DIY Mic Pre Kits, Lunchbox Mic Preamp Kits, Power Supply Kits

here's what I've got so far:
http://i134.photobucket.com/albums/q93/jeffreyandsavannah/fivefishpanels2.jpg

I'm putting an xlr input on the front and back for easy access what I need it. 10 LEDs instead of 5, big gain knob, and a old school jewel power bulb I ripped off of an ancient piece of gear. The green circles are just a guide for the knob path so I don't put anything in the way, they won't be there in the end. So what do you guys think? do I need do change anything? is it ugly? let me know. the current design for both panels is going to run be about 140 bucks so I want it to be near perfect.

Some comments.

1. Are you installing the Mini-IO module PCB upside down? The switches comes first before the line jack.

2. I'm not sure what is that "front/back" switch near the XLRs. You can just wire both the front and rear input XLRs in parallel and get rid of the switch.

Just note, you'll have a longer wire path... twist the wires or else they may become hum/noise magnets.

3. On the second channel, your input XLR is right beside the AC switch. No no no no no. You can bet that AC hum will go into that channel. I suggest putting the XLR jack to the left side, before the gain selector knob.

And try to stay away from the AC switch as far away as possible.

4. That old school jewel light bulb... is that a Neon lamp? If yes, I'd suggest don't use it. They leak and give out tremendous amount of noise, and if your input XLR is also right beside it, that's asking for trouble.

5. For the rear panel, I'd put the jacks for channel 1 right behind channel 1... so that means your rear panel jacks will be "2 1 " instead of "1 2"
(looking from behind).

Looking at the top of the unit, channel 1 will be on the left, and channel 2 will be on the right...

Otherwise, it looks good!

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oh my! thanks for the advice, I almost ordered it because I was so excited about it.

I'm using an xlr switch in case I want to switch quickly between what's in back and what's in front. like for a/b mic selection and placement. mostly it's just another semi-frivolous luxury I'm adding because I'm strange. if it's not a good idea to have a switch for sonic reasons though, let me know. Or let me know how to accomplish it well.

So the input goes to the right on the DI, thank you for that correction. Is the input hole lower or higher than the buttons? I guess I would like it to be higher so I suppose it will have to go in upside down if I'm wrong.

perhaps I'll use the jewel and a large bright LED instead of a bulb. that works right? if the everyday house lights people use are considered to be neon, then yes. it is one of those. only smaller of course. same filament and everything.

thanks again for the insight. I really like the VU above the gain knob and right next to the channel number. perhaps I assume the DI has no more fortitude than the xlr next the ac switch, right?

again thanks for the input. I'm glad I posted it. I almost didnt!

IF that's your purpose for the 2 XLRS, I guess a switch is fine.

Personally, I just want a quick short wire from the PCB to the input XLR jacks. For less chance that noise might creep in.

Is the input hole lower or higher than the buttons?

No, it's higher. Just turn your buttons and DI jack 180-degree right side up. Then the 1/4" TRS jack will be higher than the 3 buttons.

I'm talking about a 110V neon lamp (they sort of flicker if you look at it closely). If you have an incandescent, then that will be fine... but it will use up a lot more power than say a 5mA LED lamp.

I'd still move that XLR away from the AC switch (which is carrying 110V AC)... lots of hum there.

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I'll twist the wires and shrink tube them, that will help a bit I think. is it possible to wire one of those dual color LEDs to be one color when the unit is on and another when it's switched off? like just draw power for the red "off" led. I'm sure there's a name for this and some schematics out there for it. plenty of equipment does it.

I don't meant to be a bother. I've just always wanted to explore electronics and am full of questions. a big question I had for you actually is this:

are there any better components out there that I might consider upgrading? be it a cap or an opamp, any thoughts on that, in other words: and little modifications you've pondered?

also, do transformers matter a lot for this pre? I've read that cinemag and Lundahl are good and amazing and all that. here's some total novice questions about trafos: there are 3 types of transformers one would use here, power, input, and output. is that correct? Should I think about getting an input and output transformer? can two pres share the same transformer?

thanks again for all the thoughts/pointers. I don't want to seem like I'm saying I want a better kit than you offer. I was just wondering if there are any options that you didn't pursue because of cost that I could maybe add when I'm in the mood to tinker.

like just draw power for the red "off" led. I'm sure there's a name for this and some schematics out there for it. plenty of equipment does it.

You'd need a power source when it is OFF to light up the LED... to show that it is off.



You can add an input transformer, and an output transformer.



It's just for changing the flavor. (the sound) It's also bragging rights.



I have an IO-Module kit if you're interested in adding input/output trafos to your stock SC-1. Let me know if you're interested.

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so I'm still plugging away getting the layout ready and ran into a few more questions...

what is the distance between the bottom of the IO module and the bottom of the buttons on the IO module? the design I want to make work has the IO really close to the bottom of the case. I guess I should add an extra mm for solder points too. will an XLR input fit above the IO buttons in a 1U case?

Is there a +48v toggle just like the included one only vertical? anyone have a part number for it on hand? The position of it works just fine, but I want it to switch up and down because the pre is going to be mounted horizontally.

and one more thing... do they make pannel mount LED holders so I can move the +48v LED above the toggle? I guess I can dig around, but I'm not very good at finding components yet.

If I wanted to just use another jewel light bulb (for that vintage look), can I just solder the wire to the pcb? I think the old school jewels only have one wire for some reason. at least the one I ripped out of a tektronix RM181 time mark generator did. Then again the power supply on the thing is insane so that could be why.

**edit**

i found an LED that is made to look like a vintage jewel. I think it will work:

http://www.mojomusicalsupply.com/item.asp?pid=17988&pg=44997&id=8280110

yes?

No, they look like 120V neon lamp. See the voltage requirements? 120V

LEDs only require 5mA - 20mA at 1.7 to 2.x voltage drop across the LED.



It's about 0.28" distance from the bottom of the PCB to the "center line" of the switch holes.




No. an XLR hole is about 15/16" diameter. A 1u rack is only 1.75" high (but that is the panel height... the case height will be less than that... maybe 1.5", and you have to account for the thickness of the metal for your usable height.



The vertical toggle lead footprint will not match the holes on what is on the PCB.

What you can do, is use normal DPDT switch, and just run wires from the switch to the PCB if you want to relocate your switch.



Yes, there are thousands of choices, of various colors and sizes of LEDs. You can just use wires to route from the LED to the PCB. That way, you can place your LED anywhere you like.

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