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← 21HD5
Rolling Candidates to replace 21HD5
Beam Tetrode — Octal
⚠ Safety
Drop-In Replacements
✓
6HD5
Top 10 Picks
21EX6
drop-in
21V
✓ Close
Rolling Candidates (98)
i
Heater:
2.1V
0
4V
0
6.3V
31
12.6V
2
13V
0
16.5V
0
18.9V
0
19V
2
21V
1
●
22V
0
25V
0
26.5V
1
30V
1
35V
0
45V
0
show all (15)
Fit:
Drop-in
1
Adapter
0
Status:
✓ Close
3
✓ Safe
35
⚠ Close, low Pa
1
⚠ Low Pa
59
1 shown (target 21V only)
▣ Compact
⚙ Thresholds filter
21V Heater
(1 candidates)
Tube
Status ↑
Pa
Ah
Fit
21EX6
✓ Close
24
W
0.6
drop-in
Generated 2026-04-09
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