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Post by svart on May 2, 2018 11:56:34 GMT -6
So I want to build another set of clean and utilitarian preamps that don't involve a lot of crazy stuff for use with stuff like DI boxes and things I don't usually need a color preamp for.
I have a layout for 4 channels of SSL9K preamp that I've etched before, but this time I plan on having a handful of PCBs made.. However, the minimum number of PCBs is higher than I think I'll ever use so I've been entertaining the idea of building a few of these in simple chassis and selling them essentially at cost+labor, somewhere around 225-250 by my initial estimate.
The PCB is 4x preamps with power supply plus phantom supply on one PCB. There are some changes, namely there is no +/-15 and I use other JFET opamps than the TL052 and the dual gain pots are "bent" linear pots to approximate reverse log, instead of actual revlog pots.
Anybody interested?
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Post by mdmitch2 on May 2, 2018 12:01:02 GMT -6
I’m interested. Maybe even 2... would be nice for my mobile rig.
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Post by jcoutu1 on May 2, 2018 12:19:42 GMT -6
...$250 for 4 channels in a rack?
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Post by svart on May 2, 2018 12:28:43 GMT -6
Cool, let me do some more research and I'll post more info. Here's the PCB:  |
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Post by svart on May 2, 2018 12:32:07 GMT -6
...$250 for 4 channels in a rack? Yeah, just guessing so far. There isn't a whole lot to them and if you work around esoteric stuff like those revlog pots, the price drops considerably. A lot of the parts I have in bulk for other projects. I think I have around 500x NE5534 opamps in tubes, etc. |
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Post by Tbone81 on May 2, 2018 13:14:05 GMT -6
At that price I'd be very interested as well.
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Post by matt@IAA on May 2, 2018 13:23:52 GMT -6
...$250 for 4 channels in a rack? No transformers + no discrete op amps = no cost  |
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Post by gouge on May 2, 2018 15:02:05 GMT -6
I'm interested. Would they work with 240v.
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Post by svart on May 2, 2018 16:34:41 GMT -6
I'm interested. Would they work with 240v. Could be wired for 240v, sure. I'm not going to do the external switching that I did on my converters though. That was a lot of work per unit to wire that up. |
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Post by gouge on May 2, 2018 16:38:21 GMT -6
I'm easy, whatever works for you.
My only thoughts were an opamp upgrade here and there.
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Post by wiz on May 2, 2018 17:05:53 GMT -6
Interested (240V)
Cheers
Wiz
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Post by keymod on May 2, 2018 17:34:24 GMT -6
I'd be interested
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Post by svart on May 3, 2018 9:13:33 GMT -6
Ok, it seems like there's enough to maybe build 5-7 units so I'll only get 10 PCBs.
What do you guys think about the front panel switches? On my original, I only have phantom. No phase switching since I can do that in the DAW. I might do that here since it'd make it cheaper..
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Post by svart on May 3, 2018 12:38:58 GMT -6
Also, the outputs on these are unbalanced. Do you guys care if they're XLR or TRS?
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Post by mdmitch2 on May 3, 2018 13:58:26 GMT -6
I’ll be using these live, so phase switch would be nice... and xlr would be my preference but not a huge deal.
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Post by svart on May 3, 2018 14:02:40 GMT -6
I’ll be using these live, so phase switch would be nice... and xlr would be my preference but not a huge deal. Oh, I should have said XLR out.. XLR in is a given I guess. |
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Post by svart on May 3, 2018 14:30:23 GMT -6
I'm easy, whatever works for you. My only thoughts were an opamp upgrade here and there. They designed the preamps to work optimally with the 5534, so I doubt there is an "upgrade" to be had. They'll do like 10Hz to 200KHz IIRC. |
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Post by Tbone81 on May 3, 2018 15:11:45 GMT -6
Phase switch would be nice to have for stereo micing situations. I've had a few situations where things are 180 out of phase for no obvious reason. I don't want to have to wait till it's printed in the far to hear things in phase.
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Post by svart on May 3, 2018 15:36:38 GMT -6
Phase switch would be nice to have for stereo micing situations. I've had a few situations where things are 180 out of phase for no obvious reason. I don't want to have to wait till it's printed in the far to hear things in phase. Ok. I can flip phase in reaper while tracking and hear it flipped. I just assumed every other daw was like that. |
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Post by wiz on May 3, 2018 15:54:29 GMT -6
I need polarity reverse.... and phantom...would prefer TRS out as it will go straight to and 240volt
Cheers
Wiz
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Post by mulmany on May 3, 2018 18:36:51 GMT -6
I would be interested...not that I need more pres, but you know!
Vote for polarity... Pad maybe nice just to be thorough. I am a XLR i/o fan myself.
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Post by svart on May 4, 2018 8:11:18 GMT -6
OK, so the PCB isn't going to be changed at this point beyond just some tweaks I need to make for production worthyness. It wasn't meant to be a production PCB originally so I never added some of the features I'd normally like to have, which means I have to handwire some stuff that I would have normally designed to avoid all hand wiring, etc, but I'm not going to spend weeks redoing the layout just to add a few things!
This is the feature list that I will do:
XLR input
TRS output
Polarity switch
Phantom switch
Front panel will likely be decals or stencils of some type. I don't think I'll have a silkscreen made, although that would be the most ideal for a production run.
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Post by svart on May 4, 2018 11:25:35 GMT -6
Ok, so I've ordered enough chassis and transformers for 6 units (one of which is mine) so I'll make 5 units to start and then see who wants one. I'll only order 10 PCBs so I could make up to 10 units total, but that's it!
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Post by winetree on May 4, 2018 12:07:49 GMT -6
I'd be in for 1
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Post by svart on May 7, 2018 11:52:56 GMT -6
PCB should be ready to go shortly. Had to make a few changes to appease you demanding fellows and to make it a easier to assemble.
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