Tube Roller — User Guide

Rolling concepts (what "target" means, why Pa matters, pentode vs triode-strapped) live in the FAQ. This page is about how to drive the tool.

Safety first. A short disclaimer pops on your first visit. Read it. Rolling reports are a starting point, not a promise — they don't know your specific amp, your bias scheme, or how hard your circuit runs its tubes. Signed-in users see the disclaimer once; anonymous users see it once per session.

Two directions

⚡ Roll — "What can I put in my EL34 socket?" — forward rolling from a target.
⤺ Replace — "I own this 6SN7. What can it stand in for?" — reverse rolling from a tube you already have.

Both buttons live in the action row on every tube detail page. ⤺ Replace also appears on collection entries. Not every tube has rolling data — if the pill isn't there, the report wasn't pre-generated. Request one if you need it.

Reverse rolling only shows drop-in targets (no adapters) — the point is to be actionable without new hardware.

Report anatomy

From top to bottom:

Drop-In Replacements — same tube under other names (VT-229, ECC35, 6P14P…). No analysis, just aliases. If one of these is in your drawer, you're done.
Top 10 Picks — the ten most actionable candidates, ranked by drop-in first, in-your-collection second, status quality third. Filtered to the target's heater voltage because cross-voltage rolling means rewiring the amp.
Rolling Candidates — the full table. Filterable.
Adapters — pin-remapping adapters any candidate references. Collapsed by default when there are more than four.

Pentodes with triode-strapped data get separate tables per mode.

Reading a row

Tube — click to jump to its detail page. ● in collection if you own it.
Status — how well it matches the target:
- ✓ Close — behavioral params within threshold and Pa ≥ target. The safest pick.
- ✓ Safe — Pa sufficient but some params are out of threshold. Works, will sound different.
- ⚠ Close, low Pa — params pass but Pa is lower than target. Safe in lightly-loaded circuits only.
- ⚠ Low Pa — both Pa and params are off. Experimental territory.
Spec columns — candidate value plus ±% vs target. Amber means the diff exceeds threshold. Hidden in compact mode.
Pa — max plate dissipation. Hard safety limit: don't put a 15W tube in a 23W slot.
Ah — heater current. Matters because your supply has to deliver it.
Fit — drop-in (emerald) or an adapter ID (gray, hover for the full ID, scroll to Adapters for the pinout).

Filters (sticky bar)

The filter bar follows you while you scroll. Four controls:

Heater voltage — one chip per voltage present in the dataset. The target's voltage is highlighted in emerald with a ●. Only the target voltage is selected by default because anything else means modifying the heater supply. show all enables everything; target only resets.
Fit — two toggle pills, Drop-in and Adapter. Both are selected by default (drop-in candidates still sort to the top of the table as a tiebreaker). Click either to exclude it; deselect both and the empty state offers to turn one back on.
Status — Close, Safe, Close, low Pa, Low Pa. Default shows Close and Safe. The low-Pa variants are opt-in because they need circuit-specific judgement.
View (right side) — ▣ Compact toggles compact mode (ON by default — hides spec columns for a denser list). ⚙ Thresholds filter opens the threshold slider panel.

Every filter change updates the URL, so any view you shape is a shareable link. Copy from the address bar.

Threshold filter sliders

⚙ Thresholds filter opens a per-parameter ±% slider panel. Drag to tighten or loosen the tolerance bands. A * on the button means you have a custom setting.

Scope limit: the sliders only change the amber highlighting — the close / safe / low Pa labels are pre-computed with the report's original thresholds and don't move. The sliders are a visualization aid, not a reclassifier.

Slider state is not URL-persisted — it's local.

Compare selected

The target is always pre-selected. A floating pill at the bottom reads target + 0 selected when you land. Tick up to three candidate rows to add them, then hit Compare → to see everything side-by-side on the Compare page.

clear resets to just the target. The Compare → button activates once you have at least one candidate.

Use it to dig into two or three top contenders that all look promising in the table.

Filter state lives entirely in the URL:

?status=all — all four statuses (opt into low_pa variants)
?status=close — close only
?vh=all — every heater voltage
?vh=6.3,12.6 — two specific voltages
?fit=drop-in — drop-in only
?fit=adapter — adapter only
?fit=none — nothing (empty state)
(no param) — drop-in and adapter (default)
?sort=Pa_max:desc — sorted by Pa descending
?compact=0 — full view (default is compact)

Multi-mode pentode reports prefix params per mode:

?p_status=close → pentode mode
?t_status=safe&t_vh=all → triode-strapped, independently

Copy the URL, send it to someone, bookmark it — same view on the other end.

Recipes

"Swap my amp tonight with zero hardware changes" Keep defaults (target Vh, Close + Safe), then click the Adapter Fit pill off so only drop-in candidates remain. Skim for ● in collection badges — those need zero shopping.

"A different sound but still safe" Keep defaults, tick two or three candidates that catch your eye, hit Compare →. Read the side-by-side.

"Show me literally everything" show all on heaters, click the low-Pa status chips on, turn Compact off. Sort by Pa ascending to see the low-power character-changers. Be ready to buy adapters.

"What's already on my shelf?" Sign in. Scan for ● in collection badges — they float to the top of the Top 10.

Safety, for real

Rolling reports are data, not decisions. Before swapping:

Know your amp's bias scheme. Fixed-bias amps need rebiasing; cathode-bias amps forgive swaps but still have limits.
Don't trust Pa margins under 20%. A 25W tube in a circuit pushing 23W has no headroom.
Check adapter pinouts against the specific tube — not all adapters support all tubes of a given socket.
When a row looks weird, cross-reference the datasheet. The computer is not the last word.

More detail in Are rolling recommendations safe to follow blindly?.

Tube Roller — User Guide

Rolling concepts (what "target" means, why Pa matters, pentode vs triode-strapped) live in the FAQ. This page is about how to drive the tool.

Safety first. A short disclaimer pops on your first visit. Read it. Rolling reports are a starting point, not a promise — they don't know your specific amp, your bias scheme, or how hard your circuit runs its tubes. Signed-in users see the disclaimer once; anonymous users see it once per session.

Two directions

⚡ Roll — "What can I put in my EL34 socket?" — forward rolling from a target.
⤺ Replace — "I own this 6SN7. What can it stand in for?" — reverse rolling from a tube you already have.

Reverse rolling only shows drop-in targets (no adapters) — the point is to be actionable without new hardware.

Report anatomy

From top to bottom:

Drop-In Replacements — same tube under other names (VT-229, ECC35, 6P14P…). No analysis, just aliases. If one of these is in your drawer, you're done.
Top 10 Picks — the ten most actionable candidates, ranked by drop-in first, in-your-collection second, status quality third. Filtered to the target's heater voltage because cross-voltage rolling means rewiring the amp.
Rolling Candidates — the full table. Filterable.
Adapters — pin-remapping adapters any candidate references. Collapsed by default when there are more than four.

Pentodes with triode-strapped data get separate tables per mode.

Reading a row

Tube — click to jump to its detail page. ● in collection if you own it.
Status — how well it matches the target:
- ✓ Close — behavioral params within threshold and Pa ≥ target. The safest pick.
- ✓ Safe — Pa sufficient but some params are out of threshold. Works, will sound different.
- ⚠ Close, low Pa — params pass but Pa is lower than target. Safe in lightly-loaded circuits only.
- ⚠ Low Pa — both Pa and params are off. Experimental territory.
Spec columns — candidate value plus ±% vs target. Amber means the diff exceeds threshold. Hidden in compact mode.
Pa — max plate dissipation. Hard safety limit: don't put a 15W tube in a 23W slot.
Ah — heater current. Matters because your supply has to deliver it.
Fit — drop-in (emerald) or an adapter ID (gray, hover for the full ID, scroll to Adapters for the pinout).

Filters (sticky bar)

The filter bar follows you while you scroll. Four controls:

Heater voltage — one chip per voltage present in the dataset. The target's voltage is highlighted in emerald with a ●. Only the target voltage is selected by default because anything else means modifying the heater supply. show all enables everything; target only resets.
Fit — two toggle pills, Drop-in and Adapter. Both are selected by default (drop-in candidates still sort to the top of the table as a tiebreaker). Click either to exclude it; deselect both and the empty state offers to turn one back on.
Status — Close, Safe, Close, low Pa, Low Pa. Default shows Close and Safe. The low-Pa variants are opt-in because they need circuit-specific judgement.
View (right side) — ▣ Compact toggles compact mode (ON by default — hides spec columns for a denser list). ⚙ Thresholds filter opens the threshold slider panel.

Every filter change updates the URL, so any view you shape is a shareable link. Copy from the address bar.

Threshold filter sliders

⚙ Thresholds filter opens a per-parameter ±% slider panel. Drag to tighten or loosen the tolerance bands. A * on the button means you have a custom setting.

Slider state is not URL-persisted — it's local.

Compare selected

clear resets to just the target. The Compare → button activates once you have at least one candidate.

Use it to dig into two or three top contenders that all look promising in the table.

Filter state lives entirely in the URL:

?status=all — all four statuses (opt into low_pa variants)
?status=close — close only
?vh=all — every heater voltage
?vh=6.3,12.6 — two specific voltages
?fit=drop-in — drop-in only
?fit=adapter — adapter only
?fit=none — nothing (empty state)
(no param) — drop-in and adapter (default)
?sort=Pa_max:desc — sorted by Pa descending
?compact=0 — full view (default is compact)

Multi-mode pentode reports prefix params per mode:

?p_status=close → pentode mode
?t_status=safe&t_vh=all → triode-strapped, independently

Copy the URL, send it to someone, bookmark it — same view on the other end.

Recipes

"A different sound but still safe" Keep defaults, tick two or three candidates that catch your eye, hit Compare →. Read the side-by-side.

"Show me literally everything" show all on heaters, click the low-Pa status chips on, turn Compact off. Sort by Pa ascending to see the low-power character-changers. Be ready to buy adapters.

"What's already on my shelf?" Sign in. Scan for ● in collection badges — they float to the top of the Top 10.

Safety, for real

Rolling reports are data, not decisions. Before swapping:

Know your amp's bias scheme. Fixed-bias amps need rebiasing; cathode-bias amps forgive swaps but still have limits.
Don't trust Pa margins under 20%. A 25W tube in a circuit pushing 23W has no headroom.
Check adapter pinouts against the specific tube — not all adapters support all tubes of a given socket.
When a row looks weird, cross-reference the datasheet. The computer is not the last word.

More detail in Are rolling recommendations safe to follow blindly?.

Tube Roller — User Guide

Two directions

Report anatomy

Reading a row

Filters (sticky bar)

Threshold filter sliders

Compare selected

Sharing reports

Recipes

Safety, for real

Tube Roller — User Guide

Two directions

Report anatomy

Reading a row

Filters (sticky bar)

Threshold filter sliders

Compare selected

Sharing reports

Recipes

Safety, for real