Yeah my mistake it does indeed state Bi-Amp I stand Corrected.Im a NEWBIE to this stuff, but have now read several good books, and are getting to grips with the theory, Have done a course at college, and have built some useful projects to help me along the way.
Most useful so far im finding is a Function Generator kit, which Ive housed in an old MM Cartridge Presentation box with clear lid works a treat. 1HZ to 40KHZ Sine Square Sawtooth and Triangle wave, two outputs, one fixed, one variable voltage. 12v regulated supply. Perfect for trouble shooting audio amps. and only cost about £12 for parts. I found it so relaxing and rewarding building it and housing it. My scope tells me it goes just under 1HZ and custs off sharply spot on at 40kHZ.On power up defaults to 1KH would have been nice to remember last state, but resets to 1KH.
I had thought about building a frequency counter LCD kit and combining the two for a digital readout, but decided what was the point when my scope shows this anyway.
Im thinking out loud guys, I really like the sound of my Cyrus two and are planning to build my own amps, and was trying to decide which way to go whats the difference ? is it just that a mono block has to have a preamp to feed and control it and the cyrus will already have that control albeit in mono ??
so presumably you have more independent control this way. and One could use a master preamp fed into two independently adjustable amps on line level.
but it would probably sound better to build 4 mono blocks, two per channel for bi-amping speakers and Build a pre-amp to accommodate them. My speakers are Mission 753 Freedoms, and are bi-amp able.
I have Schematics for various high end designs ranging from 60wpc 90wpc, 100wpc, and 200wpc. I don't need the music to blast out, but I do find the missions on the lazy side, with a lessor amp.
Would you think that 4 * 60w monos would be sufficient to drive these speakers properly ie two per channel, note these are two way crossover design. and rated at 150w 8 ohm. But will accept 4 & 6 Ohm Loads.
Its not the base I find lazy but the mid & tweets dont sparkle with a cheap amp. they seem too polite and background, I like a lot of grip and sparkle. I have tried a pair of K5 Monitors rated at 200wpc on a+b on a different amp and find it gives me the extra detail I feel that these freedoms lack at low level.
I cant have it to loud as we live in a MDU (Multi Dwelling Unit) or block of flats if you like.
Im looking forward to the challenge of building my own units, Nothing more rewarding, and will try to source best quality components available for them. Im still thinking on how best to house them, any advice on cases etc would be appreciated.
I dont really want to gut an old amp, as rewarding as it would be for the parts factor, I would like all 4 monos to be identical, and pre-amp to compliment them.
Im thinking there must be some places that do basic cases that you can then Customized to your requirements. will have to shop around.
WILL THIS WORK I do have schematic for High end RIAA amp, but I really like the sound of Cyrus MM Stage, Is there any reason why I could not copy circuit Diagram for this stage and port it into my preamp design. would this work. I presume I would copy diagram up to where the opamps Join the Selector Switch for line level, and port it to the line level in the preamp I'm building, does this sound Reasonable. all parts needed are listed in service manual.I know this will be a big project but I think it can be done in manageable stages, starting with pre-amp then just duplicate 4 mono blocks. and im thinking the end result will be really rewarding.
Any thoughts.
Regards
Mark.
Service Manual for cyrus two
Hi Big Jim
Many thanks for your offer of the manual, yes please, Im apparently still under moderation so this is preventing me from using your email link. have just emailed DIYAudio.com to ask them to rectify this status for me, hopefully Ill be sorted soon.
Regards.
Mark.
Hi Big Jim
Many thanks for your offer of the manual, yes please, Im apparently still under moderation so this is preventing me from using your email link. have just emailed DIYAudio.com to ask them to rectify this status for me, hopefully Ill be sorted soon.
Regards.
Mark.
Hello Mark,
Everyone goes through a probation period. Yours is now over and you are free to post.
Everyone goes through a probation period. Yours is now over and you are free to post.
Cyrus Two Woes
🙁 Hi guys. Still investigating problems with my Cyrus two, Being down on the right channel by a factor of 10.v
Using a scope and signal injected at 1K to check for channel levels, getting right channel of 160mv Left only 60mv at test points. so seemed to point to previous stage transistors. but they all seem to check out, compared with right channel using diode check, readings are identical.
I have replaced all the power transistors for buv48s and have replaced JME243s and 253s.
Replaced Power supply caps 10000u and phono pre-amp 470u + The 22u filter caps. was getting hum, still getting a reduced hum.
I have just found that C43 should be 470u and gives much lower readings of just 6.7 u compared with C44 other channel. On closer inspection, The casings on both channels have started to crack up.
The part sheet says they are EL 6volt, which I take means Electrolytic Caps, but they seem large for 6v types, and are in a kind of Maroon Plastic Casing with the numbers 47016 stamped on the top.
Are these a special type, or can they be replaced by a standard Electrolytic Cap.
The voltage seems a bit low to me, Most are at least 25v, and the two 470u caps I replaced on the phono pre-amp where 63v which I upgraded to 100V nearest i could get at the time.
The transistors in the stages seem ok and Im wondering if this is the culprit.
Can any of you cyrus experts help here.
Closure of this project would be good, Im waiting to build my own pre-amp, but wont being the project, until I get this great amp working how it should again.
regards
Mark.😀
🙁 Hi guys. Still investigating problems with my Cyrus two, Being down on the right channel by a factor of 10.v
Using a scope and signal injected at 1K to check for channel levels, getting right channel of 160mv Left only 60mv at test points. so seemed to point to previous stage transistors. but they all seem to check out, compared with right channel using diode check, readings are identical.
I have replaced all the power transistors for buv48s and have replaced JME243s and 253s.
Replaced Power supply caps 10000u and phono pre-amp 470u + The 22u filter caps. was getting hum, still getting a reduced hum.
I have just found that C43 should be 470u and gives much lower readings of just 6.7 u compared with C44 other channel. On closer inspection, The casings on both channels have started to crack up.
The part sheet says they are EL 6volt, which I take means Electrolytic Caps, but they seem large for 6v types, and are in a kind of Maroon Plastic Casing with the numbers 47016 stamped on the top.
Are these a special type, or can they be replaced by a standard Electrolytic Cap.
The voltage seems a bit low to me, Most are at least 25v, and the two 470u caps I replaced on the phono pre-amp where 63v which I upgraded to 100V nearest i could get at the time.
The transistors in the stages seem ok and Im wondering if this is the culprit.
Can any of you cyrus experts help here.
Closure of this project would be good, Im waiting to build my own pre-amp, but wont being the project, until I get this great amp working how it should again.
regards
Mark.😀
The voltage doesn't matter so much, as long as it's higher than what was originally there and you can still physically fit it in, then it's fine. So I would try 470u 63V caps as I suspect it's a typo, there is either 6.3V or 63V, not 6V.
I haven't got my manual here to check.
I haven't got my manual here to check.
From earlier in this thread: 😉
http://www.diyaudio.com/forums/showthread.php?postid=1118396#post1118396
http://www.diyaudio.com/forums/showthread.php?postid=1118396#post1118396
Yep there the ones, 470uF 6volt Bipolar NP Electrolytic Caps, for feedback loop. any idea from where is best to get replacements,
Regards
Mark.
Regards
Mark.
hi,
Panasonic make a nice range of affordable bipolar electrolytic.
They are available in 16V and you could use either 330uF or 470uF.
I think 220uF is just a bit too low for the 2u2F at the input.
For the sake of the cheap cost it would be worth experimenting by adding a 1uF PP(mkp) or PE(mks/mkt) in parallel across the bipolar pins.
Panasonic make a nice range of affordable bipolar electrolytic.
They are available in 16V and you could use either 330uF or 470uF.
I think 220uF is just a bit too low for the 2u2F at the input.
For the sake of the cheap cost it would be worth experimenting by adding a 1uF PP(mkp) or PE(mks/mkt) in parallel across the bipolar pins.
Many thanks Ill give them a try. Need to re-order some more MJE243, Just blown one, trying out a Bi-polar 220uf 100v cap, in place of it, all i could find at the time, but it didnt like that much, no output for about 3 minutes then blew fuse and Transistor.
Will give the panasonics a go. I thought it was just taking a little time building the cap up but never mind. we live and learn.
Regards
Mark.
Will give the panasonics a go. I thought it was just taking a little time building the cap up but never mind. we live and learn.
Regards
Mark.
Cyrus Two Woes Now Fixed
😉 Hi All,
Id Just like to thank you all for your help, I'm now please to inform everyone that the amp is now fixed and back in service sounding absolutely wonderful.
The recommended replacements for the NP 470uF Caps " Brown / Maroon Plastic Caps Under the green ribbon C43 + C44 on my Version 7 Model" are now supplied by CapXon, the cap is CapXon 470uf 16v 710 NK Series.
I know this because Cyrus electronics just supplied me with two free of charge, and say they used to be 6.3v but cant get them any more.
But they sound really nice, give the amp 60mins just to run them in and they sound very clean.
At first they sounded a bit monophonic, but they became much more transparent after running for about 1 hour.
I replaced the TP77s for BUV48c and as a result had to re balance the bias on left channel, was up by 10mv from max recommended 20mvs so I replaced R81 for 180R from 160R. that put bias into correct spec. The right channel was already in spec.
I noticed that all the parts are given odd numbers for one channel and even for the other making it easy to do comparisons channel to channel.
All working great now, cant believe how nice it is to have it working again, and now fully understanding how it all works into the bargin.
Maybe this might help someone.
I can now listen to lovely music from my Arcam CD37FMJ the way it should sound, my Yamaha amp just not up to the same standard.
I can now concentrate on my pre-amp project i would not let myself start until Id fixed the Cyrus two. also recapped PSX, they sound great.
Regards
Mark.
😉 Hi All,
Id Just like to thank you all for your help, I'm now please to inform everyone that the amp is now fixed and back in service sounding absolutely wonderful.
The recommended replacements for the NP 470uF Caps " Brown / Maroon Plastic Caps Under the green ribbon C43 + C44 on my Version 7 Model" are now supplied by CapXon, the cap is CapXon 470uf 16v 710 NK Series.I know this because Cyrus electronics just supplied me with two free of charge, and say they used to be 6.3v but cant get them any more.
But they sound really nice, give the amp 60mins just to run them in and they sound very clean.
At first they sounded a bit monophonic, but they became much more transparent after running for about 1 hour.I replaced the TP77s for BUV48c and as a result had to re balance the bias on left channel, was up by 10mv from max recommended 20mvs so I replaced R81 for 180R from 160R. that put bias into correct spec. The right channel was already in spec.
I noticed that all the parts are given odd numbers for one channel and even for the other making it easy to do comparisons channel to channel.
All working great now, cant believe how nice it is to have it working again, and now fully understanding how it all works into the bargin.
Maybe this might help someone.
I can now listen to lovely music from my Arcam CD37FMJ the way it should sound, my Yamaha amp just not up to the same standard.
I can now concentrate on my pre-amp project i would not let myself start until Id fixed the Cyrus two. also recapped PSX, they sound great.Regards
Mark.
Hi Mark could you email me the Cyrus 2 Service manual too ?, And is it possible to make a picture of your recapped and repaired amp ?
I´m still having trouble with my beloved Cyrus 2 after attaching a used PSX unit which needs to be recapped as well. I blew the left channel after attaching the PSX, one of the 2 resisitors next to the Cyrus 2s toroid is blown. What is the value of that resistor R114 (issue 7), it is color coded. Can there be more than this part faulty ?
Any ideas ?!
Thanks in advance and best regards
Rad
I´m still having trouble with my beloved Cyrus 2 after attaching a used PSX unit which needs to be recapped as well. I blew the left channel after attaching the PSX, one of the 2 resisitors next to the Cyrus 2s toroid is blown. What is the value of that resistor R114 (issue 7), it is color coded. Can there be more than this part faulty ?
Any ideas ?!
Thanks in advance and best regards
Rad
Hi Radiance,
A bit confused how you managed to blow this resistor using a psx,
You see as far as I can see looking at the circuit diagram, someone PLEASE correct me if im wrong but when you remove the fuses from the cyrus two, WHICH IS A MUST WHEN USING THE PSX . Unless you left the fuses in line in the cyrus two, this part of Cyrus two power supply is isolated, ie its before the fuse. leaving the cyrus two power supply dedicated to the phono pre-amp section.
The voltage across fuses using cyrus two on its own should be aprox +40v F1 and -40 F2, Unregulated.
When you remove the fuses, the psx provides these two rail voltages, using its own transformer, set of regulators, and a rather substantial bank of Four Capacitors, each contributing 15000uf, as appose to the cyrus twos, own unregulated supply with two capacitors of just 10000uf.
with the fuses removed and the psx connected, the psx concentrates its load just on the power amp stages, leaving the Cyrus two to power the phono stage at regulated +18V - 18V rails. Leaving the power cord disconnected from the cyrus two will disable the phono stage, but allow the line level stages to work with the psx, some people do this if they dont require this stage. It eliminates any added noise from a faulty phono stage.
I myself recapped the two smoothing Caps 470uf C67,C68. with same value but 100v, works no problems, note these are polarised so check carefully that you put them in correct way around. (Note the two 470uf feedback loop caps under the green ribbon are Non-polarised and its a good idea to replace these as well with 470uf np 16v from CapXon see my previous reply on exact details for these.
There are also 4 filter caps C69,C70,C71,C72, 22uF polarised, I changed these as well to ensure no mains hum got through to the pre-amp stage. I do use mine, its excellent.
Resistor 114 is a 3K9 Metal Film 1Watt 5% tolerance, and It looks to be there just to provide a small load and bleed the capacitor C65 to ground when fuse blows.
Check the diodes D13,D14,D15,D16, and if Caps C65 and C66. are ok, I replaced mine anyway due to age, but these to caps might not have had any use if the amp has always been used with the psx.
Check the output from the psx is correct. if so and with the fuses removed, you should still be able to power up the cyrus two and check the line level power amp is ok. The PSX also has to in line fuses, which should protect the psx in case of a short.
Hopefully its just burnt out this resistor in the cyrus two power supply and in this case should not make any difference if you remove the fuses to disable the amps own power supply.
Note one final thing, the power switch on the cyrus two does NOT power down the pre-amp
It is permanently on all the time the power lead is plugged in, even tho the led goes on and off, and the main power amp turns on and off. but the pre-amp is still live all the time the power lead is connected so be careful. Thats why you have to disconnect the power lead to disable the pre-amp
I unfortunately I will have to disconnect my amp and take apart again for photos, I do plan to replace the phono connections for gold plated ones, at some point, plus will re-spray the casing as paint is coming off in some places, I will post a pic when all is completed.
If I can help further let me know.
email me for the other thing, regards mark. PS if anyone else has any advise or corrections to my comments, please feel free. Im still a newbee to this
regards
Mark.
A bit confused how you managed to blow this resistor using a psx,
You see as far as I can see looking at the circuit diagram, someone PLEASE correct me if im wrong but when you remove the fuses from the cyrus two, WHICH IS A MUST WHEN USING THE PSX . Unless you left the fuses in line in the cyrus two, this part of Cyrus two power supply is isolated, ie its before the fuse. leaving the cyrus two power supply dedicated to the phono pre-amp section.
The voltage across fuses using cyrus two on its own should be aprox +40v F1 and -40 F2, Unregulated.
When you remove the fuses, the psx provides these two rail voltages, using its own transformer, set of regulators, and a rather substantial bank of Four Capacitors, each contributing 15000uf, as appose to the cyrus twos, own unregulated supply with two capacitors of just 10000uf.
with the fuses removed and the psx connected, the psx concentrates its load just on the power amp stages, leaving the Cyrus two to power the phono stage at regulated +18V - 18V rails. Leaving the power cord disconnected from the cyrus two will disable the phono stage, but allow the line level stages to work with the psx, some people do this if they dont require this stage. It eliminates any added noise from a faulty phono stage.
I myself recapped the two smoothing Caps 470uf C67,C68. with same value but 100v, works no problems, note these are polarised so check carefully that you put them in correct way around. (Note the two 470uf feedback loop caps under the green ribbon are Non-polarised and its a good idea to replace these as well with 470uf np 16v from CapXon see my previous reply on exact details for these.
There are also 4 filter caps C69,C70,C71,C72, 22uF polarised, I changed these as well to ensure no mains hum got through to the pre-amp stage. I do use mine, its excellent.
Resistor 114 is a 3K9 Metal Film 1Watt 5% tolerance, and It looks to be there just to provide a small load and bleed the capacitor C65 to ground when fuse blows.
Check the diodes D13,D14,D15,D16, and if Caps C65 and C66. are ok, I replaced mine anyway due to age, but these to caps might not have had any use if the amp has always been used with the psx.
Check the output from the psx is correct. if so and with the fuses removed, you should still be able to power up the cyrus two and check the line level power amp is ok. The PSX also has to in line fuses, which should protect the psx in case of a short.
Hopefully its just burnt out this resistor in the cyrus two power supply and in this case should not make any difference if you remove the fuses to disable the amps own power supply.
Note one final thing, the power switch on the cyrus two does NOT power down the pre-amp
It is permanently on all the time the power lead is plugged in, even tho the led goes on and off, and the main power amp turns on and off. but the pre-amp is still live all the time the power lead is connected so be careful. Thats why you have to disconnect the power lead to disable the pre-amp
I unfortunately I will have to disconnect my amp and take apart again for photos, I do plan to replace the phono connections for gold plated ones, at some point, plus will re-spray the casing as paint is coming off in some places, I will post a pic when all is completed.
If I can help further let me know.
email me for the other thing, regards mark. PS if anyone else has any advise or corrections to my comments, please feel free. Im still a newbee to this
regards
Mark.
Mark Cogley said:
Just for clarity: The PSX power sent to the Cyrus Two is not regulated. The regulators in the PSX are there to supply the +/-18V for the PCMII CD player from the socket on the back panel. 😉
Yes thats correct, I think its about 18vlts if I remember, never ever used it. did think about removing regs, as I dont think ill ever use it, but decided to leave as original spec. sorry for any confusion,
PS if you still find one channel down, and blowing fuses, check the driver transistors MJE243 and MJE253, Q31,Q32,Q33,Q34, These may have received a surge, and tend to be ease to kill.
Use a diode check with power off. you can get replacements from little diode on ebay, quite cheaply,
The power transistors are all PT77s 2 per channel on my model, replacements are BUV48C. only if you need to replace these do so in channel pairs, they are cheap so if any are faulty, might be worth just replacing them all to keep amp balanced. (only if you replaced any power transistors) you will need to check bias voltage across R107 and R108 big white 3watt resistors near the heat sink. These should be between 8mv and 20mv. Let amp settle down for about 5-10 minutes.
Make sure volume is set to min, and nothing is plugged into speaker jacks or headphone jack.
If you have access to a function generator and a scope, I used a 1k test tone set to 65mv on cd input, and check base of each transistor stage Mine was down on one channel due to faulty feedback loop cap, 470uf NP, which then keeps the gain set at 1 instead of 10.
Thats why its worth replacing them, mine also showed signs of the casing fracturing.
Sorry this is sounding a bit unstructured now, start with power supply tests,
Then check for any transistors caps or resistors shorted or open. note odd numbers one channel even numbers on other channel. so comparing one component of one channel to the same component of the other channel is straight forward and very useful.
If you replace any power trans check bias current.
when youve found whats shorting fuses and fixed do a final check by checking pre-amp power amp stages for apropriate gains,
Hopefully Job done.
regards
Mark
PS if you still find one channel down, and blowing fuses, check the driver transistors MJE243 and MJE253, Q31,Q32,Q33,Q34, These may have received a surge, and tend to be ease to kill.
Use a diode check with power off. you can get replacements from little diode on ebay, quite cheaply,
The power transistors are all PT77s 2 per channel on my model, replacements are BUV48C. only if you need to replace these do so in channel pairs, they are cheap so if any are faulty, might be worth just replacing them all to keep amp balanced. (only if you replaced any power transistors) you will need to check bias voltage across R107 and R108 big white 3watt resistors near the heat sink. These should be between 8mv and 20mv. Let amp settle down for about 5-10 minutes.
Make sure volume is set to min, and nothing is plugged into speaker jacks or headphone jack.
If you have access to a function generator and a scope, I used a 1k test tone set to 65mv on cd input, and check base of each transistor stage Mine was down on one channel due to faulty feedback loop cap, 470uf NP, which then keeps the gain set at 1 instead of 10.
Thats why its worth replacing them, mine also showed signs of the casing fracturing.
Sorry this is sounding a bit unstructured now, start with power supply tests,
Then check for any transistors caps or resistors shorted or open. note odd numbers one channel even numbers on other channel. so comparing one component of one channel to the same component of the other channel is straight forward and very useful.
If you replace any power trans check bias current.
when youve found whats shorting fuses and fixed do a final check by checking pre-amp power amp stages for apropriate gains,
Hopefully Job done.
regards
Mark
Sourcing parts and what's worthwhile
Hi guys,
This is a really interesting and helpful thread. My Cyrus Two started buzzing a few months ago, after just less than a year of happy listening (bought second-hand on eBay for ~£40). I've obtained a copy of the service manual from another forum, and identified my version as a mid-late 06 version (SN 204650) with the newer MJE output transistors, but all the old capacitor values.
I've opened up the lid, and worked out how to flip the PCB without (completely) removing the heat-sink. The only capacitors I can find with visible wear are the bulky 470µF/6V feedback capacitors under the blue ribbon cable, so I've ear-marked these for replacement. Are these suitable: http://is.gd/19mj5?
The only other visible degradation is heat damage to solder joints for: voltage regulators, PSX connector, output biasing transistors (Q25/26) and phono op-amps. To my knowledge, this amp's never been used with a PSX, but I can't be sure. I'm tempted to replace the VRegs, and re-solder Q25/26 and the op-amps (or should I replace these too?). I bought the amp for it's phono stage, so the pre-amp's important to me.
I mentioned above that my amp has old capacitor values, which I discovered from notes in the service manual. I wonder, when working on the amp, if it's worthwhile replacing these capacitors with the newer values? The caps in question are C45-48 (so far as I can tell, de-coupling for Q27-30) and C69/70 (de-coupling for Q15/16). C69/70 are particularly perplexing, as the service manual quotes "PP 160V 10%" for C69 but "EL 25V -20%" for C70, despite seemingly being a stereo pair; which is right?!
For C45-48, will either of these be suitable: http://is.gd/19qJn http://is.gd/19qJi?
The manual also notes the addition of D04 since my amp was made, which looks like added protection to me. Should I add this? I'm tempted to not bother, as it's worked for more than 20 years already!
Other replacements I've considered are 22µF and 470µF capacitors in PS circuit. Should I stick to the original ratings (25/50V) or try larger ones? Will this have any discernible difference (I'm thinking not)? Are these suitable: http://is.gd/19rcG http://is.gd/19qZH?
Finally, I'm also concerned about EMI shielding, as this is a plastic cased version. My mobile phone interferes something rotten with the audio signal, so I'm open to suggestions on how to reduce this. I've thought of sticking aluminium foil to the inside of the case, but I'm worried about the thermal implications of this.
Sorry for the long post - I've been building up to this! I have a far greater respect for both Cyrus and this amp since reading this, and I'd be interested in learning more about its design, if anyone can point me in the right direction?
Hi guys,
This is a really interesting and helpful thread. My Cyrus Two started buzzing a few months ago, after just less than a year of happy listening (bought second-hand on eBay for ~£40). I've obtained a copy of the service manual from another forum, and identified my version as a mid-late 06 version (SN 204650) with the newer MJE output transistors, but all the old capacitor values.
I've opened up the lid, and worked out how to flip the PCB without (completely) removing the heat-sink. The only capacitors I can find with visible wear are the bulky 470µF/6V feedback capacitors under the blue ribbon cable, so I've ear-marked these for replacement. Are these suitable: http://is.gd/19mj5?
The only other visible degradation is heat damage to solder joints for: voltage regulators, PSX connector, output biasing transistors (Q25/26) and phono op-amps. To my knowledge, this amp's never been used with a PSX, but I can't be sure. I'm tempted to replace the VRegs, and re-solder Q25/26 and the op-amps (or should I replace these too?). I bought the amp for it's phono stage, so the pre-amp's important to me.
I mentioned above that my amp has old capacitor values, which I discovered from notes in the service manual. I wonder, when working on the amp, if it's worthwhile replacing these capacitors with the newer values? The caps in question are C45-48 (so far as I can tell, de-coupling for Q27-30) and C69/70 (de-coupling for Q15/16). C69/70 are particularly perplexing, as the service manual quotes "PP 160V 10%" for C69 but "EL 25V -20%" for C70, despite seemingly being a stereo pair; which is right?!
For C45-48, will either of these be suitable: http://is.gd/19qJn http://is.gd/19qJi?
The manual also notes the addition of D04 since my amp was made, which looks like added protection to me. Should I add this? I'm tempted to not bother, as it's worked for more than 20 years already!
Other replacements I've considered are 22µF and 470µF capacitors in PS circuit. Should I stick to the original ratings (25/50V) or try larger ones? Will this have any discernible difference (I'm thinking not)? Are these suitable: http://is.gd/19rcG http://is.gd/19qZH?
Finally, I'm also concerned about EMI shielding, as this is a plastic cased version. My mobile phone interferes something rotten with the audio signal, so I'm open to suggestions on how to reduce this. I've thought of sticking aluminium foil to the inside of the case, but I'm worried about the thermal implications of this.
Sorry for the long post - I've been building up to this! I have a far greater respect for both Cyrus and this amp since reading this, and I'd be interested in learning more about its design, if anyone can point me in the right direction?
Re: Sourcing parts and what's worthwhile
Would you share the Cyrus 2 Manual, I would like to verify the Bias in the output stage, and need the values (min..max)
Thanks !
R.C.
smiler said:
Would you share the Cyrus 2 Manual, I would like to verify the Bias in the output stage, and need the values (min..max)
Thanks !
R.C.
Re: Re: Sourcing parts and what's worthwhile
I'd be happy to, but I'm not sure how that holds with the forum rules. PM me your email address and I can email it to you. In the meantime, the biasing instructions are as follows:
If you have a version 07 Cyrus Two, then you should measure across the second resistor referenced above (with the As), and you won't have preset resistors. The instructions say to increase R81/82 to 180Ω if the voltage is too high, or connect a 220Ω to the parallel solder pins if it's too low.
Hope that helps!
Ciu said:
I'd be happy to, but I'm not sure how that holds with the forum rules. PM me your email address and I can email it to you. In the meantime, the biasing instructions are as follows:
If you have a version 07 Cyrus Two, then you should measure across the second resistor referenced above (with the As), and you won't have preset resistors. The instructions say to increase R81/82 to 180Ω if the voltage is too high, or connect a 220Ω to the parallel solder pins if it's too low.
Hope that helps!
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