OPEN SOURCE DIY Mic Project - ORS 87 - Stripped Down u87

[Khron]

Yes, I saw them.I watch them carefully
These are gratifying results. It seems we have more options than the traditionalists, the purists, claim.

I actually came across the J113 when i started my solid-state guitar (pre)amp project prototypes, a few years back, and it was the cheapest available that filled the main

an active device, in plentiful supply from all the major component distributors

requirements No NOS-nonsense going on here...

 

[micolas]

I actually came across the J113 when i started my solid-state guitar (pre)amp project prototypes, a few years back, and it was the cheapest available that filled the main

About 25 years ago, in the communities where we were active, we used 2N5457 and J201, for guitar preamplifiers, amp or cab simulators, effects pedals, etc. And now I still have these models, with very low Idss, in Shoeps or in the emitter follower, they are good.
I really don't remember if at that time we were considering J111...J113
(Also at that time, a friend came with a defective Rode NT1 (white-grey), I remember perfectly that it had J305 and the best quality parts, many green Wimas, it's a pity that the capsule was compromised. He later bought a Behri B1 and was satisfied. I'm sure the two had a lot in common)

 

[anvl]

Has anyone some information about Mic&Mod K87 capsule?

https://www.micandmod.com/microphone-parts/microphone-capsule/k87-capsule/

I'd love to choose Arienne Audio, but I try to find options in Europe

 

[micolas]

Best recommendation: Arienne K87.

Budget solutions:
Look on ebay or other similar sites, a second-hand microphone model Behringer B2-pro,for maximum 50..70 euros.It has a very good 797 capsule that will take you to the U87 sound. The microphone is good, body/headbasket etc.
Or a used AKG P420 (Takstar CTS-2 capsule) for maximum 100 euro.

@anvl

 

[micolas]

Has anyone some information about Mic&Mod K87 capsule?

M&M is a rebranded capsule.

 

[cello4u]

Post pictures though.

Is it possible that the 1.1 has this in the pcb? the middle leg is currently in a hole that has a trace going to the other hole? Or do I need to desolder the jfet to get the leg out?

 

[micolas]

Is it possible that the 1.1 has this in the pcb? the middle leg is currently in a hole that has a trace going to the other hole? Or do I need to desolder the jfet to get the leg out?

Do not solder the middle pin(Gate) of the 2N3819 on the PCB. If you soldered it, you have to unsolder it the transistor completely, quickly heating all 3 pins simultaneously, so as not to destroy it thermally or mechanically.
Do not solder the end of R7=1G on the PCB either (opposite to the one that is soldered to GND)

 

[Khron]

Is it possible that the 1.1 has this in the pcb? the middle leg is currently in a hole that has a trace going to the other hole? Or do I need to desolder the jfet to get the leg out?

The middle leg of what? And which "other hole"?

As @micolas said - POST PICTURES.

Hopefully well-lit but glare-free, and please try to zoom in on them and make sure they're also half-ass ok-ish focused. We're not dealing with film anymore nowadays, so you can retry as many times as you need to / can be bothered to, until you get it right.

Do not solder the end of R7=1G on the PCB either (opposite to the one that is soldered to GND)

I still can't comprehend why @homero.leal chose to have that "as an option" (or even a possibility)...

 

[untamedfrontier]

Is it possible that the 1.1 has this in the pcb? the middle leg is currently in a hole that has a trace going to the other hole? Or do I need to desolder the jfet to get the leg out?

My ORS87 works fine without having the middle leg isolated from the pcb. I may try it isolated on future builds, but to get a functional microphone you don't need to have it isolated. Feel free to check my prior posts for pictures of it

You may also want to check the datasheet of your jfet though, I found my 2n3819 had the same pinout as the lsk189, where it appears other manufacturers of the 2n3819 have it flipped

 

[micolas]

If the isolation of sensitive high-impedance components from the PCB surface is not respected, or if PCB is not covered with special protective materials (how does Neumann, Rode, etc.),
the quality of the sound can worsen over time, due to contamination with oxides, dust, dirt, other various particles, moisture, etc.

My ORS87 works fine without having the middle leg isolated from the pcb. I may try it isolated on future builds, but to get a functional microphone you don't need to have it isolated.

It would be helpful to read all the posts in the thread.
However, we offer an important part of our time and experience to give solutions, indications, help, in a completely altruistic way.

 

[micolas]

You may also want to check the datasheet of your jfet though, I found my 2n3819 had the same pinout as the lsk189, where it appears other manufacturers of the 2n3819 have it flipped

In many cases, for some jFETs, the Drain can be inverted with the Source and it works.
But for optimal operation it is good to respect the pinout.

 

[untamedfrontier]

I actually came across the J113 when i started my solid-state guitar (pre)amp project prototypes, a few years back, and it was the cheapest available that filled the main

requirements No NOS-nonsense going on here...

Any other recommended/necessary alterations to the current BOM to sub the j113 for lsk189/2n3819? I have a few in my inventory and could pop one in.

Also the PCB layout you posted earlier looks very cool, but I don't think I'm quite ready to learn how to etch my own pcb yet lol

 

[micolas]

I still can't comprehend why @homero.leal chose to have that "as an option" (or even a possibility)...

I am very convinced that in version v1.2 @homero.leal will give up those traces on the PCB.
They created a lot of confusion.

 

[micolas]

So the PCB layout you posted earlier looks very cool, but I don't think I'm quite ready to learn how to etch my own pcb yet lol

Maybe @Khron will take care of this, produce quality PCBs (or a partial kit) with full assembly instructions, which will be available for purchase on the Black Market.
(For 87 and maybe many other attractive projects)

 

[Khron]

Maybe @Khron will take care of this, produce quality PCBs (or a partial kit) with full assembly instructions, which will be available for purchase on the Black Market.
(For 87 and maybe many other attractive projects)

Well, i'm kinda divided on this particular topic

I (will) have my "full fat" U87A-like project available anyway, as well as a "FET847" board, while this "ORS87" is halfway between those two, on one hand. And on the other hand, i just wanted to "give something back to the community" (as i did with @rogs' RFmic board, and the initial FET847-for-BM800 some years ago) , and i'd be a bit conflicted about selling boards of this particular project. Unless, of course, @Wordsushi and/or @OneRoomStudio happen to give their blessing (and/or insist that i do)

 

[micolas]

Well, i'm kinda divided on this particular topic
i'd be a bit conflicted about selling boards of this particular project. Unless, of course, @Wordsushi and/or @OneRoomStudio happen to give their blessing (and/or insist that i do)

Unohdit Neumannin!

 

[Khron]

Unohdit Neumannin!

They make enough money as it is. Or if they don't, it's Sennheiser's fault...

 

[OneRoomStudio]

Well, i'm kinda divided on this particular topic

I (will) have my "full fat" U87A-like project available anyway, as well as a "FET847" board, while this "ORS87" is halfway between those two, on one hand. And on the other hand, i just wanted to "give something back to the community" (as i did with @rogs' RFmic board, and the initial FET847-for-BM800 some years ago) , and i'd be a bit conflicted about selling boards of this particular project. Unless, of course, @Wordsushi and/or @OneRoomStudio happen to give their blessing (and/or insist that i do)

All I did was share a perfboard layout for a simplified version of the U87 circuit. I claim no ownership of anything.

....although, I still maintain that this being "GroupDIY" and all, folks would be better off trying to understand the circuit and building it themselves on perfboard than buying yet another PCB/kit and painting by numbers.

 

[homero.leal]

I am very convinced that in version v1.2 @homero.leal will give up those traces on the PCB.
They created a lot of confusion.

Do you mean, these traces?

 

[homero.leal]

And... now that you mention about version 1.2, what additional changes would you like to have?
I expect to update it next weekend.
Regards!