Neumann W444STA

[coffeeman]

Hi all,

Does anyone know exactly how to remove the frequency limitations of these fader modules - that is to expand the module beyond the standard 40Hz - 15kHz?

I have attached a copy of the schematics and would appreciate any clues as to what needs to be removed / modified.

Thanks
Craig 

 

[RuudNL]

No idea what is going on in the MO-6A/B, but I don't see any frequency dependent components.

 

[coffeeman]

Hi RuudNL, thanks your reply and I have attached a photo of the two MO6a and 6b modules. They seem to be discrete amplifiers so I don't believe they affect the frequency either. The documentation states 40Hz - 15 kHz so there must be something affecting the top and bottom? Unfortunately I have no way of testing whether these are limited or not... but my ears tell me that all the top is and bottom is not quite there...

Any other comments?

 

[RuudNL]

The modules look like 'linear' amplifiers to me, no coils etc.
I suppose the specifications (40Hz-15KHz) are just on the 'safe' side. (Maybe within 0.1 dB or so...)
The only way to be sure, is to measure them.
I would not be surprised if they are reasonable flat from 20 Hz to 20 KHz!
By the way: did you drive them from a low impedance source?
Looking at the impedance of the fader, I have the impression that the input impedance (at the input transformer) is rather low, maybe 600 ohms. Driving the transformer from a source with a high(er) impedance may cause LF loss.

 

[[silent:arts]]

They don't have any filter (and the MO6 are fine DOAs, I guess they are unpotted OA20).
The modules from that time had to be flat from 40Hz - 15kHz, which doesn't mean everything outside was filtered.

 

[coffeeman]

Thanks to you both for your assistance and I tested the unit with a software audio tester  (not ideal but it is all I have) via my Prism Sound Orpheus and there is a drop below 40 Hz (and a complete drop below 20Hz) but not as drastic as I thought and it could be the input impedance issue. For the rest it looks pretty flat right up until 20kHz! This can serve as a reference for others in future that these faders are not frequency restricted as indicated.

Thanks again! 

 

[tubestation]

Hello,
I just checked the Inputimpedance of this Faderamp and it is 2 k Ohm.
So Your Sourcegeneratorimpedance should not be greater than  200 Ohm.
All this is written in this Technicaldocument Paper. Thanks to the Great Mister Kubarth it can be found here.
http://audio.kubarth.com/rundfunk/getfile.cgi?f=%3D%2C30S-34Q-C%28X%2CU%5DW%2BVYE%3D6UA%3BFY%3F5S0T-%22YP9%268%60%0A
Greatings
Lothar