cyrus 2

[mc square]

Thanx for the answers,guys.
I have just opened it today and the first thing I noticed was those two caps(ERO)seem to be on their last journey....

You said I could replace with polarized types,but wich way do I put in...?I have some Panasonic fc that matches them.

Thing is,everything looks okey,but yet not started up...

M@

 

[anatech]

Hi mc square,
It's been a while since I measured the voltages. You will have possibly up to 100 mV to ground. So the negative terminal of the capacitor goes towards the base. The voltages here are so small that I don't think it would make a huge difference though.

-Chris

 

[mc square]

I have now replaced them with 470uF/63v Panasonic Fc,with negative terminals running into Q21 and 22.

But I saw that R114 was a bit cracked and I want too replace both R113 and R114 before I start up,but I can only find 4.7K resistors and they are 3.9K,according to schematic.
Can I replace them with 4.7K`s or does it need to be exactly 3.9K?

 

[anatech]

Hi mc square,
Those are bleeder resistors, so their value is not critical. 4K7 will be fine, although 3K9 is a standard value and should be readily available. You could go up one wattage size while you are at it.

-Chris

 

[mc square]

Ok.What wattage are they specified at...?I am not a big fan of resistors but looks like they could be 1/4 or 1/2w...?

 

[AndrewT]

Hi,
you can check the dissipation of the bleeder resistors from Pd=V*V/R.
I would recommend that you fit a wattage about double the dissipation due to it running permanently at this dissipation when switched on.

 

[mc square]

Hi there.
I decided to put two resistors in parallel,and created ca 3.6K and it worked out well.

I found a couple thats double the size of the originals.
Have played two full albums and no noise or fault whatsoever...

Well,the led didnt worked,but thats definitly no problem right now!

Thanx for your helpful support!
🙂

 

[anatech]

Hi Andrew,
In this case I would have gone 1/4 or lower since there is no ventillation to speak of. Cyrus was still learning about thermal issues back then.

-Chris

 

[qrius4ever]

Hi Tim,

Hope you get your C2 fixed by these great guys. They were fantastic in helping me fixed my 1988C2 its now singing sweetly.
Thanks again guys.

Henry

 

[whats gan on]

need help

has any one fitted a alps blue but need a extention bar to reach the pot if you have done this were would i get a bar

thanks

 

[Sonusthree]

Hello,
I installed an Alps Blue into my latest model Cyrus 2.
It took some careful pin bending but it did work and the results were VERY worthwhile in my case. I suppose that the improvements depend on the condition of the orignal Alps pot. Mine was not scratchy at all but I still found an increased transparency with the new Blue.

I used a kind of coupler that I got from Ebay a while ago but I can't remember the proper name for it. I have seen them in electronics catalogues before. They are aluminium and secured by 2 screws at either end and mate very securely to the Alps Blue. Let me know if you decide to use these and can't find them. I'll look harder or may even have a spare one somewhere.

I didn't extend the existing shaft much but used the original which I cut slightly so that I had the correct diameter hole.

I glued some very stiff black rubber tubing inside the original shaft which then joins to the 'coupler'. The rubber has not been very durable mainly because I am always removing it for mods and repairs to the amp. I would recommend a small piece of metal here for longevity.
I will be changing mine soon but this isn't urgent.

 

[AndrewT]

Hi Sonus,
I see you have Elna smoothing caps.
Are these original in your model or swapped for the slit foil?

If substitute, how did the swap turn out? What capacitance did you choose?

 

[Sonusthree]

Hi Andrew,
These are the original caps which are, I think, the same type as my later model Cyrus 1 (which is currently awaiting repair for active Bi-amping duty). I also have a poorly earlier model plastic C1 which has Cyrus branded smoothing caps that I presume are slit foil. I haven't checked this for a while but will soon.

I use my C2 with a PSX and have disabled my phono stage by removing the regs. So, I haven't paid much attention to the markings on those caps for a while.
The PSX (latest model) caps are the 'Cyrus' branded slit foils and I am desperate to replace them to see what would happen. I have mentioned this before but Cyrus have said that they no longer stock these parts and that they are very stable anyway.

I have recapped the rest of the amp with the usuall suspects (BG, Silmic, cerafine..) and wherever possible changed from electrolytics to polypropylene. I have gained some clarity but not the amazing amounts that I had hoped.
I do have a little more peace of mind with regards to reliability.
15 year old 'lytics scare me!!!

The regs were removed to negate the possible oscillation in the Phono stage that Anatech has previously mentioned.

Like you, I wonder wether it is worth replacing the smoothing caps in these ageing amps. I have my eyes set on the Mundorf M-Lytics which for my PSX (4 X 15000uF) would be about £45. Not an unreasonable amount. But I need to sell something first.

By the way, how does the Cyrus 2 sound with your Tannoys?

Cheers,
Martin.

 

[AndrewT]

Hi,
the Cyrus 2 +Psx is out on long term loan to a colleague.

The big Tannoys have not been brought back into use since the new surrounds were fitted.

So I'm using the Tannoy Reveals set flat with balanced con from my Cyrus pre+PSXr

I ran out of timber for the horn and need to get more ordered. 15 off 4.8m lengths don't fit the car!

 

[Geoff]

These are the original caps which are, I think, the same type as my later model Cyrus 1 (which is currently awaiting repair for active Bi-amping duty). I also have a poorly earlier model plastic C1 which has Cyrus branded smoothing caps that I presume are slit foil. I haven't checked this for a while but will soon.

I find this a little surprising. Have you had the amp from new or could someone else have replaced the caps? I have four Cyrus 1s of various vintages. The earliest non-metalic case has Elna caps. The later non-metalic case and the two v07s (alloy case) all have slit foil capacitors, labelled as such and with the Cyrus branding.

I use my C2 with a PSX and have disabled my phono stage by removing the regs.

For anyone else contemplating disablement of the phono stage, an easier way (and more quickly reversable) is to lift one leg of the 0R links X24 and X25 locared next to the front of the 'Record' selector switch. Of course, if a PSX is being used there is no need for any modification - just don't plug the Cyrus 2 into the mains, only the PSX.

 

[whats gan on]

Hello,
I installed an Alps Blue into my latest model Cyrus 2.
It took some careful pin bending but it did work and the results were VERY worthwhile in my case. I suppose that the improvements depend on the condition of the orignal Alps pot. Mine was not scratchy at all but I still found an increased transparency with the new Blue.

I used a kind of coupler that I got from Ebay a while ago but I can't remember the proper name for it. I have seen them in electronics catalogues before. They are aluminium and secured by 2 screws at either end and mate very securely to the Alps Blue. Let me know if you decide to use these and can't find them. I'll look harder or may even have a spare one somewhere.

I didn't extend the existing shaft much but used the original which I cut slightly so that I had the correct diameter hole.

I glued some very stiff black rubber tubing inside the original shaft which then joins to the 'coupler'. The rubber has not been very durable mainly because I am always removing it for mods and repairs to the amp. I would recommend a small piece of metal here for longevity.
I will be changing mine soon but this isn't urgent.

hi thanks for the info i would be very greatful if you could search some more to find the shaft you have fitted the pot well tidy
i have fitted mine and it sounds very clean open is this normal for a brand new pot will it its sound change thanks for your help

 

[whats gan on]

Hi Andrew,
These are the original caps which are, I think, the same type as my later model Cyrus 1 (which is currently awaiting repair for active Bi-amping duty). I also have a poorly earlier model plastic C1 which has Cyrus branded smoothing caps that I presume are slit foil. I haven't checked this for a while but will soon.

I use my C2 with a PSX and have disabled my phono stage by removing the regs. So, I haven't paid much attention to the markings on those caps for a while.
The PSX (latest model) caps are the 'Cyrus' branded slit foils and I am desperate to replace them to see what would happen. I have mentioned this before but Cyrus have said that they no longer stock these parts and that they are very stable anyway.

I have recapped the rest of the amp with the usuall suspects (BG, Silmic, cerafine..) and wherever possible changed from electrolytics to polypropylene. I have gained some clarity but not the amazing amounts that I had hoped.
I do have a little more peace of mind with regards to reliability.
15 year old 'lytics scare me!!!

The regs were removed to negate the possible oscillation in the Phono stage that Anatech has previously mentioned.

Like you, I wonder wether it is worth replacing the smoothing caps in these ageing amps. I have my eyes set on the Mundorf M-Lytics which for my PSX (4 X 15000uF) would be about £45. Not an unreasonable amount. But I need to sell something first.

By the way, how does the Cyrus 2 sound with your Tannoys?

Cheers,
Martin.

hi martin the cyrus make the tannoys come to life very open clean detialed sound brings them to life have you any pics of the cap chenges i have 2 caps in the cyrus 2 i would want to renew they are under the green cable strip they are brown does amny one know what the values are

 

[Geoff]

i have 2 caps in the cyrus 2 i would want to renew they are under the green cable strip they are brown does amny one know what the values are

I think the caps to which you are referring are the bipolar electrolytics in the feedback network. To avoid any confusion, these are the ones that have a diameter of 12.5mm. If we are talking about the same caps then they are 470uF 6.3V non-polarised electrolytics.

If you find a source in the UK of good quality replacements (other than BG) for these caps please let me know as I have been looking, unsuccessfully, for quite some time and have had to resort to using two standard electrolytics back to back.

 

[Sonusthree]

brown does amny one know what the values are

Those feedback caps are 470uF Bipolar electrolytics. 6 Volts. Other more knowledgeable people have said that single regular polarised caps can be used here because the current is so small but please search other posts to be sure and I think a certain polarity was also mentioned.
I used black gate N type (Bi-polar) here and have bypassed them with a small value polypropylene under the board.
These are in the feedback loop so I didn't mind spending the extra on this occasion.

 

[Sonusthree]

.........have you any pics of the cap chenges........

Here's a pic of the mostly recapped Cyrus. The only original caps left are the two large smoothing caps (Not used because of PSX) and some in the phono stage.

I replaced the Bipolar electrolytic input cap for a Sonicap. It is definitely too large so I will change it soon.

I have removed the green ribbon cable in favour of silver in teflon wiring under the board. Please excuse the rather idiotic use of Grommets around the 470uF feedback caps. What was I thinking?