51x mod idea, tubes?

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mus1k_freak

Well-known member
Joined
Dec 13, 2009
Messages
156
Location
Philadelphia PA
Hey i've been thinking about this for awhile, maybe its not possible but what if i built a 51x rack and instead of pin 16-18 being NC 24+ and 24-  why couldn't they become 16- ground 17-6.3V 18 250V  for tube modules? then you could plug custom built 500 series tube modules in and have full voltage to work with instead of needing a charge pump or lots of extra parts. Could the 51x pcb's handle that kind of voltage and current draw? i'de love to start making some custom tube modules for the 51x community. You could probably fit all the parts needed in a 2ru case
 
Hey ! Why not? Go ahead and try it first?  ::)

Then, you could blow any other module designed for +/-24v, plugged into those slots not knowing of your mod.
Have a really good think about what you have written and then ask yourself why we have standards .....

Merry Christmas.
 
well i wouldn't suggest anyone mod there own case, im just saying if you wanted to run some standard modules and some tube modules you could build yourself something this and half both in one box. I do a lot of location recording and it would be nice to just grab one box and have some other flavors. Though maybe building a 8 space box box just for high voltage tube pres may be a better idea then mixing the two.
 
yes standards are there for multiple, good reasons.
maybe i've misunderstood...
what you are suggesting is to buy a £200+ 51x chassis kit, throw out the backplane, then re-purpose it into a non interchangeable format, with new, non standard edge connections for use as a seriously heavy valve unit? with limited options and space? like a standard rack chassis but with extra holes.

even if it was 11 slots across, you would need 3 spaces for the psu minimum. unless you want to house the psu externally which would mean trailing the seriously ample HT and heaters from a seperate psu chassis like 51x(not recommended) or an expensive dc-dc converter for each pre and very heavy gauge cable between? particularly if you want different 'flavours'

anyway, you suggest a more modest 8 units size, so this would leave 5 spaces max optimistically(8 with 511) next to your psu. presuming you can fit a full multi stage valve compliment for each of 5 mic pre's for example. plus IO transformers in each slot. still there are maybe a couple of designs you could do that with so lets worry about that later.

then have the option(separate power rails+card edges+connections) for an entirely different (51x) format in the same space as the tube units?


I'd love to see some of the designs you mention to gauge exactly how long you have thought about this. I first assumed you have a tube pre design using a crazy low voltage on the plates and series heaters, which may be feasible from a lofi amateur design POV, ignoring the current per unit suggestions. but then you go on to say-
Though maybe building a 8 space box box just for high voltage tube pres may be a better idea then mixing the two.
I think you might have a point there.
there are so many project designs out there, on this forum alone! in the last few weeks even! have you had a look at some/any of the other posts here?

or is this a new, different idea? I'm still confused  ???
 
I was thinking a whole lot simpler. Building the 51x set up and instead of using the last 3 pins for 24 volts use them for tube voltage thats all. Maybe on a few slots just have 15 pin edge connectors so you dont zap your standard modules. Low voltage on the left 4 slots or something. I would still keep the power supply in a 2u case. I dont see why you couldnt pull 300ma or so per module as long as the pcb could handle it. Im sure you could fit somrthing like the nyd one bottle in a 500 series size space if you wanted
 
tubes want room---they breath easier.
plus it makes it better when you want to troubleshoot or tweak the circuit.
if'n yer gonna make a modular thingy; not a bad idea, but give yourself some room to make something interesting.
 
Yea i think youre right with the more room thing. I love all things tube and i love the flexability that modualr gear gives you. I think it would be a cool platform to build on. Maybe ill just have to come up with something that fits what im after. I was just thinking the 51x stuff would be a good start since the basic layout and phantom poiwer is already figured out. A new project to start for the new year i guess  ;D
 
Is there any reason at all that this needs to be based on the 51(X) system??

Suppose it was based on the European DIN sub rack system that has been discussed here before. There would be no danger of a 51 series module being damaged because it simply would not fit. The DIN backplane connectors are shrouded so even if you forced on in you could not get power to it. A 14HP (2.8inch) wide module would fit six times into a standard sub-rack and the module is wide enough to take an 6DJ8 sized tube without having to use right angled connections to it.

Cheers

Ian
 
thanks for the information! i don't really know much about that system but i will certainly look into it, seems like it would fit the bill! I think going bigger would be a good idea specially if someone wants to try and fit a pultec type eq or compressor circuit in there, though RETRO fit 4 tubes in a 2 space 500 slot (double wide). impressive!
 
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