|Power Tubes||2x Amperex EL34/6CA7|
|Pre Amp||2x 12AX7|
|Speaker||1x 12" 8Ω|
|Speaker||1x 5" 8Ω|
|Output||40 watts peak|
The Magnatone 190 was an innovative guitar combo and quite possibly the greatest fifties guitar amplifier that no one has ever heard about. They didn't make many and they don't come up for sale very often. Produced in small numbers beginning in 1958, they soon in fell into obscurity and out of the Magnatone lineup before 1961. The basic circuit design was later re-introduced in 1964 as the M12 and M13.
So what was so innovative about the 190? It was probably the first guitar amplifier built using EL34s (in the US or in Europe) and a GZ34. Besides this fantastic feature Magna also incorporated their "treble plus" preamp which added a third gain stage following an extra tone network that allowed the musician to select from mellow, normal, bright, and treble-plus in addtion to a Baxandall treble/bass controls. Magnatone advertised that this was the answer to Rock-n-Roll and Western player's needs.
How exactly this EL34/GZ34 amp came to be will probably be forever unknown. It was likely the work of either chief engineer Don Bonham or electrical engineer Jack Bartholomew (or both) and their direction of using the latest amplifier technology in guitar amps. Close attention was given to innovations in amplification. As new technology became available it was adapted to guitar amplifiers. Besides the use of EL34's, between 1956 and 1959 Magnatone introduced amplifiers using 5881 driven ultra-linear power transformers (180) 6CZ5's and 6973's tubes in the 480's and the 6EU7 preamp tubes as soon as they were released. This connection to innovative technology was probably through close relations with tube manufacturers and a close eye on the HIFI market.
The EL34 and GZ34 had recently been introduced in England by Philips/Mullard and found their first applications in HIFI stereos like the 1955 Marantz 2 and the 1956 Dynaco Mark II. Not to be left out of the game, Sylvania USA countered with the 6CA7. While similar to the EL34, the 6CA7 was more closely based on the RCA 6L6GC tetrode design. They did this for the same reason RCA invented the 6L6 power tetrode in the 30's: a technical maneuver to avoid paying royalties to Philips for the pentode design. Modern day HIFI fanciers certainly make a distinction between the EL34 and the 6CA7 in terms of fidelity and sound. Marantz, Dynaco, Heath, and Fisher were all early adapters to the EL34, while the 6CA7 found OEM use in Gates, Altec, company used EL34's while another used 6CA7s, but it is also important to note that the tube replacement market was also of keen interest to Sylvania as they labeled their tubes as "6CA7/EL34" tubes. They made the 6CA7 to perform and behave as closely as possible to the EL34.
So what was the EL34 in the Magnatone 190? This is interesting. Magna installed Amperex bugle-boy tubes labeled "6CA7/EL34". Amperex was Hickville, NY based tube manufacturer but they had been acquired by none other than the Dutch company Philips, who also acquired Mullard! Most likely Amperex brought these in from Europe as true EL34s.
It is also interesting to point out that Mullard/Philips also invented the GZ34 to go along with the EL34 because there was no single european rectifier tube capable of delivering the current requirements of a pair of EL34's. We are used to seeing the GZ34 in later Fenders, but the original connection between the EL34 and the GZ34 is mostly lost to modern tube fanatics.
The full view of the landscape of guitar amps in the fifties does include Ampeg using the Philips EL37 in bass amps in the late fifties, which was the predecessor of the EL34. But Magna gets credit for the first EL34 guitar amp. or am I wrong on this? if so, let me know.