Telefunken Date Codes
Source Material from Eric Barbour
Originally presented in "Tube Collector" Vol.2 No.4
This list shows date codes covering Telefunken production between 1930 and 1968. It had originally come from a tube enthusiast in Europe; the German- titled chart had been retitled in English. Setting-up the original information in straight "decode" format, we get the table below.  Some of the identifications are unclear, what with smudging of the original, and are marked. A few dates are missing. The code uses pairs of lower-case letters a-z (less j), plus (to a limited degree) , , and . As a special case, for postwar Berlin-produced tubes (Berliner Rhre), the upper-case letters A and B are added. A great many letter combinations are not used. The code was random in some years. Later, the three months of a given quarter share a common first letter, and the second letters are normally in ascending order. Thus the months of 1955 are coded aq, as, at; ba, bc, bf; ca, cc, cd; db, dc, dh. However, the letter sequence was sometimes reversed, so that for 1944 the months ran ka, na, la; fk, bk, ck; ad, gd, rd; fv, mv, uv. The months May-December, 1945, all lack codes, a sign of the then-times, and a hint that this code gives month of manufacture, not of warranty expiration. 
11-43
a 9-67
k 4-43
z 6-43
aa 6-35?
aA 1-46
aB 2-46
ab 4-31
ac 1-49
ad 7-44
ae 4-32
af 2-49
ag 5-32
ah 7-47
ai 5-31?
ak 6-32
al 5-35
am 4-36
an 4-35?
ao 3-49
ap 1-45
aq 1-55
ar 1-39
as 2-55
at 3-55
au 6-31?
av 4-61
aw 5-61
ax 6-61
ay 7-67
az 8-67
ba 4-55
bb 10-67
bc 5-55
bd 10-46
be 10-52
bf 6-55
bg 7-61
bh 8-61
bi 9-61
bk 5-44
bl 11-67
bm 12-67
br 5-41
bt 11-52
by 12-52
ca 7-55
cb 10-49
cc 8-55
cd 9-55
ce 9-33
cf 1-30
cg 1-36
ch 12-49
ci 10-61
ck 6-44
cl 11-49
cm 11-61
cn 12-61
co 7-33
cp 2-30
cq 1-68
cr 5-46
cs 8-33
ct 2-41
cu 2-68
cv 3-68
cw 3-30
cy 10-40
cz 4-41
da 2-31
db 10-55
dc 11-55
dd 1-62
de 7-30?
df 2-36
dg 9-30
dh 12-55
di 2-62
dk 4-38
dl 3-62
dm 1-31
dn 3-31
do 4-68
dp 5-58?
dq 5-68
dr 9-39
dt 7-36
du 6-30?
dw 8-47
ea 1-56
eb 10-53
ec 2-56
ed 3-56
ee 4-61
ee 4-62
ef 5-62
eg 6-62
eh 8-58?
ei 2-34
ek 11-30
el 10-36
em 11-53
en 1-34
e 3-34
eo 8-68?
ep 2-45
eq 9-58
er 10-30
es 12-30
et 9-47
ez 12-53
fa 1-53
fb 4-56
fc 1-54
fd 5-56
fe 6-56
ff 8-46
fg 7-62
fh 3-40
fi 8-62
fk 4-44
fl 9-62
fm 2-53
fn 10-68
fo 2-39
fp 2-54
fq 11-68
fr 12-68
fu 7-42
fv 10-44
fw 3-54
fx 3-53
fy 2-42
fz 9-41
ga 4-50
gb 10-51
gc 7-56
gd 8-44
ge 8-56
gf 9-56
gg 10-62
gh 11-62?
gi 12-62
gm 5-50
go 10-47
gr 6-50
gt 4-45
gu 1-38
gy 12-51
gz 11-51
ha 10-56
hb 11-56
hc 7-50
hd 10-33
he 11-33
hf 7-46
hg 10-38
hh 12-56
hi 6-39
hk 8-50
hl 3-63
hm 2-63
hn 3-63?
hr 12-33
hu 9-50
ia 7-37
ib 4-33
ic 5-36
id 6-33
ie 1-57
if 4-53
ig 2-57
ih 3-57
ii 5-40
ik 4-37
il 4-63
im 5-53
in 5-33
io 5-61?
io 5-63
ip 4-39
iq 6-63
it 11-47
iu 2-40
iv 6-53
iy 1-43
iz 11-42
ka 1-44
kb 1-50
kc 4-54
kd 12-46
ke 2-37
kf 9-40
kg 11-37
kh 2-50
ki 4-57
kk 10-41
kl 12-32?
km 10-42
kn 5-57
ko 11-32
kp 5-54
kq 6-57
kr 4-42
ks 7-63
kt 8-63
ku 10-32
kv 5-39
kw 6-54
kx 9-68?
ky 3-50
kz 11-40
la 3-44
lb 7-57
lc 8-57
ld 9-57
le 2-33
lf 10-63
lg 11-63
lh 12-63
ln 3-33
lr 6-46
lt 1-33l
lx 11-39
ma 10-57
mb 11-41
mc 1-51
md 11-57
me 3-32
mf 8-42
mg 4-47
mh 12-57
mi 1-32
mk 4-40
ml 1-64
mm 2-51
mn 2-32
mo 2-64
mp 3-64
mv 11-44
mw 6-38
my 3-51
mz 6-42
na 2-44
nb 1-58
nc 2-58
nd 3-36
ne 3-56
nf 4-64
ng 5-64?
nh 5-64
nn 7-39
nr 4-46
z 5-43
oa 5-30
ob 8-39
oc 4-58
od 5-58
oe 12-34
of 12-47
og 6-58
oh 7-64
oi 1-41
ok 2-38
ol 8-64
om 3-41
on 6-30
oo 12-41
op 9-64
or 11-34
ot 10-34
ou 4-30
pa 10-39
pb 7-58
pc 8-58
pd 9-53?
pe 10-64
pf 11-64
pg 5-47
ph 12-64
pn 7-34
po 8-36?
pr 9-34
pt 6-40
qa 10-58
qb 11-58
qc 12-58
qd 1-65
qe 2-65
qf 3-65
ql 3-47
qr 2-47
qz 1-47
ra 1-48
rb 1-59
rc 2-59
rd 9-44
re 9-32
rf 9-36
rg 10-50
rh 11-50
ri 8-37
rk 8-41
rl 3-59
rm 4-65
rn 12-50
ro 5-65
rp 3-45
rq 6-65
rr 7-32
rs 8-32
ru 11-38
rw 2-48
rx 3-48
rz 1-42
sa 4-52
sb 4-59
sc 5-59
sd 6-59
se 11-35
sf 5-37
sg 5-52
sh 7-65
si 1-40
sk 12-35
sl 9-48
sm 8-48
sn 8-65
so 7-48
sp 10-35
ss 3-37
st 12-38
su 3-38
sy 6-51
ta 8-35
tb 8-40
tc 8-31
td 7-53
te 7-31
tf 7-59
tg 6-47
th 8-59
ti 9-59
tk 10-65
tl 6-35
tm 8-53
tn 9-31
to 11-65
tp 12-65
tq 6-41
tr 7-35
tw 9-53
k 3-43
12-43
ua 11-48
ub 10-59
uc 11-59
ud 12-59
ue 1-66
uf 7-52
ug 12-32
uh 11-31
ui 7-43
uk 8-43
ul 9-38?
um 3-42
un 10-48
uo 12-48
up 2-66
uq 3-66
ur 8-52
uv 12-44
uw 9-52
uy 7-41
uz 10-31
va 4-49
vb 1-52
vc 7-54
vd 3-40?
ve 1-60
vf 2-60
vg 3-60
vh 6-36
vi 4-66
vk 6-49
vl 5-66
vm 2-52
vn 6-66
vp 8-54
vr 5-49
vs 7-38?
vt 3-52
vw 9-54
vz 11-36
wa 9-37
wb 5-38
wc 4-60
wd 5-60
we 12-39
wf 8-38
wg 8-51
wh 7-51
wi 6-37
wk 4-48
wl 6-60
wm 9-51
wn 7-66
wo 12-37
wp 5-48
wq 8-66
wr 9-66
wt 6-48
xa 5-34
xb 7-36?
xc 10-54
xd 7-60
xe 4-34
xf 9-46?
xg 8-60?
xh 6-34
xi 9-60
xk 10-66
xl 11-66
xm 12-66
xp 11-54
xr 7-40
xw 12-54
xy 9-42
ya 10-60
yb 11-60
yc 12-60
yd 9-49
ye 2-35
yf 1-67
yg 2-67
yh 3-67
yi 5-42
ym 8-49
yn 3-35
yq 12-40
ys 1-35
yt 7-49

zb 1-61
zc 2-61
ze 3-61
zf 4-67
zm 5-67
zn 6-67
zu 10-43
zw 5-51
zz 12-42