Blue Robbie Mic Pre......any schematics....info....

Anyone know whats inside a Blue Robbie mic pre for 700 pounds.....no transformers I read....ECC88 I also read....would love to see a schematic

Hi Gary

Try

http://www.groupdiy.com/index.php?action=dlattach;topic=44845.0;attach=7977

Page 2 of the Tech Docs

Cheers

tc

Wow thanks TC you are Top Cat!.......very interesting to see what they sell for 725 pounds......1 tube 12 transistors & and a few other bits.....

Now what I need is someone clever to come along and give me the idiots guide to how this circuit works ......and to have a guess as to is it any good...why so many transistors......I often read that less is more......

thanks once again TC...PS only one page tho....was there more ? no matter if not schematic is very interesting.

It's derived from the typical Cohen architecture.
Main differences are:
The opamps are tube-based, with the tube providing all the voltage gain and the transistors delivering current under a low impedance.
Inputs are cascodes, so more open-loop gain there, so more voltage to drive the grid, helping reduce noise.
Since the tube is under heavy NFB, I don't think it colours much the sound.

Thankyou Abbey very interesting will keep this information for sure...

Thanks once againg TC dont suppose you know where I can see schematic for a Violet design Globe microphone solid state  body.....I think Blue & Violet related companies

thanks guys...

Hi.
Could someone please repost a link for the Blue Robbie schematik? The one at "http://www.groupdiy.com/index.php?action=dlattach;topic=44845.0;attach=7977" seams not to be available any more...

I have a Blue Robbie preamp problem: after a few seconds the low frequencies fade out and any mic stars to sound "thin". It also starts makink a lot of noise, no matter the gain setting. I have already tried a different tube (Phillips Miniwatt E88CC NOS), and the thin sound and noise are still there.
No warranty left on the preamp, either. And according to what I read regarding Blues service and quality, I'd rather fix it myself.

Thanks

link works fine (dl's .pdf) - try on another system?

I just managed to open it.
Thanx