Hi , I'm From ITALY I'd like to buy your PhonoClone Kit PC Boards , Power supply . Is it still available the Kit ?
Roberto
Roberto
The Phonoclone is longer available. It has been replaced by the Emerald. Pls email or pm me if interested.
Hi Richard, boards arrived to UK in exactly 2 months as you said, it gave me plenty of time to get all the parts together!!. I'm all assembled but without the op amps in place I'm getting 13.3v across both V+ and Ref, and V- and Ref on one board and 12.6V across both on the other, is this ok?
Yes, you can expect a slight variation because the regulators use the Vbe of the transistors as voltage references. It works, but the values vary a fair bit between transistors. It won't make any difference to the circuit performance and nothing to worry about.
That's great, I was concerned that the 13.3v was a bit high plus the lack of symmetry between the channels. Time to fire up, will report in due course with photos.
Hallo all and happy new year!!!
My question is about the op amp.
Can i use a diferent op amp like OPA637?
My question is about the op amp.
Can i use a diferent op amp like OPA637?
Attached is a photo of my build. Apart from a couple of out of stock resistors it is exactly as per the BOM and construction guide, 2 case version with power supply from original VSPS. Recycled the case and Mundorf caps from the VSPS also. After 48hrs warm up initial listening is very impressive, it actually sounds like a deluxe version of the VSPS and ghostly quiet as well.
I have a small problem however. There is now a pop through the speakers when I turn off my turntable (a lesser one when I power it on). This was not present with the VSPS and I have just put another phono amp in place and there is no pop there also. The switch itself has a cap across it and seems fine so all points to the emerald as somehow the culprit but I'm baffled as to how?
I have a small problem however. There is now a pop through the speakers when I turn off my turntable (a lesser one when I power it on). This was not present with the VSPS and I have just put another phono amp in place and there is no pop there also. The switch itself has a cap across it and seems fine so all points to the emerald as somehow the culprit but I'm baffled as to how?
Attachments
Hey folks - I'm wiring up my first PSU and want to be careful with the transformer connections. I'm using the Triad VMP24-1040 recommended on the BOM but am a tad confused with the 120 VAC to 12 VAC wiring (I'm in the US). Based on everything I've read and watched in preparation, I would expect to connect the black and red wires to one bridge rectifier and the orange and yellow wires to another. The "jumper black and orange" and "jumper red to yellow" language doesn't jive with my reading of the schematic though.
What do they mean by "jumper" in the output options and what am I missing here?
Full datasheet is here, screenshot of the confusing bit is below.
What do they mean by "jumper" in the output options and what am I missing here?
Full datasheet is here, screenshot of the confusing bit is below.
What TT are you using and does it have an external ground cable? I'm using a Rega Planar 3 and had some switch on/off pops. I ended up running a bit of wire between the ground on the two RCA inputs similar to this video and that fixed things for me.
Its a Lenco PTP6 where the motor is earthed and the arm ground connects to the emerald ground. I will try a separate earth cable when I get home but I am curious as to what is happening with the emerald as other phono amps have no problem.
That one doesn't seem to work well, and given it is so expensive I can't recommend giving it a try either. If you have one in hand though there is no reason not to give it a shot.
For 120 V both windings are connected in parallel to the line voltage. So white and brown go to say Neutral, and blue and violet go to Live. Jumper here means "connect the wires together".
The usual reason given for turn on kicks is a voltage spike caused by sudden interruption of current flow through a coil inductance, which you can dampen by connecting a capacitor across the power switch for example. I'm not sure why the Emerald should be more sensitive to this, however, and I haven't any reports of this happening before now. Certainly I never had any issues with mine.
I don't have any quick answers unfortunately, but I would be interested to learn if you still hear the pops with the input cables are unplugged, i.e. no cartridge connected.
Thanks Richard, I will double check when I get home but I think when I tested with the headshell and cartridge removed from the turntable the switch on/off pop was present but only when the arm and ground cable were unplugged from the Emerald did the pop disappear.
Hm, well that narrows it down. It's not pickup by the cartridge coils, nor is it induced directly into the emerald box. I also highly doubt its the ground cable (you can verify this), so it seems like the phono cable itself is acting is an antenna to pick up the electromagnetic spike of the turn on/off and coupling it back into the Emerald input stage. It may be that the OPA27 are relatively sensitive to this kind of pickup, due to being bipolar rather than FET input type. And the Emerald has no filter circuits on the input to try and prevent RF pickup or this kind of induced noise.
If you are using the Emerald as a MM stage, you can try replacing the input op amp with a FET or biFET type like OPA134.
You can try using a different phono cable with better shielding or more tightly twisted wires.
You can also try adding RF beads or a little cap across the input.
Correction to the above, on/off pop is present also when the phono cable from the turntable is removed from the emerald which i find strange, I will try the RF beads first and report back.
Okay, the comment above about the OPA27 being over-average sensitive to this kind of interference still stands, but the part about the antenna doesn't.
I'd check whether the interference is airborne or through the ground/power cables by separating the Emerald from the TT as much as possible and see if the pop noise stays at the same intensity. Experiment by lifting the ground connections and see if that makes any difference...
I'd check whether the interference is airborne or through the ground/power cables by separating the Emerald from the TT as much as possible and see if the pop noise stays at the same intensity. Experiment by lifting the ground connections and see if that makes any difference...
Just disconnected the ground cables from each board to the case but no difference, also disconnected the tonearm ground from the emerald, no change except a lot of hum. The only way of losing the pop is disconnecting the cable from emerald to preamp!!! It's a real head scratcher because all I have changed is a vsps board for 2 emerald boards. Its the same power supply and same case.
Your reply #737 "on/off pop is present also when the phono cable from the turntable is removed from the emerald" and #739 "The only way of losing the pop is disconnecting the cable from emerald to preamp" appear at odds which each other.
How much "stuff" do you have to connect to the Emerald before you get the pop noise? (no input, phono cable only , cable + tonearm, cable+tonearm+cartridge?)
(note that the only relevant difference between the VSPS and Emerald that I can think of is the OPA27 vs OPA2134 opamps.)
How much "stuff" do you have to connect to the Emerald before you get the pop noise? (no input, phono cable only , cable + tonearm, cable+tonearm+cartridge?)
(note that the only relevant difference between the VSPS and Emerald that I can think of is the OPA27 vs OPA2134 opamps.)