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Post by stratotarts on Sept 28, 2018 16:13:05 GMT -5
Now that the first run of boards (V5.5) are almost gone, I decided to update the board and also place the Eagle files on Github so anybody can build them, and also provide a place to incorporate other user's suggestions and improvements.
The current version is 5.8, which has some changes. All the toggle switches have been placed on the board, to improve manufacturability and also minimize lead capacitance. The input network now has a variable capacitor for easier calibration (previously, different fixed trim caps were substituted in to achieve calibration). There is now a bypass switch, to allow optional use of the high impedance preamplifier part of the circuit without any integration of the signal. I have not built any boards yet, as I expect to collect a bit of feedback and review the board thoroughly before submitting a build. The documentation needs a lot of work, which I have little time for now, but will try to move forward as fast as I can. FYI, I left out mounting holes because I think the toggles will support the board.
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Post by stratotarts on Sept 29, 2018 11:52:48 GMT -5
Showing the board with front and back ground planes:
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Post by reTrEaD on Oct 3, 2018 8:41:16 GMT -5
Now that the first run of boards (V5.5) are almost gone, I decided to update the board and also place the Eagle files on Github so anybody can build them, and also provide a place to incorporate other user's suggestions and improvements. The current version is 5.8, which has some changes. All the toggle switches have been placed on the board, to improve manufacturability and also minimize lead capacitance. The input network now has a variable capacitor for easier calibration (previously, different fixed trim caps were substituted in to achieve calibration). There is now a bypass switch, to allow optional use of the high impedance preamplifier part of the circuit without any integration of the signal. I have not built any boards yet, as I expect to collect a bit of feedback and review the board thoroughly before submitting a build. The documentation needs a lot of work, which I have little time for now, but will try to move forward as fast as I can. FYI, I left out mounting holes because I think the toggles will support the board.
win-win- .... win!I like the way you make this info available for anyone who wants to use it. It reminds me of the way Daniel Meyer, Don Lancaster, Lou Garner, et al, presented articles in Popular Electronics, back-in-the-day.
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Post by stratotarts on Oct 4, 2018 15:16:22 GMT -5
Thanks. The most recent version looks like this:
50 boards are 28% of the way through production according to the fab facility.
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Post by stratotarts on Oct 9, 2018 20:19:10 GMT -5
SMD version looks like this:
Size is 1.4x1.8 in. I am still vetting the BOM for this one, I haven't ordered any boards yet. The general idea is to have parts placed in factory. I'm looking into it.
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Post by stratotarts on Oct 24, 2018 5:52:35 GMT -5
I assembled a board for a quick evaluation test. I'm still waiting on the switches before I can put it in a box. The integrator bypass and calibration adjustment work well.
As expected, when the unit is set to bypass and a square wave is applied to the input, the input network calibration can be performed with a screwdriver, exactly as a scope probe is done:
The unit can be used as a high impedance, relatively flat preamplifier with the integrator bypassed...
or with the integrator in line, for response plots (Suhr V60 shown):
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Post by stratotarts on Nov 20, 2018 14:50:32 GMT -5
An assembled unit:
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Post by antigua on Nov 20, 2018 15:37:39 GMT -5
That looks real nice. Are you going to sell assembled units? If so, I'd like to order one.
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Post by stratotarts on Nov 20, 2018 16:57:40 GMT -5
That looks real nice. Are you going to sell assembled units? If so, I'd like to order one. With everything on board, I can now sell fully populated and tested boards. I'm launching with a US$27.50 price. I have not decided on a housed unit cost, because I lack a drill press for the housing holes for example. Another unsolved problem is how to make a decent labelled front panel. So all that needs some thought. In the meanwhile, I have a proper bulk order of 50-100 component sets coming, which will allow me to standardize the populated boards. Those are about 2-4 weeks away.
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Post by newey on Nov 20, 2018 19:57:55 GMT -5
On pedals I have built housings for, I used waterslide decal paper for an inkjet printer (Laser printer decal sheets are also available). After applying the decals, you "bury" the edges under several coats of clear from a spraycan. That's the same technique as for guitar headstock logos.
Probably would work fine for a handful of units. But that's not going to cut it if you will have any volume of production. If so,for volume and professional looks, you would want to screenprint the label, then clearcoat over it. Since you will have (presumably) only one color and one design, a single screen would be all that was needed. Of course, the kicker here is the upfront cost of the screening equipment and ink.
A simple sticker, printed on your computer, would also work, but wouldn't be very durable and would look much more "homebuilt"
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Post by antigua on Nov 21, 2018 11:04:43 GMT -5
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