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24V PSU for vintage German modules

Discussion in 'Electronic Repair Modifications DIY' started by flextone, Jul 4, 2014.

  1. flextone

    flextone Active Member


    I've been trying to get around to racking a few modules for years now and still haven't. Some Filtek and TAB stuff. At the moment I'd be happy with simply getting a PSU and testing them out to see if I even like them before forking out the cash for professional racking. So, I just need a PSU and a few xlr cables basically, and I'm researching this now. What do you guys use?

    I've seen a lot of recommendations for the Power One units, but I'll have to find an enclosure for them which seems like a hassle. Plus, I'm located in Germany where I can easily find an old TAB N324 4A PSU or similar. Nevertheless, I feel something is escaping me and I can't figure this out...

    Are the only options these exposed unracked units? isn't there something a bit more elegant and safe? Preferably something already connected with a power cable?

    Another option would be something like this http://www.conrad.com/ce/en/product/511409/VOLTCRAFT-FSP-1243-72W-Fixed-Voltage-Linear-Power-Supply-Bench-24Vdc-3A

    does this have all I need? missing a ground connection maybe (or is in this case - = ground?)

    I'd love to get some help with this so I can finally start enjoying these modules. been laying around here for too long.

  2. Boswell

    Boswell Moderator Distinguished Member

    The engineering involved in setting up an edge connector socket, XLR cabling and a PSU just for test purposes is not difficult. Similarly, assuming these are 500 series boards, choosing a 500 series rack with integral power supply is not difficult. The real problem is deciding which way to go.

    If you are certain you want to go the module route, then I would say that buying a rack with integral power supply should be the next step, as it avoids unnecessary expenditure on connectors, cabling and a PSU bought for experiments. However, I'm unclear from your post what your intention is: you have the modules and you want to hear what they sound like - fair enough. BUT, what if you like the sound of even just one of them? How are you going to set that one up in a usable way for studio use? What if you come across tracks in the future that would benefit from the sonics of some the other modules you didn't think you had a use for when you first heard them?

    No, my suggestion is to get the empty rack with power supply and then cable it up to give yourself the flexibility of using any or all of the modules under real tracking, mixing or channel processing conditions.
  3. flextone

    flextone Active Member

    If this was a 500 series project I would have no trouble at all as there are so many products on offer at reasonable prices.

    I'm referring to "Danner" modules from the likes of Neumann, BFE, Filtek, NTP etc. Should have made that clear, sorry.

    With these, buying a purpose built rack with connectors and PSU would set me back 1000€. And that's just the rack, without the "racking" itself and without a built in PSU. Not something I am willing to spend at the moment on this project. I already have 6 modules, and yes I will eventually either keep all of them or buy different ones until I hit 10 modules. So I need a decent racking solution. But for the time being I want to give them a try before I start getting quotes from pro tech's to rack and possibly recap them. To do this I need a PSU, and I was wondering what do other users of these type of modules use, and how. Internal or external? inside enclosure or not? makes, models, etc.
  4. RemyRAD

    RemyRAD Guest

    Folks like myself will purchase an outboard power supply from companies like Power One. They offer all types from single polarity +24 V types to the bipolar ± 15 V / ± 24 V, types.

    Normally, anything that has to do with audio, I generally prefer to have the power supply separate from the device. This is done to minimize electromagnetic interference, hum and buzz in the audio circuitry. Quality recording consoles and other outdoor equipment is frequently manufactured that way, for those reasons. It's only the OCD folks that need the power supplies to be internal. I would have to say, I've thought many times about modifying my API 3124 mixers, to utilize an outboard power supply. Why? Because even though those have a low noise power transformer that can be positioned and tweaked for lowest hum, it still doesn't cut the mustard on Channel 4 when used with passive ribbon microphones. Of which I use a lot of. And that was a $2500 4 x 2 mixer. Not a piece of crap. Yet... without a nasty external power supply that would have made all the difference. But folks want convenient drive-through that just looks right. So that's how my friend/buddy/colleague Paul Wolff designed it. And he knows, I won't use channel 4 with any ribbon microphone. So there is the answer to your external versus internal power supply question. Don't make it internal if ya care about your audio.

    Racking up items is an inexpensive venture. I don't know why you think it would set you back €1000? It won't. It might set you back €100? Because all you need are generic rack shelves. A couple of edge connectors and a power supply or two or three or four?

    If you are using like equipment all rated for the same voltages such as ± 15? You can generally feed multiple devices, from a single power supply without problems. Some of your stuff might just require +24? So you couldn't feed that from the ± 15 V supplies. You would need a pair of power supplies. And then if you want phantom power for your microphones? You would need an additional +48 V, highly filtered, power supply.

    Folks like myself have obtained a rack chassis. I have mounted within that chassis all of the above power supplies. On a single rack shelf chassis. So between the power supplies and the chassis, it ran a little over $100 US.

    Now if you want to be completely obsessive-compulsive and anally oriented? And you believe that each separate piece of outboard equipment, needs a nice single individualized custom enclosure? Well then you're out of your mind up LOL. You're not in the manufacturing business. Don't worry about it. It only has to work it doesn't have to look totally pretty. It's a piece of industrial equipment not a birthday present from Guitar Center.

    And that's the way we all did it, do it. You can also. I know you can. We won't tell anybody that you're a slob.
    Mx. Remy Ann David
    kmetal and bigtree like this.
  5. flextone

    flextone Active Member

    I was merely mentioning the fact that a purpose built rack for this specific type of modules costs 1000€. Obviously I will end up spending no more than 200 on this racking business. That was exactly my point. I just want to do it the best way possible.

    I need +24V. I scored a TAB N324 supply yesterday on Ebay for 17€. That's 4A and was made to work with these german modules. So I guess this issue is solved. I'll keep it outside the rack, it's too big anyway. Just need to think of some box/enclosure/rack chassis for it as you said.

    That's more or less what I wanted to know, because I doubt anything I'll make will look good! ok, psu, wires, xlrs, box, go!

    Thank you for those encouraging words.
  6. RemyRAD

    RemyRAD Guest

    Many of the purpose built boxes, frequently come from commercially available chassis. Requiring one to only come up with a silkscreen printed faceplate. Which is something that one can actually do from home. Many have. Now if you're talking about specially printed anodizing on aluminum faceplates? Yeah... that's likely to cost a bundle. Of course that never wears off as was evidenced by the Auditronics 501/110 series consoles. Where repeated use would not have your finger oils eventually wiping off the silkscreen printing. That we've all seen on many older classic pieces of equipment. Perfectly great stuff but ya can't read anything LOL. You just have to know what it is your turning or switching. Which a green engineer couldn't do, without the intimate familiarity with the equipment.

    You get to go two ways with your power supply. Some folks will rackmount them. Others will just mount them into a chassis box, that sits on the floor, external to the equipment. Which is what you find on many decent consoles from numerous manufacturers big and small. That manufacture quality portable consoles. My SOUNDTRAC 16-8-16, from 1984 had a power supply in a box. Connected with a 5 pin XLR connector.

    Whereas my Sphere and Neve had rackmounted power supplies. So did API. But with my API 3124 mixers, Paul built the power supply into the mixer. Which always caused Hum on Channel 4. That sucked! And those are $2500 each. Paul just wanted to make them self contained. And at the expense of hum on Channel 4. Miniscule as it may be. It's not all that miniscule with passive ribbon/velocity microphones. It's obvious. At least to me it is. Yet likely here again, most people don't give a damn as these units are very popular. Maybe today they're building them with greater mu metal shielding, between the power supply and Channel 4 microphone preamp? Which therein, is a great reason to externally build the power supply.

    I've actually recycled old chassis, from defunct equipment, to build up power supplies in, for rack mounting purposes. And then sticking a couple of groovy voltmeters, into the front panel. Which makes it look a lot like an old-fashioned black-and-white science-fiction movie. And I love old-fashioned black-and-white science-fiction movies LOL.

    I remember when I first saw Ray Malan, in the Man with the X-ray Eyes, on our then only black-and-white television. So I figured the movie was in black-and-white until years later, when I saw it in color. It had not been colorized. I just didn't have a color TV when I first saw that movie and I thought it was much better in the fine Alfred Hitchcock-esque manner of shooting black-and-white rather than color. So while I loved the movie in black-and-white I really didn't like it in color. Not that this has anything to do with the power supplies but... I'm just saying.

    Beauty is in the eye of the butt holder.
    Mx. Remy Ann David
  7. flextone

    flextone Active Member

    well it turns out I was way off on that 1000€ thing. more like 500€


    but with connectors it will be 800 so... anyway that's waaaay too much to charge for a piece of metal, especially when I have a 5U front plate for the modules, and that can be installed in just about any rack.

    what would you do with this guy?


    again, I got this for 17€, they want 240... I don't know how they come up with these prices. I'd definitely like to keep it outside the rack, but still in some kind of box.


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