I'm trying to bring an old synthesizer back to life. (Sequential Circuits Multi-Trak) I purchased it years ago, without the power supply, thinking it would be easy to find. Well.....it was, but procrastination on my part means the supplier no longer has any of them in stock today.
So, time to build one myself. I've built a regulated AC/AC power supply in the past, using a circuit diagram, but this time, I'm working from scratch, so some assistance would be great.
A reputable Sequential Circuits rebuilder, winecountrysequential.com, gave me the following specs for the power transformer:
Input: 120VAC, 60Hz, 25W
Output: 15 VAC, 1162mA; with Center Tap (C.T.)
5-pin DIN/Pin Outs: Pins #1 & #5 = AC, Pin #3 = C.T.
I understand 15vac w/ CT is the same as 7.5-0-7.5. Correct?
From this, I believe that each half would supply 581mA.
Assuming I can find a 7.5-0-7.5 transformer, I should be on a good start. I'm curious if I should be concerned about adding a filtering or regulation stage after the transformer. Would it make sense to start with a 9-0-9 tranformer, then add voltage regulators or zener diodes, to drop it down to +/- 7.5? (If I recall, I believe you can run a Zener in reverse direction, to take advantage of it's voltage-limiting properties, right?)
I may be way off base, so any help/suggestions are greatly appreciated.
Interesting thing to note is that on the back of the synthesizer, the power jack shows "15VAC @ 1.25A". So, the synth indicated 1.25A, but the transformer specs I got from WineCountrySequential state 1.16A
Thanks in advance,
Cameron Miller
So, time to build one myself. I've built a regulated AC/AC power supply in the past, using a circuit diagram, but this time, I'm working from scratch, so some assistance would be great.
A reputable Sequential Circuits rebuilder, winecountrysequential.com, gave me the following specs for the power transformer:
Input: 120VAC, 60Hz, 25W
Output: 15 VAC, 1162mA; with Center Tap (C.T.)
5-pin DIN/Pin Outs: Pins #1 & #5 = AC, Pin #3 = C.T.
I understand 15vac w/ CT is the same as 7.5-0-7.5. Correct?
From this, I believe that each half would supply 581mA.
Assuming I can find a 7.5-0-7.5 transformer, I should be on a good start. I'm curious if I should be concerned about adding a filtering or regulation stage after the transformer. Would it make sense to start with a 9-0-9 tranformer, then add voltage regulators or zener diodes, to drop it down to +/- 7.5? (If I recall, I believe you can run a Zener in reverse direction, to take advantage of it's voltage-limiting properties, right?)
I may be way off base, so any help/suggestions are greatly appreciated.
Interesting thing to note is that on the back of the synthesizer, the power jack shows "15VAC @ 1.25A". So, the synth indicated 1.25A, but the transformer specs I got from WineCountrySequential state 1.16A
Thanks in advance,
Cameron Miller