Thanks for the reply, Milan -- do you know if pins 1 and 3 are in phase or out of phase?
Since I inherited this mixer and I'm not sure of it's condition, I'm trying to find a power supply that I can use to test it before purchasing a new PSU from Soundcraft. I'm wondering if I can use any 18V .6A AC transformer, tap the secondary windings to pins 1 and 3, and either leave pin 2 disconnected, or run a separate wire to earth from the primary.
Thanks,
jjai
If anyone is interested, I was able to get a schematic for this unit from a very helpful Soundcraft technician.
Since I inherited this mixer and I'm not sure of it's condition, I'm trying to find a power supply that I can use to test it before purchasing a new PSU from Soundcraft. I'm wondering if I can use any 18V .6A AC transformer, tap the secondary windings to pins 1 and 3, and either leave pin 2 disconnected, or run a separate wire to earth from the primary.
Thanks,
jjai
If anyone is interested, I was able to get a schematic for this unit from a very helpful Soundcraft technician.
I checked out the schematic and was wondering... Can I bypass the AC supply completely, and supply 15 DC directly to the output legs of the bridge rectifier? (Or would I actually need 30V?) I'm really just interested in powering the board up to test it (and see if it's worth spending more time on/worth ordering a new PSU from Soundcraft).
There are two rectifiers: one appears to supply the phantom power circuit at +48v, while the other supplies the rest of the board at +/-15v. If I connect the +/- leads from a DC power supply to the output leads of the rectifier connected to the two voltage regulators supplying +/-15v, shouldn't everything work but the phantom power?
(Actually, couldn I connect to the outputs of both rectifiers in parallel from the same power supply, given it is supplying double the current - 1200mah?)
Alternately, I happen to have an 18v AC power supply laying around -- I'm wondering if I connect it to pins 1&2 of the PSU connector, will that give the board just enough juice to power up?
Sorry for the newbie questions, but I wanted to check in with folks more experienced than myself to try and prevent frying the board if it's good!
Thanks again,
jjai
BTW, here's a link to the schematic:
http://www.showmestatetheband.com/image/folio102schem.pdf
There are two rectifiers: one appears to supply the phantom power circuit at +48v, while the other supplies the rest of the board at +/-15v. If I connect the +/- leads from a DC power supply to the output leads of the rectifier connected to the two voltage regulators supplying +/-15v, shouldn't everything work but the phantom power?
(Actually, couldn I connect to the outputs of both rectifiers in parallel from the same power supply, given it is supplying double the current - 1200mah?)
Alternately, I happen to have an 18v AC power supply laying around -- I'm wondering if I connect it to pins 1&2 of the PSU connector, will that give the board just enough juice to power up?
Sorry for the newbie questions, but I wanted to check in with folks more experienced than myself to try and prevent frying the board if it's good!
Thanks again,
jjai
BTW, here's a link to the schematic:
http://www.showmestatetheband.com/image/folio102schem.pdf
jjai said:
It's possible to use +/- unregulated or regulated 19-20VDC power supply instead of 2x18 VAC. You can connect them before or after the bridge, whichever. Of course, the phantom power supply will then be inoperative.
This would then be a half-wave rectifier (higher ripple than the full wave rectifier). IMO, the console should work OK with the half wave rectifier, but an additional caps parallel to 1000uF/25 might be necessary to insert.
Regards,
Milan
Actually, 17-0-17
If you are looking for a transformer that puts out 18-0-18, you might have a really hard time of it. Hammond makes audio transformers for this very purpose, and they are 17-0-17.
http://www.clrwtr.com/PDF/Hammond/Hammond-Power-Transformers.pdf
If you are looking for a transformer that puts out 18-0-18, you might have a really hard time of it. Hammond makes audio transformers for this very purpose, and they are 17-0-17.
http://www.clrwtr.com/PDF/Hammond/Hammond-Power-Transformers.pdf
I have to know if this power supply is continuous or alterned current ? If anyone knows please respond or send me to mushroomfiles@hotmail.com
Apologies if posting in this (related) thread is bad form, I can create a new one if that's preferred.
I have a second-hand spirit folio 10:2 board. All of the channels hum noticeably (but not overpoweringly) with or without inputs connected.
When adjusting the pre-amp gain, there is no increase in hum level; however the EQ alter the tonal character of the hum.
I examined the power supply section of the board, thinking there was a problem between pre-amp and the EQs.
The PSU "brick" is not a standard spirit one, but I have confirmed that it is supplying ~20V (rms) either side of a centre tap.
The regulators are producing solid -16.8 and +16.8 DC rails. I'm at a loss.
If the regs are producing +/-16 ok, is it likely that the smoothing caps are shot - they don't look bulging or leaky. How can I tell without replacing them?
I don't have a 'scope at home, but I can take the board to borrow one of the university's in the electronics lab downtime over the summer.
Any thoughts? do these symptoms sound familiar / easily diagnosable?
thanks!
I have a second-hand spirit folio 10:2 board. All of the channels hum noticeably (but not overpoweringly) with or without inputs connected.
When adjusting the pre-amp gain, there is no increase in hum level; however the EQ alter the tonal character of the hum.
I examined the power supply section of the board, thinking there was a problem between pre-amp and the EQs.
The PSU "brick" is not a standard spirit one, but I have confirmed that it is supplying ~20V (rms) either side of a centre tap.
The regulators are producing solid -16.8 and +16.8 DC rails. I'm at a loss.
If the regs are producing +/-16 ok, is it likely that the smoothing caps are shot - they don't look bulging or leaky. How can I tell without replacing them?
I don't have a 'scope at home, but I can take the board to borrow one of the university's in the electronics lab downtime over the summer.
Any thoughts? do these symptoms sound familiar / easily diagnosable?
thanks!
Hi thomolwly
I'd be looking for cracked tracks on the 0V line of the PCB. I had a similar problem with an Allen & Heath Mixwizard. Other thing to check for would be fractured solder joints with components around the 0V. Both these type of desks have cheap single sided biscuit PCB's.
Also if anyone does know what the original Folio PSU brick, (as used on the 10/2 and 18/2,) consists of I would love to know. Considering Flebaying one without a PSU.
I'd be looking for cracked tracks on the 0V line of the PCB. I had a similar problem with an Allen & Heath Mixwizard. Other thing to check for would be fractured solder joints with components around the 0V. Both these type of desks have cheap single sided biscuit PCB's.
Also if anyone does know what the original Folio PSU brick, (as used on the 10/2 and 18/2,) consists of I would love to know. Considering Flebaying one without a PSU.
Hi jjai..... any chance you could re-link that schematic as it seems to be longer at the above address ... many thanks Steve
A quick thank you to those who contributed here.
I bought a Spirit Folio Si today, minus PSU, from second-hand place here in Tokyo (the tremendously-named Hard Off ????? HARD OFF-????????????????????-??? ???? ??, which is full of hifi separates and guitars priced at chump change).
Thanks to your advice I got a 18VAC transformer from Radiobiru at Akihabara.
And hours later the mixer is working well.
Cost: mixer 2000 yen, transformer 1313 yen
Thanks!
I bought a Spirit Folio Si today, minus PSU, from second-hand place here in Tokyo (the tremendously-named Hard Off ????? HARD OFF-????????????????????-??? ???? ??, which is full of hifi separates and guitars priced at chump change).
Thanks to your advice I got a 18VAC transformer from Radiobiru at Akihabara.
And hours later the mixer is working well.
Cost: mixer 2000 yen, transformer 1313 yen
Thanks!
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