No. 2 running!!!
Hi all,
happy days! No. 2 Phonoclone RC Limited is up, running and sounding pretty good!
First to let you know: I connected the PS up initially as per the other phonoclone first ie dual mono, COM posts tied together and connected to TT grounding post. Hummed like crazy - but I was expecting that!
So to solve the issue, all that was required was to connect the grounds of the inputs together. Hum diminished greatly. I actually also connected my tonearm ground wire to this point as well - and I think its a bit more hummy than the last phonoclone. However I'm going to let it run for a little and see. If you are using dual mono, it would seem that you need to tie the input grounds together. If you need to use the tonearm ground then only join it to one of the COM pins.
And where would we be without pics!!
So you can see front and back of the cases, PS layout - I made a small PCB for this for neatness (! your opinion of my neatness might be different than mine! and yes that is a little bit of left over flux, its clean now!), the boards in the second case and an overall view.
Hi all,
happy days! No. 2 Phonoclone RC Limited is up, running and sounding pretty good!
First to let you know: I connected the PS up initially as per the other phonoclone first ie dual mono, COM posts tied together and connected to TT grounding post. Hummed like crazy - but I was expecting that!
So to solve the issue, all that was required was to connect the grounds of the inputs together. Hum diminished greatly. I actually also connected my tonearm ground wire to this point as well - and I think its a bit more hummy than the last phonoclone. However I'm going to let it run for a little and see. If you are using dual mono, it would seem that you need to tie the input grounds together. If you need to use the tonearm ground then only join it to one of the COM pins.
And where would we be without pics!!
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
So you can see front and back of the cases, PS layout - I made a small PCB for this for neatness (! your opinion of my neatness might be different than mine! and yes that is a little bit of left over flux, its clean now!), the boards in the second case and an overall view.
Very nice cases!!
and much space inside.
I have the phono clone also running
the sound is very very good !!
But i must solve the hum problem it is not much but there is also a radio in it.
When i lift the needle from te simply red record i hear the beatles softly singing, let it be
For simplicity i build the phono clone suply in the first place with 1 transformer and do it as Richard advised on his home page
the com together on the groundlug then to the xlr and the rca's isolated.
Advice is welcome
Is this "radio problem" common ?
and much space inside.
I have the phono clone also running
the sound is very very good !!
But i must solve the hum problem it is not much but there is also a radio in it.
When i lift the needle from te simply red record i hear the beatles softly singing, let it be
For simplicity i build the phono clone suply in the first place with 1 transformer and do it as Richard advised on his home page
the com together on the groundlug then to the xlr and the rca's isolated.
Advice is welcome
Is this "radio problem" common ?
I haven't had the RF interference problem, but I notice on this one that when I turn on my tape deck a faint buzz through the phonoclone.
Listening impressions:
Sound is still developing but, after 3 hours of running it has smoothed out nicely. I haven't A-B tested yet, but it would seem that maybe its a little more dynamic, but I don't think the treble it yet quite as clear as the other phonoclone. Soundstage is very good, and very solid placement within that stage. Bass is also excellent and mids, voices float nicely. Very good overall sound, but you know what? - I think it has a bit more to give yet.
I don't know what has been said about burn in before on the phonoclone - and it seems that RJMs own one is probably the one longest built so he may be able to comment more - but from what I'm hearing a few days of patience will be rewarded.
I think it is appropriate to thank RJM here and now for a fantastic kit and design. It really is superb. And that also goes for the VSPS which is about the best MM phonostage I've heard no matter where I've gone.
On dual mono: I wonder if some of the hum issues would be eliminated if the common of both transformers were tied together before the rectifiers. I'll try it soon, but if anyone is doing this dual mono at the moment maybe they could try it? (my transformers were dual secondaries, so I joined them in series to create a centre tap which is my common)
Comments?
Fran
Listening impressions:
Sound is still developing but, after 3 hours of running it has smoothed out nicely. I haven't A-B tested yet, but it would seem that maybe its a little more dynamic, but I don't think the treble it yet quite as clear as the other phonoclone. Soundstage is very good, and very solid placement within that stage. Bass is also excellent and mids, voices float nicely. Very good overall sound, but you know what? - I think it has a bit more to give yet.
I don't know what has been said about burn in before on the phonoclone - and it seems that RJMs own one is probably the one longest built so he may be able to comment more - but from what I'm hearing a few days of patience will be rewarded.
I think it is appropriate to thank RJM here and now for a fantastic kit and design. It really is superb. And that also goes for the VSPS which is about the best MM phonostage I've heard no matter where I've gone.
On dual mono: I wonder if some of the hum issues would be eliminated if the common of both transformers were tied together before the rectifiers. I'll try it soon, but if anyone is doing this dual mono at the moment maybe they could try it? (my transformers were dual secondaries, so I joined them in series to create a centre tap which is my common)
Comments?
Fran
Hi guys,
Fran, Im slightly worried about your decision to go with unshielded, wooden boxes for the case .... fantastic looking as the are. The phonoclone is a high gain preamp, one would not normally attempt to use it outside of a grounded metal enclosure, likewise all the cables .. except the power umbilical .. should technically be shielded as well.
Burn in. I've gone through it more times than I care to remember, and it goes something like this: (assuming powered up 24h, listning to one record or so every day)
Day 1: horrible, congested sound for perhaps one day
Day 2-3: rapid change to the direct opposite, a hyperextended bass and treble... sounds good in a way, but maybe too much, especially the treble which is rather harsh.
Day 4: the extension recedes, to the point where you think its actually sounding rather closed in.
Day 5-14: Gradually opens up again, this time giving way to natural extension and clear sound.
By the third week, its basically 95% of its final sound I think.
tube300,
I had one person report a problem of radio interference to me. We never could solve it .. the OP27 op-amps, being bipolar, are sensitive to RF, this could be fundamenally the problem. Most people, including myself, do not experience the issue so its hard for me to test. If you cant change anything by grounding and shielding or RF beads, you might try replacing the input op-amp with a FET type, OP134 or something like that.
/Richard
Fran, Im slightly worried about your decision to go with unshielded, wooden boxes for the case .... fantastic looking as the are. The phonoclone is a high gain preamp, one would not normally attempt to use it outside of a grounded metal enclosure, likewise all the cables .. except the power umbilical .. should technically be shielded as well.
Burn in. I've gone through it more times than I care to remember, and it goes something like this: (assuming powered up 24h, listning to one record or so every day)
Day 1: horrible, congested sound for perhaps one day
Day 2-3: rapid change to the direct opposite, a hyperextended bass and treble... sounds good in a way, but maybe too much, especially the treble which is rather harsh.
Day 4: the extension recedes, to the point where you think its actually sounding rather closed in.
Day 5-14: Gradually opens up again, this time giving way to natural extension and clear sound.
By the third week, its basically 95% of its final sound I think.
tube300,
I had one person report a problem of radio interference to me. We never could solve it .. the OP27 op-amps, being bipolar, are sensitive to RF, this could be fundamenally the problem. Most people, including myself, do not experience the issue so its hard for me to test. If you cant change anything by grounding and shielding or RF beads, you might try replacing the input op-amp with a FET type, OP134 or something like that.
/Richard
RJM: on the cases - I'll observe, evaluate and report on hum and noise. I'm hoping they'll be OK as WAF is high!
hum is not noticeable right now at normal listening levels. I have a much treasured pair of ESL 57's and I don't drive them to trouser flapping levels, so it might not be an issue for me.
From your burn in description, I think what I'm hearing corresponds to what you have there for day 2.
good things to come!
Fran
hum is not noticeable right now at normal listening levels. I have a much treasured pair of ESL 57's and I don't drive them to trouser flapping levels, so it might not be an issue for me.
From your burn in description, I think what I'm hearing corresponds to what you have there for day 2.
good things to come!
Fran
I tryed a lot of things to get the humm lower
the radio is gone i must turn the volume very high to hear it now
so thats ok.
Dont want to use a different opamp i have not a gainclone limited then anymore.
I Think the hum is only wiring things when i connect the the input and output ground together the hum halves but is stil a little to much
the com is also on the casing then .
The sound is realy amazing i am very happy with it
the radio is gone i must turn the volume very high to hear it now
so thats ok.
Dont want to use a different opamp i have not a gainclone limited then anymore.
I Think the hum is only wiring things when i connect the the input and output ground together the hum halves but is stil a little to much
the com is also on the casing then .
The sound is realy amazing i am very happy with it
It are the cables 
The cable from te cartridge and the output cable working like antennes i can lay them so that there is no hum but if i move them only a few mm the humm get there and the radio plays louder.
If i unplug the cartridge cable the phono clone is totaly humm free
i can turn op the volume of the preamp totaly and there is absolute no humm is this a good sign or is it always quied then?
pfffffff
The cable from te cartridge and the output cable working like antennes i can lay them so that there is no hum but if i move them only a few mm the humm get there and the radio plays louder.
If i unplug the cartridge cable the phono clone is totaly humm free
i can turn op the volume of the preamp totaly and there is absolute no humm is this a good sign or is it always quied then?
pfffffff
mmmm thats what I saw too.
I'm wondering if the grounding arrangement for dual mono needs to be looked at.
Tube300 - I'm not going to get to it for a few days. Could you maybe rewire yours at the phonoclone case so that the phonoclone is running from just one transformer and see if the hum goes? (ie exactly as per RJMs site?)
Fran
I'm wondering if the grounding arrangement for dual mono needs to be looked at.
Tube300 - I'm not going to get to it for a few days. Could you maybe rewire yours at the phonoclone case so that the phonoclone is running from just one transformer and see if the hum goes? (ie exactly as per RJMs site?)
Fran
When I was doing this first: yes, if I disconnected even one cartridge cable then the hum was gone...
BUT:
I didn't think I would get time to try this: I tried connecting the COM points together before the rectifiers - result was huge hum and buzz - so this is out.
However, I had a bit of a look again, and with some careful routing of cables my hum is now gone - or at least so small as to not be audible at even loud listening levels.
So my arrangement then: Dual mono - each side fed completely separately through 2 cables through 2 3 way XLR jacks to each board. Inputs and outputs connected as normal. Ground of both inputs (ie RCA sockets) are connected together and also to the TT ground lug. Careful arrangement of my non shielded interconnect results in v. small noise. My tonearm cable is shielded - moving this doesn't affect hum. Interconnect from PC to preamp is non -shielded and here is where my noise is getting in.
I think I will have to shield it too.
My cables are DIY silver with eichmann bullets. An easy way to shield, if your cables are DIY is to use the copper braid from TV coax and connect to ground at one end only. Or leave a fly-wire and connect to the TT ground lug.
Fran
BUT:
I didn't think I would get time to try this: I tried connecting the COM points together before the rectifiers - result was huge hum and buzz - so this is out.
However, I had a bit of a look again, and with some careful routing of cables my hum is now gone - or at least so small as to not be audible at even loud listening levels.
So my arrangement then: Dual mono - each side fed completely separately through 2 cables through 2 3 way XLR jacks to each board. Inputs and outputs connected as normal. Ground of both inputs (ie RCA sockets) are connected together and also to the TT ground lug. Careful arrangement of my non shielded interconnect results in v. small noise. My tonearm cable is shielded - moving this doesn't affect hum. Interconnect from PC to preamp is non -shielded and here is where my noise is getting in.
I think I will have to shield it too.
My cables are DIY silver with eichmann bullets. An easy way to shield, if your cables are DIY is to use the copper braid from TV coax and connect to ground at one end only. Or leave a fly-wire and connect to the TT ground lug.
Fran
But if i have totaly no sign of hum when i disconect the input than it must be the tone arm cable the cartridge or the grounding here.
I think that the phono clone and supply is good then
the tone arm cable is one piece from the cart to the input plugs
the cable is shielded there is a groundcable comming out.
I connect this to the phonoclone but i dont think the shielding is connected in the arm i measure infinite ohm between the groundcable and the alluminium tone arm and iron arm base
should this arm and base also grounded ?
the arm and base is mounted on lexaan (sort plexiglass)
I think that the phono clone and supply is good then
the tone arm cable is one piece from the cart to the input plugs
the cable is shielded there is a groundcable comming out.
I connect this to the phonoclone but i dont think the shielding is connected in the arm i measure infinite ohm between the groundcable and the alluminium tone arm and iron arm base
should this arm and base also grounded ?
the arm and base is mounted on lexaan (sort plexiglass)
No, I went through this with Richard. As I recall, there is a ground loop being induced through the input cables. Thats why when you even disconnect one input cable, the hum is gone.
Try connecting your input grounds together at the back of the RCA jacks and see does the hum reduce. Then try disconnecting the COM to phonoclone case/TT ground lug connection.
What arm are you using? The TT ground cable should be connected to the arm.
Fran
Try connecting your input grounds together at the back of the RCA jacks and see does the hum reduce. Then try disconnecting the COM to phonoclone case/TT ground lug connection.
What arm are you using? The TT ground cable should be connected to the arm.
Fran
grounding issues
Issues with hum always leave me scratching my head, because it was never a problem for me. No, not "so low I cant hear it". Really, no hum. Zero. Nada. Nothing. The 60 Hz and even 120 Hz barely peak above the measured noise floor, no way can you pick it out above the rushing, pink noise background of the op-amp noise. At normal listening levels I can not decide if the system is powered up by putting my ear to the tweeter for example, though at max volume I get clearly audible, but not deafening, pink noise...
The best test is the following: at your normal listening level, you should not be able to detect whether your preamp is switched to the CD player or the turntable if there is no music playing, unless you have your ear closer than 30 cm from the speakers.
People in really quiet environments may find it more easily detectable, but as a rough guide thats the best thing I can think of. Also since all RC kits came with the same R2, those of you using low impedance carts will have more gain, and more sensitivity to noise pickup as a result.
Some helpful ( I hope ) hints for getting the grounding issues fixed:
Start with one channel. Disconnect the other one from the power supply entirely, and unplug its inputs and outputs as well. Get one channel working hum free, then worry about getting both to work.
The phonoclone channel will always be noise and hum free with the input unplugged, because without the cartridge load (or a dummy resistor as substitute) the gain of the first stage is zero. Thus the best route in my opinion is to temporarily solder resistors across the inputs equal to your cartridge impedance (or make a RCA terminator), and forget about the turntable and cartridge completely until both channels work properly with the dummy load.
The strategy should be self-evident, but just in case: the game plan is always "disconnect things until the hum goes away, and then connect things until it comes back". Although more time consuming this is actually much more effective than the "poke at things and see if the hum changes" strategy... though the latter has some merit when dealing with RF pickup.
Issues with hum always leave me scratching my head, because it was never a problem for me. No, not "so low I cant hear it". Really, no hum. Zero. Nada. Nothing. The 60 Hz and even 120 Hz barely peak above the measured noise floor, no way can you pick it out above the rushing, pink noise background of the op-amp noise. At normal listening levels I can not decide if the system is powered up by putting my ear to the tweeter for example, though at max volume I get clearly audible, but not deafening, pink noise...
The best test is the following: at your normal listening level, you should not be able to detect whether your preamp is switched to the CD player or the turntable if there is no music playing, unless you have your ear closer than 30 cm from the speakers.
People in really quiet environments may find it more easily detectable, but as a rough guide thats the best thing I can think of. Also since all RC kits came with the same R2, those of you using low impedance carts will have more gain, and more sensitivity to noise pickup as a result.
Some helpful ( I hope ) hints for getting the grounding issues fixed:
Start with one channel. Disconnect the other one from the power supply entirely, and unplug its inputs and outputs as well. Get one channel working hum free, then worry about getting both to work.
The phonoclone channel will always be noise and hum free with the input unplugged, because without the cartridge load (or a dummy resistor as substitute) the gain of the first stage is zero. Thus the best route in my opinion is to temporarily solder resistors across the inputs equal to your cartridge impedance (or make a RCA terminator), and forget about the turntable and cartridge completely until both channels work properly with the dummy load.
The strategy should be self-evident, but just in case: the game plan is always "disconnect things until the hum goes away, and then connect things until it comes back". Although more time consuming this is actually much more effective than the "poke at things and see if the hum changes" strategy... though the latter has some merit when dealing with RF pickup.
hi Richard
The hum goes away is diconnecting the input
but this is clear now.
The hum is audible at 9 meters (27 feet) from the speakers
and the radio can play loud and clear when i move the phonoclone a few inches and lay the cables around.
But if i place the phono cube under a good angle and lay the cables in a good direction the hum is almost gone but if i move it a very little it comes quick back.
When i pick up the phono cable or interconnect or hold my hand near the cables the hum is also stronger.
i try today again things with one channel as you say
and call the arm builder if there is a ground fault.
The hum goes away is diconnecting the input
but this is clear now.
The hum is audible at 9 meters (27 feet) from the speakers
and the radio can play loud and clear when i move the phonoclone a few inches and lay the cables around.
But if i place the phono cube under a good angle and lay the cables in a good direction the hum is almost gone but if i move it a very little it comes quick back.
When i pick up the phono cable or interconnect or hold my hand near the cables the hum is also stronger.
i try today again things with one channel as you say
and call the arm builder if there is a ground fault.
tube300 - What you're going through now, I went through all that.
You need to:
1. connect the RCA input grounds together.
2. Separate the COMs that you have joined together at the phonoclone case. You have a 7 pin jack, just run and extra wire to another pin for now.
3. Either connect ONE of the COM pins to the TT grounding post, or even none. Connecting both will give you back hum.
Try those things and report back....
I will try to take another photo of my wiring up close later today and post it here.
Fran
You need to:
1. connect the RCA input grounds together.
2. Separate the COMs that you have joined together at the phonoclone case. You have a 7 pin jack, just run and extra wire to another pin for now.
3. Either connect ONE of the COM pins to the TT grounding post, or even none. Connecting both will give you back hum.
Try those things and report back....
I will try to take another photo of my wiring up close later today and post it here.
Fran
Hi Richard and Fran
youre very helpfull.
The first thing i did was made a dummy
i must do things 1 by 1 now.
I soldered a 47 ohm resistor in an RCA plug
and use this the amp is complete humm free now .
With an open input there is still a very little pink noize with the volume open this is no hum but some pink noize but it is an such a level that i never use
with the dummy its complete silence even with the volume full open.
youre very helpfull.
The first thing i did was made a dummy
i must do things 1 by 1 now.
I soldered a 47 ohm resistor in an RCA plug
and use this the amp is complete humm free now .
With an open input there is still a very little pink noize with the volume open this is no hum but some pink noize but it is an such a level that i never use
with the dummy its complete silence even with the volume full open.
uh oh...
There should be some noise at max volume when the dummy input load attached. Are you sure?
your build is impecable, with the photos to prove it, so I cant understand whats up.
Please make a second dummy input for the other channel. See if you can get two hum and RFI free channels powered up simultaneously in that configuration.
If you can then, then its one of two possible things:
Either you have to connect the case/TT ground to the IN- wire (at the input RCA jack ring) and disconnect the case/TT ground from COM. Like Fran did.
or.
not sure.
something else.Certainly Id try a different turntable if I could, maybe at a friends place. Also consider trying a single transformer rather than dual mono for now. Though if I understand you this is what you are doing now, right?
.....
re Frans advice, which is mostly right
You need to:
1. connect the RCA input grounds together.
no no no! shorting the inputs will cause the gain of the first stage to skyrocket, and the phonoclone will be VERY noisy. Most amps are noisiest wih he inputs open, quietest with them shorted, the phonoclone is backwards, because the gain is dependent on the input load.
2. Separate the COMs that you have joined together at the phonoclone case. You have a 7 pin jack, just run and extra wire to another pin for now.
agreed. you have the extra pin, so for now at least wire it with 6 conductors (e.g. V+,Com,V-,n/c, V+,COM,V-)
3. Either connect ONE of the COM pins to the TT grounding post, or even none. Connecting both will give you back hum.
ok, try lifting one of the COM pins... if it makes a difference remove both and connect the case/TT grounding port to the input RCA jack outer ring (IN-) instead. Once you have the case connected to IN-, dont go back and connect COM to the case! COM and IN- are one and the same thing, (ground!), connected together through the PCB. The ground only needs to be connected to the case at one point, and technically I think only one channel needs to be connected, though normally I connect both.
Excellent. Unfortunately you arent going to be able to listen to any records with this configuration! Your phonoclone is all proper and correct, but now we have to figure out how to get it to play nice with your turntable.
I would appreciate it if you could, for the sake of keeping this thread as clear and uncluttered as possible (huh?!), get in touch with me directly by email to continue the discussion.
Once we get he problem sorted out, then you or I can report back to the DIY forum.
Anyhow, your next step (you've made great progress today, by the way) is to connect the turntable to one channel only, and leave the other with the dummy load...
Your phonoclone is all proper and correct, but now we have to figure out how to get it to play nice with your turntable.I would appreciate it if you could, for the sake of keeping this thread as clear and uncluttered as possible (huh?!), get in touch with me directly by email to continue the discussion.
Once we get he problem sorted out, then you or I can report back to the DIY forum.
Anyhow, your next step (you've made great progress today, by the way) is to connect the turntable to one channel only, and leave the other with the dummy load...