It all started with a single horn, totally different feeling.
Around year 2000, I bought a pair of vintage tube amps through ebay, but the seller suggested to buy a horn as a package deal, mentioning that the horn is almost free. His name was Jonathan Weiss from NYC(what a small world).
At first, I was hesitant because the horn was very big and would cost a lot for shipping.
I accepted the offer and the horn arrived with the amps.
I did not know RCA produced horns and that was in the 1930’s.
I was experimenting with various Altec/JBL horns so knew pretty well about Altec/JBL compression driver/horns but became very curious because this RCA 12 cell multicellular horn gave me totally different impression.
So I decided to check out what was this different feeling.
First I searched for RCA horns and bought a pair of 15 cell horns.
Next, I looked up the compression driver, then the 15 inch field(electro-dynamic) woofers.
And enclosure for woofer…it was so big so I was hesitant, but pull the trigger and imported by air.
Finally original crossover network.
There was chalk mark of the engineers and theater installed date…1937!
I was impressed by the massive air-core network coils and was thinking how I am going to replace the oil-filled capacitors. After I measure the capacitances, I was shocked because after 60+ years, the capacitance of every network capacitors were all perfectly same as the original numbers. That was 1930’s theater field speaker build quality.
It took about 2 years to gather all the parts from all around USA.
It was very difficult because there was rarely a document about this system and could not even find out which actual component model is for this system.
After I complete the 1937 RCA Photophone Field Theater System, first listen made me lose my appetite for audio. It was like I am listening to the live concert. The singer was singing in front of me and the band, trumpet, drums, strings, they were all playing their instrument for me.
Even though the frequency range was limited on both top and bottom, the speaker did not care at all but just delivered real music.
After this life-changing moment, I decided to match this amazing speaker with the best tube amplifier. I was collecting mostly vintage tube amps at that time so mated with more than 100 famous tube amps from 1920’s to 1980’s but found out that what this heritage from the past was not content with any of the existing amplifiers. The brand of the tube amps encompass the history of tube amp manufacturers: Mcintoch, Marantz, RCA, Quad, Leak, Harmon Kardon, Dynaco, Heathkit, EICO, Western Electric, Stromberg-Carlson, IPC, …
So I decided to make my own and from the experience with many amplifier matching, about 20W output is suitable for this speaker. I chose 6L6 because as push-pull design, they can produce about 20 watts and maybe 6L6 pushpull tube amp have driven this RCA speakers in the 1930’s.
I decided A class to make pure sound, and designed UL(ultra linear) output transformer for linear music reproduction.
Also all the tubes were AC heated for more “warm” sound and Zero Negative Feedback was applied for natural, dynamic transient reproduction.
Power supply is designed massively for powerful representation of music and choke transformer was used for great natural regulation and reliability.
Most of all, <Terra> 6L6PP integrated was designed to drive the life-like RCA photophone speaker so it has the warm and emotional content of RCA Photophone systems.
After the successful match, <TERRA> 6L6PP was tested with many vintage & modern speakers.
<TERRA> has great driving ability and makes pure, warm, dynamic, and musical sound.
Matches well with any quality modern speakers like Dynaudio, ProAc, Spendor, Verity, etc.
<TERRA> output transformer has 4, 8 and 16 ohm speaker tap and 8 ohm and 16 ohm speaker terminal is available on the back panel.
16 ohm tap was prepared for vintage speakers like JBL, ALTEC, Jensen etc made in the heydays of tube amplifier.
For most of the modern speakers, 8 ohm terminal can be used.