Ok Rudi you want me to match the ldrs? I have done it before when I built a lightspeed. I think I bought about twenty and only got a few good matched sets. I am on the other side of the world to you in case that matters?
An Apple remote is one of the best and a good candidate for a nice preamp....it is also quite "preiswert".
http://en.wikipedia.org/wiki/Apple_Remote
BTW it seems the VCPre is getting better and better by the time (at least on paper). Still worried about the close distance between the transformer and the relays/inputs. Will see if it works out. i will be building one.
You could have used SMD 0805 resistors/diodes/caps around the PIC and save board space. Then the transformer could go to the lower side of the PCB (a tad to the right) and the 230 V connector could be left of the transformer.
Regarding the transformer: we used a small and silent Tamura type that has 2 x 8 V secondaries and 2 x 115 V primaries which makes it easy for US guys. The outer pins are 115 V on the US version and the EU people can use a small bridge wire and use the 2 x 115 V version. Please see this impression of the PSU PCB:
http://www.diyaudio.com/forums/grou...-wm8804-spdif-power-supply-pcb-group-buy.html
You probably get an idea why designing my PCBs takes months.....Well it is a virtue to know your own shortcomings
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Regardless of loving or hating Apple, their remote is really a piece of work. Feels good and functions just like it should. Way better than all those plastic universal stuff.
Did you also get my point of the 115 V versus 230 V transformer ? That is if you want to make the PCB available for US citizens. They don't deserve it for PRISM but hey let's be flexible The NSA already know of this project anyway and they're decrypting the BOM and schematics right now...
Rudi, do you really think I will be using an external transformer ? I just love the VCPre's one board approach. I happen to have sheets of mumetal that will solve any "not yet existing" problem with 50 Hz hum. And I can use a small toroid transformer and drill a hole just right of the 230 V tracks with an insulation washer in it for M4 screws:
http://nl.farnell.com/multicomp/mcfm32-07/transformer-mini-3-2va-2-x-7v/dp/9531386
Please move the track to pin1 of the EI38 transformer just a millimeter to the left You see for 10 Euro you can not go wrong with these small toroids. I use them a lot and they're silent and have a virtually non existent stray field compared to EI transformers. In fact it is a worthwhile upgrade and solves the 115 V /230 V dilemma.
Did you also get my point of the 115 V versus 230 V transformer ? That is if you want to make the PCB available for US citizens. They don't deserve it for PRISM but hey let's be flexible
The NSA already know of this project anyway and they're decrypting the BOM and schematics right now...Rudi, do you really think I will be using an external transformer ? I just love the VCPre's one board approach. I happen to have sheets of mumetal that will solve any "not yet existing" problem with 50 Hz hum. And I can use a small toroid transformer and drill a hole just right of the 230 V tracks with an insulation washer in it for M4 screws:
http://nl.farnell.com/multicomp/mcfm32-07/transformer-mini-3-2va-2-x-7v/dp/9531386
Please move the track to pin1 of the EI38 transformer just a millimeter to the left
You see for 10 Euro you can not go wrong with these small toroids. I use them a lot and they're silent and have a virtually non existent stray field compared to EI transformers. In fact it is a worthwhile upgrade and solves the 115 V /230 V dilemma.
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I myself am using the ones shown on the image attached. Both of them "talk RC5".
BillyK has agreed to check my BoM. Thank you very much,Billy.
Concerning the additional PCB (HomeTheatre Bypass, SoftPowerOn and DIL-to-SIL Adapter):I have asked the etching company,
if they support perforated PCBs or if they will do 3 additional cuts.
I have not yet received an answer.
Best regards - Rudi_Ratlos
BillyK has agreed to check my BoM. Thank you very much,Billy.
Concerning the additional PCB (HomeTheatre Bypass, SoftPowerOn and DIL-to-SIL Adapter):I have asked the etching company,
if they support perforated PCBs or if they will do 3 additional cuts.
I have not yet received an answer.
Best regards - Rudi_Ratlos
Attachments
Jean-Paul, I assume that your torroid will hardly fit! Shown is a circle with a diameter of 42 mm.
I have done a more flexible layout for the transformer, in case somebody uses a 2x115 VAC primary and/or 2 x ? VAC secondary transformer.
Voxxonline: the transformer is the highest part; its height is 41 mm.
Best regards - Rudi_Ratlos
I have done a more flexible layout for the transformer, in case somebody uses a 2x115 VAC primary and/or 2 x ? VAC secondary transformer.
Voxxonline: the transformer is the highest part; its height is 41 mm.
Best regards - Rudi_Ratlos
Attachments
Gentlemen: find attached an image of my VCPre - prototype, playing / attenuating a CDP's track with a 1KHz sine wave on it.
The attenuated sine wave looks perfectly on the oscilloscope! Despite the vicinity of the RCA-connectors, relay, ... to the transformer.
So please don't argue anymore.
Best regards - Rudi_Ratlos
The attenuated sine wave looks perfectly on the oscilloscope! Despite the vicinity of the RCA-connectors, relay, ... to the transformer.
So please don't argue anymore.
Best regards - Rudi_Ratlos
Attachments
Bill, I have prepared a small EXCEL and will collect the names of all participants into it.
I will keep the group-buy open for about 2 weeks.
Then I will order the PCBs and parts.
I know from experience that the delivery of the PCBs will take about 3 weeks.
So the question to your answer is: you will have the parts by end of July.
Best regards - Rudi_Ratlos
I will keep the group-buy open for about 2 weeks.
Then I will order the PCBs and parts.
I know from experience that the delivery of the PCBs will take about 3 weeks.
So the question to your answer is: you will have the parts by end of July.
Best regards - Rudi_Ratlos
Attachments
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