C. G. Conn Basses - A Complete List

Ever since a couple of dear friends surprised me with a vintage Conn tuba back in February, I've enjoyed digging into the history of Conn basses - and quite a history it is!

Here is my attempt at a complete list of the bass instruments built by Conn over the years, which is pulled together from various sources, including The Conn Loyalist and Horn-U-Copia websites, the many Conn publications posted by Mark Overton at saxophone.org, and a complete 1921 Conn catalog shared by Mark Jones at C. G. Conn Postcards and Ephemera. At some point, I hope to visit the National Music Museum to complete my Conn research and clean up some of the data below, but that is still a ways off. This at least gets the tuba-ball rolling!

The dates listed are not complete, but represent what I could piece together from the sources mentioned above. TA = top action, and FA = front action. I also included weight and bell diameter, where I could.

Upright Tubas (before the use of factory numbers)

Conic Clear Bore Valve (1878) / Patent Light Valve (1881) / Equa-Tone Valve (1882) / Ultimatum Models (1885)

1881-1885    Eb Bass, Short Pattern (3 or 4 valves, TA, 10 lbs)
1881-1885    Bb Bass, Short Pattern (3 valves, TA)
1881-1885    BBb Bass, Short Pattern (3 or 4 valves, TA, 15 lbs)

New Perfection Models

1885-188?    Eb Bass, Short Pattern (3 valves, TA)
1885-188?    Bb Bass, Short Pattern (3 valves, TA)

Wonder Valve Models

1886-1889    Eb Bass (3 or 4 Wonder valves, TA, 10 lbs)
1886-1889    Bb Bass (3 or 4 Wonder valves, TA)
1886-1889    Double Bb Bass (3 Wonder valves, TA, 13 lbs, 14.5 in)

American Models (all FA, an innovation)

1888-1909    Eb Bass (3 or 4 valves, 10 lbs, 14.5 in)
1889-1894    Bb Bass (3 or 4 valves)
1889-1909    Monster BBb Bass (3 or 4 valves, 20.5 lbs, 17.5 in)
1899-1909    Giant Eb Bass (3 or 4 valves)

Wonder Models (all TA, with new slides, an innovation)

1890-1909    Eb Bass (3 or 4 valves, 11 lbs, 14.5 in)
1890-190?    Bb Bass (3 or 4 valves)
1890-1909    Monster BBb Bass (3 or 4 valves, 20.5 lbs)
1899-1909    Giant Eb Bass (3 or 4 valves)

Wonderphone Models (with forward-facing bells, an innovation)

1908-1923    Standard Eb Bass (3 or 4 valves, TA)
1908-1923    Standard Eb Bass (3 or 4 valves, FA)
1908-1923    Monster BBb Bass (3 or 4 valves, TA)
1908-1923    Monster BBb Bass (3 or 4 valves, FA)
1908-1923    Giant Eb Bass (3 or 4 valves, TA)
1908-1923    Giant Eb Bass (3 or 4 valves, FA)
1910-19??    Jumbo BBb Bass (3 or 4 valves, FA)
1913-19??    Medium/Professional Eb Bass (3 or 4 valves, TA)
1913-19??    Medium/Professional Eb Bass (3 or 4 valves, FA)

Perfected Models (new lead pipe w/tuning slide, an innovation)

1910-1912    Eb Bass (3 or 4 valves, TA)
1910-1912    Eb Bass (3 or 4 valves, FA)
1910-1912    Monster BBb Bass (3 or 4 valves, TA)
1910-1912    Monster BBb Bass (3 or 4 valves, FA)
1910-1912    Giant or Contra Eb Bass (3 or 4 valves, TA)
1910-1912    Giant or Contra Eb Bass (3 or 4 valves, FA)
1911-19??    BBb Bass, Jumbo size (3 or 4 valves)

New Invention Models (similar to the previous models)

1911-19??    Bb Bass (3 valves, TA)
1911-1918    Eb Bass, Standard (3 or 4 valves, TA, 12.5 lbs, 14 in)
1911-1918    Eb Bass, Standard (3 or 4 valves, FA, 12.5 lbs, 14 in)
1911-1918    Eb Bass, Giant or Contra (3 or 4 valves, TA, 16 lbs, 20 in)
1911-1918    Eb Bass, Giant or Contra (3 or 4 valves, FA, 16 lbs, 20 in)
1911-1918    Monster BBb Bass (3 or 4 valves, TA, 18 lbs, 21 in)
1911-1918    Monster BBb Bass (3 or 4 valves, FA, 18 lbs, 21 in)
1911-19??    "Jumbo" Model BBb Bass (3 or 4 valves, TA, 25 lbs, 22 in)
1911-19??    "Jumbo" Model BBb Bass (3 or 4 valves, FA, 25 lbs, 22 in)
1913-1918    Eb Bass, Professional (3 or 4 valves, TA, 13 lbs, 16 in)
1913-1918    Eb Bass, Professional (3 or 4 valves, FA, 13 lbs, 16 in)
1913-1918    Orchestra Grand BBb Bass (4 valves, FA, 25 lbs, 22 in)
1913-1918    Orchestra Grand CC Bass (4 valves, FA)


Upright Tubas (after the use of factory numbers)

Factory numbers begin appearing in catalogs around 1921, and they eventually included a five letter "Code Word," which corresponds to the "J" in the number; those will be included where they are known. Also, LP = low pitch, HP = high pitch, "sa" = short action valves, TA = top action, and FA = front action. Finally, you'll notice that Conn reused many factory numbers, which is confusing!

In Order of Factory Numbers:

02-J    1919-1931    New Wonder Standard Eb (LP, 3v, TA, 12 lbs, 16 in, "japan")
02-J    1971-19??    CC Tuba (4v, FA)
03-J    1919-1931    New Wonder Standard Eb (HP, 3v, TA, 12 lbs, 16 in, "jaunt")
03-J    1986-19??    CC Tuba (4v, FA, 18 lbs, 18 in; replaced 02-J?)
04-J    1919-1934    New Wonder Standard Eb (LP, 3v, FA, 12 lbs, 16 in, "jelly")
04-J    1971-19??    BBb Tuba (4v, FA, 21 lbs, 16 in)
05-J    1919-1931    New Wonder Standard Eb (HP, 3v, FA, 12 lbs, 16 in, "jenny")
05-J    1986-today    BBb Tuba (4v, FA, 20 lbs, 18 in; replaced 04-J?)
06-J    1921-19??    New Wonder Standard Eb (LP, 4v, TA)
06-J    1924-1934    "Junior" Model Bass (LP, 3v, TA, 15 lbs, 18 in, "jugal")
07-J    1921-19??    New Wonder Standard Eb (HP, 4v, TA)
07-J    1924-1931    "Junior" Model Bass (HP, 3v, TA, 15 lbs, 18 in, "jyrzo")
08-J    1921-19??    New Wonder Standard Eb (LP, 4v, FA)
09-J    1921-19??    New Wonder Standard Eb (HP, 4v, FA)
10-J    1919-1928    New Wonder Prof. Eb (LP, 3v, TA, 14.5 lbs, 18 in, "jetty")
10-J    196?-1971    BBb Bass Tuba (3v, TA, 16 lbs, 18 in)
11-J    1919-1928    New Wonder Prof. Eb (HP, 3v, TA, 14.5 lbs, 18 in, "jewel")
11-J    1958-1960    BBb Tuba (3v, FA)
12-J    1919-1931    New Wonder Prof. Eb (LP, 3v, FA, 14.5 lbs, 18 in, "jiffy")
12-J    1986-1988    BBb Tuba (3v, FA, 16 lbs, 18 in)
13-J    1919-1928    New Wonder Prof. Eb (HP, 3v, FA, 14.5 lbs, 18 in, "jimmy")
14-J    1921-19??    New Wonder Prof. Eb (LP, 4v, TA)
14-J    1955-1964    Director Bass in Eb (3v, TA, 13 lbs, 16 in)
15-J    1921-19??    New Wonder Prof. Eb (HP, 4v, TA)
15-J    1986-1988    BBb Convertible Tuba (3v, FA, 17 lbs, 18 in)
16-J    1921-19??    New Wonder Prof. Eb (LP, 4v, FA)
16-J    1937-1939    Eb Recording Bass (3v, FA)
17-J    1921-19??    New Wonder Prof. Eb (HP, 4v, FA)
18-J    1919-1926    New Wonder Giant Eb (LP, 3v, TA, 17 lbs, 20 in, "jingo")
19-J    1919-1926    New Wonder Giant Eb (HP, 3v, TA, 17 lbs, 20 in, "joint")
20-J    1919-1928    New Wonder Giant Eb (LP, 3v, FA, 17 lbs, 20 in, "joist")
20-J    1934-1980    BBb Recording Bass (bell front, 3v-sa, TA, 29 lbs, 24 in, "jalit")
21-J    1919-1928    New Wonder Giant Eb (HP, 3v, FA, 17 lbs, 20 in, "joker")
21-J    1957-1971    Artist Recording Bass in BBb (bell up, 3v-sa, TA, 29 lbs, 24 in)
22-J    1921-19??    New Wonder Giant Eb (LP, 4v, TA)
22-J    1934-1941    BBb Recording Bass (bell front, 3v-sa, FA, 29 lbs, 24 in)
23-J    1921-19??    New Wonder Giant Eb (HP, 4v, TA)
24-J    1919-1926    New Wonder Giant Eb (LP, 4v, FA, 19 lbs, 20 in, "jorum")
24-J    1934-1971    BBb Recording Bass (bell front, 4v-sa, TA, 30 lbs, 24 in)
25-J    1919-1926    New Wonder Giant Eb (HP, 4v, FA, 19 lbs, 20 in, "jolly")
25-J    1957-1971    Artist Recording Bass in BBb (bell up, 4v-sa, TA, 30 lbs, 24 in)
26-J    1919-1931    New Wonder Monster BBb (LP, 3v, TA, 25.52 lbs, 22 in, "joule")
26-J    1934-1941    BBb Recording Bass (bell front, 4v-sa, FA, 30 lbs, 24 in)
27-J    1919-1931    New Wonder Monster BBb (HP, 3v, TA, 25.5 lbs, 22 in, "joust")
28-J    1919-1928    New Wonder Monster BBb (LP, 3v, FA, 25.5 lbs, 22 in, "judge")
29-J    1919-1928    New Wonder Monster BBb (HP, 3v, FA, 25.5 lbs, 22 in, "juice")
30-J    1921-19??    New Wonder Monster BBb (LP, 4v, TA)
30-J    1932-1934    De Luxe Recording Bass in BBb (bell front, 3v, TA)
31-J    1921-19??    New Wonder Monster BBb (HP, 4v, TA)
32-J    1919-1931    New Wonder Monster BBb (LP, 4v, FA 27 lbs, 22 in, "julep")
32-J    1932-1934    De Luxe Recording Bass in BBb (bell front, 3v, FA)
33-J    1919-1928    New Wonder Monster BBb (HP, 4v, FA 27 lbs, 22 in, "juxta")
34-J    1919-1923    New Wonder Orchestra Grand BBb (LP, 4v, FA, 26 lbs, 23 in)
34-J    1928-1934    De Luxe Rec. Bass, BBb (bell up, 4v, FA, 32 lbs, 26 in, "jaker")
35-J    1921-19??    New Wonder Orchestra Grand BBb (HP, 4v, FA)
36-J    1919-1923    New Wonder Orchestra Grand CC (4v, FA, 26 lbs, 26 in)
36-J    1928-1938    De Luxe Rec. Bass, BBb (bell front, 4v, FA, 32 lbs, 26 in, "jakpa")
44-J    1921-1926    New Wonder Bb (LP, 3v, TA)
45-J    1921-1926    New Wonder Bb (HP, 3v, TA)
46-J    1924-1926    New Wonder Standard Bb (LP, 3v, FA, 7 lbs, 12 in, "jabir")
47-J    1924-1926    New Wonder Standard Bb (HP, 3v, FA, 7 lbs, 12 in, "jabot")
48-J    1921-1926    New Wonder Phonograph CC (LP, 4v, FA, 18 lbs, 15 in, "juror")
52-J    1926-19??    Phonograph BBb, small bore (bell front, LP, 4v, FA, 16 in)
52-J    1996-2011    CC Tuba (5v, FA, 18 in)
54-J    1996-2011    CC Tuba (5v, FA, 19 in)
56-J    1996-2011    CC Tuba (5v, FA, 20 in)
80-J    1924-1934    Monster BBb Wonderphone (LP, 3v, FA, 25 lbs, 23 in, "jacky")
81-J    1924-1928    Monster BBb Wonderphone (HP, 3v, FA, 25 lbs, 23 in, "jason")
82-J    1924-1931    Monster BBb Wonderphone (LP, 4v, FA, 27 lbs, 23 in, "jaded")
83-J    1924-1926    Monster BBb Wonderphone (HP, 4v, FA, 27 lbs, 23 in, "jerky")
84-J    1924-1926    New Wonder Symphony CC (LP, 4v, FA, 20 lbs, 20 in, "jagua")
85-J    1924-1926    New Wonder Symphony CC (HP, 4v, FA, 20 lbs, 20 in, "jaina")
86-J    1924-1926    NW Symphony Grand CC (LP, 4v, FA, 20 lbs, 20 in, "jargo")
87-J    1924-1926    NW Symphony Grand CC (HP, 4v, FA, 20 lbs, 20 in, "jocos")

Donatelli Model?

Bell-Front (Recording Bell) Tubas Over the Years:

1908-1914    Wonderphone Standard Eb Bass (3 or 4 valves, TA)
1908-1914    Wonderphone Standard Eb Bass (3 or 4 valves, FA)
1908-1914    Wonderphone Monster BBb Bass (3 or 4 valves, TA)
1908-1914    Wonderphone Monster BBb Bass (3 or 4 valves, FA)
1908-1914    Wonderphone Giant Eb Bass (3 or 4 valves, TA)
1908-1914    Wonderphone Giant Eb Bass (3 or 4 valves, FA)
1910-19??    Wonderphone Jumbo BBb Bass (3 or 4 valves, FA)
1913-19??    Wonderphone Medium/Professional Eb Bass (3 or 4 valves, TA)
1913-19??    Wonderphone Medium/Professional Eb Bass (3 or 4 valves, FA)
1921-1926    48-J New Wonder Phonograph CC (4v, FA, 18 lbs, 15 in, "juror")
1924-1934    80-J, Monster BBb Wonderphone (LP, 3v, FA, 25 lbs, 23 in, "jacky")
1924-1928    81-J, Monster BBb Wonderphone (HP, 3v, FA, 25 lbs, 23 in, "jason")
1924-1931    82-J, Monster BBb Wonderphone (LP, 4v, FA, 27 lbs, 23 in, "jaded")
1924-1926    83-J, Monster BBb Wonderphone (HP, 4v, FA, 27 lbs, 23 in, "jerky")
1926-19??    52-J, Phonograph BBb, small bore (LP, 4v, FA, 16 in)
1928-1934    34-J, De Luxe Rec. Bass, BBb (bell up opt., 4v, FA, 32 lbs, 26 in, "jaker")
1928-1938    36-J, De Luxe Rec. Bass, BBb (4v, FA, 32 lbs, 26 in, "jakpa")
1932-1934    30-J, De Luxe Recording Bass in BBb (3v, TA)
1932-1934    32-J, De Luxe Recording Bass in BBb (3v, FA)
1934-1980    20-J, BBb Recording Bass (3v-sa, TA, 29 lbs, 24 in, "jalit")
1934-1941    22-J, BBb Recording Bass (3v-sa, FA, 29 lbs, 24 in)
1934-1971    24-J, BBb Recording Bass (4v-sa, TA, 30 lbs, 24 in)
1934-1941    26-J, BBb Recording Bass (4v-sa, FA, 30 lbs, 24 in)
1937-1939    16-J, Eb Recording Bass (3v, FA)
1957-1971    21-J, Artist Rec. Bass in BBb (bell up option, 3v-sa, TA, 29 lbs, 24 in)
1957-1971    25-J, Artist Rec. Bass in BBb (bell up option, 4v-sa, TA, 30 lbs, 24 in)

 

C. G. Conn with a Wonderphone Monster BBb Bass in 1908

Helicons (before the use of factory numbers)

Clear Conic Bore Valve (1878) / Equa-Tone Valve (1882) / Ultimatum Models (1995)

1880-1885    Eb Bass Helicon (3 or 4 valves)
1880-1885    Bb Bass Helicon (3 or 4 valves)
1880-1885    BBb Bass Helicon (3 or 4  valves)

New Perfection Models

1885-1887    Eb Bass Helicon (3 Equa-Tone valves)
1885-1887    Bb Bass Helicon (3 Equa-Tone valves)
1885-1887    BBb Bass Helicon (3 Equa-Tone valves)

Wonder Valve Models (and their successors, up to 1913)

1888-1910    Eb Bass Helicon (3 or 4v)
1888-1900    Bb Bass Helicon (3 or 4v)
1888-1910    Monster or Giant BBb Bass Helicon (3 or 4v, 20 lbs, 19.5 in)
1911-1910    Giant Eb Bass Helicon (3 or 4v)

New Invention Models

1911-1918    Eb Bass Helicon (3 or 4v)
1911-1918    Monster BBb Bass Helicon (3 or 4v)
1911-1918    Giant Eb Bass Helicon (3 or 4v)

1919-1922    New Wonder Medium/Professional Eb Helicon (3 or 4v)

Helicons (after the use of factory numbers)

Factory numbers begin appearing in catalogs around 1921 and eventually came with a five letter "Code Word" that corresponds to the "K" in the number. I've included those, when they are known, along with the weight and bell diameter.

02-K    1919-1931    New Wonder Standard Eb (LP, 3v, 14 lbs, 16 in, "kamis")
03-K    1919-1931    New Wonder Standard Eb (HP, 3v, 14 lbs, 16 in, "kayak")
04-K    1921-19??    New Wonder Eb (LP, 4v)
05-K    1921-19??    New Wonder Eb (HP, 4v)
06-K    1919-1926    New Wonder Medium Eb (LP, 3v)
07-K    1919-1926    New Wonder Medium Eb (HP, 3v)
08-K    1921-19??    New Wonder Medium Eb (LP, 4v)
09-K    1921-19??    New Wonder Medium Eb (HP, 4v)
10-K    1919-1928    New Wonder Giant Eb (LP, 3v, 18.5 lbs, 20 in, "knave")
11-K    1919-1927    New Wonder Giant Eb (HP, 3v, 18.5 lbs, 20 in, "knead")
12-K    1921-19??    New Wonder Giant Eb (LP, 4v)
13-K    1921-19??    New Wonder Giant Eb (HP, 4v)
30-K    1919-1931    New Wonder Monster BBb (LP, 3v, 21 lbs, 22 in, "krone")
31-K    1919-1931    New Wonder Monster BBb (HP, 3v, 21 lbs, 22 in, "kutch")
32-K    1919-1926    New Wonder Monster BBb (LP, 4v, 21 lbs, 22 in)
33-K    1919-1926    New Wonder Monster BBb (HP, 4v, 21 lbs, 22 in)

Helicon production seems to have ended after 1931.

Sousaphones (before the use of factory numbers)

Wonder Models (with upright bells, the original design)

1898-1912    Wonder Monster BBb Helicon Sousaphone (4v, 33 lbs)
1902-1912    Wonder BBb Helicon Sousaphone (3v)
1907-1912    Giant Eb Bass Sousaphone (3 or 4v)

Wonderphone Models (with forward-facing bells, an innovation)

1908-1910    Wonderphone Helicon Eb Bass (3 or 4v)
1908-1910    Wonderphone Helicon Monster BBb Bass (3 or 4v)
1908-1910    Wonderphone Helicon Giant Eb Bass (3 or 4v)

New Invention Models (with either original bell up, BU, or bell front, BF, which came to be called "Sousaphone Grands")

1911-1918    Monster BBb Bass Sousaphone (BU, 3 or 4v, 21-22 in)
1911-1918    Giant Eb Bass Sousaphone (BU, 3v)
1911-1918    Monster BBb Wonderphone Helicon (Sousaphone Grand, BF, 3 or 4v)
1911-1918    Giant Eb Wonderphone Helicon (Sousaphone Grand, BF, 3 or 4v)
1913-1918    Eb Bass Sousaphone (BU, 3 or 4v)

1917-19??    Jumbo Sousaphone Grand in BBb (3v?)
1920-1922    New Wonder Medium Eb Sousaphone (BU, 3 or 4v)

Herman Conrad with Conn's first Sousaphone in 1898

Sousaphones (after the use of factory numbers)

Factory numbers begin appearing in catalogs around 1921, and they eventually included a five letter "Code Word," which corresponds to the "K" in the number; those will be included where they are known. Also, BU = bell up (original Sousaphone design), BF = bell front (first called Wonderphones, then, starting in 1913, called Sousaphone Grands), LP = low pitch, HP = high pitch, and "sa" = short action valves. Finally, you'll notice that Conn reused some factory numbers, which is confusing!

In Order of Factory Numbers:

10-K    1962-1971    Artist Sousaphone in BBb (BF, 3v, 28 lbs, 26 in)
14-K    1921-19??    New Wonder Eb (BU, LP, 3v)
14-K    1955-1971    Director Sousaphone in BBb (BF, 3v, 23 lbs, 24 in)
15-K    1921-19??    New Wonder Eb (BU, HP, 3v)
16-K    1921-19??    New Wonder Medium Eb (BU, LP, 4v)
17-K    1921-19??    New Wonder Medium Eb (BU, HP, 4v)
18-K    1919-1927    New Wonder Giant Eb (BU, LP, 3v, 20 lbs, 20 in, "kneel")
19-K    1919-1926    New Wonder Giant Eb (BU, HP, 3v, 20 lbs, 20 in, "knell")
20-K    1919-1926    New Wonder Giant Eb (BU, LP, 4v, 21.5 lbs, 20 in, "knife")
20-K    1935-2022    BBb Sousaphone Grand (BF, 3v-sa, 30.5 lbs, 26 in, "knife")
21-K    1919-1926    New Wonder Giant Eb (BU, HP, 4v, 21.5 lbs, 20 in, "knock")
21-K    1957-1964    Artist Sousaphone in BBb (BU, 3v-sa, 24 in)
22-K    1921-19??    Medium Eb Sousaphone Grand (BF, LP, 3v)
22-K    1941-19??    BBb Sousaphone, lighter in weight (BF, 3v-sa, 24 in)
22-K    1964-1986    BBb Fiberglass Sousaphone (BF, 3v-sa, 23 lbs, 26 in)
23-K    1921-19??    Medium Eb Sousaphone Grand (BF, HP, 3v)
24-K    1921-19??    Medium Eb Sousaphone Grand (BF, LP, 4v)
25-K    1921-19??    Medium Eb Sousaphone Grand (BF, HP, 4v)
26-K    1920-1969    New Wonder Giant Eb (BF, LP, 3v, 23 lbs, 23 in, "knoll")
27-K    1920-1931    New Wonder Giant Eb (BF, HP, 3v, 23 lbs, 23 in, "knout")
28-K    1920-1931    New Wonder Giant Eb (BF, LP 4v, 24.5 lbs, 23 in, "kodak")
29-K    1919-1931    New Wonder Giant Eb (BF, HP, 4v, 24.5 lbs, 23 in, "koran")
32-K    1929-1943    New Junior BBb Sousaphone (BF, LP, 3v, 26 lbs, 24 in)
34-K    1919-1926    New Wonder Monster BBb (BU, LP, 3v, 25.5 lbs, 22 in, "kopra")
35-K    1919-1926    New Wonder Monster BBb (BU, HP, 3v, 25.5 lbs, 22 in, "kitch")
36-K    1919-1926    New Wonder Monster BBb (BU, LP, 4v, 27 lbs, 22 in, "klept")
36-K    1960-20??    BBb Fiberglass Sousaphone (BF, 3v, 17-18 lbs, 24-26 in)
37-K    1919-1926    New Wonder Monster BBb (BU, HP, 4v, 27 lbs, 22 in, "krieg")
38-K    1919-1941    New Wonder Monster BBb (BF, LP, 3v, 29 lbs, 24 in, "kiter")
39-K    1919-1938    New Wonder Monster BBb (BF, HP, 3v, 29 lbs, 24 in, "kinka")
40-K    1919-1931    New Wonder Monster BBb (BF, LP, 4v, 31 lbs, 24/26 in, "ketch")
40-K    2016-2022    New version of previous 40-K (BF, 4v, 31 lbs, 26 in)
41-K    1919-1931    New Wonder Monster BBb (BF, HP, 4v, 31 lbs, 24/26 in, "keeve")
42-K    1924-1926    NW Monster BBb Jumbo (BU, LP, 3v, 38 lbs, 26 in, "kenda")
44-K    1924-1926    NW Monster BBb Jumbo (BU, LP, 4v, 40 lbs, 26 in, "kenot")
46-K    1924-1931    NW Monster BBb Jumbo (BF, LP, 3v, 40 lbs, 28 in, "keros")
48-K    1924-1934    NW Monster BBb Jumbo (BF, LP, 4v, 43 lbs, 28 in, "kilta")

Original bell up Sousaphone design ceased production by 1927, although it was revived again, for the new 21-K, from 1957-1964.

Conn advertisement from 1952, in The Instrumentalist

The large paragraph in the black box in the ad above is incorrect. It is not true that "Conn made the world's first sousaphone," whether in 1908 or any other year; J. W. Pepper did, in 1895, which was three years prior to Conn introducing his version to the world in 1898 (see image above). However, Sousa did prefer Conn Sousaphones, and stuck with them from that point on.

Conn 20K and 40K today, at the Conn-Selmer website