Great River OpAmp

[gyraf]

I just had contact with Jeffry (TwinX) - I was starting to worry for him. He's allright - but had a lot to do with new house, new job and all. He'll look into the upload problem - and he'll be back here for sure when he's settled..

Jakob E.

 

[Samuel Groner]

Thanks for the help on the bias generator.

I'd be happy to host the files.

Samuel

 

[soundguy]

I can host files as well, no prob.

dave

 

[Family Hoof]

My site's bandwidth is nearly unlimited. I'd be happy to host a mirror. E-mail me the zip or I can send you ftp log-in for my site.

 

[gyraf]

Just got word from Jeffry (Twin-X); the GroupDIY upload space is up and running again!

Upload away, good folks..!

Jakob E.

 

[wiggins productions]

bump

 

[chrissugar]

Hi Dan

Any chance to upload the gerbers and schematics?
Many thanks.

chrissugar

 

[OneRoomStudio]

I have the schematic and the board (which I could do a hi-def scan of in place of the gerbers) and with Dan's permission, I'll post them here. I'd still like to hear his take on the parts list though...

I'll check back for his reply, he's a busy man and I don't want to disturb him.


-Peter

 

[DaxLiniere]

Uhoh! I wonder if Dan will get back to us?

 

[OneRoomStudio]

OK, I made a decision. Dan is a busy guy and it may be months before he reads this thread. I was given permission to distribute the schematic to some AES compadres, so I guess I can extend that to you guys as well (and you can all just join AES if you haven't already). I don't have time to scan the board right now, plus it's masked and I don't know if the scan would turn out well...but for now, here's the schematic you've all been waiting for:

schematic
large image converted to link by moderator --PRR

In return, you'll all have to share your knowledge with me because I have a lot to learn. Oh, and if the image is too small to read, PM me and I'll try to send you the original PDF.

-Peter


DAN: If you didn't want me to share this, let me know and I will take it down immediately and apologize profusely.

 

[rafafredd]

wow, that´s what I call a gain cap. That´s surely much more complex than my last creation, based on quad eight AM-4...

 

[Quattor]

I've designed and made PCB for this preamp but unfortunately haven't being able to test it yet. However, since it'll work as unity gain buffer I'm interested in your experiences. PCB contains just a basic OP AMP. The rest is on the mother board(s). Output stage has a supply of its own. C12 in parallel of those two 22u low esr elcos is 10nF polystyrene. Compensation is modified since I couldn?t get 75 pF capacitors. It is changed to 91 Ohm / 82pF polystyrene capacitor. Vbe multiplier and current mirrors are made of 2N4401/2N4403, second diff. pair is made of PN2907A, output drivers are MPSA06/56 and the output consists of BD139/140. All diodes are 1N4148.

I'll post a picture of the finished unit soon. Maybe we could make this discussion alive again until final and complete version is finished and tested.

Best regards to ya all and hope to hear from you soon!

Almost to forget - the PCB picture is here:
http://s65.photobucket.com/albums/h239/quattor/

 

[Bauman]

Hey! Looks very good, look forward to try it! :thumb:

 

[Quattor]

There is a picture of the finished unit on the site that I've mantioned above. 3+3 current mirrors needs to be tied up together and output trannies should get a heatsink.

Regards!