Oh wow, I hadn't realised! That pic's really too small - care to post some for us to see?Mark Cogley said:
Aren't yours plastic though?
I actually remember you mentioned this in an earlier post. Silly of me to ask! What kit was it/where did you buy it?
A nice easy way to do this! I don't own a scope, but I theoretically have access to one at uni. Obviously this job would be made a hell of a lot easier if I could do it at uni, but I suspect the health and safety regs won't allow it. (No exposed voltages > 30V dc apparently!)
Then again, if I do it at home, I can do listening tests as I go...
Yup, the case on my feedback capacitors is cracking up as well. I only noticed earlier today under close examination with a very bright bike light! I also noticed that the two 470µF pre-amp reservoir capacitors are bulging underneath. I think these two areas may well be the source of my buzz.
I intend to
Thanks for your help =)
Hi smiler,
My previous comments apply to anyone who is working on one of these amps. I'll make a couple more comments.
Do not attempt to tweak bass by playing with filter capacitors. This doesn't work, contrary to what you may read. Please, pick up Douglas Self's book on amplifiers before continuing on this course of action.
You know, you have the answer. You know you need larger speakers. This is the correct and only way to improve the bass response in your system other than room placement or adding a sub woofer system.
-Chris
My previous comments apply to anyone who is working on one of these amps. I'll make a couple more comments.
You are correct, the AC voltage reading will vary quite a lot depending on loading and the mains voltages. To figure out your DC rectified and filtered voltages, you take your AC voltage, multiplying by 1.414 approx. and subtracting the diode drops. That gives you :33 * 1.414 - 1.4 = 45 VDC approx. Just like magic. Remember, the rectifiers and caps form a peak detector. If your AC has a flattened top, the voltage will be lower.
Relax! Don't get all freaked out over capacitor brands. As long as you are using capacitors from good manufacturers, you will be fine. Just avoid the junk. There is quite a lot of nonsense written about capacitors. In fact, the better "audio" caps are simply better capacitors all around. Hint: The capacitor has no idea whether the signal they are passing is for industrial control / instrumentation or audio. Audio is not some special signal with magical qualities, you just happen to be listening to these signals.
The transformer losses probably exceed the power used by the preamp circuit. I would be concerned about the amount or run time wasted with the regulators and hence shorter life from your perspective.
Nice control. Better tracking and nice feel.
No!!!
Do not attempt to tweak bass by playing with filter capacitors. This doesn't work, contrary to what you may read. Please, pick up Douglas Self's book on amplifiers before continuing on this course of action.
You know, you have the answer. You know you need larger speakers. This is the correct and only way to improve the bass response in your system other than room placement or adding a sub woofer system.
-Chris
Hi smiler,
Now for the real question I feel was completely mishandled.
1. A good multimeter. A good DVM is needed today, but if it;s a cheap one you should also have a VTVM in order to make reasonable AC measurements. Both the Fluke and Agilent brands have very good DVMs that will cover your needs. Remember, check the frequency range that the AC voltmeter covers.
2. A half decent oscilloscope. No, computer or PCI "scopes" are not suitable. It's far too easy to damage them, but they make an excellent additional instrument for specific needs. An analog scope is still the best under $6,000. These days you can buy a new 20 MHz 'scope that will be good enough to service CD players for much less than what it used to cost. There is also a number of good used 'scopes on the market. Here, Leader, Hitachi and Kenwood would be good brands to look for.
An oscilloscope is almost used as much as a multimeter, or DVM. You really should have one.
It's telling that it is impossible to become authorized warranty for anything unless you have these two basic instruments.
An audio signal generator should be easily bought. A Leader LAG 120A or B (or equivalent) would be a good starting point. A function generator (like what Mark has) has it's uses, but it is useless to try and judge THD with one of these. The sine function is rarely better than 0.5% THD and often much worse. You can build one as Mark has, but a sine wave generator is harder. The alignment requires the use of a THD meter.
Speaking of which, a THD meter is another advanced but basic instrument. You can use a sound card based solution for this, BUT you must design an interface between your sound card inputs and any amplifier output. The sound card is very easy to damage, and so are USB based oscilloscopes unless you get a good one. Then you are in the entry DSO price range anyway.
To measure turntable speed, you either use a test record and a wow and flutter meter (test signal is 3 KHz BTW), or use a strobe disc. If you want, you can use a calibrated flasher instead of the neon lamp or florescent lamps overhead. With a frequency counter you can calibrate a square wave generator and run an LED off it.
Hi Mark,
It takes more skill to use fewer instruments and the job to do has nothing to do with the finances available. So while I could do things like this without a scope, someone starting out can't. Not only that, but I would know what I haven't been able to test for and I would definitely use a 'scope as soon as possible. Otherwise you are just rolling the dice. A complete guess with partial information.
I don't mean to come down on you, but around here I have plenty of "hacks" that do things after reading instructions and advice that you don't need to check things out properly.
If you charge for your work, you had better use the proper instruments and do the required tests. Even if you don't charge, working improperly at no charge is not a responsible thing to do. I feel very strongly on this. I've been cleaning up messes for over 30 years.
-Chris
Now for the real question I feel was completely mishandled.
Any time you do anything with an amplifier, you need to check the operation with some of the most basic test instruments in use today. In fact, since the field of electronics started to mature. The two most basic instruments that every bench should have are:
1. A good multimeter. A good DVM is needed today, but if it;s a cheap one you should also have a VTVM in order to make reasonable AC measurements. Both the Fluke and Agilent brands have very good DVMs that will cover your needs. Remember, check the frequency range that the AC voltmeter covers.
2. A half decent oscilloscope. No, computer or PCI "scopes" are not suitable. It's far too easy to damage them, but they make an excellent additional instrument for specific needs. An analog scope is still the best under $6,000. These days you can buy a new 20 MHz 'scope that will be good enough to service CD players for much less than what it used to cost. There is also a number of good used 'scopes on the market. Here, Leader, Hitachi and Kenwood would be good brands to look for.
An oscilloscope is almost used as much as a multimeter, or DVM. You really should have one.
It's telling that it is impossible to become authorized warranty for anything unless you have these two basic instruments.
An audio signal generator should be easily bought. A Leader LAG 120A or B (or equivalent) would be a good starting point. A function generator (like what Mark has) has it's uses, but it is useless to try and judge THD with one of these. The sine function is rarely better than 0.5% THD and often much worse. You can build one as Mark has, but a sine wave generator is harder. The alignment requires the use of a THD meter.
Speaking of which, a THD meter is another advanced but basic instrument. You can use a sound card based solution for this, BUT you must design an interface between your sound card inputs and any amplifier output. The sound card is very easy to damage, and so are USB based oscilloscopes unless you get a good one. Then you are in the entry DSO price range anyway.
To measure turntable speed, you either use a test record and a wow and flutter meter (test signal is 3 KHz BTW), or use a strobe disc. If you want, you can use a calibrated flasher instead of the neon lamp or florescent lamps overhead. With a frequency counter you can calibrate a square wave generator and run an LED off it.
Hi Mark,
I think you are doing more harm than good by marginalizing the proper ways to troubleshoot.
It takes more skill to use fewer instruments and the job to do has nothing to do with the finances available. So while I could do things like this without a scope, someone starting out can't. Not only that, but I would know what I haven't been able to test for and I would definitely use a 'scope as soon as possible. Otherwise you are just rolling the dice. A complete guess with partial information.
I don't mean to come down on you, but around here I have plenty of "hacks" that do things after reading instructions and advice that you don't need to check things out properly.
If you charge for your work, you had better use the proper instruments and do the required tests. Even if you don't charge, working improperly at no charge is not a responsible thing to do. I feel very strongly on this. I've been cleaning up messes for over 30 years.
-Chris
Hi smiler,
Now for the real question I feel was completely mishandled.
1. A good multimeter. A good DVM is needed today, but if it;s a cheap one you should also have a VTVM in order to make reasonable AC measurements. Both the Fluke and Agilent brands have very good DVMs that will cover your needs. Remember, check the frequency range that the AC voltmeter covers.
2. A half decent oscilloscope. No, computer or PCI "scopes" are not suitable. It's far too easy to damage them, but they make an excellent additional instrument for specific needs. An analog scope is still the best under $6,000. These days you can buy a new 20 MHz 'scope that will be good enough to service CD players for much less than what it used to cost. There is also a number of good used 'scopes on the market. Here, Leader, Hitachi and Kenwood would be good brands to look for.
An oscilloscope is almost used as much as a multimeter, or DVM. You really should have one.
It's telling that it is impossible to become authorized warranty for anything unless you have these two basic instruments.
An audio signal generator should be easily bought. A Leader LAG 120A or B (or equivalent) would be a good starting point. A function generator (like what Mark has) has it's uses, but it is useless to try and judge THD with one of these. The sine function is rarely better than 0.5% THD and often much worse. You can build one as Mark has, but a sine wave generator is harder. The alignment requires the use of a THD meter.
Speaking of which, a THD meter is another advanced but basic instrument. You can use a sound card based solution for this, BUT you must design an interface between your sound card inputs and any amplifier output. The sound card is very easy to damage, and so are USB based oscilloscopes unless you get a good one. Then you are in the entry DSO price range anyway.
To measure turntable speed, you either use a test record and a wow and flutter meter (test signal is 3 KHz BTW), or use a strobe disc. If you want, you can use a calibrated flasher instead of the neon lamp or florescent lamps overhead. With a frequency counter you can calibrate a square wave generator and run an LED off it.
Hi Mark,
It takes more skill to use fewer instruments and the job to do has nothing to do with the finances available. So while I could do things like this without a scope, someone starting out can't. Not only that, but I would know what I haven't been able to test for and I would definitely use a 'scope as soon as possible. Otherwise you are just rolling the dice. A complete guess with partial information.
I don't mean to come down on you, but around here I have plenty of "hacks" that do things after reading instructions and advice that you don't need to check things out properly.
If you charge for your work, you had better use the proper instruments and do the required tests. Even if you don't charge, working improperly at no charge is not a responsible thing to do. I feel very strongly on this. I've been cleaning up messes for over 30 years.
-Chris
Now for the real question I feel was completely mishandled.
Any time you do anything with an amplifier, you need to check the operation with some of the most basic test instruments in use today. In fact, since the field of electronics started to mature. The two most basic instruments that every bench should have are:
1. A good multimeter. A good DVM is needed today, but if it;s a cheap one you should also have a VTVM in order to make reasonable AC measurements. Both the Fluke and Agilent brands have very good DVMs that will cover your needs. Remember, check the frequency range that the AC voltmeter covers.
2. A half decent oscilloscope. No, computer or PCI "scopes" are not suitable. It's far too easy to damage them, but they make an excellent additional instrument for specific needs. An analog scope is still the best under $6,000. These days you can buy a new 20 MHz 'scope that will be good enough to service CD players for much less than what it used to cost. There is also a number of good used 'scopes on the market. Here, Leader, Hitachi and Kenwood would be good brands to look for.
An oscilloscope is almost used as much as a multimeter, or DVM. You really should have one.
It's telling that it is impossible to become authorized warranty for anything unless you have these two basic instruments.
An audio signal generator should be easily bought. A Leader LAG 120A or B (or equivalent) would be a good starting point. A function generator (like what Mark has) has it's uses, but it is useless to try and judge THD with one of these. The sine function is rarely better than 0.5% THD and often much worse. You can build one as Mark has, but a sine wave generator is harder. The alignment requires the use of a THD meter.
Speaking of which, a THD meter is another advanced but basic instrument. You can use a sound card based solution for this, BUT you must design an interface between your sound card inputs and any amplifier output. The sound card is very easy to damage, and so are USB based oscilloscopes unless you get a good one. Then you are in the entry DSO price range anyway.
To measure turntable speed, you either use a test record and a wow and flutter meter (test signal is 3 KHz BTW), or use a strobe disc. If you want, you can use a calibrated flasher instead of the neon lamp or florescent lamps overhead. With a frequency counter you can calibrate a square wave generator and run an LED off it.
Hi Mark,
I think you are doing more harm than good by marginalizing the proper ways to troubleshoot.
It takes more skill to use fewer instruments and the job to do has nothing to do with the finances available. So while I could do things like this without a scope, someone starting out can't. Not only that, but I would know what I haven't been able to test for and I would definitely use a 'scope as soon as possible. Otherwise you are just rolling the dice. A complete guess with partial information.
I don't mean to come down on you, but around here I have plenty of "hacks" that do things after reading instructions and advice that you don't need to check things out properly.
If you charge for your work, you had better use the proper instruments and do the required tests. Even if you don't charge, working improperly at no charge is not a responsible thing to do. I feel very strongly on this. I've been cleaning up messes for over 30 years.
-Chris
Outch Well that told me didnt it,
Hi Chris,
Well I have to say Ive taken on board your Constructive Criticism, and my comments are as follows,
Im still getting to grips with this forum / internet stuff. and its easy to forget that when your talking amonst like minded persons, one assumes that the basic knowledge is there at least, but when I take a step back, and realise that its not just people who are into electronics, but the whole world that can read these comments, I can see where your coming from, one should check and check again that
a) The asked question is fully understood.
b) That the information given to help is not flawed, and as safe as possible.
c) That if the subject is aimed at a select audience, it is clearly stated who and what its for.
d) That the subject has not already been adequately covered elsewhere in the forum.
So sorry if I forgot some of these things,
I thought the question was simply could you trouble shoot a Cyrus two amp without a scope, Not everyone may be able to, or wishes to purchase one, if all they wanna do is fix a one off cherished amp. and are not going any further than fixing this amp.
The method of using an injected signal and tracing its path thru the amp with a small audio amp, is not my idea, but well documented in several text references I have on fault finding. and although a scope is to hand, this was the authors preferred method of quickly locating a faulty stage, then by all means from there start taking readings with a DVM to Identify the fault in the stage.
I used a scope in place of an audio amp. and checked the base of each transistor in the signal path comparing the wave form for each channel until the fault was found.
Yes I agree that if one is interested in the subject, its right to start down the path of as good as you can afford DVM, and a reasonable scope, doesn't matter if new or not as long as they function properly, But I have my doubts that someone new to this would know enough about a second hand scope to fully check all of its functions correctly.
As for my Function Generator, Its a Micro Controller type, which has been built using 0.1% tolerance resisters, and Polyester Caps, and is more than adequate for my needs. I also have a Factory Built Model 8052 5MHz function generator, but much prefer my own built one.
For me the Advantages of building your own test equipment are:
The pure pleasure of building your own.
The understanding of why and how it works.
The quality of build determined by yourself
Knowing the limitations you can get them to work for you.
A huge savings on cost of setting up an electronics work bench.
So why put down this idea, I bet there are plenty of people who are happily repairing and building projects using equipment built by themselves and proud of it. and im sure its perfectly adequate for the job.
Oh by the way, my hifi news test record is 300Hz not 3Khz ,The test album was produced by Leonard Gregory, a personal friend of mine known as The Cartridge Man, http://www.thecartridgeman.com/. and again as I said earlier, you can and would use a strobe disk but was merely using this as an example of how you could if you did not have one of these discs to hand use a scope to calibrate the correct speed, which is just as accurate as a 50hz strobe disc.
Oh and yes I do use proper instruments thank you. My DVM is a Robin Professional 930 with built in Frequency, Capacitance, Transitor, and Diode settings Rate to 1000v
I have two scopes, a philips and a velleman. and fore mentioned function generators, factory one has sweep mode. and am function.
I have had no complaints about my work thanks but im not beyond making sure I get the right help from more knowledgeable people when Im not sure about something, after all new thing can and do change all the time, and I would be very foolish to claim I dont need any help from time to time, we all do else there wouldnt be a need for this forum
Regards
Mark.😀
Hi Chris,
Well I have to say Ive taken on board your Constructive Criticism, and my comments are as follows,
Im still getting to grips with this forum / internet stuff. and its easy to forget that when your talking amonst like minded persons, one assumes that the basic knowledge is there at least, but when I take a step back, and realise that its not just people who are into electronics, but the whole world that can read these comments, I can see where your coming from, one should check and check again that a) The asked question is fully understood.
b) That the information given to help is not flawed, and as safe as possible.
c) That if the subject is aimed at a select audience, it is clearly stated who and what its for.
d) That the subject has not already been adequately covered elsewhere in the forum.
So sorry if I forgot some of these things,
I thought the question was simply could you trouble shoot a Cyrus two amp without a scope, Not everyone may be able to, or wishes to purchase one, if all they wanna do is fix a one off cherished amp. and are not going any further than fixing this amp.
The method of using an injected signal and tracing its path thru the amp with a small audio amp, is not my idea, but well documented in several text references I have on fault finding. and although a scope is to hand, this was the authors preferred method of quickly locating a faulty stage, then by all means from there start taking readings with a DVM to Identify the fault in the stage.
I used a scope in place of an audio amp. and checked the base of each transistor in the signal path comparing the wave form for each channel until the fault was found.
Yes I agree that if one is interested in the subject, its right to start down the path of as good as you can afford DVM, and a reasonable scope, doesn't matter if new or not as long as they function properly, But I have my doubts that someone new to this would know enough about a second hand scope to fully check all of its functions correctly.
As for my Function Generator, Its a Micro Controller type, which has been built using 0.1% tolerance resisters, and Polyester Caps, and is more than adequate for my needs. I also have a Factory Built Model 8052 5MHz function generator, but much prefer my own built one.
For me the Advantages of building your own test equipment are:
The pure pleasure of building your own.
The understanding of why and how it works.
The quality of build determined by yourself
Knowing the limitations you can get them to work for you.
A huge savings on cost of setting up an electronics work bench.
So why put down this idea, I bet there are plenty of people who are happily repairing and building projects using equipment built by themselves and proud of it. and im sure its perfectly adequate for the job.
Oh by the way, my hifi news test record is 300Hz not 3Khz ,The test album was produced by Leonard Gregory, a personal friend of mine known as The Cartridge Man, http://www.thecartridgeman.com/. and again as I said earlier, you can and would use a strobe disk but was merely using this as an example of how you could if you did not have one of these discs to hand use a scope to calibrate the correct speed, which is just as accurate as a 50hz strobe disc.
Oh and yes I do use proper instruments thank you. My DVM is a Robin Professional 930 with built in Frequency, Capacitance, Transitor, and Diode settings Rate to 1000v
I have two scopes, a philips and a velleman. and fore mentioned function generators, factory one has sweep mode. and am function.
I have had no complaints about my work thanks but im not beyond making sure I get the right help from more knowledgeable people when Im not sure about something, after all new thing can and do change all the time, and I would be very foolish to claim I dont need any help from time to time, we all do else there wouldnt be a need for this forum
Regards
Mark.😀
Cyrus Thread mixed up.
'😱' Hi all,
I have just realized that a bookmark I created on this thread, has been leading me on a merry dance, The post numbers, were all over the place, and I didnt even notice. That explains why I thought people were answering the wrong people, and I got topics mixed up. I have now sorted the problem out, and reading again, all seems quite logical now. I thought eveyone was just jumping in on the band wagon, with no sense of direction, but now I know why.
Chris Ive only just started to read replies to things I wrote which have been hidden from me by this bookmark thing. I think it must act a kind of filter in firefox when you bookmark something, cause its missed loads of thread numbers out. but this goes for everyone else that has taken the time to reply to me, many thanks guys, sorry its a bit late.
Ok, I would like to post a larger picture of my cyrus but don't know how you do this without having a web hosted site to give the address. Any advice would be welcome.
I had not realized that regs go noise with age, just thought they either worked or failed. So you would recommend replacing them anyway. What would you replace with any ones which regulate the same voltage, or are some better than others.
The BUV48Cs that I replaced were in two per channel pairs, when I said balance, I perhaps should have said tonal balance of each channel. I did not know if they would be a different sounding Transistor to PT77s, so replace all 4 two per channel to make sure I got the same characteristics on both channels. If that makes sense?.
Hence I now have 3 spare PT77 Transistors that check out ok.
OK you called me, on the relay, Ive so many projects waiting to be started, that I really have to revisit at another time. so spot on there.
Im starting on building a pre-amp from a book on building hi end audio, and so far have only got as far as putting tracks onto Transparency, and securing the Copper cladding and ferric oxide.
I really would like to crack on with this pre-amp. But im a little worried that after all the time money and love spent on this project, sourcing the very best components for it, That its not going to sound much better than my newly restored Cyrus Two. How much better does it get.
But I still feel something driving me to take the plunge anyway. I guess you cant know how much better it gets until you here it.
My source equipment is excellent, and probably held back by as good as it is, the amp. so Id like to try and build my own, but trying to minimise on compromised quality vers cost.
The book this is taken from is called Build Your Own High-End Audio, and is by Elector Electronics and covers a wide range of equipment, from amps to surround sound to loud speakers, to audio testing with spectrum Annaliser, AF measurent systems ect.
Seems to be of very high standard circuits, but how this compares with Cyrus Two ???
If anyone has seen this book, any comments before getting to far into the project at hand would be appreciated.
I had also toyed with the idea of building another two pairs of cyrus two type amps, and running both pairs in mono mode to bi-amp my 753 freedoms. I could do this by feeding the circuit diagram in the service manual into my Circuit Wizard Pro, and simply ask it for a PCB Track Layout Printout.
What to do, any ideas, or have I lost the plot here.
Regards
Mark.😀
'😱' Hi all,
I have just realized that a bookmark I created on this thread, has been leading me on a merry dance, The post numbers, were all over the place, and I didnt even notice. That explains why I thought people were answering the wrong people, and I got topics mixed up. I have now sorted the problem out, and reading again, all seems quite logical now. I thought eveyone was just jumping in on the band wagon, with no sense of direction, but now I know why.
Chris Ive only just started to read replies to things I wrote which have been hidden from me by this bookmark thing. I think it must act a kind of filter in firefox when you bookmark something, cause its missed loads of thread numbers out. but this goes for everyone else that has taken the time to reply to me, many thanks guys, sorry its a bit late.
Ok, I would like to post a larger picture of my cyrus but don't know how you do this without having a web hosted site to give the address. Any advice would be welcome.
I had not realized that regs go noise with age, just thought they either worked or failed. So you would recommend replacing them anyway. What would you replace with any ones which regulate the same voltage, or are some better than others.
The BUV48Cs that I replaced were in two per channel pairs, when I said balance, I perhaps should have said tonal balance of each channel. I did not know if they would be a different sounding Transistor to PT77s, so replace all 4 two per channel to make sure I got the same characteristics on both channels. If that makes sense?.
Hence I now have 3 spare PT77 Transistors that check out ok.
OK you called me, on the relay, Ive so many projects waiting to be started, that I really have to revisit at another time. so spot on there.
Im starting on building a pre-amp from a book on building hi end audio, and so far have only got as far as putting tracks onto Transparency, and securing the Copper cladding and ferric oxide.
I really would like to crack on with this pre-amp. But im a little worried that after all the time money and love spent on this project, sourcing the very best components for it, That its not going to sound much better than my newly restored Cyrus Two. How much better does it get.
But I still feel something driving me to take the plunge anyway. I guess you cant know how much better it gets until you here it.
My source equipment is excellent, and probably held back by as good as it is, the amp. so Id like to try and build my own, but trying to minimise on compromised quality vers cost.
The book this is taken from is called Build Your Own High-End Audio, and is by Elector Electronics and covers a wide range of equipment, from amps to surround sound to loud speakers, to audio testing with spectrum Annaliser, AF measurent systems ect.
Seems to be of very high standard circuits, but how this compares with Cyrus Two ???
If anyone has seen this book, any comments before getting to far into the project at hand would be appreciated.
I had also toyed with the idea of building another two pairs of cyrus two type amps, and running both pairs in mono mode to bi-amp my 753 freedoms. I could do this by feeding the circuit diagram in the service manual into my Circuit Wizard Pro, and simply ask it for a PCB Track Layout Printout.
What to do, any ideas, or have I lost the plot here.Regards
Mark.😀
Hi Mark,
Please accept that I had no intentions of criticizing you here. What works for you is fine, but as you've noted, everyone reads these posts and it's very easy to take suggestions out of context. I try to make sure that doesn't happen, so I do try to focus on the proper way to do things. Any shortcuts taken really are for people who are very good at servicing. This for two reasons. When we open a unit up, we take in information from many sources and some measurements. What appears to be a short cut isn't really. The stuff that we do in our head is not apparent to onlookers. Second. If we mess up, we know how to save the situation and avoid really bad things to begin with.
By all means, build and experiment. The Cyrus only has a phono preamp. The rest is only switches and controls, nothing active before the amp.
You will also find plenty excellent designs here in the threads. At some point in time, we hope to organize all the successful projects so they can be easily located.
Having bought a few extremely good preamps, and worked on many more, the results can get as close to perfect as one can reasonably expect - or better. 😉 I have built gain blocks that sound and measure extremely well.
A good PCB layout will not happen with an auto router. All that will do is make sure everything is connected together. I'd recommend you look at several PCB designs to get the basics down. In the Symasym thread, the effect of changing the PCB layout has been demonstrated. That's a decent amp as well.
-Chris
Please accept that I had no intentions of criticizing you here. What works for you is fine, but as you've noted, everyone reads these posts and it's very easy to take suggestions out of context. I try to make sure that doesn't happen, so I do try to focus on the proper way to do things. Any shortcuts taken really are for people who are very good at servicing. This for two reasons. When we open a unit up, we take in information from many sources and some measurements. What appears to be a short cut isn't really. The stuff that we do in our head is not apparent to onlookers. Second. If we mess up, we know how to save the situation and avoid really bad things to begin with.
Attachments of limited size can be attached by pushing on the "Browse" button just over where it says "Submit Reply" at the bottom here. I think there is a 100 K limit in force.
There will normally not be a problem with this. You could have left the other channel alone. As I said, no harm done.
Yes, just put new parts of similar number back in. Check the voltages to be sure the new parts are good parts.
Cool! Right on! (okay, I'm old)
By all means, build and experiment. The Cyrus only has a phono preamp. The rest is only switches and controls, nothing active before the amp.
By all means, you should try and build no matter how it turns out. Consider that each time you build something, it will be a learning experience. I would suggest you do one thing though. Save the expensive parts for now. Build with normal parts and when you hear something that has promise, replace the parts you used with the "better" parts. Do one at a time so you can determine what does and does not matter. The results are more than worth the time investigating. Besides, a "less good" design will not sound great with better parts.
You will also find plenty excellent designs here in the threads. At some point in time, we hope to organize all the successful projects so they can be easily located.
Having bought a few extremely good preamps, and worked on many more, the results can get as close to perfect as one can reasonably expect - or better. 😉 I have built gain blocks that sound and measure extremely well.
Only you can be the judge of that.
Excellent idea, and it has been done before. Have a look here. See, it was such a good idea that someone developed it already!
A good PCB layout will not happen with an auto router. All that will do is make sure everything is connected together. I'd recommend you look at several PCB designs to get the basics down. In the Symasym thread, the effect of changing the PCB layout has been demonstrated. That's a decent amp as well.
-Chris
Hi Mark,
I just want to comment on a couple things if I may. Take my comments from the perspective of how the work will turn out please. Reality is not always kind, and that is where I come from. 😉
Can I do it without? Maybe, probably. It wouldn't be a good or complete job. I need the same equipment to ensure a reliable repair.
If anyone is determined to do this, I offer a couple choices.
1. Give it to someone who cares instead of destroying it.
2. Pour fuel on it, light it and watch it burn. This way of destroying something offers more entertainment and less cost.
I really miss Heathkit equipment. A great loss for all new DIYers!
Now, what does buying a Fluke or Agilent buy you? An instrument that is probably in tolerance for one. Also one that remains in tolerance over time. I spent time in a calibration lab. I kid you not when I say the other meters may as well have the last digit removed - and maybe the next as well.
I once received a receiver for repair. Blown outputs - again. It was repaired a year previously by someone else. None of the outputs were the proper type, and all had different case styles! Just to add insult to injury, the thermal compound was the original material, but full of debris now. Some resistors where the incorrect value.
This unit actually worked for a year!!! The customer did say it sounded much better after I serviced it though.
Another shop wrote-off a new Denon receiver that they repaired - under warranty! Needless to say, I can't mention their name, but it was a major company in Toronto that advertises their excellent service. The distributor agreed with me after they examined the set. The customer got a new one, the dealer lost the line. You would not believe the silliness in the audio service industry (if I can call it that). Still, there is never any reason to compound the existing problems.
Be honest, work clean and do it right. That's all anyone can ask.
-Chris
I just want to comment on a couple things if I may. Take my comments from the perspective of how the work will turn out please. Reality is not always kind, and that is where I come from. 😉
The likelihood of a successful outcome is very low, and fading fast. The less experience someone has, the more they absolutely need access to proper test equipment.
Can I do it without? Maybe, probably. It wouldn't be a good or complete job. I need the same equipment to ensure a reliable repair.
In that case, the cover should remain firmly affixed to the chassis. The only thing I see is a false sense of economy and a complete lack of respect for people who do this job for a living. To be sure, some of those deserve contempt but there are many who do an excellent job.
If anyone is determined to do this, I offer a couple choices.
1. Give it to someone who cares instead of destroying it.
2. Pour fuel on it, light it and watch it burn. This way of destroying something offers more entertainment and less cost.
This is one troubleshooting method that works for experienced people. Everyone else tends to get lost.
That's why you secure some help in order to learn. If this can not be done, it serves as a clue that you should not proceed any further.
That's fine. However, I did say that you really should be using an audio oscillator instead of a function generator. You should be using a low distortion source for checking out audio equipment. Otherwise, the tone will sound distorted. How can you tell between that and something wrong with the amp?
I agree with everything on your list except for the last point. Otherwise, absolutely!
I really miss Heathkit equipment. A great loss for all new DIYers!
Depends on the level you service or experiment at for one. It also depends greatly on your skill level.
I know for a fact that this is not so. I do believe that people who do this do believe what you said is correct.
That may be, but the standard test frequency that all wow and flutter meters use is either 3K00 Hz or 3K15 Hz. A 300Hz test tone for wow and flutter is useless. These meters also indicate speed and drift and the test records I used had a 3K00 tone for this reason. I'm sorry, but the test record you have is not terribly useful since it is off standard. It's curious, because recording a 300 Hz signal is as easy as recording a 3,000 Hz tone. Why the difference?
Okay, what are it's AC frequency characteristics? What I would normally recommend is a Fluke 87 or similar, or an Agilent U1242A minimum, or better yet, a U1252A. At least the 1252A has a useful frequency response. Other meters are iffy much past 120 Hz and are not an RMS type device.
Now, what does buying a Fluke or Agilent buy you? An instrument that is probably in tolerance for one. Also one that remains in tolerance over time. I spent time in a calibration lab. I kid you not when I say the other meters may as well have the last digit removed - and maybe the next as well.
By the time you get complaints, the damage has been done over time. Believe me when I say that a complete hack can survive with minimal complaints for an entire career. The work is still terrible / destructive and the person is still a hack.
I once received a receiver for repair. Blown outputs - again. It was repaired a year previously by someone else. None of the outputs were the proper type, and all had different case styles! Just to add insult to injury, the thermal compound was the original material, but full of debris now. Some resistors where the incorrect value.
This unit actually worked for a year!!! The customer did say it sounded much better after I serviced it though.
Another shop wrote-off a new Denon receiver that they repaired - under warranty! Needless to say, I can't mention their name, but it was a major company in Toronto that advertises their excellent service. The distributor agreed with me after they examined the set. The customer got a new one, the dealer lost the line. You would not believe the silliness in the audio service industry (if I can call it that). Still, there is never any reason to compound the existing problems.
Be honest, work clean and do it right. That's all anyone can ask.
-Chris
Hi Chris,
Many thanks for the advice, glad im on the right track with pre-amp / cyrus clones. will check out the forum for best ideas. Its giving me the push i need thanks again.
I cant find my booklet that came with my DVM, Ive had it for some time now, and cant even find ref to that particular model on line, but of the range, if memory serves correct they are not your average DVM Quality. Im sure that its quite respectable, but if you can suggest where I could get a replacement book from, Ill give it a go, It has some Automated functions, that I use manually because I forget how you call them up and cant find the book.
One nice touch is a dual scale, giving an analogue as well as a digital readout, which works like an avo type scale.
Fortunately, I am not the kind of person that would even dream up servicing something the way you described in your horror story, sounds like they should try patchwork quilt manufacturing. but I can well believe it takes place. and then have the cheek to charge someone for it Ive got a lot more respect for myself and others safety, Ive got a lot more sense and take pride in whatever I do.
Im a firm believer that if its worth doing, then its worth doing properly. else why even bother. How do some people sleep at night.
It reminds me of the phantom dabbler. Im sure you've met them, there the people who bring you something saying its just gone wrong, and when you ask if anyone else has looked at it. are assured OH NO that no one else has. except the inside tells rather a different story.
A little bit about me.
Im very logical minded, and have several BTEC, and City &Guilds qualifications, from programming to electronics, Im happy to say I passed mostly with distinctions but all passes. about 17 I think, After gaining my JEB Teachers Diploma, I taught various courses in IT at Delmont University for a few years, before going back into industry as a Telewest service engineer.
These days I do the odd repair for people, but its my hobby now really.
I'm 47 this year so its never to late to learn a new skill if one really wants to.
Amongst other things, The courses instilled in me the importance of approaching a problem in a focused orderly structured, manner.
This approach can be used to solve most problems, not just in electronics, but one finds that many principles learned can be used in so many other areas that just requires a steady methodical logical analytical approach.
I started re-educating myself late in life, when I decided my skills were getting out of touch with the Job Market. I used to do injection mould setting, but moved to an area where this was not required. so decided to retrain my skills and changed direction towards computers, and electronics, as at time all work seemed to be in this area, so i tend to think that if I can learn, so can everyone else, but it seems not to be the case as we are all built differently with different sets of useful skills, I cant draw to save my life. And I suppose therefore not everyone is suited to this end. and those that aren't suited should leave things to those that are.
Enough rambling on about me,
Any Views on the BLUE ESR meter kit. Im thinking it would be a useful addition to my equipment, and may have more uses than just caps. I dont currently have an ESR meter. but again this comes in kit form or ready built, Is this a worthy tool to have. do you use one.
Im sure your right about audio oscillator, although the tone I here sounds crystal clear to me, and the wave form on scope shows no distortion, but as you said probably needs a THD METER which I don't have.
Do you recommend any particular model of THD Meters or Oscillators.
Here is a feed to the Blue ESR http://www.flippers.com/BlueEsr.html
Thanks for info about pics I will have to down scale them first and then post
regards
Mark
Many thanks for the advice, glad im on the right track with pre-amp / cyrus clones. will check out the forum for best ideas. Its giving me the push i need thanks again.
I cant find my booklet that came with my DVM, Ive had it for some time now, and cant even find ref to that particular model on line, but of the range, if memory serves correct they are not your average DVM Quality. Im sure that its quite respectable, but if you can suggest where I could get a replacement book from, Ill give it a go, It has some Automated functions, that I use manually because I forget how you call them up and cant find the book.
One nice touch is a dual scale, giving an analogue as well as a digital readout, which works like an avo type scale.
Fortunately, I am not the kind of person that would even dream up servicing something the way you described in your horror story, sounds like they should try patchwork quilt manufacturing. but I can well believe it takes place. and then have the cheek to charge someone for it Ive got a lot more respect for myself and others safety, Ive got a lot more sense and take pride in whatever I do.
Im a firm believer that if its worth doing, then its worth doing properly. else why even bother. How do some people sleep at night.
It reminds me of the phantom dabbler. Im sure you've met them, there the people who bring you something saying its just gone wrong, and when you ask if anyone else has looked at it. are assured OH NO that no one else has. except the inside tells rather a different story.
A little bit about me.
Im very logical minded, and have several BTEC, and City &Guilds qualifications, from programming to electronics, Im happy to say I passed mostly with distinctions but all passes. about 17 I think, After gaining my JEB Teachers Diploma, I taught various courses in IT at Delmont University for a few years, before going back into industry as a Telewest service engineer.
These days I do the odd repair for people, but its my hobby now really.
I'm 47 this year so its never to late to learn a new skill if one really wants to.
Amongst other things, The courses instilled in me the importance of approaching a problem in a focused orderly structured, manner.
This approach can be used to solve most problems, not just in electronics, but one finds that many principles learned can be used in so many other areas that just requires a steady methodical logical analytical approach.
I started re-educating myself late in life, when I decided my skills were getting out of touch with the Job Market. I used to do injection mould setting, but moved to an area where this was not required. so decided to retrain my skills and changed direction towards computers, and electronics, as at time all work seemed to be in this area, so i tend to think that if I can learn, so can everyone else, but it seems not to be the case as we are all built differently with different sets of useful skills, I cant draw to save my life. And I suppose therefore not everyone is suited to this end. and those that aren't suited should leave things to those that are.
Enough rambling on about me,
Any Views on the BLUE ESR meter kit. Im thinking it would be a useful addition to my equipment, and may have more uses than just caps. I dont currently have an ESR meter. but again this comes in kit form or ready built, Is this a worthy tool to have. do you use one.
Im sure your right about audio oscillator, although the tone I here sounds crystal clear to me, and the wave form on scope shows no distortion, but as you said probably needs a THD METER which I don't have.
Do you recommend any particular model of THD Meters or Oscillators.
Here is a feed to the Blue ESR http://www.flippers.com/BlueEsr.html
Thanks for info about pics I will have to down scale them first and then post
regards
Mark
As Promised Pics of painted Cyrus Two
Hi all
Here is a pic of the re-vamped Cyrus Two, hopefuly, beats battleship grey Im thinking.
Hi Chris, Would you believe it, Found out that Robin are now part of Fluke. and my Robin RD 930 is still service by Fluke at a cost of £33,
They say its a very good DVM and is now 15yrs old. The equivalent spec they matched to is a Fluke 177 at £199, but say that the Robin has a superior frequency range up to 1Mh, to go to that spec would take the DVM into the next range 280 series, which cost £360, but all other ranges would be an improvement at this level over both RD930 and Fluke 177, a lot of money though.
They dont recommend replacing it, they recommend servicing and again stated its a very good DVM. So as its 15yrs old, Ill have to get it serviced by Fluke, just to keep it properly adjusted
I cant believe how expensive they have become now, I think I paid £70 back then, but guess that was a lot back then too.
Worth keeping then. any thoughts.
Hi all
Here is a pic of the re-vamped Cyrus Two, hopefuly, beats battleship grey Im thinking.
Hi Chris, Would you believe it, Found out that Robin are now part of Fluke. and my Robin RD 930 is still service by Fluke at a cost of £33,
They say its a very good DVM and is now 15yrs old. The equivalent spec they matched to is a Fluke 177 at £199, but say that the Robin has a superior frequency range up to 1Mh, to go to that spec would take the DVM into the next range 280 series, which cost £360, but all other ranges would be an improvement at this level over both RD930 and Fluke 177, a lot of money though.
They dont recommend replacing it, they recommend servicing and again stated its a very good DVM. So as its 15yrs old, Ill have to get it serviced by Fluke, just to keep it properly adjusted
I cant believe how expensive they have become now, I think I paid £70 back then, but guess that was a lot back then too.
Worth keeping then. any thoughts.
Attachments
Hi Mark,
You have a very good meter then. Excellent!
I had never heard of that make, so this is a pleasant surprise. I do think it's time for a calibration though. Especially since the high frequency cal may be off by now. Can't hurt!
Certainly, keep it. Look after it, but do have it calibrated so you know where you are. They should give you any out of tolerance data so you can tell how it's drifting. This will probably be good for another 5~10 years before the next cal or replacement. If the changes are very large, a shorter calibration frequency is indicated. Normally, these would be calibrated every one or two years. If they are really like a Fluke, it should hold it's calibration pretty well.
-Chris
You have a very good meter then. Excellent!
I had never heard of that make, so this is a pleasant surprise. I do think it's time for a calibration though. Especially since the high frequency cal may be off by now. Can't hurt!
Certainly, keep it. Look after it, but do have it calibrated so you know where you are. They should give you any out of tolerance data so you can tell how it's drifting. This will probably be good for another 5~10 years before the next cal or replacement. If the changes are very large, a shorter calibration frequency is indicated. Normally, these would be calibrated every one or two years. If they are really like a Fluke, it should hold it's calibration pretty well.
-Chris
Many Thanks Chrs, will send meter off for calibration, got a hol comming up soon so can lose it for a while then. here is a link that shows Robin is part of the Fluke Group, as you say wonderful news.
http://www.robinelectronics.com/
mark
Any thoughts on the Blue ESR meter, oh and on another note. back to the Cyrus subjects
What are your thoughts about replacing the op amps in the Cyrus with Burson Op amps
they are not cheap, but seem to be getting a following now. are a pin for pin match, any thoughts.
http://www.audioupgrades.co.uk/burson.shtml
sorry if im taking to much of your focus, but your opinion is valued
regards
Mark
http://www.robinelectronics.com/
mark
Any thoughts on the Blue ESR meter, oh and on another note. back to the Cyrus subjects
What are your thoughts about replacing the op amps in the Cyrus with Burson Op amps
they are not cheap, but seem to be getting a following now. are a pin for pin match, any thoughts.
http://www.audioupgrades.co.uk/burson.shtml
sorry if im taking to much of your focus, but your opinion is valued
regards
Mark
Cyrus Two opamps
Hi all
I have had an email from paul whom is or has upgraded the opamps in his cyrus two. reporting great improvements.
The opamps are Burson Discrete Opamps at £90 a matched pair
Im looking at the circuit diagram and getting confused as to what difference it will make. to anything other than the phono stage.
NE5532 is used for MM and Moving Coil Preamp
NE5534 is used for RIAA EQ,
So it looks to me like all line level stuff will go straight in to the discrete part of the amp bypassing the opamps.
Can someone please put me back on track as I think I must be missing something here
Regards
Mark.
Hi all
I have had an email from paul whom is or has upgraded the opamps in his cyrus two. reporting great improvements.
The opamps are Burson Discrete Opamps at £90 a matched pair
Im looking at the circuit diagram and getting confused as to what difference it will make. to anything other than the phono stage.
NE5532 is used for MM and Moving Coil Preamp
NE5534 is used for RIAA EQ,
So it looks to me like all line level stuff will go straight in to the discrete part of the amp bypassing the opamps.
Can someone please put me back on track as I think I must be missing something here
Regards
Mark.
All inputs, except for phono, pass directly to the power stage. 😉
Adding the Burson opamp should only affect the phono stage.
Adding the Burson opamp should only affect the phono stage.
Many thanks, Im not losing the plot just yet then, Its as I thought.
Well they would probably improve the phono stage, but I think Im looking for an overall improvement and in that case if my understanding is correct, the volume control is a passive input direct into the power amp and should in theory show some improvement by replacing with a high caliber device,
Ive heard good reports about a ALPS RK27 (alias, “Blue Velvet”), but wondered about pushing the boat a bit further, any thoughts on a DACT CT2 http://www.dact.com/html/attenuators.html
My pot is original and a bit scratchy, I dont think cyrus can get the original replacements anymore, but anyway thinks it would benefit from a better control, without the balance which I dont use anyway,
Any thoughts.
Well they would probably improve the phono stage, but I think Im looking for an overall improvement and in that case if my understanding is correct, the volume control is a passive input direct into the power amp and should in theory show some improvement by replacing with a high caliber device,
Ive heard good reports about a ALPS RK27 (alias, “Blue Velvet”), but wondered about pushing the boat a bit further, any thoughts on a DACT CT2 http://www.dact.com/html/attenuators.html
My pot is original and a bit scratchy, I dont think cyrus can get the original replacements anymore, but anyway thinks it would benefit from a better control, without the balance which I dont use anyway,
Any thoughts.
I fitted a Blue Velvet in my Cyrus 2 and the pins needed a little bending before it would fit.
I later bypassed all of the switching/volume controls and built a stepped attenuator into an external box.
At 36mm high, a DACT would probably fit in the case but I'm not sure about the pins lining up.
You'll probably need some kind of joining mechanism to use the DACT's smooth shaft with the Cyrus' plastic volume knob.
There's a picture of my ALPS blue and how I used a coupler to make it work in post 71 of this thread.
I later bypassed all of the switching/volume controls and built a stepped attenuator into an external box.
At 36mm high, a DACT would probably fit in the case but I'm not sure about the pins lining up.
You'll probably need some kind of joining mechanism to use the DACT's smooth shaft with the Cyrus' plastic volume knob.
There's a picture of my ALPS blue and how I used a coupler to make it work in post 71 of this thread.
Just viewed your pic, nice job, it just goes in as you say. when you say you have done away with the switching, how do you now choose which source feeds the power amp. Have you included this in your external control.
What did you use in your external vol control, was it better than the alps. did you lose any quality by lengthening the connections between external contol and the power amp.
How was this done, does this mean you now control the sources via your in effect external passive pre-amp feeding from this into one permanent connected in line RCA at full power ie now a power amp.
Im trying to get my head around it, if this has now been set as a power amp how do you still use the phono stage?.
Any Pics of this,
regards
mark.
What did you use in your external vol control, was it better than the alps. did you lose any quality by lengthening the connections between external contol and the power amp.
How was this done, does this mean you now control the sources via your in effect external passive pre-amp feeding from this into one permanent connected in line RCA at full power ie now a power amp.
Im trying to get my head around it, if this has now been set as a power amp how do you still use the phono stage?.
Any Pics of this,
regards
mark.
Hi Mark, I'll get a pic soon. It's just a small Maplin aluminium project box. Inside is a stepped attenuator and an AlPS rotary switch wired with silver/teflon.
The box sits between my CD player and Cyrus amps and uses very short cables. To me, it sounds great!
I 'think' that the stepped attenuator sounds more transparent to me. I'm glad I fitted it but the ALPS was good enough anyway.
A little unorthodox, but I've currently got a bi-amped setup with a Cyrus One for the Tweeters and Cyrus Two and PSX for the rest. I'm breaking a lot of rules by not having some kind of buffer after the attenuator but I don't like to put anything else in the way of the sound. All of my experiments with buffers so far have muddied up the sound in some way.
I've changed the input filter on the Cyrus One so at least it's not sucking up too much current across the lower frequencies.
The phono section of either amp is not being used at the moment. As you've probably seen, I would have to add a switch to the Cyrus to allow this..... and an extra output to go to the Cyrus One.
The box sits between my CD player and Cyrus amps and uses very short cables. To me, it sounds great!
I 'think' that the stepped attenuator sounds more transparent to me. I'm glad I fitted it but the ALPS was good enough anyway.
A little unorthodox, but I've currently got a bi-amped setup with a Cyrus One for the Tweeters and Cyrus Two and PSX for the rest. I'm breaking a lot of rules by not having some kind of buffer after the attenuator but I don't like to put anything else in the way of the sound. All of my experiments with buffers so far have muddied up the sound in some way.
I've changed the input filter on the Cyrus One so at least it's not sucking up too much current across the lower frequencies.
The phono section of either amp is not being used at the moment. As you've probably seen, I would have to add a switch to the Cyrus to allow this..... and an extra output to go to the Cyrus One.
Hi Guys
This is my first post. A few months back I found that the output on the left channel on my C2 (owned since new circa 1988) was well down.
I've since replaced it with a C8vs2 +PSX-R with which I am delighted.
However I don't want to give up on my 2 (for which I also have a PSX).
Having no background whatsoever in electronics and having waded through all 12 pages of this thread I now know that I have to find a local(ish) hifi repairer.
I guess in order to feel confident with this option I should ideally have a C2 repair manual. Can anyone advise me if this is possible to get hold of? I've downloaded the one for the C1 but would feel nervous giving it to a repairer of whom I have no experience for a repair to a C2.
Any help will be much appreciated.
Thanks
This is my first post. A few months back I found that the output on the left channel on my C2 (owned since new circa 1988) was well down.
I've since replaced it with a C8vs2 +PSX-R with which I am delighted.
However I don't want to give up on my 2 (for which I also have a PSX).
Having no background whatsoever in electronics and having waded through all 12 pages of this thread I now know that I have to find a local(ish) hifi repairer.
I guess in order to feel confident with this option I should ideally have a C2 repair manual. Can anyone advise me if this is possible to get hold of? I've downloaded the one for the C1 but would feel nervous giving it to a repairer of whom I have no experience for a repair to a C2.
Any help will be much appreciated.
Thanks
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!
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!
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