You mean Cyrus 1 right? I've just changed the 40V 7000uF slit foil caps in a Cyrus one to, physically smaller, 63V 10,000uF Slit Foil (by BHC). Wow! It'll never have the power of my Cyrus 2 with PSX but my little Cyrus One now has much more powerful, accurate bass as long as I don't turn it up too much. Trouble is..... it really makes you want to!
@Andrew, I'm sure this won't surprise you!
The more powerful but identical looking Cyrus Two came with 10,000uF caps as standard.
Later versions of each amp, 1 and 2,came with Slit foil caps (rebranded BHC) while the earlier seem to have had Elna.
I haven't got around to comparing the sound difference between slit foil and regular caps yet.
Sorry i can't be of more practical help.
That's strange that it has 7000uF. Which version of the Cyrus Two is it (plastic or metal case, toggle switch or push button)?
The few Cyrus Twos that I've seen had 10,000uF and the Cyrus Ones had 7,000uF. Maybe yours is an earlier plastic cased version or maybe someone else has replaced them before?
Slit foils are kinda hard to get for a reasonable price these days. I was lucky to get a cheap pair, re-badged as an OEM part for another manufacturer.
http://www.dnm.co.uk/acatalog/CapacitorShop.html
Seems like there's a lot of personal preference in capacitor choice and I don't know enough to recommend the slit foil caps over Mundorf or Elna. Lots of people seem to like the Panasonic caps but I've never tried them.
Whatever you try, I would definitely have at least 10,000uF and maybe 12,000uF. Modern caps are a lot smaller than the original parts so you should have a wider choice.
The few Cyrus Twos that I've seen had 10,000uF and the Cyrus Ones had 7,000uF. Maybe yours is an earlier plastic cased version or maybe someone else has replaced them before?
Slit foils are kinda hard to get for a reasonable price these days. I was lucky to get a cheap pair, re-badged as an OEM part for another manufacturer.
http://www.dnm.co.uk/acatalog/CapacitorShop.html
Seems like there's a lot of personal preference in capacitor choice and I don't know enough to recommend the slit foil caps over Mundorf or Elna. Lots of people seem to like the Panasonic caps but I've never tried them.
Whatever you try, I would definitely have at least 10,000uF and maybe 12,000uF. Modern caps are a lot smaller than the original parts so you should have a wider choice.
Cyrus II Repair
New here, my Cyrus II/PSX is getting old and when cold looses the low frequency in left speaker, kind of goes crackily, when warm it is better, i have a pair of used 780 Arganughts coming to really recreate the 80's feeling.
Anyone repair these amps? Maybe in the USA if not Canada would be OK too.
Anthony
New here, my Cyrus II/PSX is getting old and when cold looses the low frequency in left speaker, kind of goes crackily, when warm it is better, i have a pair of used 780 Arganughts coming to really recreate the 80's feeling.
Anyone repair these amps? Maybe in the USA if not Canada would be OK too.
Anthony
Hi Sonusthree,
Hi Tazzer9999,
You have more than one fault there. The hissing is probably the regulator ICs oscillating. The loss of bass are the capacitors that AC couple the feedback from the inverting input to ground. As they go open, the gain drops to one at higher and higher frequencies. The distortion increases as well. Those are the brownish hard encased caps under the ribbon wire.
Don't go too high on the supply capacitance! Keep thinking about the peak current pulses and smaller conduction angles. It really doesn't buy you as much as you think it does. Even then, only near clipping. There are many other changes you can make that will affect the sound quality far more than the supply caps. Going with a higher voltage capacitor will work better, like 63 volt (a common voltage). That should fill up the hole better as well.
Well, the ribbon cable alternates ground with signal, shielding the signal runs. The fact it's a flat ribbon keeps the shielding in alignment. These are made of copper wire and replacing with Teflon and silver wire doesn't buy you anything except higher crosstalk. There are times when the factory gets it right, even when popular press doesn't agree.
Hi Tazzer9999,
You have more than one fault there. The hissing is probably the regulator ICs oscillating. The loss of bass are the capacitors that AC couple the feedback from the inverting input to ground. As they go open, the gain drops to one at higher and higher frequencies. The distortion increases as well. Those are the brownish hard encased caps under the ribbon wire.
Cyrus One - 1 output 'near silent'
Hoping someone out there can shed some light on this; I've got a 20yr old Cyrus one (all metal case) which outputs on one channel (other silent or crackles or very low sound). I've reflowed the soldering on the speaker terminals, but after reading this forum I've now looked at the capacitors, the big ones (C65/66) are 40V 7000uF - for some reason C65 (only) has another 50V 1000uF cap attached? Any clues as to why?
Given I should replace the big capacitors, any tips on good source appreciated.
Thanks for any info.
Hoping someone out there can shed some light on this; I've got a 20yr old Cyrus one (all metal case) which outputs on one channel (other silent or crackles or very low sound). I've reflowed the soldering on the speaker terminals, but after reading this forum I've now looked at the capacitors, the big ones (C65/66) are 40V 7000uF - for some reason C65 (only) has another 50V 1000uF cap attached? Any clues as to why?
Given I should replace the big capacitors, any tips on good source appreciated.
Thanks for any info.
Hi Colin,
RCA jack centers also have a habit of breaking. Did you try other sources?
The volume control is a weak spot as well. No support from the chassis, only the leads into the PCB. Broken connections at the bottom of the control are pretty common after one of thees have been shipped with improper packaging.
-Chris
RCA jack centers also have a habit of breaking. Did you try other sources?
The volume control is a weak spot as well. No support from the chassis, only the leads into the PCB. Broken connections at the bottom of the control are pretty common after one of thees have been shipped with improper packaging.
-Chris
Cyrus 1
Thanks for the feedback. When looking at the PCA I noticed that C68 has leaked electrolytic fluid and so looks like may be culprit. I got hold of circuit schematic and noticed a few differences vs my Cyrus 1 PCA...
C68 was 50V on the PCA vs 63V in schematic
C53-56 were 220uF 50V on the PCA vs 100uF 50V in schematic
I've decided to replace all the electrolytic caps (per schematic) and take it from there...
Thanks for the feedback. When looking at the PCA I noticed that C68 has leaked electrolytic fluid and so looks like may be culprit. I got hold of circuit schematic and noticed a few differences vs my Cyrus 1 PCA...
C68 was 50V on the PCA vs 63V in schematic
C53-56 were 220uF 50V on the PCA vs 100uF 50V in schematic
I've decided to replace all the electrolytic caps (per schematic) and take it from there...
...well as it happens I've noticed that C43/44 are in fact bipolar (the ones I removed were not), i'd just fitted the replacement same way as old...though these are only 6V...
Struggling to understand why so many things on this PCA are different from the schematic. I put it in for repair around 10yrs ago and wondering whether I got the same one back...
Thanks for the feedback, I'll persevere bit longer...
Struggling to understand why so many things on this PCA are different from the schematic. I put it in for repair around 10yrs ago and wondering whether I got the same one back...
Thanks for the feedback, I'll persevere bit longer...
Hi, just to let to know that with the help of this board I managed to service my Cyrus II, Iss07, with success! Thanks to everyone. After having recapped the amp, I still had some problems e.g. loosing sound from right channel. I managed to gain sound again by switching the source selector but that did not help that long. After getting a hint from another guy I soldered out the ALPS source selector switch, opened it and saw the mess... The metal silver contacts were oxidized and black. So I decided to take very fine lapping paper and metal polishing paste and cleaned/polished the two contact bars as well as the gold contacts which ride upon them when moved by the switch. This was worth all the effort, the amps sounds like new. I can recommend this procedure to anyone having problems with one or two channel dropping out. Contact spray won´t help here!
Best regards
Rad
Best regards
Rad
It's 2010, time for another post on this long-running thread!
I recently purchased a C1 (the TOG version) here in the 'States, and I also purchased a 500W-rated voltage converter for our 117V mains (for a 220V Cyrus One). First impressions have been very good, possibly because I'm using very efficient speakers--Klipsch Heresy's--so the amp doesn't have to work very hard to get plenty loud. The amp and the converter stay very cool over long periods of use. I like how this little integrated sounds even more than my Superphon Revelation/Dynaco ST-70 combo. The ST-70 is rewired in triode mode and has a number of mods. So it kills me a little to admit that I like the Cyrus more . . .
I'm shocked that my Denon DL-103 works in the MM stage (but it sounds worse when switched to MC, though it's subjectively about 10dB louder). I also have a DB Systems MC phono pre, and the DL-103 sounds just a tiny bit better through the pre into a line input. The seller thought I had to be wrong when I reported my experience. Anyway, I felt this needed to be documented in case anybody else could take advantage of this "feature". The difference in sound quality between the MC outboard pre and the MM stage is vanishingly small. I'm just floored by this discovery . . .
I've read this entire thread, and I will be replacing the smaller caps, having taken Chris's sage advice to heart and ignoring the filter caps, which look and work fine as-is.
I recently purchased a C1 (the TOG version) here in the 'States, and I also purchased a 500W-rated voltage converter for our 117V mains (for a 220V Cyrus One). First impressions have been very good, possibly because I'm using very efficient speakers--Klipsch Heresy's--so the amp doesn't have to work very hard to get plenty loud. The amp and the converter stay very cool over long periods of use. I like how this little integrated sounds even more than my Superphon Revelation/Dynaco ST-70 combo. The ST-70 is rewired in triode mode and has a number of mods. So it kills me a little to admit that I like the Cyrus more . . .
I'm shocked that my Denon DL-103 works in the MM stage (but it sounds worse when switched to MC, though it's subjectively about 10dB louder). I also have a DB Systems MC phono pre, and the DL-103 sounds just a tiny bit better through the pre into a line input. The seller thought I had to be wrong when I reported my experience. Anyway, I felt this needed to be documented in case anybody else could take advantage of this "feature". The difference in sound quality between the MC outboard pre and the MM stage is vanishingly small. I'm just floored by this discovery . . .
I've read this entire thread, and I will be replacing the smaller caps, having taken Chris's sage advice to heart and ignoring the filter caps, which look and work fine as-is.
Hi soldersmoker,
The phono sections in these are extremely good. Your report is no surprise to me, and I just received another email earlier on today where the owner of a unit I repaired was very happy with the unit's phono section.
Hi Rad,
Never, never, never use anything abrasive on switch or relay contacts - ever! The plating is not that thick, and once you're down to base metal the switch is perma-toast.
What you should have done was disassemble that switch (may as well do the other also) and worked a business card soaked in contract cleaner back and forth. That will clean up these contacts like new. Not much in the way of wear to shorten the life of the switch. Once you're done, use a non-residue cleaner to wash the contacts out. Then you can apply a small amount of cleaner on those contacts to slow down the aging process.
You're not done yet! Apply some "white grease" along the contact areas with the plastic contact holder. You can use some oil on the shaft bearings (single weight, no additive, light machine oil) and also on the detent mechanism, or a little heavier grease if you'd rather. Now you can carefully reassemble the switch and crimp the base back on. If you aren't careful when crimping, you can break a lead off, or cause the case to become a trapezoid. That won't be helpful, so stay alert.
Hi cosmo181,
Sounds like you blew up a channel there. Better check your speaker cables.
-Chris
The phono sections in these are extremely good. Your report is no surprise to me, and I just received another email earlier on today where the owner of a unit I repaired was very happy with the unit's phono section.
Hi Rad,
Never, never, never use anything abrasive on switch or relay contacts - ever! The plating is not that thick, and once you're down to base metal the switch is perma-toast.
What you should have done was disassemble that switch (may as well do the other also) and worked a business card soaked in contract cleaner back and forth. That will clean up these contacts like new. Not much in the way of wear to shorten the life of the switch. Once you're done, use a non-residue cleaner to wash the contacts out. Then you can apply a small amount of cleaner on those contacts to slow down the aging process.
You're not done yet! Apply some "white grease" along the contact areas with the plastic contact holder. You can use some oil on the shaft bearings (single weight, no additive, light machine oil) and also on the detent mechanism, or a little heavier grease if you'd rather. Now you can carefully reassemble the switch and crimp the base back on. If you aren't careful when crimping, you can break a lead off, or cause the case to become a trapezoid. That won't be helpful, so stay alert.
Hi cosmo181,
Sounds like you blew up a channel there. Better check your speaker cables.
-Chris
Thanks for piping up, Chris! I haven't done a thing to "improve" my Cyrus since I've been so satisfied with how it's sounding, a real testament to the little integrated. I'm waiting for a QUAD 33 to finally get here, in addition to a Bottlehead Quickie, either one of which will be acting as the preamp for my favorite amp, a Sure Tripath. But the Cyrus One has kept me very happy in the meantime. I'm surprised and pleased at how cool the amp remains, as does the voltage converter, but that is probably in part a function of my efficient 97dB speakers, which allow the amp and converter to coast.
One fly in the ointment: the RCA jacks seem to be a bit flaky on a couple of settings (AUX and CD have intermittent dropouts), so I may just replace all the jacks in the future. Using DeoxIT and Caig Gold contact cleaner didn't remedy the problem. But I'm satisfied, thus lazy. Besides, I listen to vinyl most of the time, and those jacks are fine.
--Alan
One fly in the ointment: the RCA jacks seem to be a bit flaky on a couple of settings (AUX and CD have intermittent dropouts), so I may just replace all the jacks in the future. Using DeoxIT and Caig Gold contact cleaner didn't remedy the problem. But I'm satisfied, thus lazy. Besides, I listen to vinyl most of the time, and those jacks are fine.
--Alan
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