The box is the easy part. Part of what you pay for on a used Quad Cortex is a Neural DSP account, and that does not come in the carton. Plugin licences stay with whoever bought them, and a unit still tied to the seller's Cortex Cloud account is the seller's unit until they remove it. Sort that first. Then the price: €1,250 is what one sells for right now, from 173 recorded sales in the last 90 days, against €1,690 new at Thomann on 16 September.
The licence, before the price
Neural DSP plugin licences, including plugins bought to run on the unit, do not transfer with the hardware. What transfers is the unit and whatever is natively on it after a factory reset and a proper account handover. Before money moves: the seller performs a factory reset, removes the device from their Cortex Cloud account, and you register it to yours while they are still on the phone. A unit still bound to another account cannot take CorOS updates properly, and "I'll unlink it later" is how that stays forever. We would not send money to a seller who wants to do the handover after the sale.
Two listings seen this month show the range. A Reverb listing from the Netherlands at €1,465 pastes Neural's own FAQ from before plugin compatibility existed: "If I have bought Neural DSP plugins, can I get them on QC? Not currently." Text that old in a listing tells you the seller has not opened the account side of the sale at all. A US listing at €1,300 seen 11 September, says the unit is one CorOS update behind and offers to run the update before shipping. That is the seller to buy from. Someone who knows which version they are on has been inside the account.
What to check on the hardware
- The screen. It is the interface. Look for scratches under light at an angle and dead zones by dragging a block across the whole grid. Screen replacements are expensive relative to the price of the unit.
- The stem knobs. The combined footswitch-encoders take the abuse of both jobs. Press and twist all eleven; any that register inconsistently will only get worse.
- CorOS version. Have the seller update to current CorOS in front of you or before collection. An update that fails is diagnostic gold.
- Captures included? Captures made on the unit stay on the unit and do transfer. A seller's capture library is worth something; confirm they are not wiping it out of spite during the reset, or accept that they will.
What it sells for
As of 18 September 2026: €1,250 typical used, from 173 recorded sales in the last 90 days, most of them between €1,200 and €1,350. The 90 days before that it was about €1,290. Drifting, not falling. Against Thomann's €1,690 a used one at the typical saves about 26%.
There are 124 for sale today, asking a median of €1,515 about 20% over what they actually sell for. About one live listing in five is already under the typical, which for a €1,250 unit is a lot of choice. Supply this deep keeps sellers honest and makes patience a strategy: skip the first fair one, another arrives next week.
The Quad Cortex Mini complicates the decision less than it looks. Used, it sells for €1,150 (34 sales); new it is €1,299. So a used full-size Cortex costs about €100 more than a used Mini, while new the gap is €390. If you are choosing between them, compare the two used numbers, not the two shop prices. The units it is cross-shopped with have pages of their own: the Helix Floor, which sells for about half the money, the Fractal FM3 and FM9, and the Kemper Profiler Stage.
The snapshot below is live, with its window and sample; the listings under it are ranked by how far under the typical each one sits.
Live market snapshot: Neural DSP Quad Cortex
Typical used €1,300, the middle of 202 sales, last 90 days. Each card compares to its condition where eight sales carry it, to that figure otherwise.
Reverb
