Are there are any existing DIY PCB designs for a 103?
- Thread starter DaveLTX
- Start date
Help Support GroupDIY Audio Forum:
I intend to mount a cardioid-only U87 circuit inside of 103 body,without hi-pass or sensitivity attenuator.
I haven't designed the PCB for the through-hole parts yet, it's possible to make it point-to-point, something like:
https://groupdiy.com/threads/u87-clone-from-recycled-parts.86367/post-1129084
My attempts at point-to-point over the years ended up in either tears or escaping magic smoke so I would prefer something more permanent...
I tried the OPA Alice round pcb over at pcbway but they're asking 40usd for the boards. Ouch!
Well, I started a clone of the tlm103 circuit a while ago, it sounds great, but I was too lazy to design a PCB for it with through-hole components.
I used to make my own PCB, by hand, by corroding with hydrochloric acid and perhydrol, but I became comfortable, I don't have much patience anymore and then I always end up with fast point-to-point constructions.
Anyway, you can use other types of boards, convenient, cheap.
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I'm actually perfectly fine with SMD components, I have been doing SMD for years. Shoot away with SMD if you would be so kind to help me out.
At this rate I might redo the OPA alice round pcb but with SMD parts... PCBway's pricing is over the top for X cut
If you like working with SMDs then you can modify PCB that you have tested and are not happy with, either they have high inherent self-noise or an inappropriate sound for the capsule used.
Have you tried drawing the schematic and then finding a suitable de-emphasis mod for the RK-87?
It seems to me the most logical solution.
Is this a Shoeps circuit without de-emphasis?
My pal, Duffy Weber at Hula Cow Studios just designed an ORS87 board to go into the slightly smaller TLM-102 sized body on AliExpress that is often sold as a 103. The middle actually punches out to fit the Neutrik 10/3 transformer or can be left in and used as a switchable pad. He said he has prototypes on the way and assuming they work as well as his regular ORS87 boards, should be available soon. This should easily fit within the true 103 body.
MidnightArrakis
Well-known member
I have designed PCB's that were only 1.25"-square, had 8-layers and had over 200 "0201-sized" SMD capacitors and resistors on both sides for The Department of Homeland Security "covert intelligence-gathering and surveillance" projects, should you need any assistance.
If you can get or if you already have this OPA "Alice" PCB, I could "Reverse-Engineer" it for you. Or, if the GERBER and N/C Drill files are available, I have a program that can modify the files for you as well.
I also own 2 - TLM-102's, but I'm not taking them apart!!!
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Dont know why I didn't think of that...
The issue is that OPA Alice https://www.pcbway.com/project/shareproject/OPA_Alice_Microphone_round_PCB_cc6947c0.html
in any guise is locked behind pcbway
In the TLM103 audio circuit, both jFETs are N-channel
https://groupdiy.com/threads/neuman...est-affordable-replacement.85985/post-1136407
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MidnightArrakis
Well-known member
With the information contained within the attached files, there is enough here to "Reverse-Engineer" the PCB. The ONLY piece of information that isn't listed and/or shown anywhere are the mechanical dimensions of the PCB itself and the hole-size and location dimensions of the various connector and mounting holes. With all of that, a new and "original" PCB could be designed.
My 2-cents!!!.....
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I see. Read the direction wrong but still, it's nowhere close a 103 given a 103 has 60v on the capsule, this.... who knows.
I used a simple classic DC/DC converter with a BJT for the tests
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What capsule do you use? RK-87?
A collection of either CK12 or RK87 capsules
RK-87 needs high-frequency attenuation.
I am aware of that, I'm gonna give it a shot first then modify some HF mods if i need to
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