cyrus 2

[AndrewT]

will 5mm or 7.5mm pitch film caps fit the space available?

 

[radiance]

Hi Andrew !

First thanks for your fast replies !

Hmm, I think pitch is 5mm.

Rad

 

[AndrewT]

Cyrus spent a lot of time developing the "sound" to suit their expected customers.
You may find that changing the caps changes the sound and you may want to revert to the original caps. Listen and decide.

 

[anatech]

Hi Andrew,
Most caps are in fact 5mm pitch, improvements are positive and the sound is not affected adversely at all. In fact, these amps no longer sound as they did anyway. I do rebuilds often.

Hi Rad,
Keep the values to original specs, your filter caps are probably good anyway. It is the exception to find bad filter capacitors in these. They are run cool for one.

CE-BP are bipolar. So buy the same parts and install them. They should be available from major suppliers.

Does anyone have an idea whether it makes sense to replace C11, C12, C27 which are green WIMA foil capacitors with a tolerance of 10% against WIMA´s with 2.5 % tolerance ?

No, it doesn't make any sense to do that, but go for it if you want to.

You really need to borrow a 'scope to look at what your supplies are doing. You do have a good DVM, right? That is also required. Your resistor is a non-inductive flat type. Go searching, they are Japanese and very good.

-Chris

 

[radiance]

Hi Sounusthree and Co !

Any recommendation how to replace best the 4 slit foil caps (15.000uF,50V) in my recently acquired used PSX ? Which type of caps will fit best ? Can I use 4 10.000uF, 63V Slit foils ? Will the lower capacity but higher voltage affect the sound in a negative manner ?
Can I use 22.000uF instead ? Will this slow down the acoustic performance ?

Thanx again for a fast answer !

Best regards

Rad

PS: I managed to replace all the caps in my beloved Cyrus II with ELNA Silnic IIs and also replaced the 2 big ELNA cans with 2 10.000uF, 63V slit foils. The amp sounds better than new 20 years ago ! Excellent!

 

[anatech]

Hi Rad,
You could order replacement parts from Cyrus. Just a suggestion. Failing that, install the 10,000 uF 63 VDC caps. The higher voltage rating means a better dielectric or a thicker one. Either way, the high frequency performance is a touch better.

Of course, just about everyone else will install the largest capacity capacitors they can get that will fit. The 10,000 uF units are large enough.

-Chris

 

[radiance]

Chris,

thanks for that quick reply !

Do you really think I can get the 15.000uF, 50V Slit foil capacitors from Cyrus directly ? As far as I know these ratings are not produced any longer. Slit foils are only available in 10.000uF, 63V or 22.000uF. At least that´s what I figured out by searching the www.
Going down from a total of 60.000uF (4 x 15.000uF) to 40.000uF (4x10.000uF) will thus not worsen the sound ?

Thanks again for some clarification from anyone !

Best regards

Rad

 

[AndrewT]

Hi,
I recommend +-20mF or so for driving 8ohm speakers.
using 4off 15mF allows 6ohms speakers or 4 to 8ohms speakers as well as 8ohms.
I reckon 4ohms needs +-40mF to +-45mF of smoothing to get the best out of bass extension. This would need 6off 15mF caps.

What impedance do you normally use?

 

[radiance]

Hi Andrew,

I still listen to a bi-wired pair of Linn Nexus speakers from 1990, having an impedance of 6 ohms. My plans are to switch to Magnepans MG 12 or 1.6QR if I have the money to buy´em !
They have a straight 4 ohm impedance all over the frequency range. With the high current the Cyrus Combo is able to deliver, it should be capable to drive these current-hungry planars.
Which kind of caps would you then recommend for the PSX ? Still 4x 10.000uF slit foils ?

Best regards

Rad

 

[AndrewT]

The little Cyrus models are great 8ohm capable amplifiers.
They will safely drive a 4r0 test resistor in the short term, until the devices start to overheat.
I do not recommend using the little Cyrus for 4ohm speaker duty.
Cyrus' use of +-30mF inside PSX and PSXr seems to confirm it's limitations.
If you reduce this to 4off 10mF you are removing the 6ohm capability.

 

[radiance]

Hi Andrew,

increasing the PSX caps to 4off 18.000uF would make any sense then ? Need to change the diodes and voltage regulators then as well ?

Best regards

Rad

 

[AndrewT]

I don't think small changes to smoothing capacitance will require any other component changes.

 

[Sonusthree]

Hi Guys,
As you probably know, I changed my slit foils for Mundorf M-lytics and changed the capacity from 4x15,000uF to 4x20,000uF. I also changed other caps in the Cyrus 2 and the sound is definitely 'slower' at higher frequencies.

I really can't say why.

The truth is, I can blindly theorise that power supply impedance has changed or that slit foils are better for high frequency response or that the new PSX diodes are adding noise to the HF or that the new electrolytics in the Cyrus 2 are the problem or the polypropylene input caps (replacing original electrolytic) ........

I just kept tweaking and now it's just not as good as it should be! A lesson for us all. 😉

The good news is that I've just bought two slit foil, 10, 000uF caps. I can try these in the PSX and see what happens and maybe also try them in the Cyrus Two afterwards. That's all I can do.

Im not sure if this is even wise but it would be great if I could use 2xslit foils (10,00uf) and 2xmundorf (20,000uf). Once again blindly, I'm hoping that I'd get faster HF from the slit foil and still have the full original capacitance of 60,000uF.

I hope this helps in some way.

 

[radiance]

Hi Sonusthree,

thanks a lot for your input here !

as already mentioned, I replaced the 2 original ELNA caps in my Cyrus II with 2x 10mF, 63V slit foil caps. The improvement is dramatic ! I never heard my nearly 20-year old Cyrus II that good. The bass response is excellent. After adding a recently acquired used PSX (Holden&Fisher 500VA toroid, Slit foils (4of 15mF, 50V) the sound was getting thin with no B of bass at all ! So I assume the 4 slit foil smoothing caps are dry. So I need to replace them and have not figured out what to take yet.

Best regards

Rad

 

[Sonusthree]

Hi Rad,

Nooo, Thanks for your input! I'm now going to try new slit foils in the Cyrus 2. This should give me lots of useful information about my problems. Cheers. 😉

I emailed Cyrus last year and they were saying that they considered the slit foils to be still within tolerance after all this time. Apparently, they don't replace them as part of the rejuvenation service they offer. They may have changed their mind since then but still ...... it's very interesting. 🙂

Best wishes,
Martin.

 

[anatech]

Hi Martin, Rad,
I am the warranty servicer for all of Eastern Canada for Cyrus. I can tell you with certainty that those original capacitors are fine as long as:
1. The vent seals are intact.
2. The rectified waveform across the capacitor looks normal.

In every case I have seen here, a customer will insist on replacing their main filter caps. This done I generally receive email extolling the virtues of replacing the main filters. Then I may get email asking why the improved effect comes and goes. Some are now on the hunt for power line conditioning equipment. Next, they aren't sure what is going on. Later the may listen to their significant other and admit the money was wasted.

The amps sound the same, they measure the same and the residuals look the same from before and after. It's all in their head.

Having said that, if there is something wrong with a filter cap and it's replaced, the sound quality generally improves. Most notable is less noise in the background or idling.

I rebuild older Cyrus amplifiers to new performance as well. The difference is dramatic. The main filter caps are rarely replaced. The same goes for Marantz or any other good amplifier. There is too much hype in this world.

Also, I have yet to hear a difference in the sound with higher filter capacitor sizes, within reason. Defective caps yes, replacing good ones with higher capacitance types - no. Not even into 4 ohm loads unless you are near clipping the amp.

-Chris

 

[radiance]

Hi Chris,

first of all, thanks for your reply !

As I´ve written before, I noticed a dramatic improvement of sound over the whole frequency range after having replaced all the capacitors in my Cyrus II, except for the bipolar caps. I changed the original ELNA 10mF, 50V against Slit foils (10mF, 63V each).
I got an PSX from "the bay", which is Rev 7 design, having 4off Slit foils (15mf, 50V each), Holden&Fisher toroid (500VA) and toggle switch (not the "older" push button switch type).
After attaching it to the recapped Cyrus II (after having removed the 2 fuses in the Cyrus II , of course), I noticed a general degradation. This affects specially the bass range. I opened the PSX and noticed that the seals of the 4 slit foil caps are bloated (swelled) a little. So I assume the caps need to be changed against new ones. Maybe you can tell me which is the best way to bring back life into the PSX ?

Thanks for any help and best regards

Rad

 

[SQLGuy]

I can tell you with certainty that those original capacitors are fine as long as:
1. The vent seals are intact.
2. The rectified waveform across the capacitor looks normal.

Hi Chris,

Does your experience here apply to most/all PS filter caps? I've noticed a generally accepted opinion from many posters here that PS filter caps have a lifespan of about 20 years and that amps shoud be "recapped" after that.

Back in my bench days my main analog work was on monitors. We had a nice Sencore Auto-Z for cap testing, and we found some general rules about lifespans of electrolytics. 1. Small caps died sooner than big caps. 2. Caps near heat sources (like right next to a heat sink) had much shorter lifespans, especially if they weren't high temp. 3. Certain brands were much better than others: Matsushita was top tier, followed closely by Rubycon and Nichicon; at the bottom end were Nicons and some caps that were marked only CEHTR. Those bottom end caps we would replace without checking, regardless of size or location, they were always bad or close enough that they would have caused warranty failures.

I also noticed that really big caps, like PS filter caps, were hardly ever out of spec, even in really stressful units like IBM monitors or Disney's SONY's (which ran 15 x 7 in Florida heat).

Now, at home and as a hobby, I have a pretty good Fluke meter that does capacitance, but I don't have an Auto-Z, and I don't have an ESR meter.

Can you provide a bit more detail on what your experience has been as to how long the PS caps last and how often you've seen them need to be replaced? What is "normal" for the rectified DC on the caps (in terms of ripple)?

I have three amps that would need to be recapped under the "about 20 years rule", (Bryston 2B LP, Adcom GFA-555ii, and PS Audio 200c) and I would appreciate the benefit of others' experience.

Thanks,
Paul

 

[anatech]

Hi Rad,
Often the plastic caps will expand. This has exactly zero to do with the health of the capacitor. Now, if the metal case has bowed out or the seals have ruptured, that capacitor requires replacing.

Often what people hear as they change things around has more to do with what goes on between their ears than what they hear. Sorry but this is true, especially when "tweaking".

Hi Paul,

Does your experience here apply to most/all PS filter caps?

Yes. However, the waveform that switching supplies use and also horizontal drive is a far greater stress than normal supply ripple. These high frequency current spikes will heat up the capacitor form the inside much faster.

I've noticed a generally accepted opinion from many posters here that PS filter caps have a lifespan of about 20 years and that amps shoud be "recapped" after that.

I guess if you're not about to test those caps, this is a good plan.

1. Small caps died sooner than big caps.

Yes. Ones with epoxy seals on the bottom last much longer though. You probably have never seen these in monitors.

2. Caps near heat sources (like right next to a heat sink) had much shorter lifespans, especially if they weren't high temp.

Yes, no surprise there at all. Even 105 ° caps don't like heat.

3. Certain brands were much better than others:

Suffice to say that good quality, name brand parts are better than no-name parts. All these manufacturers may lead in quality at different times. Just choose a good brand and be happy.

I also noticed that really big caps, like PS filter caps, were hardly ever out of spec, even in really stressful units like IBM monitors or Disney's SONY's (which ran 15 x 7 in Florida heat).

That can depend. Most capacitors are within tolerance if they are any good.

I have a pretty good Fluke meter that does capacitance

If it's an 87 or similar, it reads value fairly well. It does not indicate other aspects of a capacitors condition. I'm not familiar with the Sencore unit, I use an HP 4263A LCR meter. It's very good at indicating the overall condition of a capacitor. DA results in a higher dissipation reading. Still, for large power supply capacitors I'll look at the waveform across it before measuring it. The waveform across a supply capacitor gives an excellent indication of that parts health.

Can you provide a bit more detail on what your experience has been as to how long the PS caps last and how often you've seen them need to be replaced?

Nope. This depends on a number of factors. Best to look at the supply using an oscilloscope. If you are in doubt, change them. You'll feel better at least, even if you are no further ahead.

What is "normal" for the rectified DC on the caps (in terms of ripple)?

That is a function of current draw. There is no short answer. Experience is sometimes the only way to learn something.

I would appreciate the benefit of others' experience.

I have pretty much outlined how you would check them. I can say that the Adcom used good caps and ran fairly cool. It's capacitors are probably okay. The Bryston runs stinking hot normally, caps are typically less expensive types. Just check, they may even be good capacitors in your amp. PS Audio. Just check it and see.

Really, capacitor life depends greatly on how it was run and the ambient temperature throughout it's life.

-Chris

 

[SQLGuy]

Hi Chris,

FWIW, the PS Audio caps are Mallory CGS's.

The meter in question is an 89IV.

The Sencore Auto-Z, aka LC-102, does capacitance, ESR, dielectric absorbtion, and leakage (at rated voltage, up to 999V) for caps. It also does a few tests for inductors, and does coil ring testing. It was actually somewhat useful as a low current programmable DC supply in other areas, like checking rectifier reverse blocking or blowing out shorts in CRT guns.

I was thinking of trying to test ESR by running some DC biased AC out of my function generator through the cap and a series resistor, then read the AC voltage across the cap to see how much, if any, was being dropped. The function generator is an older, but pretty flexible, HP unit (DC - 13Mhz or so, with offset, duty cycle, and, should I need it, modulation). Does this sound practical?

By the way, I did sometimes see epoxy-sealed caps in monitors. Some of those monitors ran oven-hot, and a few manufacturers either cared enough to put in expensive parts in the right places or had to to make reasonable MTBF numbers.

Thanks again,
Paul