CHEAP!RE V3 "Updated"

This preamp ROCKS!!!!

Designed V2.Corrected OEP transformer placement!

You can pre-order.

Working on V3.

Hi,

What changed from the V1 boards that i have. Please send some pics if you get the new boards.

Best,
Iwan

DjaiTeam said:

Hi,

What changed from the V1 boards that i have. Please send some pics if you get the new boards.

Best,
Iwan

Click to expand...

Changed OEP transformer's placement.V1 was wrong.You have to place OEP transformers to bottom side with V1.With V2 i corrected it.And with V3 ,i changed only one decoupling cap.It was wrong.

So not big changes.Only little changes with new versions.Like new batch...

When are you expecting the v3 boards? I'd be in for two.

FEELER.

Hi I´m starting to build the preamps now.
A question: You mentioned you changed a capacitor in V3 which one was it and what did you change it to?
Which Diodes are needed for the HI-Z Input? Any Zehner?

Cheers

Eric

cromwell said:

Hi I´m starting to build the preamps now.
A question: You mentioned you changed a capacitor in V3 which one was it and what did you change it to?
Which Diodes are needed for the HI-Z Input? Any Zehner?

Cheers

Eric

Click to expand...

Which version you have? First version has two errors.First,one of decoupling caps (C16.Place it reversed) placed wrong.If you check schematic you can see.And thw second one,if you use OEP transformers,you have to place them to bottom side.

Zener 12 or 24 V.

i'm in for two rev 3's.  how much are they?

burglar said:

i'm in for two rev 3's.  how much are they?

Click to expand...

PM sent.

Sorry for late reply, yes I have V1.

Placing both OEP to the bottom side would mean I need a bigger chassis....shit

Cheers

Eric

cromwell said:

Sorry for late reply, yes I have V1.

Placing both OEP to the bottom side would mean I need a bigger chassis....sh*t

Cheers

Eric

Click to expand...

Unfortunately , yes.

But you can place it to top side with zip tie and use wires to solder it.

What is RC and RZ needed for and what are the values?
I´ll use OEP transformer looks like they are just for the CAPI trafo?

Thanks

Eric

I have no idea about OEP's zobel network.There must be specific calues for OEP.I didn't use OEP transformers for this projects.

But you don't have to install zobel network.My friend build it without RC and RZ and it's working great.No strange freq responses or peaks.

cromwell said:

What is RC and RZ needed for and what are the values?
I´ll use OEP transformer looks like they are just for the CAPI trafo?

Thanks

Eric

Click to expand...

No need for zobel network in this preamp,but if you wanna be sure you can put 12k resistor over RZ and RC instead resistor and cap!

This information about putting just one resistor over zobel network I found here!

http://www.racknrollaudio.com/Classic-Audio-Products-of-Illinois-Heider-FD312WHR-p/capi-heider-312.htm

I will open White Market thread,soon.You can find PCBs in there.

iprovlek said:

No need for zobel network in this preamp,but if you wanna be sure you can put 12k resistor over RZ and RC instead resistor and cap!

Click to expand...

Iprovlek,

thanks for your input. Now I have all the parts together, to finally build the preamp.
Did you mean to put two 12K resistors in series (one for RZ and one for RC) or just one for RZ and bridge RC to ground?

Regards

Eric

Dont need for zobel network for OEP input Cromwell for this API 312 there is no ringing!!!

You can leave that....