[BUILD] CAPI 511-VPR~Filtered 500 Series 11 Space Rack~Official Support Thread

[Ricardus]

Hi all,

I delivered two db25 11 racks with filtered power to friend who describes the following issue with one of them.

The unit stopped working after 3 days of the unit working as expected with power on / off.

On subsequent powerons there seem to be a fluttering with units temporarily lighting up but unable to remain on.

When the load is reduced to 8 units it always powers on and three units can then be added in and power will remain stable. With nine units the power issue occurs sometimes.

The unit is currently stocked with 11 preamps in the following order: two stam 312 tube, two stam 312, two capi 312, two capi vp28, two avedis ma5 and one capi vp28 Platinum.

The second unit is filled with parametric eqs and has no issue. Switching power supply has no effect.

Thoughts?
Thanks,
Harry

You probably answered your own question here. The racks are not active, they're just wiring, so if you wired them correctly you should be fine.

Sounds like a current draw issue to me. Add up the current draw of each of the modules in the first rack and see if it exceeds the (switching?) power supply.

Did you test the voltage rails on the power supply by itself to make sure it's OK?

You'll probably need to take half the units from the first unit and fill the other half with the parametric EQs. So both racks will be half (ish) EQs and half (ish) of the high current drain other modules.

Perhaps not what the end user was looking to do, but it might work if it's simply you exceeding the current output of the PSU.

Otherwise maybe one of the PSUs is bad.

Otherwise if you want to keep all of those higher current draw devices in the first rack you're going to need to source a higher current power supply.

 

[hzjr88]

Hi Ricardus, thanks for your reply.
I suspect same issue, but wanted to see if I could be overlooking something.
I checked the rails months ago when I built it, but has since been moved around and set up in new studio. -wouldn't hurt to recheck.
I did try alternative power supply but not any better, and both able to power alternative rack.
I have the currents for 9 of the units, just hoping to hear back from Stam regarding their 312 tube pres.
I'll post back if I hear from them.

Best,
Harry

 

[hzjr88]

You probably answered your own question here. The racks are not active, they're just wiring, so if you wired them correctly you should be fine.

Sounds like a current draw issue to me. Add up the current draw of each of the modules in the first rack and see if it exceeds the (switching?) power supply.

Did you test the voltage rails on the power supply by itself to make sure it's OK?

You'll probably need to take half the units from the first unit and fill the other half with the parametric EQs. So both racks will be half (ish) EQs and half (ish) of the high current drain other modules.

Perhaps not what the end user was looking to do, but it might work if it's simply you exceeding the current output of the PSU.

Otherwise maybe one of the PSUs is bad.

Otherwise if you want to keep all of those higher current draw devices in the first rack you're going to need to source a higher current power supply.

Wanted to close the loop on this issue.
I summed up the current demands from the preamps and I was well under. In trying different combinations of units, the rack seems to work as expected when the Avedis MA5s are removed. I found on the Avedis site that the MA5 cause an initial current surge that can trigger the regulators to turn off on some power supplies. I'm not sure if that is exactly what is happening here, but things are now working with them removed and two more vp28 Platinum in their place.

 

[gwpt]

Just finished building a DB25 version, and everything is working fine.

Two questions:
1. (I know this was answered above but I still don't get it) What do the switches do? Above it says 'Pin 6 DC Link' and not stereo link. What is DC Link? and what is it used for?

2. What are these 16 unused pads for? I assume it's 2 of something for the 1st 8 slots. Which Pin do they go to? What could it be used for?

Thanks

 

[CaptainVideo]

Hello to all! I am posting on this forum as I am having issues with resolving a F1 fuse blowing on the 511 VPR floor power supply when
I connect a VPR 11 space rack The PSU is fine and will run for hours if the rack is not connected. I have been troubleshooting with and without the rack connected to the PSU and cannot find a short in the PSU or the rack.. Therefore I am progressing to removing components but wanted to reach out to the comunity first to see if there is any historical issue when dyi’rs assemble the rack. My testing notes are below.

Equip:

Dual VPR DC PSU 2x11

VPR filtered 11 space XLR in/out rack

Problem statement: F1 (48v supply) fuse blows (value 160mA) for both cable supplies

Testing/Measurements:

PSU; turns on fine and all voltages stable, (not plugged into rack): 48.49v, 16.7 +/-, unit will happily run for hours with no issues.

Measurements taken at PSU (from JP1-1 both 48v supply terminals) to the backplane of the VPR rack. No fuse in place:

48v circuit reading at both PSU terminals to pin 5: 0.1 ohm

48v circuit to card land 15 (all): 1.5/1.6 ohms

48v circuit to CHA ground: min: 0.10 M ohm, max: open and average:5.29 M ohm (sweep reading due to caps in line)

I cannot find a short with the components mounted. Before I start removing parts in the 48v circuit (7 pin xlr, c9, ck2, c10, c18, c11 and c17) I wanted to ask the communities opinion first.

Please let me know your thoughts/ history on the rack for 48v issues encountered!

Thank you for your time and help with this matter.

 

[jsteiger]

Is the rack empty when testing as you mentioned above?

 

[CaptainVideo]

Is the rack empty when testing as you mentioned above?

Yes, no modules are present.

 

[CaptainVideo]

This weekend I will pull all of the caps and test them as I am not finding any direct shorts on the board. I am referencing the attached pin listing for troubleshooting.

 

[CaptainVideo]

All;

Update on testing of the PSU and VPR rack:
I pulled all components in the 48v curcuit and tested, all seemed in spec (caps and inductor). I jumped pin 5 to C11 + ibis board lands and PSU powered up and all rack card pin 15s were reading 48.5v.
Power result via replacement:
I reinstalled all the components one at a time and after each addition I powered up the PSU. The PSU properly powered up until C11 (last cap) was added and then the fuse blew.
I verified R1 and R2 in the 48v circuit of the PSU and they are correct. With C11 removed the 48v circuit runs for hours. I’m thinking the current inrush with the total capacitance is the issue. I checked for shorts and there are none with C11 lands. Any thoughts on what could be causing the inrush issue??? Are the resistors the only limiting mechanism?

Looking forward to responses

Regards

 

[CaptainVideo]

All;

Update on testing of the PSU and VPR rack:
I pulled all components in the 48v curcuit and tested, all seemed in spec (caps and inductor). I jumped pin 5 to C11 + ibis board lands and PSU powered up and all rack card pin 15s were reading 48.5v.
Power result via replacement:
I reinstalled all the components one at a time and after each addition I powered up the PSU. The PSU properly powered up until C11 (last cap) was added and then the fuse blew.
I verified R1 and R2 in the 48v circuit of the PSU and they are correct. With C11 removed the 48v circuit runs for hours. I’m thinking the current inrush with the total capacitance is the issue. I checked for shorts and there are none with C11 lands. Any thoughts on what could be causing the inrush issue??? Are the resistors the only limiting mechanism?

Looking forward to responses

Regards

In case anyone is interested testing results (All from the 48v circuit):



Caps 0.1 uf: 103nf, D 0.0159, theta 89, ESR 206 ohms, Q 62.4. Similar caps are representative of these numbers.



Caps 470uf: 436 uf, D 0.0444, theta 87, ESR the other cap was similar.



Ck2 inductor: 2m Henry per side at 1ohm each

 

[CaptainVideo]

In case anyone is interested testing results (All from the 48v circuit):



Caps 0.1 uf: 103nf, D 0.0159, theta 89, ESR 206 ohms, Q 62.4. Similar caps are representative of these numbers.



Caps 470uf: 436 uf, D 0.0444, theta 87, ESR the other cap was similar.



Ck2 inductor: 2m Henry per side at 1ohm each

Sorry all forgot to add in that all testing was conducted at a freq of 120hz

 

[jsteiger]

Sorry I did not realize you were using a Floor Box with a filtered rack. In that case I recommend changing the 160mA Fast Blow fuse to a 160mA Slow Blow.

 

[CaptainVideo]

Sorry I did not realize you were using a Floor Box with a filtered rack. In that case I recommend changing the 160mA Fast Blow fuse to a 160mA Slow Blow.

Jeff;

Thank you for that response and conformation. I have already ordered slow blow to see what happens. The floor VPR PSU transformer is capable of 250mA at ohmic load so Another option would be to limit current within the floor PSU itself. Once I receive the new fuses I will report back. Also within the CAPI web site I located the VPR slot 9 to 11 filtered assembly and was wondering if that might be available, outside of the full rack package, for purchase?

Please let me know and thank you.

Regards
CCR

 

[jsteiger]

Jeff;

Thank you for that response and conformation. I have already ordered slow blow to see what happens. The floor VPR PSU transformer is capable of 250mA at ohmic load so Another option would be to limit current within the floor PSU itself. Once I receive the new fuses I will report back. Also within the CAPI web site I located the VPR slot 9 to 11 filtered assembly and was wondering if that might be available, outside of the full rack package, for purchase?

Please let me know and thank you.

Regards
CCR

We are coming out with a standalone filter for the SMPS.

 

[CaptainVideo]

We are coming out with a standalone filter for the SMPS.

Jeff;

Thank you so much for the help with the build. The T160mA250v fuses arrived this weekend, replaced and hot the power, it worked, slowly rebuilt the rack and tested, all worked. I now have that rack filled with 8 modules and so far its works well!!

Thank you and have a great weekend (until I build my next rack!!!), regards

CCR

 

[tbodenchuk]

Having an issue where when I turn on phantom power in my slot 1 preamp it caused my slot 3-4 preamps to click and pop. Happened when I had 8 preamps and 2 compressors slotted into the rack.

And then slot 3 stopped passing audio.

Caps seem to be correct orientation.

Using the switching power supply.

Pin 15 voltage is 48.3
Pin 14 is -16.7
Pin 12 is 16.2

Must be a Solder bridge happening somewhere but I'm having trouble finding it

 

[jsteiger]

Having an issue where when I turn on phantom power in my slot 1 preamp it caused my slot 3-4 preamps to click and pop. Happened when I had 8 preamps and 2 compressors slotted into the rack.

And then slot 3 stopped passing audio.

Caps seem to be correct orientation.

Using the switching power supply.

Pin 15 voltage is 48.3
Pin 14 is -16.7
Pin 12 is 16.2

Must be a Solder bridge happening somewhere but I'm having trouble finding it

It might be the module? Have you swapped them around to see if the issue follows the module or stays with the slot?

 

[tbodenchuk]

The modules are working now thank you!

The only thing I notice is when plugging in an LDC that needs phantom power an AKG414 for example. Without phantom power engaged plugging into a Neve 1073LB there is considerable hum. When phantom is engaged the hum goes away. If that's just normal operation I can totally live with it.

 

[jsteiger]

The modules are working now thank you!

The only thing I notice is when plugging in an LDC that needs phantom power an AKG414 for example. Without phantom power engaged plugging into a Neve 1073LB there is considerable hum. When phantom is engaged the hum goes away. If that's just normal operation I can totally live with it.

I have no idea about that. I guess that is not normal operating procedure so it kinda doesn't matter.

 

[tbodenchuk]

Thank you for your quick response Jeff. Love your stuff. Built 4 Capi vp28 and they are great sounding! Looking forward to getting some EQs soon as well