I've seen mention of +/-8v, +/-9v & +/-12v regs used for these. Are the servo driver ICs not bothered about the voltage as long as it's stable?
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Cheers guys. I'll just get some 8v regs for now if they work better with the standard transformer 
Also, I'm trying to work out which ceramics and resistors need removing if I'm putting some good quality electrolytics for the local decoupling caps like rubycon ZLG 220uF to the servo driver ICs. Has anyone got info or a diagram for that?
Also, I'm trying to work out which ceramics and resistors need removing if I'm putting some good quality electrolytics for the local decoupling caps like rubycon ZLG 220uF to the servo driver ICs. Has anyone got info or a diagram for that?
Actually, I've had a good study of the schematics and I've got it all now, other than the 2 ceramics c146 and c148 being a bit too close together to swap for the ZLG caps and c144 being kind of in the way, but I guess it's nothing a bit leg bending and maybe swapping c144 to the bottom of the board won't sort out. Is that the usual method?
Hi,
That's the idea indeed
If thing get really tight, you can move some small ceramics to the back of the board, but if you leave the electrolytics a few mm from the board, it fits nicely.
Here's a picture of how I did it. I didn't use separate regulators for each driver, but replaced U234 and U237 with regulators later on.
Regards,
Ray
That's the idea indeed
If thing get really tight, you can move some small ceramics to the back of the board, but if you leave the electrolytics a few mm from the board, it fits nicely.
Here's a picture of how I did it. I didn't use separate regulators for each driver, but replaced U234 and U237 with regulators later on.
Regards,
Ray
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That's perfect, thanks RayHi,
That's the idea indeed
If thing get really tight, you can move some small ceramics to the back of the board, but if you leave the electrolytics a few mm from the board, it fits nicely.
Here's a picture of how I did it. I didn't use separate regulators for each driver, but replaced U234 and U237 with regulators later on.
Regards,
Ray
Would you recommend running these Electrolytic caps for the driver ICs on their own or with something like a 100nf XR7 alongside too?
Does this look like the right kind of thing if I wanted to beef up my power supply properly?
http://bit.ly/100ckPi
Toroidal 230V Mains Transformer 50VA 0-12V 0-12V
Seems like a no brainer at that price
Can I just patch this in to power my current 10v -/+ rails, but keep the standard transformer in place for the rest? (I have a seperate supply for my output stage already)
http://bit.ly/100ckPi
Toroidal 230V Mains Transformer 50VA 0-12V 0-12V
Seems like a no brainer at that price
Can I just patch this in to power my current 10v -/+ rails, but keep the standard transformer in place for the rest? (I have a seperate supply for my output stage already)
Yes, that's a suitable transformer. You can put the two secondaries in series and use them instead of the 9.6V stock windings, center to GND.
You should keep an eye on the electrolytics working voltages, because 12V AC can go towards 20V DC unloaded (also depends on your local mains voltage) and that's too much for a 16V cap. So C813, C814 and CN01 have to be replaced by 25V types. The caps around the drivers should be fine at 16V if you're going to use 12V regulators for this. Also, you should check the heat development of Q811 because of the higher input voltage.
Regards,
Ray
You should keep an eye on the electrolytics working voltages, because 12V AC can go towards 20V DC unloaded (also depends on your local mains voltage) and that's too much for a 16V cap. So C813, C814 and CN01 have to be replaced by 25V types. The caps around the drivers should be fine at 16V if you're going to use 12V regulators for this. Also, you should check the heat development of Q811 because of the higher input voltage.
Regards,
Ray
so, I've had a look today at the voltages in my machine and run some simple tests using my multimeter.
I know people like pictures, so here's a picture of some measuring happening:
No particular dig at anyone here, but I've read a huge load of this massive thread and I've seen a huge load of "improved bass", "better definition" & "brought new details to life I've never heard before" but very little actual measured or tested data. I know you can't measure everything and some kit is specialised and expensive, but some things can be looked at quite simply and without cost.
In my machine currently (standard non-SE cd63), I have a 22,000uf tsup C813 (positive 10v), and a 4700uf C814 (negative 10v) as well as basic upgrades to most of the smaller electrolytics.
I'm looking at power supply, specifically on the 10v rails too see whether I need a large 50va toroidal transformer or whether the standard one is adequate given the larger bulk capacitors on the rails as well as some additional voltage regulation further down the line. I was also basing this requirement on the fact that it has been mentioned about as much as a 4v drop at times with the standard kit.
The first thing I found was that just after pressing play, when the motor first spins up, there is almost a 2v drop for 1-2 seconds as the disc accelerates, but after that it becomes relatively stable. I don't really mind about that first second or so as there's no musical output at that point anyway.
what I measured over a couple of hours playing was:
Idling voltage on the +10v rail with the unit on, but doing nothing, was 11.58v and very stable.
during regular playing I saw:
Max
11.27v
Min
10.96v
on the +10v rail
And on the -10v rail.
Min
-11.57v
Max
-11.95v
Measured right at one of the driver ICs, taking the reading from the IC end of the ceramic cap C137 I saw min +10.63v, max +10.90v
voltages measured at the 3 parts of the dac and the display IC which I've fed using 7805 regulators fed from the 10v+ rail were all +5.00v bang on, totally stable.
What this says to me is I can stick to the standard power supply, but I should regulate the driver ICs, and 8V regulators seem like a good call there as I can guarantee more than 2.5v dropout during normal operation. A few more simple 5v regulators to other parts wouldn't hurt either as they're obviously effective.
Does that sound about right?
I know people like pictures, so here's a picture of some measuring happening:
No particular dig at anyone here, but I've read a huge load of this massive thread and I've seen a huge load of "improved bass", "better definition" & "brought new details to life I've never heard before" but very little actual measured or tested data. I know you can't measure everything and some kit is specialised and expensive, but some things can be looked at quite simply and without cost.
In my machine currently (standard non-SE cd63), I have a 22,000uf tsup C813 (positive 10v), and a 4700uf C814 (negative 10v) as well as basic upgrades to most of the smaller electrolytics.
I'm looking at power supply, specifically on the 10v rails too see whether I need a large 50va toroidal transformer or whether the standard one is adequate given the larger bulk capacitors on the rails as well as some additional voltage regulation further down the line. I was also basing this requirement on the fact that it has been mentioned about as much as a 4v drop at times with the standard kit.
The first thing I found was that just after pressing play, when the motor first spins up, there is almost a 2v drop for 1-2 seconds as the disc accelerates, but after that it becomes relatively stable. I don't really mind about that first second or so as there's no musical output at that point anyway.
what I measured over a couple of hours playing was:
Idling voltage on the +10v rail with the unit on, but doing nothing, was 11.58v and very stable.
during regular playing I saw:
Max
11.27v
Min
10.96v
on the +10v rail
And on the -10v rail.
Min
-11.57v
Max
-11.95v
Measured right at one of the driver ICs, taking the reading from the IC end of the ceramic cap C137 I saw min +10.63v, max +10.90v
voltages measured at the 3 parts of the dac and the display IC which I've fed using 7805 regulators fed from the 10v+ rail were all +5.00v bang on, totally stable.
What this says to me is I can stick to the standard power supply, but I should regulate the driver ICs, and 8V regulators seem like a good call there as I can guarantee more than 2.5v dropout during normal operation. A few more simple 5v regulators to other parts wouldn't hurt either as they're obviously effective.
Does that sound about right?
thanks Ian
No, I haven't bridged the fuses yet. I'll get that done and report back.
Like I say, I'm not having a dig at anyone, I just like seeing the workings out and being able to see things working well as well as hearing them
I'd love to see scope plots for example showing the difference in the stability of voltages at the actual component inputs between a 50p 78XX regulator and a £50 low noise audiophile one.
cheers,
James
No, I haven't bridged the fuses yet. I'll get that done and report back.
Like I say, I'm not having a dig at anyone, I just like seeing the workings out and being able to see things working well as well as hearing them
I'd love to see scope plots for example showing the difference in the stability of voltages at the actual component inputs between a 50p 78XX regulator and a £50 low noise audiophile one.
cheers,
James