TUBEOFILE
Search
Compare
FAQ
Tube+
Sign In
Sign In
☰
Loading...
← MU12
Rolling Candidates to replace MU12
Rectifier — B4
⚠ Safety
Top 10 Picks
V41
drop-in
4V
⚠ Close, low Pa
IW3
drop-in
4V
⚠ Close, low Pa
AZ31
adapter
4V
✓ Close
UU4
adapter
4V
✓ Close
UU5
adapter
4V
✓ Close
UU6
adapter
4V
✓ Close
IW4/350
adapter
4V
✓ Close
RGN1064
adapter
4V
⚠ Close, low Pa
RGN2304
adapter
4V
⚠ Close, low Pa
Rolling Candidates (64)
i
Heater:
2.5V
3
4V
5
●
5V
24
6.3V
7
7.5V
0
10V
1
12.6V
2
16.8V
1
18.9V
1
22.4V
1
25V
1
show all (11)
Fit:
Drop-in
0
Adapter
5
Status:
✓ Close
23
✓ Safe
23
⚠ Close, low Pa
6
⚠ Low Pa
12
5 shown (target 4V only)
▣ Compact
⚙ Thresholds filter
4V Heater
(5 candidates)
Tube
Status ↑
Pa
Ah
Fit
AZ31
✓ Close
—
1.9
adapter
IW4/350
✓ Close
—
2
adapter
UU4
✓ Close
—
2.3
adapter
UU5
✓ Close
—
2.3
adapter
UU6
✓ Close
—
1.4
adapter
Generated 2026-04-09
Status legend →
User Guide →
Rolling FAQ →
target +
0
selected
pick 1+ to compare
select 1+ candidate to compare