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- Location: Toronto (age 57)
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Just joined this forum after finding this interesting thread while researching the Sundragon. I too love the LZ 1 tone and upon seeing the rock and roll hall of fame amp did some research on the old Supros and purchased a 1615T from the late 50s. This amp has an identical circuit compared to the Coronado only it outputs into a single 15” speaker. As expected I quickly learned that it did not have nearly enough distortion to approximate the Page tone although it’s lovely edge of breakup tone and tremolo made it to a few of my recordings. When the sundragon came out I came to all the same conclusions as listed in the first post. I was never going to recone an Oxford with a pulsonic in this lifetime and believing Colbys test results with the Jensen alnico compared to 40 other speakers, I installed a baffle adapter and a modern jensen carefully removing the original p15p. Still sounds great but as expected not the zeppelin tone.
I proceeded to contact Mitch who I met on one occasion to see if I could get more info out of him but unfortunately I couldn’t learn anything new that would help us only that there are some vague minor differences in the circuit.
The first place to start would be to change my output transformer to the Coronado output transformer which I believe measures in the 2 ohm range. This impedance mismatch from 8 to 2 will surely decrease output and increase distortion. The sundragon reaches its full output level almost immediately and then just gets more distorted and bassy as dialed further up and I attribute this in large part to the mismatch. The best I could recommend with regards to the circuit changes is to wait and for hope for some more info from an owner after the release of the second run of the amps but without the correct transformers it’s a nonstarter.
I have already reached out to classic tones who happen to be the original manufacturers of the supro transformers but they tell me these part numbers are proprietary. Maybe someone else will have better luck.
If I could be if any further assistance in this quest let me know how I can help. I will continue to share any info I gain and hope we can all figure this out collectively.