the new V72 (pre order closed)

Hey guys,

it took me a long time to finish this Project. It stopped for the last year because of a bigger health issue. But finally it´s done And it sounds awesome.

https://www.dropbox.com/s/zyhty675qco3xih/SAM_4650.JPG
https://www.dropbox.com/s/kq9qsxqequvp331/SAM_4653.JPG
https://www.dropbox.com/s/renwiuj4gh6qi3c/SAM_4695.JPG
https://www.dropbox.com/s/jo3ehzlu6j59mby/V72%20Front.pdf

The last picture is what the Frontpanel looks like on my prototype. Top left is a DI Input with volumepot.
The middle row on the left is a switch for ramped phantompower, a bright switch for the DI Input with two options in the middle and a switch between Mic and DI. DI goes straight to the grid of the first tube.
Then there is a switch for highpass wich is nothing else than a cap between the two primary windings with a slightly lower value than in the original. Next to it you can switch the primary windings from the input tranny between parallel and series connection of the two windings. All this switches are point to point wired and not on the pcb.
Then there are three rotary switches on the pcb. First is a simple Pad. It´s the same as they used in the V76. Then you can switch between the original V72 and variable gain. So you can choose between both worlds . Then you can switch between 25dB and 55dB. Should be enough for the most situations.

I love this little sucker Would be nice to hear your thoughts on this project.

Cheers
Martin

very cool! i love the layout, looks really nice, where did you get the pcb's from? ive been thinking about building something simliar, a pcb would sure make life alot easier!

Beautiful build!
Mike

That is lovely!

Ive done V76:s from scratch and looking forward to try these units with homespun trafos/plate choke. Is this the Drip?

Shed som light on the DI. Is the DI-signal put directly on grid of first tube? I've thougt about this a lot and ended up with installing a Bo Hansen DI box inside my V76 for instrument in.

PSU-wise? External trafo?

Kindly

J

Beautifully crafted. How did you manage to extend the gain range down to 25dB?

Cheers

Ian

@ mus1k_freak: i did the layout by myself. The pcbs are manufactured in Germany. I thought about offering a kit for this one if there´s enough interest. Everything would be included except the case and Transformers. Power transforers would be included in the kit.

@ sodderboy: thanks. it was a long way to go.

@ Landins: The DI Input goes directly to the grid of the first tube. I heard that they did it the same way at Abbey Roads but i don´t know if it´s true. But it sounds fantastic for direct bass recordings. The input impedance could be a bit higher since it´s only 400k. But i like that on bass and it wouldn´t be a prolem to switch it.
PSU is the left part of the main pcb in the first picture. The screw terminal on top is for the toroid which is wound by the same company that made my pcb. They are really good and not expensive.

cheers guys

very cool! do you have the schematic you went off of? ive been thinking of building something simliar for awhile, im in the middle of a four channel nyd one bottle build and 2 nyd 500 pre amps )

Thank you very much for clarification and response! Ill try the bass/guitar-amp approach and connect directly to grid and let my ears guide.

Kindly

@mus1k_freak: I checked every schematic i got my hands on. The best thing to start with is the one from the IRTs Braunbuch.
http://www.irt.de/IRT/publikationen/braunbuch.htm
The only real difference i noticed was the grid resistor from the first tube ranging from 400k to 475k. Of course there is the V72s with a differnt approach in the feedback path. But my experiene is that the different input transformer on the V72s is much more important.

@Landins: Please let me know what you think about going directly to the first grid.

cheers

MRecords said:

I thought about offering a kit for this one if there´s enough interest. Everything would be included except the case and Transformers. Power transforers would be included in the kit.

Click to expand...

+1

Interested in a stereo pair.

Looks Great!!!

I would also be interested in a stereo pair if your kit becomes reality 

sharpeleven said:

+1

Click to expand...

Ok, what the heck, let's make that a stereo pair also 

A Stereo Pair please.

Ok let´s do it. Which voltages do we need on the primary side of the power transformer?

US -120v

Great built.....

Im for two....

MRecords said:

Ok let´s do it. Which voltages do we need on the primary side of the power transformer?

Click to expand...

EU 230V 

230V

amazing project.
if you bring it to a kit i'm in.  ;D