cyrus 2 amplifier

[mjona]

Hello Puresound,

Re- Cyrus2 and PSX in combo.

I read earlier you removed the Cyrus mains fuse (and reconnected the mains plug for signal earthing reasons).

That would have depowered the phono section.

If you have not removed the rail fuses FS1 and FS2 as discussed by "alohka" and "Martin", this would be a necessary next step.

If the switch on noise remains then "alohka's" intuition on the grounding resistor in the PSX is certainly worth checking.

The noise from your speakers must be driving you mad by now. You can protect by using a 5 watt 100 ohm resistor between the amplifier output and either of the two speakers.

Michael Jonassen

[Pure sound]

Yes michael its driving me bonkers,the noise is pushing 14v through to the speakers when power button is turned on then back to zero.

The noise is there when fusses are in when using cyrus as a intergrated ,

take fusses out and no noise on switch on,

plug psx in to cyrus (with fusses still out) and the noise rears it horrible ugly head once again!!!
ive checked / replaced all main caps in cyrus 2, checked all diodes etc. Ive just ordered the rest of caps for the board about 15 or so to see if its a bad cap.

But i cant use it due to the fact i dont want to damage my speakers on turn on.(or will it not?)

The units are in mint condition and dont want to let them go !

any more suggestions???

[Tekko]

The turn on thump is completely 100% normal for an amp with AC coupling through capacitors that doesent have the dc protect/delayed speakers connection relay.

[Pure sound]

I have noticed that c63 c64 are cracked they are 4700pf. But they seem to be many different types on Internet . Manual says 4700pf mp3y 250ac. On the cap I can read 271y and cx2 if this helps. Can some one share a link to the correct cap in the uk possibly please
Thanks

Richard Tonge

[mjona]

Hello Richard,

C63 and C64 are what I previously described as snubbing caps - they prevent sparking across the switch contacts at switch on.

Class Y and Class X2 are different capacitor types whereas C63 and C64 should be identical. A mix of types would indicate a repair having been made. A google search on MP3y led me to WIMA brand capacitors.

If the capacitors are not doing their job the switch contacts would suffer.

Having found a circuit diagram I can see R121 is the 15 ohm resistor mentioned by "alokha". This should be a carbon type.

The 5 watt 100 ohm resistor use was to avoid damage during testing.

Michael Jonassen

[richie00boy]

Originally Posted by Pure sound

take fusses out and no noise on switch on,

Unsurprisingly really as that's because the amp is no longer receiving any power.

The amp does thump at turn on even when new.Perhaps you can put a video of the speakers moving on Youtube and we can see if it really is that bad or just normal.

Check the link resistor mentioned by alokha.

[Pure sound]

Hi all i have now posted a video of fault for you all to watch. i turn the psx on on the video, but when using cyrus 2 as normal without psx same fault so its the cyrus2

Cyrus 2 and psx fault - YouTube

[richie00boy]

It looks completely normal to me for that amp. If you don't like it the only option is a relay inbetween your amp and speakers, that is either switched manually by you or by a timer circuit.

[sippy]

I've got 2 Cryus 2 amps and neither behave like in the video, never seen any Cyrus amp do that old or new.

[tauro0221]

It is look like the power supply is not coming smooth. That's sound it is like the power supply is loaded coming up. That's not normal. It is sound like spring sound. At the beginning you said if you remove the PSX you didn't have the sound. Now you said that with or without you still have the sound. Which it is right?