Sonusthree said:If you 'unhide' your email address in your control panel options then I'll happily send it to you.
You cannot email me through the forum due to restrictions for new members. Actually, you're not that far away from me in Brighton so maybe I could fold a copy into a paper aeroplane and throw it towards you when the winds in the right direction!
Martin
I hadn't realised it was hidden - unchecked now, many thanks
Chris
@Sonusthree et al.
Hi, since I also want to replace the "old" ALPS volume/Balance pot in my Cyrus 2, I need to know what happens if I replace it against this one:
http://www.thel-audioworld.de/bauteile/regler/Potis.htm (sorry, it´s German)
My choice would be the CP601 (40€) since it seems to fit into place. Am I wrong ?
I assume it is the 10k/log version, right ?
What happens with the non-existent stereo channel balance feature ? The CP601 is only Stereo, no balance. Is this a problem ? I never used the balance knob on my amp.
It´s OK if there is nothing soldered in then ?
Thanks a lot for some fruitful answers !
Best regards
Rad
@sonusthree: The ALPS blue velvet you put in is 10k/log as well, right ?
Hi, since I also want to replace the "old" ALPS volume/Balance pot in my Cyrus 2, I need to know what happens if I replace it against this one:
http://www.thel-audioworld.de/bauteile/regler/Potis.htm (sorry, it´s German)
My choice would be the CP601 (40€) since it seems to fit into place. Am I wrong ?
I assume it is the 10k/log version, right ?
What happens with the non-existent stereo channel balance feature ? The CP601 is only Stereo, no balance. Is this a problem ? I never used the balance knob on my amp.
It´s OK if there is nothing soldered in then ?
Thanks a lot for some fruitful answers !
Best regards
Rad
@sonusthree: The ALPS blue velvet you put in is 10k/log as well, right ?
Hi Rad,
I don't know for sure if your potentiometer will fit. Probably. Measure the holes inside your amp. I 'think' it should be ~7-8mm between front and back row of pins in my last version of Cyrus1/2. My Alps pot had ~10mm spacing between front and back rows so I had to bend them slightly to fit.
Yes. I used 10K log. Alps.
Losing balance is no problem really. You can replace with fixed resistors if you like but it's not needed. Removing balance raises input impedance very slightly I think.
Good luck,
Martin.
I don't know for sure if your potentiometer will fit. Probably. Measure the holes inside your amp. I 'think' it should be ~7-8mm between front and back row of pins in my last version of Cyrus1/2. My Alps pot had ~10mm spacing between front and back rows so I had to bend them slightly to fit.
Yes. I used 10K log. Alps.
Losing balance is no problem really. You can replace with fixed resistors if you like but it's not needed. Removing balance raises input impedance very slightly I think.
Good luck,
Martin.
@Sonusthree: Thanks for your answer, I ordered the TKD pot. We´ll see how it´ll fit !
Another question: In my Cyrus Two, issue 07, I replaced several caps some time ago. Now after having opened the case again to replace the ALPS volume pot against a better one I can see that C37 and C38, which I did not replace are 22uF, 50V types. In the Cyrus 2 service manual which I have C37 and C38 are 22uF, 25V types ! What about that ? Since I plan to replace these two guys as well should I take 22uF, 25V as stated in the manual, or 22uF, 50V as existing in my amp ?!
Thanks and best regards
Rad
Another question: In my Cyrus Two, issue 07, I replaced several caps some time ago. Now after having opened the case again to replace the ALPS volume pot against a better one I can see that C37 and C38, which I did not replace are 22uF, 50V types. In the Cyrus 2 service manual which I have C37 and C38 are 22uF, 25V types ! What about that ? Since I plan to replace these two guys as well should I take 22uF, 25V as stated in the manual, or 22uF, 50V as existing in my amp ?!
Thanks and best regards
Rad
Hi realoldfart,
Use the 50 VDC types. The dielectric is better as well. There are times when a production run may use a different part than specified for a number of reasons. For one, sometimes the lower voltage part may be more expensive, or they may use a 50 VDC part elsewhere and are simply reducing they parts storage. No biggie there.
I do worry about non-technical people working on good equipment though. I've seen more than my share of damaged units and would prefer not to see any more. There are subtle things about even some simple looking amps. Even soldering on a PCB without damaging it requires a "feel". That is the reason why Cyrus will not release service information. Carver did the same thing, for the same reasons. Unparalleled destruction otherwise.
Your newer products are mostly surface mount, double sided PCBs. Every one I have seen that was worked on by the dealer had damaged PCBs. The stuff done to these by our local "modders" was even more graphic - and final. Believe it or not, I match the surface mount transistors. Something you should be doing with the diff pair in your Cyrus II.
How much does the factory want to rebuild it? They do have that service put in place. I believe they have set a flat rate for this.
Hi Andrew,
They are 390 pF and tie the two bases in the diff pair together in my information. I show C39/40 as 22 uF parts, rated at 25 VDC. They provide a time constant to the CCS for the diff pair. They are fed with a 22 K resistor to + Vcc. Are these the ones you are looking at?
-Chris
Use the 50 VDC types. The dielectric is better as well. There are times when a production run may use a different part than specified for a number of reasons. For one, sometimes the lower voltage part may be more expensive, or they may use a 50 VDC part elsewhere and are simply reducing they parts storage. No biggie there.
I do worry about non-technical people working on good equipment though. I've seen more than my share of damaged units and would prefer not to see any more. There are subtle things about even some simple looking amps. Even soldering on a PCB without damaging it requires a "feel". That is the reason why Cyrus will not release service information. Carver did the same thing, for the same reasons. Unparalleled destruction otherwise.
Your newer products are mostly surface mount, double sided PCBs. Every one I have seen that was worked on by the dealer had damaged PCBs. The stuff done to these by our local "modders" was even more graphic - and final. Believe it or not, I match the surface mount transistors. Something you should be doing with the diff pair in your Cyrus II.
How much does the factory want to rebuild it? They do have that service put in place. I believe they have set a flat rate for this.
Hi Andrew,
They are 390 pF and tie the two bases in the diff pair together in my information. I show C39/40 as 22 uF parts, rated at 25 VDC. They provide a time constant to the CCS for the diff pair. They are fed with a 22 K resistor to + Vcc. Are these the ones you are looking at?
-Chris
anatech said:
Last I heard, I think it was £159 for the 1, 2 or 3. That's quite a wedge to pay but I'm sure they do an excellent job.
I can never work out if Andrew is asking for himself or doing his usual thing of prompting people to learn a bit for themselves.
I think he's referring to the issue 7 version of a previous poster while you seem to be looking at the issue 06 schematic.
I wish I knew what their function was. I've got a lot to learn but at least the manual gives me the keywords to search for. I hope that a long tail pair is as exciting as it sounds!!
Hi Martin,
Could be. I just get what I get. The circuit's the same, but the values have been changed to protect the innocent! I take it you have more versions than I do in that case. Figures.
"But I can buy another for a lot less" **
Yes, you can. Problem is that it needs the same work done, so you are now the purchase price behind.
-Chris
** Something I used to hear a lot when my shop was open to the public.
Could be. I just get what I get. The circuit's the same, but the values have been changed to protect the innocent! I take it you have more versions than I do in that case. Figures.
I assume these are off the current source (amplified Vbe, or two transistor CCS). I'm not sure how effective it would be at filtering anything really, not against the impedance of a pair of active transistors. If they had split the 22K and put the cap higher up, it might perform a filter function more effectively.
Only if you match them by hand, then they can be all kinds of fun.
That's actually not too bad. I'm slightly less expensive, depending on what the fault is and if we need to replace major items. Normally, that is not any concern. Considering you get a reliable amp that sounds really good, I think it's a bargain.
"But I can buy another for a lot less" **
Yes, you can. Problem is that it needs the same work done, so you are now the purchase price behind.
-Chris
** Something I used to hear a lot when my shop was open to the public.
@Anatech: I´m not the realodfart but assume that your answer is targeted to me. First, thanks for that. I´m a mass spectrometry engineer, developing and servicing mass spectrometers worldwide. So if you are in the middle of nowhere, eg. some place in India or the U.S. far away from the company, you better know how to hold the soldering iron javascript:smilie('').
I can easily solder out and in even the tiniest SMD devices at midnight, that´s not an issue.
Thanks anyway for any comment to my little Cyrus baby.
BTW, looking at my PCB I also found out that there are no C3 and C4 (phono stage) soldered in, in contrast to the issue 07 Cyrus 2 service manual, any clue about that ?
Best regards
Rad
').I can easily solder out and in even the tiniest SMD devices at midnight, that´s not an issue.
Thanks anyway for any comment to my little Cyrus baby.
BTW, looking at my PCB I also found out that there are no C3 and C4 (phono stage) soldered in, in contrast to the issue 07 Cyrus 2 service manual, any clue about that ?
Best regards
Rad
I was asking so that we all know which components he is referring to.Sonusthree said:I can never work out if Andrew is asking for himself or doing his usual thing of prompting people to learn a bit for themselves.
I think he's referring to the issue 7 version of a previous poster while you seem to be looking at the issue 06 schematic.
That way we can all take a share in helping solve the problem.
Hi guys,
Looking for a little reassurance here. I've replaced the capacitors I wanted to, and the Vregs. Fired up the pre-amp and all it's voltages are perfect.
Secondary ac voltage is fine too.
Switch on the power amp, and R110 (180Ω power LED current limit) starts to smoke after a few seconds. Otherwise, all seems fine - power amp supply voltages are ±41.2V dc. I can't think why it should be doing this - perhaps it always has?
Am I worrying needlessly, or can you suggest something specific I should check for? I checked all my solder joints before powering up, and there's no shorts or dry joints. If there were any shorts, I wouldn't have solid power supplies, right?
It's interesting that this resistor is mounted on little stands to hold it away from the PCB. Cyrus obviously expected it to get hot. Maybe it just needs replacing? I don't have the courage to carry on testing the power amp while this resistor's smoking away, even though it's only for the power LED!
Any suggestions gladly received.
Looking for a little reassurance here. I've replaced the capacitors I wanted to, and the Vregs. Fired up the pre-amp and all it's voltages are perfect.
Secondary ac voltage is fine too.
Switch on the power amp, and R110 (180Ω power LED current limit) starts to smoke after a few seconds. Otherwise, all seems fine - power amp supply voltages are ±41.2V dc. I can't think why it should be doing this - perhaps it always has?
Am I worrying needlessly, or can you suggest something specific I should check for? I checked all my solder joints before powering up, and there's no shorts or dry joints. If there were any shorts, I wouldn't have solid power supplies, right?
It's interesting that this resistor is mounted on little stands to hold it away from the PCB. Cyrus obviously expected it to get hot. Maybe it just needs replacing? I don't have the courage to carry on testing the power amp while this resistor's smoking away, even though it's only for the power LED!
Any suggestions gladly received.
Hi Rad,
Ah, seems I was referring to you on those capacitor voltages.
Now, some concerns for the Cyrus service department, and myself as well center on the actual understanding a servicer has on the actual circuits involved. There are many subtle things that need checking even when the repair seems to be straight forward (like blown outputs for example).
While you are looking in there, have a look at C13/C14 in the MM section. Those are to load your cartridge and really should be changed or padded to present your MM phono cartridge with the correct capacitance. Measure the capacitance of the phono leads (disconnect on jumper to the cartridge for this), then the capacitance of the input circuit in the Cyrus. Add these figures together and subtract the recommended cartridge load capacitance figure listed on the data sheet of your cartridge. If you get close to "0.0" pF, then great. Do nothing. If the figure is negative, you need to reduce the values of these caps by that value. Obviously, if the number is positive, you need to add some capacitance. This is the one thing I often see not done, or done improperly.
-Chris
Ah, seems I was referring to you on those capacitor voltages.
Well, that is one concern. Much destruction does occur even in repair shops. From what I have seen over the years, all service people should be licensed or accredited in several areas. Soldering would be one (believe it or not), smd soldering would be another. Even the thought process involved in servicing these customer equipment, some thought must be given before any changes are applied. That's for those folks that charge for modifying equipment, and normally impairing the performance instead.
Now, some concerns for the Cyrus service department, and myself as well center on the actual understanding a servicer has on the actual circuits involved. There are many subtle things that need checking even when the repair seems to be straight forward (like blown outputs for example).
Now here is one of the subtleties I was referring to. C3/C4 are for the phono cartridge filtering on the MC circuit, I suspect they are very effective as a cartridge load in the normal sense. It's possible that some of the MC circuits might be prone to oscillation with certain cartridges too, these would have helped prevent that from happening.
While you are looking in there, have a look at C13/C14 in the MM section. Those are to load your cartridge and really should be changed or padded to present your MM phono cartridge with the correct capacitance. Measure the capacitance of the phono leads (disconnect on jumper to the cartridge for this), then the capacitance of the input circuit in the Cyrus. Add these figures together and subtract the recommended cartridge load capacitance figure listed on the data sheet of your cartridge. If you get close to "0.0" pF, then great. Do nothing. If the figure is negative, you need to reduce the values of these caps by that value. Obviously, if the number is positive, you need to add some capacitance. This is the one thing I often see not done, or done improperly.
-Chris
Thanks for the reassurance anatech.
I've since finished all the replacements, and the Cyrus has been producing wonderful buzz-free music for the last few days. I swear separation has improved, but that might be my new listening set up as much as the capacitors (since I've moved house over the course of this thread!).
However, it seems to be running really hot - much hotter than I remember from before. Also, where the heat used to be concentrated over the big heat sink, it now seems to spread fairly evenly across the whole top surface (though still hotter over the heat sink and the pre-amp area).
How hot do these usually get? When I put mine back together, I wiped off all the old heat sink paste and applied a thin new layer. Could it be that the heat's actually being radiated better now, hence the warmer case?
I've since finished all the replacements, and the Cyrus has been producing wonderful buzz-free music for the last few days. I swear separation has improved, but that might be my new listening set up as much as the capacitors (since I've moved house over the course of this thread!).
However, it seems to be running really hot - much hotter than I remember from before. Also, where the heat used to be concentrated over the big heat sink, it now seems to spread fairly evenly across the whole top surface (though still hotter over the heat sink and the pre-amp area).
How hot do these usually get? When I put mine back together, I wiped off all the old heat sink paste and applied a thin new layer. Could it be that the heat's actually being radiated better now, hence the warmer case?
Hi smiler,
Now it sounds like you have problems. A hot heat sink is not normal. It normally runs cool unless you are playing really loud music. The excessive heat suggests that the bias is far too high, or that the amps are oscillating (less likely). Is it possible that the bias sense transistors have either a cracked solder connection, or a shorted connection?
The best thing to do right now is discontinue using the amplifier until you find and correct the problem. Carefully examine the output sections on both channels. You should also measure the voltage drop across the emitter resistors in order to get some idea of how much current is passing through the outputs. Do that before taking anything apart.
Cleaning the old grease off and replacing it is the proper way to do the work you have done. Make sure there are no short circuits through the insulators to the heat sink. New insulators would eb a good idea.
-Chris
Now it sounds like you have problems. A hot heat sink is not normal. It normally runs cool unless you are playing really loud music. The excessive heat suggests that the bias is far too high, or that the amps are oscillating (less likely). Is it possible that the bias sense transistors have either a cracked solder connection, or a shorted connection?
The best thing to do right now is discontinue using the amplifier until you find and correct the problem. Carefully examine the output sections on both channels. You should also measure the voltage drop across the emitter resistors in order to get some idea of how much current is passing through the outputs. Do that before taking anything apart.
Cleaning the old grease off and replacing it is the proper way to do the work you have done. Make sure there are no short circuits through the insulators to the heat sink. New insulators would eb a good idea.
-Chris
radiance said:
Hi Rad, I'll try my best to remember!
I bought the RCA plugs online a long time ago and I'm not sure where. I was buying a lot of capacitors at the the same time and they came with an order. I don't think I paid much for them.
They look a lot like these: http://www.soniccraft.com/products/connections/rca/chassis/vampire_cm1f.htm
The only problem I had was that the plastic panel, with the writing, wouldn't slip ove the RCA plugs any more.
I had to make a choice and so the plastic panel is now clamped down by the jacks and permanently attached to the jacks and the circuit board. A more elegant solution could be to modify the holes so that the panel will slip over the RCA sockets.
My panel doesn't fit exactly perfectly at the moment but is OK.
Also, I replaced the ribbon cable with silver/teflon wire that travels -under- the board and goes directly to the RCA. Otherwise, wire links would need to be used when adding new sockets.
Martin.
Stu
Hi, Just joined because I noticed during a web search this forum and the answer to a problem with a Cyrus II amp I have been given.
It seems the noise I experience is probably due to caps that are old. I know I can easily replace most, but the two large 7000uf 40V are odd balls and I can't seem to track any locally in New Zealand.
Any ideas on alternative values?
Stu
Hi, Just joined because I noticed during a web search this forum and the answer to a problem with a Cyrus II amp I have been given.
It seems the noise I experience is probably due to caps that are old. I know I can easily replace most, but the two large 7000uf 40V are odd balls and I can't seem to track any locally in New Zealand.
Any ideas on alternative values?
Stu
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