DIY mic pre based on Studer 169 (DOCUMENTS PUBLISHED FINALLY)

[joshco]

Always looking forward to build your projects....

 

[Albrebreton]

Looks great , nice projet

 

[superslaukey]

Me too!
I`d love to build a couple. I built 4 of your 169 EQs - very nice project and nice sounding eq!
Are the documents available somewhere? I do etch boards myself - if you could share the layers it would be too kind of you.

Thanks in advance!!!
Max

 

[etheory]

Did anyone happen to find out what the values of the L2 and L3 inductors are on the previously posted schematic?
L2 sits between the input transformer and the preamp stage, and L3 sits in the feedback loop of the preamp to ground.
I'd love to know what those values are if anyone would care to measure them.
Thanks!

 

[etheory]

One more random point,
I just ordered 4 NTL1's from http://www.canford.co.uk/ - they seemed to have them at the cheapest price by miles at around $62US each - which is even better than Thomann, FYI

 

[etheory]

I'm looking into this project at the moment and I've come up with something quite interesting - here is a potential schematic for an entire Studer 169 input channel:

 

[Pliplo]

Is this project still alive?

 

[RuudNL]

@etheory: thanks for the schematic, but it is not readable here...
A higher resolution version (PNG or GIF) would be welcome. JPG soon looks a bit blurred because of the compression.
(Maybe it has to do with my eyes, but I don't think so.)

 

[etheory]

A higher resolution version (PNG or GIF) would be welcome. JPG soon looks a bit blurred because of the compression.

Here you go:

 

[RuudNL]

Thanks!!! This one is much better.

 

[etheory]

No worries.

Please note that it's still not entirely finished.

The two things that are distinctly different (mostly for simulation purposes) are that the mid-band is not stepped - it's still like the original with it's potentiometer (which I would change), and that the fader buffer is not like it is in the original (and not really that good as presented either).

However, it could serve as a rather reasonable basis for further research for someone.

Due to other commitments I can't get back to this project until maybe end of this year or early next. But when I do, I'll post an updated schematic.

Also I found that changing the supply rails from the original +-15V to +-24V improved things somewhat without overloading any of the parts - so that's the direction I was heading in.

 

[etheory]

OK, this one is also back on.
So I'll keep you all updated on the status of:

1.) The dual DOA API-inspired preamp.
2.) The API225L-inspired comp.
3.) This Studer 169 inspired DIY.

And let you all know how it goes. Shouldn't be too long now I'm hoping before they are all in full swing.

 

[audiox]

Is this project still alive?

To be honest I didn't remember the whole project...  I checked the files earlier today and the printed circuit board is ready (has been since 2009). I haven't been able to locate the final schematic diagram yet, but it must be somewhere.

 

[RuudNL]

Looking at the schematic, I get the impression that the Gain positions C and D will give the same gain.
Is it a mistake in the drawing, or am I wrong?
Personally I don't like the idea of having resistors in series with the input, since they contribute to the noise.
In fact it is an extra noise source in series with the input signal.

 

[etheory]

Looking at the schematic, I get the impression that the Gain positions C and D will give the same gain.
Is it a mistake in the drawing, or am I wrong?
Personally I don't like the idea of having resistors in series with the input, since they contribute to the noise.
In fact it is an extra noise source in series with the input signal.

With regards to the Gain positions, indeed, the schematic was incomplete when I posted it. I haven't touched it for a while, but I will relatively soon, probably early next year.
Since I didn't have access to a 6 position 3 pole switch, or even a supplier of one at the time, I started to, but never finished, an alternative arrangement to the original. I might just go back to the original now.

I will keep you posted about the updated design when I finally get around to it. Cheers!

 

[audiox]

Documents for the original project finally published. First edition - may contain errors...

Schematic
https://docs.google.com/open?id=0B_XBYPfmG8pVWkFtYXhNNDZhb0k

Component designations
https://docs.google.com/open?id=0B_XBYPfmG8pVeGJqYU5qTEZkZTA

Components values
https://docs.google.com/open?id=0B_XBYPfmG8pVRmNoQzlfaHZ5eG8

Copper layer (for home etchers)
https://docs.google.com/open?id=0B_XBYPfmG8pVOXM2VE9mMGt2UUk

 

[joaquins]

Are neutrik transformers really good, they are almost the only ones I could get for most of my projects here in Argentina, but their price is a little high, about U$90 for a NTM4, everything is high priced here around, but overpaying a couple of resistors doesn't make so much harm as it would be with a couple of transformers...

I'm looking personal opinions about those little ones, I don't know the price in other countrys though.

JS

 

[RuudNL]

Here in Europe they are 50 Euro. (~ US $66,--)

 

[joaquins]

Not so bad for me, most things are twice what ever are there, from rice to headphones... But, this is the aprox price for a carnhill, are they as good as carnhill too? or just the price? (I'm asking for personal taste here... I'll give them a shot when I can)

JS

 

[dirtyhanfri]

What's the value for L1?