Mission-Cyrus PSX circuit

Will · 18th November 2002, 07:27 AM

Hi guys,
Does anyone know where I can obtain a Mission-Cyrus PSX circuit disgram? Or better still, has anyone cloned a PSX before ?

Kees · 19th November 2002, 06:59 PM

There is nothing magic about such a power supply.
Just buy the service info and check for the supply voltages.
Build a (big) symmetric power supply with high quality capacitors.
In the amp you cut the power supply for the end stage (+ and -, not the ground)
Connect the "PSX" power supply ground with the amp ground.
Connect the final stage with the + and - of your "PSX".
Make sure your PSX is well protected with fuses. There is a risk that you connect 2 different power supplies with each other, which may cause some fire and smoke!

There is enough info on this site about power supplies.

Actually this can be done for any amp, not just Mission Cyrus

Will · 20th November 2002, 06:53 AM

Hmm, I didn't know the service info is for sale.
Ok, that sounds pretty straight forward, building a symmetric power supply. Cyrus requires a +/- 40v. What about active regulation in the supply stage ? It seems that the later
generation PSX-R has the feature.
Come to think of it, another way to approach the task
of building a PSX is to actually order a 400VA trans to replace the
existing 200VA and beef up the supply caps fr. 10K uF to 20K uF.
Should do the trick. Of course unless we're talking about the advantages of the PSX powering the output stages separately while the existing trans powering the input section.

Kees · 20th November 2002, 08:09 PM

The trick is to make a separate power supply for the end stage only. The internal power supply is used to feed the front stages.

You can't do this with a regulated power supply. Such a power supply needs massive transistors and heatsinks. In that case you'd better build a new amplifier.

tubenut · 24th November 2002, 07:05 PM

Where in the world are you?
I have a PSX R that should work, nothing to test it with though, it is a "intelligent" device and I do not think it switches on completely if not connected to a Cyrus device.
I would be very keen to sell it at a modest price, rediculous offers have been ignored so far as I would than rather strip out the toroid and T network caps. The rub is I am in South Africa and shipping prices would kill the joy. Any family out here maybe/business?

Will · 27th November 2002, 02:30 AM

I'm residing in Singapore at the moment. But thanks anyway, cos' I think the shipment will cost more than the PSX itself.

18th November 2002, 07:27 AM	#1
Will diyAudio Member Join Date: Sep 2001 Location: Kuala Lumpur	Mission-Cyrus PSX circuit Hi guys, Does anyone know where I can obtain a Mission-Cyrus PSX circuit disgram? Or better still, has anyone cloned a PSX before ?

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19th November 2002, 06:59 PM	#2
Kees diyAudio Member Join Date: Oct 2002 Location: The Netherlands	There is nothing magic about such a power supply. Just buy the service info and check for the supply voltages. Build a (big) symmetric power supply with high quality capacitors. In the amp you cut the power supply for the end stage (+ and -, not the ground) Connect the "PSX" power supply ground with the amp ground. Connect the final stage with the + and - of your "PSX". Make sure your PSX is well protected with fuses. There is a risk that you connect 2 different power supplies with each other, which may cause some fire and smoke! There is enough info on this site about power supplies. Actually this can be done for any amp, not just Mission Cyrus

20th November 2002, 06:53 AM	#3
Will diyAudio Member Join Date: Sep 2001 Location: Kuala Lumpur	Hmm, I didn't know the service info is for sale. Ok, that sounds pretty straight forward, building a symmetric power supply. Cyrus requires a +/- 40v. What about active regulation in the supply stage ? It seems that the later generation PSX-R has the feature. Come to think of it, another way to approach the task of building a PSX is to actually order a 400VA trans to replace the existing 200VA and beef up the supply caps fr. 10K uF to 20K uF. Should do the trick. Of course unless we're talking about the advantages of the PSX powering the output stages separately while the existing trans powering the input section.

20th November 2002, 08:09 PM	#4
Kees diyAudio Member Join Date: Oct 2002 Location: The Netherlands	The trick is to make a separate power supply for the end stage only. The internal power supply is used to feed the front stages. You can't do this with a regulated power supply. Such a power supply needs massive transistors and heatsinks. In that case you'd better build a new amplifier.

24th November 2002, 07:05 PM	#5
tubenut diyAudio Member Join Date: Nov 2002 Location: South Africa, Jhb	Where in the world are you? I have a PSX R that should work, nothing to test it with though, it is a "intelligent" device and I do not think it switches on completely if not connected to a Cyrus device. I would be very keen to sell it at a modest price, rediculous offers have been ignored so far as I would than rather strip out the toroid and T network caps. The rub is I am in South Africa and shipping prices would kill the joy. Any family out here maybe/business?

27th November 2002, 02:30 AM	#6
Will diyAudio Member Join Date: Sep 2001 Location: Kuala Lumpur	I'm residing in Singapore at the moment. But thanks anyway, cos' I think the shipment will cost more than the PSX itself.