[BUILD] CAPI Dual VPR & 51x Floor Box PSU~Official Support Thread

[kante1603]

Hi Paul!

Update2: Measured resistance between middle pin on Voltage regulators and chassi:
+16V - starting at approx 200Ω and moving upwards
-16V - 7Ω
+24V - zero Ω
-24V 6Ω
+48V - starting at approx 200Ω and moving upwards

Is this ok?..

The negative regs seem to be o.k.,the positive 16 & 48vdc too (caps start charging here,that´s why they move),

but the +24vdc definetely isn´t!

Don´t know why you measured a probe on chassis,you would normally do it at the GND of the psu,and the middle pin of the regulators is their output (!),so you don´t measure them at all.
But:You have found a dead short there by accident,hahahaha.......
And I think already know what is happening:This pin 2 on the regulator connects to the metal plate on the back too,that´s why we have to mount them isolated using a silicone rubber pad and a plastic washer guiding the mounting screw.
I´m close to 100% sure that you can measure (dmm set to ohms) continuity between the metal plate on its front and the screw head (which then connects to the chassis).
If that is the case then you must do the regulator mounting again,use a new pad/washer.
If you can´t find spare parts here´s a link that could work for you,otherwise do a search like "transistor isolation" and "Glimmer" or "silicone" and "pad":

http://www.conrad.de/ce/de/product/155140/Montagematerial-Set-fuer-TO-220-Gehaeuse-SCI-A18-9B-Passend-fuer-TO-220-Material-Glimmer/?ref=no_search_results&rt=no_search_results&rb=1


Easy to overtighten this screw,so be careful and measure after that again.There should be no continuity between the metal part of the reg and the chassis.I do that all times on all regs before proceeding,better safe than sorry,right?

Report back here please,I guess you found it!

Best,

Udo.

 

[kante1603]

Hi Paul,

if you find the plastic washers are o.k. then reuse them (I´m german,so this is "Deutsche Gründlichkeit" ;D).
Take care of the regulators back sides,the must be clean,any even microscopic part of residual cut of wire or so can damage the rubber pad!
I guess this short affects the load on the transformer,specs will change then the more you load it down.Just a guess....
But you should get the psu up and running first anyway,if you find a fault like this you must fix it before doing anything else.

I´m also quite sure that once the psu is fixed your TB550As won´t cause a voltage drop anymore.

Tell us what you get,have fun,

Udo.

 

[[silent:arts]]

So the low resistance on the -16V and -24V is ok (my DMM beeps....)?

yes. look at the schematic. the output from the regulator goes to ground at the negative voltages.

 

[kante1603]

Thanks for chiming in Volker,forgot that question.
I also opened up one of my "monster-psu´s" to confirm that,all good here!

Best,

Udo.

 

[kante1603]

Thanks again Udo and Volker!

It's Sunday and without material here I used some thin compact cardboard, the ones that some small transistors comes with. I cut small pieces of that, made holes, and put between the old rubber pad and the regulators. Did it on all five regulators,

Hahaha...that´s true diy........hopefully they do a good thermal transfer!

so perhaps it could be called a semi-german solution, or at least quarter-german    Everything is now measuring ok on that side.

Good to hear/read!

BUT the +16V is still dropping, more for each TB550A I put in.

Bad to hear/read.
What confuses me is that you stated that your LC53s worked in the same situation (sure they didn´t load down the+16vdc same way as two TB550As?).Since both builds are somewhat similar (at least concerning power consumption) I absolutely don´t get it,especially when you say that the TBs do work in a Purple rack.
I´m running out of ideas at the moment.....sorry.

Just got email from Brian that he suggests that I resolder the big caps, and a possible fault with a regulator. Should I perhaps swap regulators to see if the problem moves? Or do you have any other ideas on were to search?

Thank You!
Paul

I´d say follow Brian´s instructions first,and swap out the LM350T to a new one.It´s a cheap standard part.
But I must say I never heard an LM go down load dependent,only latch up issues if so.......

Best,

Udo.

 

[Unit7]

Edit: To use a little less space on this thread I'm going to delete my recent posts and compress into this post instead:
Problem: 1) Mains fuse blowing frequently 2) When I had more than four units in the rack the level fell about 10-15dB 3) General random behaviour
I found three mistakes on my PSU build: A) Continuity between chassi and middle pin on one of the voltage regulators B) Didn't notice that voltage regulator called IC1 was different than the others (for the 48V) and it ended up at IC5 (+16V) C) Forgot to solder one leg on one of the large caps.
Everything looked ok at power up so I didn't notice anything strange until I got the hooked up in my studio. The drop in level was beacuse of the misplaced regulator causing voltage to drop for every module put in the rack. With more than four modules in, the voltage dropped below 13V and modules didn't work properly

Success finally! Moved that TL783 regulator that I had mistakenly put at IC5 instead of instead of IC1. The fix was a bit messy and I was afraid that the regulators got too much of my soldering iron, but now voltage remains the same with all my seven eqs in the rack.

BTW Udo, Brian commented that his 550As draws a bit more current than the LC53As (edit: TB550A with GAR2520: 125mA @ +16V/110mA @ -16V compared to Udo's measurement on the LC53A: 75mA), among other things because he has added relays to the design to make the unit go into hard bypass mode and still passing audio if power goes down.

I know it was a real noob mistake. And I'm spoiled by Horvitz's assembly guides and Chunger's detailed photo documentation, but I'd like to humbly suggest a little addition to the Floor Box Assembly Aid, pg3, part 9, it says 'Following the BOM' (which is obviously what I missed...), following that it would be nice with a little heads up, like 'note that the single TL783 goes into the IC1'

Best
Paul

 

[kante1603]

Success finally! Moved that TL783 regulator that I had mistakenly put at IC5 instead of instead of IC1. The fix was a bit messy and I was afraid that the regulators got too much of my soldering iron, but now voltage remains the same with all my seven eqs in the rack.

BTW Udo, Brian commented that his 550As draws a bit more current than the LC53As, among other things because he has added relays to the design to make the unit go into hard bypass mode and still passing audio if power goes down.

After building more than ten 500 format units without any big problem I'm a bit dissapionted that I did two major ones on this build...

I know it was a real noob mistake. And I'm spoiled by Horvitz's assembly guides and Chunger's detailed photo documentation, but I'd like to humbly suggest a little addition to the Floor Box Assembly Aid, pg3, part 9, it says 'Following the BOM' (which is obviously what I missed...), following that it would be nice with a little heads up, like 'note that the single TL783 goes into the IC1'

Best
Paul

Hello Paul,

poooooohhhhhh.......you did it!That was a hard road,hahaha.......
Glad you got it all solved and running now,sh*t happens!
About the additional current draw of the TB550As,it will still be in the ballpark even with 1 or two relays,so within the specs for one slot.I was looking for some kind of general behaviour concerning loading down the psu.

And about the regs and putting them in the wrong place:I always start to read the BOM and look for parts I don´t know exactly.
Then I google and study them until it makes "click" in my brain.Therefore I would have known that a LM350 handles up to roughly 35vdc while a TL783 goes up to 125 vdc,but at a way lower current.So it is the phantom power rail at +48vdc (...the brain starts working........"click!"... ;D).
I collect all data,it´s always a good source to have them handy.Just a suggestion........

Congrats Paul,have fun EQing now!

Best regards from germany,

Udo.

 

[Unit7]

I always start to read the BOM and look for parts I don´t know exactly.Then I google and study them until it makes "click" in my brain.
[/quote]
You are an übermench, that's totally clear! I've read about what different components do, Ohms law etc etc many times, but it still doesn't make a click in my brain, and it doesn't stick. For you I guess that's what a C major scale is for me. Very basic.
I'm thinking that by offering full kits ready for building, and by having assembly guides etc - a very different thing from the guy building a 670 from the ground up - people with little theoretical knowledge but ok assembling/soldering skills like me are invited, and the crowd is getting bigger. So, even if it's not hard core DIY, optimizing assembly guides like Horwitz and Chunger would perhaps save time for everybody? But that's another topic. Perhaps I'll bring it up in the Brewery...
Cheers
Paul

 

[taliska]

Hello there.

First post, so I should probably introduce myself!

I'm Kaz, from the UK. Software Engineering (indie) Game Dev looking for a new hobby, and DIY recording gear seems to be it! (need something to stop me coding 16 hours a day!)

I've been lurking for a while trying to work out whether the DIY thing was something I was comfortable with, and I've had time to read many of the posts, so I should say a big thank you to all of you for providing such a great resource. I already feel like I've learnt stuff!

I plan on ordering and building the 51x rack and PSU (assuming they're still available), but have been reading up to try and get my understanding to a level where I'm not going to kill myself if I do this! ;-)

I have some questions, which I hope are not entirely silly, and hopefully will have fairly straightforward answers! My apologies if any of the terminology is wrong, as I'm a software engineer by profession and was never really great at the electronics stuff.

I've (briefly) looked at the PSU schematic, and it seems to suggest that different component choices in the PSU circuit choose between 16/24 vdc for the last secondary in the transformer. Is the transformer the same in both the VPR and 51x variants of the PSU? My assumption is that they must be different, as one of the secondaries would need to be wound differently, right? (just trying to work out whether the kit I get limits my choices up front!)

I'm a bit of newbie at this stuff, as it's been a long time since I've had to do any electronics (15+ years!), but it looks like there are two outputs from each of the circuits attached to each of the secondaries. I'm guessing that each of the output As from each circuit are bundled together and sent to a rack. The same for the B outputs too. Umm, a bit like:

16 | 16                24 | 24            48 | 48
|      |                    |      |                |      |---------------|
|      |----------------)-----)-------------)--------------|      |
|                          |      |-------------)------------- -)--|  |
|                          |                      |                  |  |  |
|-------------------|  |  |-----------------                  |  |  |
                          |  |  |                                      |  |  |
                          rack 1                                      rack 2
                         
That means that the VPR build gets sent 16/16/48, and the 51x build gets sent 16/24/48, right?

So this leads me to thinking the following:

- If i were to run two VPR racks (with the VPR PSU of course), then all of the modules would always have enough power all the time.

- If I were to run two 51x racks, then the overall module composition would have to 50/50 right? That is, 11 VPR modules and 11 51x modules. That means that if I can't find enough 51x modules that I want to put in my rack, then I might not be able to use VPR modules instead, because the 16vac transformer secondary can't do more than 11 modules...right?

I realise I'm assuming that all modules are operating at the limits of the VPR spec / power supply spec, etc..

FWIW, I'm planning for most of my modules to be DIY initially as I'm cheap, so I plan on configuring for 24v as much as I can anyway, so it's not of a huge consequence, I just want to make sure that my understanding of the configuration and it's limitations is correct.

So unless I've really misunderstood something, all this means that I can get the 51x (extra pins) rack and 51x PSU as my initial setup, and have 100% 51x modules in there, or 100% vpr modules there, and any composition in between, because I'm not trying to power a second rack yet. At the point I get a second 51x rack, I would then just have to be careful about how i compose my racks, right?

Apologies for the lengthy post, and sorry if this isn't the best place for this. It seemed the best place due to the PSU aspects, but feel free to move it if it's better placed elsewhere!

Thanks for all your helps guys!

P.S. I just previewed my post and realised it's hard to pick out the questions, so I've highlighted the key ones in light green.

P.S.S. Sorry for all the "right?"s! It's not that bad....right?  ;D

 

[[silent:arts]]

So unless I've really misunderstood something, all this means that I can get the 51x (extra pins) rack and 51x PSU as my initial setup, and have 100% 51x modules in there, or 100% vpr modules there, and any composition in between, because I'm not trying to power a second rack yet. At the point I get a second 51x rack, I would then just have to be careful about how i compose my racks, right?

absolutely right!

however, we do not know the modules. there are some less consuming, some more consuming modules out there.
one day there might be a module taking everything from 16V and 24V.

this is the downside of a modular / open system ...

 

[taliska]

That's great, thanks for clarifying that for me [S:A]!

Well, in that case, I imagine I'll be getting the "proper" 51x rack and PSU soon then!

I'll send a mail through to you at [email protected] to order properly.

Oh, and I noticed that you've got a few other things (on your whitemarket listing) I'd quite to order too, so I'll include questions about those things off-thread too.

Thanks!

 

[Toure14]

Calling it a night for now. But I finished most of my PSU.

I stopped because I'm at the step where I had to power it on. When I did, it popped a few times so I cut it off. Checked to make sure everything was tight connection wise; and powered it back on. It popped maybe 10-12 seconds afterwards. I powered it back off and checked my fuses. None are blown and all my lights came on and nothing is smoking.

So my question is why is my PSU doing that?

I'm wired up for 115v US. I didn't check voltages yet because I'm unsure of putting my hands in there until I get a little feed back on what couble be causing the popping/sparking. It looks and sounds like its coming from the plug/IEC area.

Hope I have provided enough info.
G

 

[kante1603]

Hello,

looks like a loose mains connection or so.
What exactly do you mean by popping?
Have you seen a spark in that area?
Does it smell burnt?
May even something visible there?
Anyway,power off,remove the power cable and put it away for now....I mean that,this is dangerous stuff!

Tell us what you see or smell from the inside.
Can you post a good pic from that area?

Best,

Udo.

 

[Unit7]

Udo, when I built my PSU you recommended me to measure the outputs (secondaries) from the transformer before hooking up to the PCB, which was a very good and orderly way to go. Seems like a good idea for Toure, not? Also previous posters having problems with the input (primaries) of the xformer has been successful getting help when they posted pics of the primary wiring/IEC plug area.

 

[kante1603]

Hi Paul,

nice seeing you back here!
Yes,but that should be a next step.
But first Toure should check the mains connections and related parts there to get out of the "danger zone".
A loose wire carrying live ac can seriously be f****ng dangerous.Given the house fuse dosn't work properly it can kill you,not joking!

Hope you're fine,best,

Udo.

 

[Unit7]

Thx Udo! But I don't know about 'back'… With no projects currently on my desk = a dull and empty life, I'm here all the time! Waiting for a pair of LC53 kits though. And you're right about the procedure of course, as usual. I know that regarding the major f***ups I did with my PSU I shouldn't be giving advice. Did I mention my life is dull and empty? ;D

 

[kante1603]

Lots of work with the lovechildren,promised ;D

Chairs,

Udo. ;D

 

[Toure14]

Here are the pictures as requested. I took a pic of the power cord too, which is rated for 10A 125V 1250 Watts.

I cut the heat shrink so that I could check all contact points for pitting or burn marks. The connections are solid and the only loose thing I feel is when the IEC moves itself from the little wiggle room it has in the cut out hole but I assume this will happen or is normal given the pressure I am applying to check it.

I see a small gap at the bottom of the case, don't know if that has to do with anything. I also used brown wire for the brown and black connection so expect to see brown on brown instead of black on black for that connection.

I took these on my iphone-5 and I am no means a photographer:

 

[Toure14]

Don't know why I can't post pictures inside the actual post like members, it only lets me do attachments and only 1 at a time so there will be another post with 1 picture after this 1....sorry

 

[Toure14]

And another....