Date: 1942. Owned by Ed Solomon
The 70H bass trombone has a #5 bore (0.562"), and a F rotary attachment. It also has the tuning slide in the hand slide, not in the bell. The advantage of having the tuning slide in the hand slide is that this allows the entire bell section to be conical, in stead of there being a cylindrical section to allow for the tuning slide. The description in both the 1938 and 1955 catalogs states that the 70H has a "spring barrel". However, the owner of this instrument tells me it doesn't have a spring barrel. The 70H was produced from 1937 to 1955.
What Conn said in 1938:
The 70H bass trombone is now supplied in a new model with a straight bore. This is sometimes called the "Gerhard" model because it has been used for so many years by Charles Gerhard, celebrated bass trombone with the Philadelphia Orchestra. Acknowledged the finest on the market. Tuning in slides. Key Bb. Rotary to F, slide to E. Spring barrel for playing closed position in tune. Bell lock. Standard 9½-inch bell.
What Conn said in 1950:
More 70H bass trombones are used by top symphony and concert band artists than all other makes combined. It is the bass trombone without a rival. Built in large bore Bb, with rotary valve to F and slide to E, 9½-inch bell. Spring barrel for closed position; bell lock, tuning in slides.
What Conn said in 1955:
This Conn bass trombone in Bb, with large bore, has rotary valve to F and slide to E. It is used and preferred by more top bass trombone artists than all other makes combined! Has extra large 9 1/2" bell, is 47" long, and weighs 4 lbs. 13 oz. Spring barrel slide permits first position to be played without being completely closed, thus enabling player to control the pitch. Outside slides made of special Conn formula brass alloy. Inside slides have integrally-drawn stockings. Has bell lock; tuning in slides. Comes in attractive Stratoliner plush lined case, with mouthpiece and music lyre.
Highly polished brass, durable nickel trim, clear lacquered.