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Post by unit7 on Jan 19, 2015 8:17:42 GMT -6
I'm slowly filling an 11 way 500 rack with Heiders and VP28s that I'll put in a portable rack case, probably an SKB plastic case as my sessions takes place like 99.9% in my home town and I don't need a heavy duty case. What's the word on the heat issue with these? 20+ opamps generate quite some heat. Is it recommended or even crucial to add an extra rackspace above the 500 rack? Most rack cases provide about an inch of space on the bottom/top but they're not open on the front so no possibility for the air to really move. jsteiger? Anyone else? |
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Post by jsteiger on Jan 19, 2015 9:11:20 GMT -6
You will probably be OK with heat if your PSU is running in the 16V area. The opamps do run a little warm though. It would not hurt to check it out first and see what you think.
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Post by svart on Jan 19, 2015 9:22:37 GMT -6
My 11 space rack is mostly full with 312's and a couple other things. I run +/- 17V and the chassis is barely warmer than when it's off. I would expect modules with two opamps per card to be only slightly warmer than mine. I wouldn't worry about heat at all.
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Post by keymod on Jan 19, 2015 16:01:25 GMT -6
SVART, Are you saying that we can boost the voltage up and maybe get better performance, without damaging the modules?
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Post by Randge on Jan 19, 2015 16:07:11 GMT -6
That is why I have the RTZ rack system with built in fans. My modules are cool as a cucumber and I have had them running all day. That's even with tube gear like the Doublewide in them.. Parts in modules dry out and fail because of heat. That is a sad fact.
R
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Post by svart on Jan 19, 2015 16:11:03 GMT -6
SVART, Are you saying that we can boost the voltage up and maybe get better performance, without damaging the modules? Not really. You can do it on some units, maybe not others. It's unknown since 500 modules are generally being designed around the +/-16 supply specifications. Some units might have plenty of voltage headroom while others might be on the edge. i can tell you that the CAPI VP25 modules configured as 312's with the kit 2520's take 17V just fine. I don't know about any others. Besides, you aren't going to get much headroom improvement, maybe a quarter dB or so depending on the module. I just run +/-17V because I had a spare power supply for my mixer and didn't feel like building a supply for the rack box at the time, so I just made a cable and put a military circular connector on it and in the rack. It was only intended to be temporary but it's been on there for a few years with no issues so I just leave it be. |
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Post by tonycamphd on Jan 19, 2015 17:20:27 GMT -6
SVART, Are you saying that we can boost the voltage up and maybe get better performance, without damaging the modules? Not really. You can do it on some units, maybe not others. It's unknown since 500 modules are generally being designed around the +/-16 supply specifications. Some units might have plenty of voltage headroom while others might be on the edge. i can tell you that the CAPI VP25 modules configured as 312's with the kit 2520's take 17V just fine. I don't know about any others. Besides, you aren't going to get much headroom improvement, maybe a quarter dB or so depending on the module. I just run +/-17V because I had a spare power supply for my mixer and didn't feel like building a supply for the rack box at the time, so I just made a cable and put a military circular connector on it and in the rack. It was only intended to be temporary but it's been on there for a few years with no issues so I just leave it be. cool idea man, i have an extra psu laying around that i think i'll adapt for my 3rd capi rack, it's got 17v +- rails 8) Also agreed, heat isn't an issue, you'll need to recap in 20 years no matter what, everything else will be fine, i have an 11 space rack chock full of double opamp'd vp28's/lc53a's, it's not an issue at all. Aren't API consoles loaded with hundreds of op amps? they don't seem to get particularly hot that i can remember? I don't think they even have fans? maybe i wasn't paying attention. |
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Post by Randge on Jan 19, 2015 17:28:31 GMT -6
Every time I touch those cheap API type racks they nearly burn my hand. I think heat is a big issue. I guess time will tell, but I bet you all are servicing your modules before I have to do mine.
R
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Post by unit7 on Jan 19, 2015 17:44:00 GMT -6
Not really. You can do it on some units, maybe not others. It's unknown since 500 modules are generally being designed around the +/-16 supply specifications. Some units might have plenty of voltage headroom while others might be on the edge. i can tell you that the CAPI VP25 modules configured as 312's with the kit 2520's take 17V just fine. I don't know about any others. Besides, you aren't going to get much headroom improvement, maybe a quarter dB or so depending on the module. I just run +/-17V because I had a spare power supply for my mixer and didn't feel like building a supply for the rack box at the time, so I just made a cable and put a military circular connector on it and in the rack. It was only intended to be temporary but it's been on there for a few years with no issues so I just leave it be. cool idea man, i have an extra psu laying around that i think i'll adapt for my 3rd capi rack, it's got 17v +- rails 8) Also agreed, heat isn't an issue, you'll need to recap in 20 years no matter what, everything else will be fine, i have an 11 space rack chock full of double opamp'd vp28's/lc53a's, it's not an issue at all. Aren't API consoles loaded with hundreds of op amps? they don't seem to get particularly hot that i can remember? I don't think they even have fans? maybe i wasn't paying attention. Tony, is your 11 space rack in a rack case? I also have a 11 space CAPI VPR rack filled with double DOA modules, but it's not racked, and it get's warm but not hot, so I'm unsure if I should get a 3 or 4 unit rack case for this new VPR rack. |
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Post by tonycamphd on Jan 19, 2015 18:12:39 GMT -6
Every time I touch those cheap API type racks they nearly burn my hand. I think heat is a big issue. I guess time will tell, but I bet you all are servicing your modules before I have to do mine. R U'll generally get 20 years out of electrolytic caps even if it sits unused. OP is using a capi 51x rack, very HQ, far from cheap, and no fan noise on your your recordings 8) I keed, they're probably very quiet, those RTZ units look very nicely built and well thought out, but $1,600 for 10 spaces is too rich for my blood, I built 3-51x racks= 33 spaces including psu's for less, BUT, you gotta build em. I still have about a rack and a half of space to fill with modules. |
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Post by tonycamphd on Jan 19, 2015 18:33:29 GMT -6
cool idea man, i have an extra psu laying around that i think i'll adapt for my 3rd capi rack, it's got 17v +- rails 8) Also agreed, heat isn't an issue, you'll need to recap in 20 years no matter what, everything else will be fine, i have an 11 space rack chock full of double opamp'd vp28's/lc53a's, it's not an issue at all. Aren't API consoles loaded with hundreds of op amps? they don't seem to get particularly hot that i can remember? I don't think they even have fans? maybe i wasn't paying attention. Tony, is your 11 space rack in a rack case? I also have a 11 space CAPI VPR rack filled with double DOA modules, but it's not racked, and it get's warm but not hot, so I'm unsure if I should get a 3 or 4 unit rack case for this new VPR rack. Hi Paul, no, mine are in a regular rack, regardless, i'd get a 4 space so you have bottom/front pull through ventilation, even a 500 enclosure like randge is talking about with the fan benefits from that in a small case. All my new racks will have draw holes at the bottom front, and release holes at the top front and back. |
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Post by gar381 on Jan 19, 2015 19:28:42 GMT -6
I'm slowly filling an 11 way 500 rack with Heiders and VP28s that I'll put in a portable rack case, probably an SKB plastic case as my sessions takes place like 99.9% in my home town and I don't need a heavy duty case. What's the word on the heat issue with these? 20+ opamps generate quite some heat. Is it recommended or even crucial to add an extra rackspace above the 500 rack? Most rack cases provide about an inch of space on the bottom/top but they're not open on the front so no possibility for the air to really move. jsteiger? Anyone else? I can’t speak for Scott but I bet his Red Dots run heat wise about the same as my gars. 1U space above is always nice but not necessary running +/-16v or in svart’s case an unsued Console supply at +/- 17v. If you are in the +/- 18v-20v Range I would be a bit more concerned about heat. The higher voltages produce a lot more heat with only a marginal increase in headroom. So the short answer Paul.. Don’t worry about it. Gary |
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Post by Randge on Jan 19, 2015 21:24:49 GMT -6
The RTZ racks are $1400 with the stoutest power supply in the business. Mercury is the only company building anything as close and they are a couple hundred more. The RTZ's are also vented on the other end so air is drawn across all of the modules for proper heat dissipation. Bottom line is that they work, they aren't hot to the touch and I have a hundred bucks that says they will out live the modules in your rack.
R
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Post by Randge on Jan 19, 2015 21:26:15 GMT -6
Just go by VK Nashville and stand by their stacked racks of modules. It is like a furnace in the back of their store.
R
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Post by tonycamphd on Jan 19, 2015 23:14:57 GMT -6
TBC, i'm not saying the RTZ stuff isn't good, because it is really great stuff.
I think the capi 51x psu has more headroom than any 500 psu on the market by a long shot, 5.4 amps if i remember correctly? probably has something to do with the fact that you can run the PSU at 24v+- on the rails, this is the ONLY 500 series rig that does this, it was put in the design so people could design, build and run "true" 24v modules like actual Neve clones vs nevealikes that use voltage dividers to jump 16v up to 24v, some would say that would give said units superior headroom.
As far as heat, electronics are rated by hours at temp, so barring something being improperly implemented, heat in these is not an issue to longevity, by the time yours or mine reaches 20 years old, even if mine is off the entire time, we both need to recap, they get old and leak, everything else in these will last a lifetime.
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Post by Randge on Jan 20, 2015 8:35:39 GMT -6
I have Melcore modules that have never been touched other than pulled out of a console and racked with a power supply. . They are working perfectly because the are well vented and used often. I don't buy into the "well, it's been twenty years, time to recap" ideology, either. I recap if a piece of gear starts sounding bad.
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Post by svart on Jan 20, 2015 8:53:52 GMT -6
Every time I touch those cheap API type racks they nearly burn my hand. I think heat is a big issue. I guess time will tell, but I bet you all are servicing your modules before I have to do mine. R I thought about this yesterday and never remembered if my rack even got warm, so I measured mine last night while using it. Measured the rack box itself (11 space VPR rack), middle of the rack on top and middle in back. later I measured directly on the BJTs of a 2520 opamp inside the rack. Room temp at turn on: 68F Rack temp top at turn on: 68F Rack temp back at turn on: 68F Room temp +1hour: 72F Rack top +1hour: 81F Rack temp back +1 hour: 76F Room temp +2 hours: 73F Rack top +2 hours: 83F Rack back +2 hours: 77F Opamp +2 hours: 88F This is barely warm to the touch. I think the big difference is that my power supply is not inside the rack, it's on the floor behind the racks. |
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Post by Randge on Jan 20, 2015 9:26:18 GMT -6
If you have a chance, go by VK's shop here in Nashville and feel the 500 series furnace they have at the back of the control room. They have all of the biggest selling brands of 500 series racks there. All of them get pretty warm stacked up like they have them there. If they are warm to the touch, that means they are damn hot on the inside.
R
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Post by tonycamphd on Jan 20, 2015 10:49:03 GMT -6
I would venture to say that Jeff Steiger knows what he's doing, I believe he and volker designed the 51x rack under the scrutiny of the entire Groupdiy site(a lot of brain power over there), if heat was an issue, we'd have all heard about it before now. Beside this, svarts a high level EE and he just gave us real time temperature readings off the highest heat op amp components in these things at 88*, thats nothing. Maybe VK needs to rethink their layout to provide better air circ? a fan in a small closed up room doesn't do much either...if you know what i'm saying.
in any rack, allowing air to enter at the bottom front and leave at the top back is a way to take the natural physics of convection and use them to ur advantage for cooling, heat rising will actually create an accelerated sort of vacuum, kinda like the breezing when you crack a window open upstairs in your house vs opening it all the way.
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Post by unit7 on Jan 20, 2015 12:23:21 GMT -6
in any rack, allowing air to enter at the bottom front and leave at the top back is a way to take the natural physics of convection and use them to ur advantage for cooling, heat rising will actually create an accelerated sort of vacuum, kinda like the breezing when you crack a window open upstairs in your house vs opening it all the way. Yeah, dealing w heat can be a bit tricky. I've had a few situations. My control room is fairly cool and my rack wasn't that filled up back then and had many vent panels, but because I had no fans and didn't get the air moving my ADL 1500s got so burning hot that the audio xformers potting compound mealted and leaked. Another thing I learnt was that if I switch on the AC in my machine room too late and the temp has gone up enough, despite that the AC is over powered it won't get the temp down again. I'll probably go for a four unit rack despite some of the advices here. That will provide room enough also for the floor box PSU while transporting. |
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ericn
Temp
Balance Engineer
Posts: 16,103 
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Post by ericn on Jan 20, 2015 12:33:10 GMT -6
I am sure with a certain combination of modules heat could be an issue depending upon how the rack is mounted. The Concept of fan cooling in the studio always leads to the trade off of cooling vs noise.
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