From NVT4 to CLASS S+ — NNVT's new naming and the "NVT8" myth

Compare two NNVT spec sheets today and you'll run into two different naming systems. The first one says NVT4, NVT5, NVT6, NVT7, NVT7+ — that's the old one. The second one says CLASS C, CLASS B, CLASS A, CLASS A+, CLASS S, CLASS S+ — that's the official one since 2026.

The manufacturer unified its range under a single, more readable system. Performance hasn't moved by a single lp/mm; only the name changed. Here's the mapping, and why a reseller pitching you an "NVT8" should make you wary.

Why the naming changed

The old NVT4 / NVT5 / NVT6 / NVT7 / NVT7+ system had two flaws. First, NVT5 and NVT6 actually designated very close performance grades — the distinction was more manufacturer marketing than a real technical break. Second, the NVT7 line covered an FOM range from 1800 to 2100+ all on its own, with no clear way for the end buyer to distinguish levels.

The CLASS system fixes both. Six discrete levels, one typical performance per CLASS, a teaching arc from C (basic) up to S+ (top-end). Easier to present, easier to choose.

The mapping table

The official mapping, as communicated by the JPNV sales contact in May 2026:

• CLASS C — formerly NVT4. FOM 1400. Entry level, not gated.
• CLASS B — formerly NVT5 and NVT6. FOM 1600. Auto-gating standard. The civilian core.
• CLASS A — formerly NVT7. FOM 1800. First flagship step — optical reflection reduction + enhanced NIR sensitivity.
• CLASS A+ — formerly NVT7. FOM 2000. Price / performance sweet spot at the top of the range.
• CLASS S — formerly NVT7. FOM 2100. New-generation micro-channel plate.
• CLASS S+ — formerly NVT7+. FOM 2300. The summit of the NNVT range, with the manufacturer acknowledging technological parity with PHOTONIS 4G.

You'll notice CLASS A, A+ and S all come from the old NVT7 line. That's the main upside of the new naming: structuring the intermediate range that used to be murky.

The persistent "NVT8" myth

If someone offers you an "NVT8" tube, here's what the manufacturer says officially, word for word in the May 2026 email:

"NNVT has never promoted or officially released any product under the name ‘NVT8’. This appears to be a term invented by some sellers. Please disregard it."

Translation: NNVT has never released or promoted a product called NVT8. Any "NVT8" offer on the market comes from a reseller inventing a designation, typically to dress up unsold inventory by riding the numerical continuity of the old range (NVT7+ → NVT8).

The test is simple. Ask your supplier for two documents: the signed NNVT factory data sheet and the tube's serial number. Neither will ever show "NVT8" — by definition, since the tube doesn't exist at the manufacturer. If your seller dodges or provides non-official paperwork, you have your answer.

What hasn't changed

Three things, important to remember, didn't move with the naming change.

Measured performance. A CLASS B is, unit for unit, the equivalent of a legacy NVT5 or NVT6. A CLASS A+ is the equivalent of an upper-line NVT7. FOM, SNR, resolution, gain, halo: all identical. If you had an NVT6 at FOM 1600 in mind, ask for a CLASS B and you get exactly that.

Gating logic. Auto-gating remains standard from CLASS B onward (so from the legacy NVT5). CLASS C, which maps to the legacy NVT4, remains not gated in standard build.

Phosphor choice. P43 green or P45 white is a visual preference, not a performance choice — the manufacturer confirms it explicitly. No difference in FOM, SNR, resolution or gain between the two phosphors. Pick on aesthetics only.

How to use this in your research

Practically: if you type "NNVT NVT7" into Google, you'll still find masses of content indexed under the old naming. That's normal — the SEO transition will take time. Just read the mapping both ways. On our Tubes page, each CLASS is listed alongside its ex-NVT name to make the equivalence easy.

And when "NVT8" shows up somewhere, ask for the signed factory data sheet. It really is that simple.