head-fi forums and subreddits) report:
Schiit Magni Heresy: Slightly warmer in character relative to the Atom Amp+. Some describe it as smoother or less clinical. Whether this is the amplifier circuit, psychological expectation, or confirmation bias is uncertain. The character difference is small.
JDS Labs Atom Amp+: More “textbook transparent” — if you expect nothing from an amplifier except amplification with no colouration, the Atom Amp+ is the archetype. Some listeners find it slightly analytical compared to the Magni Heresy.
In practical use, the synergy between your DAC and headphones will dominate any perceived character difference between these two amplifiers.
Power Output
Both output approximately 1,000mW into 32Ω. This is enough to drive essentially every consumer headphone to dangerous volumes, including the Sennheiser HD 600/650 (300Ω), Beyerdynamic DT 880/990 Pro (250Ω), and HiFiMAN Sundara (37Ω).
For reference: the Topping DX3 Pro+ all-in-one DAC/amp outputs 640mW. Both the Magni Heresy and Atom Amp+ output more power in their dedicated amplifier role — a meaningful advantage when driving demanding loads.
Preamp Output
Both include RCA preamp outputs for connecting powered speakers or a subwoofer. Pair either amp with a DAC and powered speakers and you have a desktop speaker system controlled by the amplifier’s volume knob. The Schiit Magni Heresy’s preamp output uses a relay to switch between headphone and preamp mode. The Atom Amp+ routes preamp output continuously — headphone and speakers can both be active simultaneously (though listening on both at once is rarely useful).
Build and Origin
Both are assembled in the United States.
The Schiit Magni Heresy has a recognisable Schiit aesthetic: all-aluminium chassis, front volume knob, rear RCA inputs and outputs, and an LED power indicator. Build quality is excellent and the finish is consistent.
The JDS Labs Atom Amp+ has a similar compact footprint but a slightly more industrial look. JDS Labs manufactures entirely in-house in Illinois, with tight quality control and good customer service.
Both are built to last. Either will outlast most headphones you pair with them.
What DAC to Pair With?
Since both are standalone amplifiers requiring a separate DAC, the pairing matters.
For budget ($50-100): Topping E30 II or SMSL SU-1 pair well with either amp. The Atom Amp+ and E30 II is a popular stack in this price range.
For mid-range ($100-200): Topping DX3 Pro+ includes its own amplifier, making a separate amp redundant — but as a DAC-only source, it pairs well. The Schiit Modi Multibit is a popular R2R pairing with the Magni Heresy if you want to add R2R DAC character to an otherwise transparent system.
Buying: Direct Only
Both brands sell direct — neither the Schiit Magni Heresy nor the JDS Labs Atom Amp+ is available through Amazon. You buy from Schiit’s website (schiit.com) or JDS Labs’ website (jdslabs.com). Both ship within the US in 2-5 business days.
Which Should You Buy?
Buy the Schiit Magni Heresy if:
- You prefer the Schiit ecosystem and may add a Schiit Modi DAC
- You want a slightly warmer character (by small margin)
- You value the Schiit brand’s customer service reputation
Buy the JDS Labs Atom Amp+ if:
- You want the lowest measured distortion at this price
- You prefer JDS Labs’ US manufacturing model
- You are building a stack with a separate DAC and want the most transparent amp available
Either choice is correct. The $10 price difference is less important than selecting the right DAC and headphones for your listening goals.