The two black wires connect together to AC neutral, the two red wires connect together to AC live (for N. America).
Here's the likely problem, the transformer manufacturer has poorly chosen the wire colors for the output windings, you can't tell which blue wire and which green wire connect to a common winding, but you can easily check for connectivity with a multimeter.
The blue and green wires from one secondary winding go to the ~ terminals of one of the rectifiers, the blue and green wires from the second secondary winding go to the ~ terminals of one of the other rectifier.
Again: the blue and green wires connecting to a rectifier must be connected inside the transformer, check resistance using a meter/tester. If they are from separate windings things will not be good.
After that it's easy: + if one rectifier goes to - of another (arbitrary), defining COM. The remaining + is your V++ and the remaining - is your V--.
Here's the likely problem, the transformer manufacturer has poorly chosen the wire colors for the output windings, you can't tell which blue wire and which green wire connect to a common winding, but you can easily check for connectivity with a multimeter.
The blue and green wires from one secondary winding go to the ~ terminals of one of the rectifiers, the blue and green wires from the second secondary winding go to the ~ terminals of one of the other rectifier.
Again: the blue and green wires connecting to a rectifier must be connected inside the transformer, check resistance using a meter/tester. If they are from separate windings things will not be good.
After that it's easy: + if one rectifier goes to - of another (arbitrary), defining COM. The remaining + is your V++ and the remaining - is your V--.
Hi RJM,
This is how I wired it. No issues there.
Yes I used this method for determining the winding pairs after seeing it somewhere in this forum. Before I checked continuity I was blowing fuses this is because I had crossed a green and blue wire from the secondaries, after I did a continuity check and verified that I had the right blue/green pair and connected to ~, no more blown fuses but read on.
All good after continuity check.
Now I have made a "Y" adapter that goes from + of the first rectifier to - on the second creating my "COM". This is where the problem starts, no blown fuse, but I am getting close to 30v on the remaining + (v++) and - (v--) terminals.
Btw, I get close to 12v AC when I check the secondary windings and when I connect a single winding pair to one bridge rectifier I see about 15v DC on the +/- terminals.
Thanks for all you help!
This is how I wired it. No issues there.
Yes I used this method for determining the winding pairs after seeing it somewhere in this forum. Before I checked continuity I was blowing fuses this is because I had crossed a green and blue wire from the secondaries, after I did a continuity check and verified that I had the right blue/green pair and connected to ~, no more blown fuses but read on.
All good after continuity check.
Now I have made a "Y" adapter that goes from + of the first rectifier to - on the second creating my "COM". This is where the problem starts, no blown fuse, but I am getting close to 30v on the remaining + (v++) and - (v--) terminals.
Btw, I get close to 12v AC when I check the secondary windings and when I connect a single winding pair to one bridge rectifier I see about 15v DC on the +/- terminals.
Thanks for all you help!
So I wired just one secondary to one bridge rectifier and have com going to chassis ground. I get about 15v at the v+/v- terminals on the pcb and around 12v at the opamp. I am listening to Blue Train right now and it is working, but I would still like to now why I get double the voltage with two rectifiers? Please bare with me I am a total electronics noob.
After reading your detailed reply (thanks, that makes my job easier) I'm pretty sure everything working as it should. The hard part is how to convince you this is indeed the case.
Voltages and how to measure and report them:
"I get about 15v at the v+/v- terminals on the pcb" is poor wording as it can mean two totally different things:
1. There is 15 volts measured between the positive (V++) and negative (V--) terminals on the PCB
or,
2. both terminals measure +/-15 volts above/below ground(COM).
Whether one rectifier or two, you should have the same result:
The voltage measured between V++ and COM is about 15 V.
The voltage measured between V-- and COM is about -15 V.
The voltage measured between V++ and V-- is about 30V.
If that's what you measure then you can safely connect the circuit board.
If you only measure 15 V between V++ and V-- then there is a problem, but the circuit will still power up and play music. If you measure 60 V between V++ and V-- then do not connect the circuit board as all the electrolytic caps will blow since they are only rated for 25 V.
Voltages and how to measure and report them:
"I get about 15v at the v+/v- terminals on the pcb" is poor wording as it can mean two totally different things:
1. There is 15 volts measured between the positive (V++) and negative (V--) terminals on the PCB
or,
2. both terminals measure +/-15 volts above/below ground(COM).
Whether one rectifier or two, you should have the same result:
The voltage measured between V++ and COM is about 15 V.
The voltage measured between V-- and COM is about -15 V.
The voltage measured between V++ and V-- is about 30V.
If that's what you measure then you can safely connect the circuit board.
If you only measure 15 V between V++ and V-- then there is a problem, but the circuit will still power up and play music. If you measure 60 V between V++ and V-- then do not connect the circuit board as all the electrolytic caps will blow since they are only rated for 25 V.
A few remarks about sound quality.
Everything worked normally from the start.However on first audition I did not like the sound at all.Despite good dynamics the mid/high-range was very hard and unnatural (compared to Naim phono boards).I am not a huge believer in break -in effects so I was initially disappointed.
However 48 hours later everything is much better .Although I am still not 100% sure of the midrange I clearly have much better bass , micro and macro dynamics as well as very good soundstaging.
One remaining problem is that of high buzz and hum.I put in some C0 Rf suppressors since I did notice some rf breakthrough and everything is grounded as per schematic and the PS is in a different case.But this circuit must be very sensitive to noise issues -any ideas?.
Of course not to forget to congratulate rjm on an excellent piece of work and general and generous support to the diy community.
Everything worked normally from the start.However on first audition I did not like the sound at all.Despite good dynamics the mid/high-range was very hard and unnatural (compared to Naim phono boards).I am not a huge believer in break -in effects so I was initially disappointed.
However 48 hours later everything is much better .Although I am still not 100% sure of the midrange I clearly have much better bass , micro and macro dynamics as well as very good soundstaging.
One remaining problem is that of high buzz and hum.I put in some C0 Rf suppressors since I did notice some rf breakthrough and everything is grounded as per schematic and the PS is in a different case.But this circuit must be very sensitive to noise issues -any ideas?.
Of course not to forget to congratulate rjm on an excellent piece of work and general and generous support to the diy community.
@protos
I'm still not sure exactly why, but the phonoclone circuit takes a couple of weeks to settle down. I've seen that myself time and time again, and many others have observed the same thing.
Also, statistically about 4-5% of phonoclone builders seem to experience problems with RF and noise. For the VSPS it is 0%. Unfortunately (in a sense) I have never had such a problem, so I've been unable to look at the issue myself directly. Gain set too high, incompatibility with tonearm grounding scheme (seems to affect people with DIY tonearms/turntables/phono interconnects more than others), noisy RF environment (near radio towers, cell phones, or even WiFi routers)... there are many factors. Perhaps the best thing is for you to email me directly and we can go through things step by step.
[[OK, "never had a problem" isn't quite true: my phonoclone was not happy sitting next to my wireless router, and turning off the lights in the room can generate audible ticks from the speakers. ]]
One thing to try: 50ohm carbon resistor from COM after the rectifier diodes to the power supply case. The other thing is a 330pF between the op amp inputs. The last thing (if you have a dual mono power supply) is do disconnect COM from the phonoclone chassis and reconnect it at the input RCA jacks of both channels by removing the insulating washers from the back for example.
@davidmartin
Glad to hear it works, and I'll keep your comments in mind.
I'm still not sure exactly why, but the phonoclone circuit takes a couple of weeks to settle down. I've seen that myself time and time again, and many others have observed the same thing.
Also, statistically about 4-5% of phonoclone builders seem to experience problems with RF and noise. For the VSPS it is 0%. Unfortunately (in a sense) I have never had such a problem, so I've been unable to look at the issue myself directly. Gain set too high, incompatibility with tonearm grounding scheme (seems to affect people with DIY tonearms/turntables/phono interconnects more than others), noisy RF environment (near radio towers, cell phones, or even WiFi routers)... there are many factors. Perhaps the best thing is for you to email me directly and we can go through things step by step.
[[OK, "never had a problem" isn't quite true: my phonoclone was not happy sitting next to my wireless router, and turning off the lights in the room can generate audible ticks from the speakers. ]]
One thing to try: 50ohm carbon resistor from COM after the rectifier diodes to the power supply case. The other thing is a 330pF between the op amp inputs. The last thing (if you have a dual mono power supply) is do disconnect COM from the phonoclone chassis and reconnect it at the input RCA jacks of both channels by removing the insulating washers from the back for example.
@davidmartin
Glad to hear it works, and I'll keep your comments in mind.
Actually I was naughty and never connected PS com to PS AC ground lug so the PS is not AC grounded (the ps case is grounded of course) to avoid ground loops.Of course the com is then grounded on the phonoclone chassis.The C0 is 220pf and cures the rf problem.The hum problem is not really unacceptably bad .At normal/average listening levels you can just about hear from the listening position when the music stops but of course at louder levels it is more obvious .
That level of hum is not normal.
Nice to learn that C0 200 pF (across IC1 in+ and in-) gets rid of the RF at least. There are actually a number of things you can do to "RF proof" your phonoclone. I've been reading up on them:
1. 1-10 nF cap between the insulated RCA shields and the chassis, for both the inputs and outputs, and also for COM to chassis at the power supply connection.
2. 100-1000 pF cap between the input wires (IN+ to IN-), but don't do this for the outputs (out- to out-) as the driving op amp may not like it.
Just to be clear, normally COM is not connected to AC earth ... ie you have it as I have it, and how I tell people to do it. There may be some advantage in connecting COM to AC earth via the power supply chassis, but not directly ... use a 47 ohm resistor and say 10 nF in parallel, to avoid ground loops.
re. the hum issue, just for reference please let me know which cartridge and arm, and what value of R2... thanks!
/rjm
Nice to learn that C0 200 pF (across IC1 in+ and in-) gets rid of the RF at least. There are actually a number of things you can do to "RF proof" your phonoclone. I've been reading up on them:
1. 1-10 nF cap between the insulated RCA shields and the chassis, for both the inputs and outputs, and also for COM to chassis at the power supply connection.
2. 100-1000 pF cap between the input wires (IN+ to IN-), but don't do this for the outputs (out- to out-) as the driving op amp may not like it.
Just to be clear, normally COM is not connected to AC earth ... ie you have it as I have it, and how I tell people to do it. There may be some advantage in connecting COM to AC earth via the power supply chassis, but not directly ... use a 47 ohm resistor and say 10 nF in parallel, to avoid ground loops.
re. the hum issue, just for reference please let me know which cartridge and arm, and what value of R2... thanks!
/rjm
Using a 103R and r2 is the standard 1.3k if I remember.
As I said the main problem is hum not rf hash now
I connected another turntable yesterday with a simple 103 and there was huge hum problem.Must have been a combination of other problems because I can't imagine the phono stage is to blame.
As I said the main problem is hum not rf hash now
I connected another turntable yesterday with a simple 103 and there was huge hum problem.Must have been a combination of other problems because I can't imagine the phono stage is to blame.
I further investigated the source of hum and noise by switching various cmponents around or off.My conclusions:
1.The phonoclone is extremely sensitive to magnetic coupling from adjacent transformers etc.Not the circuit itself which is quiet when disconnected from source but when a cartridge plus cables are connected this becomes a source of noise injection.For example the input (cartridge/cable) picks up the transformer hum from the valve amp in the shelf below(about 35cm).This i tested with a headphone amp connected to the output of the phonoclone so I could see the effect of switching the main amp on or off.The valve amp was not connected at all to the phonoclone.
2.The cables themselves are a source of noise.If one moves the input or output(!) cables around a higher pitched buzz increases or decreases.These cables are not close to any transformer or other equipment .I was surprised how moving the output cables affected noise levels .
3.Trying different ac mains grounding or taking components off the system did not affect hum levels.So it is basically the circuit which when connected to source becomes a sensitive type of antenna for noise including RF which is still around if volume is at very high levels.
Now I wonder if there is something wrong with my circuit or do others experience similar problems? As I said before the phonoclone is playable and most of the the time the hum problems are covered by the surface noise of vinyl and of course the music but it is there when you lift the cartridge.
1.The phonoclone is extremely sensitive to magnetic coupling from adjacent transformers etc.Not the circuit itself which is quiet when disconnected from source but when a cartridge plus cables are connected this becomes a source of noise injection.For example the input (cartridge/cable) picks up the transformer hum from the valve amp in the shelf below(about 35cm).This i tested with a headphone amp connected to the output of the phonoclone so I could see the effect of switching the main amp on or off.The valve amp was not connected at all to the phonoclone.
2.The cables themselves are a source of noise.If one moves the input or output(!) cables around a higher pitched buzz increases or decreases.These cables are not close to any transformer or other equipment .I was surprised how moving the output cables affected noise levels .
3.Trying different ac mains grounding or taking components off the system did not affect hum levels.So it is basically the circuit which when connected to source becomes a sensitive type of antenna for noise including RF which is still around if volume is at very high levels.
Now I wonder if there is something wrong with my circuit or do others experience similar problems? As I said before the phonoclone is playable and most of the the time the hum problems are covered by the surface noise of vinyl and of course the music but it is there when you lift the cartridge.
Hi,
just added 330pF caps to input IC1. The RF noise is reduced a lot, but there is still some hum.
As in the case of Protos the noise is very low and cannot be heard from the listening position.
When I listen to the music by the CD player the noise is much lower, but a bit is still there. So, I am also going to add the caps to the input of my lm3875 Gainclone.
Renato
just added 330pF caps to input IC1. The RF noise is reduced a lot, but there is still some hum.
As in the case of Protos the noise is very low and cannot be heard from the listening position.
When I listen to the music by the CD player the noise is much lower, but a bit is still there. So, I am also going to add the caps to the input of my lm3875 Gainclone.
Renato
Note this post, a really stunning build of the Phonoclone 3. The builder, Insides, says his is completely silent, as is most often the case.
http://www.diyaudio.com/forums/analog-line-level/133191-phonoclone-3-a-66.html#post1966207
Yet a number of you run into hum and noise problems, and even if your Phonoclone might not look quite as nice as his does I believe the responsibility lies with me rather than you. I think you've connected everything correctly, just that something, some oversight on my part in the design, is such that the Phonoclone does not "play nice" on 100% of systems or 100% of situations.
One point, directed at protos: the input cables are not noise sensitive so much as without the cartridge load attached the gain of the first IC stage is zero. The output noise is reduced by 30 dB or so, and whatever ground loops or oscillations present are killed also. To make a proper comparison you should replace the input cables with a dummy input load of 10 ohms or whatever your cartridge impedance is.
Even after 4-5 people reporting these sorts of problems to me I am still no closer to figuring out what the cause is, and why it should only crop up in such rare situations.
The phonoclone should be quiet, with only a soft "rush" of Gaussian noise heard when the volume is turned up. By definition it will be noisier than the CD player, but you should never be able to hear anything at normal listening levels unless your ear is right next to the speaker or the room is fantastically quiet.
My advice is unchanged: attack the problem step by step. remove the input cable and replace with dummy resistors, disconnect one channel from the power supply, change the ground connection from the board to the case from the COM to the IN- instead. Lower the gain by reducing R2. Try a 47 ohm resistor between COM and EARTH in the power supply. Try different phono cables / cartridge.
It's frustrating work. Oscillations and hum will change with every change you make, but this doesn't always mean that the change is directly influencing anything. When oscillating the circuit becomes hypersensitive to external stimuli of any kind. Basically you have to cut things out until it stops and then add things back one at a time until it starts again.
http://www.diyaudio.com/forums/analog-line-level/133191-phonoclone-3-a-66.html#post1966207
Yet a number of you run into hum and noise problems, and even if your Phonoclone might not look quite as nice as his does I believe the responsibility lies with me rather than you. I think you've connected everything correctly, just that something, some oversight on my part in the design, is such that the Phonoclone does not "play nice" on 100% of systems or 100% of situations.
One point, directed at protos: the input cables are not noise sensitive so much as without the cartridge load attached the gain of the first IC stage is zero. The output noise is reduced by 30 dB or so, and whatever ground loops or oscillations present are killed also. To make a proper comparison you should replace the input cables with a dummy input load of 10 ohms or whatever your cartridge impedance is.
Even after 4-5 people reporting these sorts of problems to me I am still no closer to figuring out what the cause is, and why it should only crop up in such rare situations.
The phonoclone should be quiet, with only a soft "rush" of Gaussian noise heard when the volume is turned up. By definition it will be noisier than the CD player, but you should never be able to hear anything at normal listening levels unless your ear is right next to the speaker or the room is fantastically quiet.
My advice is unchanged: attack the problem step by step. remove the input cable and replace with dummy resistors, disconnect one channel from the power supply, change the ground connection from the board to the case from the COM to the IN- instead. Lower the gain by reducing R2. Try a 47 ohm resistor between COM and EARTH in the power supply. Try different phono cables / cartridge.
It's frustrating work. Oscillations and hum will change with every change you make, but this doesn't always mean that the change is directly influencing anything. When oscillating the circuit becomes hypersensitive to external stimuli of any kind. Basically you have to cut things out until it stops and then add things back one at a time until it starts again.
Thanks, but with the DL-103 in particular you should not have any trouble at the default settings which makes it all the more frustrating. Though if it is truly very low level it could be something simple like pickup from the turntable motor...
If you learn anything more about the source of the noise or how to silence your phonoclone please let me know.
If you learn anything more about the source of the noise or how to silence your phonoclone please let me know.
Hmmmm, I just noticed yesterday that one channel is giving all the hum problems.What I mean is that if I leave only the left channel connected there is no hum at all.When the right channel connects the hum starts in both channels.This is very suspicious and points to some internal grounding problem.I will investigate further.
RF noise?
Hi,
just to complete the information.
My amp is an audiosector gainclone (2 monoblocks). The first tests I did with an ipod cable to the amp (without the ipod).
When I connected a simple passive pre to the amp with shielded cables the rf noise almost disappeared.
The situation now with the phonoclone (and small caps at the IC1 input) is that I hear a very low rf noise with the input selector to CD. The noise slightly increase when I select the phonoclone pre and the phonoclone is turned on.
This is the reason why I think the the noise could vanish when I connect also in the amp the cap to the op-amp input.
One more thing: I have a Rega P3 turntable which has not the ground cable.
Renato
Hi,
just to complete the information.
My amp is an audiosector gainclone (2 monoblocks). The first tests I did with an ipod cable to the amp (without the ipod).
When I connected a simple passive pre to the amp with shielded cables the rf noise almost disappeared.
The situation now with the phonoclone (and small caps at the IC1 input) is that I hear a very low rf noise with the input selector to CD. The noise slightly increase when I select the phonoclone pre and the phonoclone is turned on.
This is the reason why I think the the noise could vanish when I connect also in the amp the cap to the op-amp input.
One more thing: I have a Rega P3 turntable which has not the ground cable.
Renato