The most versatile preamp EVER

[michal_k]

Ladies and Gentleman,
I give the most versatile preamp you've ever seen:



but more seriously, recently I started wondering why people in here seem to prefer to buy PCBs from our (awesome) forum designers than rolling something unique on their own. I'm watching diy stompbox community and lots and lots of people try the circuits on perfboard first and swap some components to make it sound unique.
is studio gear so much more complicated that 'moding' is too difficult?
I'm rather new to recording and studio equipment and I've also built some preamps with premade PCBs, convenient partlists etc, but I realised how easy it is to try your own ideas supposing you have 51x rack or even regular power supply and 51x connector. I hope that writting it all here will motivate me to work in that direction btw

Anyway, I'm curious what you guys think about building unique pieces of gear. Perhaps lots more of people do this but they just don't show the results?

m.

ps. I'll probably order some of that universal 51x boards so if anybody is interested than write me a pm.

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estimated price is 10EU per PCB if we reach 50 pieces, 9EU for 100+ pieces.

I'll make a GB thread in black market as soon as I recieve a prototype and confirm that PCBs look nice.

 

[shabtek]

these were available before though only 15 contacts on the edge.
might still be available on the pico forum

really good idea
plated holes for durability
less paint-by numbers
bring back diy

 

[haima]

can i suggest more than one pad on the end of each "finger" - like silent-arts / jeff's card edge sticks...

makes it easier when i comes to power supply, 0v etc connections...

BTW - i like the idea! it has been done before for 500 series, but i don't think anyone has done 51X - i'm definitely down for some, especially if they work out to be a good price... maybe this is something gustav would be interested in stocking?

 

[jsteiger]

...I give the most versatile preamp you've ever seen...

Preamp?? Hmmm...at first glance, I thought it was a compressor.  ;D

I think it's a great idea.

I thought Colin use to have some on the AM site for 500 series but I don't see them now.

I think maybe a dedicated track from the Chassis finger to the top right mounting hole would be cool. Or at least a jumper spot to connect them.

Also, maybe add pin #6 for the DC link options.

 

[dmp]

I think it is a great idea and I would be very interested in getting some.
I agree with:

dedicated track from the Chassis finger to the top right mounting hole

I don't think there is a situation where you would not want your metal work to be connected to the chassis ground.
Also, I'll throw out the idea of a 2520 footprint for millmax sockets in the middle. It would be easy to work around if not needed, but would be very handy for a lot of projects.

 

[haima]

agreeeeed on all above counts!

 

[[silent:arts]]

Nice! I'm sure it sounds very clean ;D

 

[kepeb]

looks like a good plan to me  ;D

 

[michal_k]

I don't follow pico forums so I wasn't aware that somebody was already making those. crap, I wanted to be first 
Anyway, dear forum members, let me present Rev. A:



list of changes:
-added two extra pads for each contact(as suggested by haima)

-added a trace from chassis contact to one of the mounting holes(as suggested by jsteiger)
I think there's no use to add a jumper - if somebody really doesn't want that connection trace can be cut easly.

-added pin #6(jsteiger once again )

-moved mounting holes a little bit. Is there a standard placement of those?

plated holes for durability

I don't know about that. It improves durability but it's bitch to desolder. What you other folks think?

Now a couple of my questions:

- what is optimal drill and pad size for DOA sockets?

- is spacing of the pins/sockets the same for DOA and Hi-Z plugins?

- some time ago I've seen some efforts to make universal pinout and PCBs for transformers, what happend to this idea? It  would be cool to have adaptors from different transformers pinout to the regular 1mil spacing

 

[desun]

What about adjusting the keying and depth of the 51X pins, so that the card can fit into a regular API rack without having to take a file to the board?

 

[Slenderchap]

I thought Colin use to have some on the AM site for 500 series but I don't see them now.

This thing.....

Just out of stock that is all.

I did do a 51x version without the front cutouts... it just didn't get asked for so was never sent to fabrication.

Colin
www.audiomaintenance.com

 

[tv]

I have been building prototypes on Vero for decades.

I also built stuff on PCB's.

But I make genuinely awsome ratnests ...

 

[haima]

-moved mounting holes a little bit. Is there a standard placement of those?

i dunno... jeff? do you think you will offer your L-brackets with a standard pcb mounting hole pattern? to fit your card edge and other boards like these?

colin - i knew you'd done something like this before, however i looked and couldn't see it... i thought i was imagining things!

 

[shabtek]

yeah, 'twas colin.
there used to be a a 500 card-edge available with the pico--
colin did the full board, nice quality too.

 

[jsteiger]

i dunno... jeff? do you think you will offer your L-brackets with a standard pcb mounting hole pattern? to fit your card edge and other boards like these?

Volker and I talked about that when we did the run of blank 51x L-brackets. For some reason that now escapes me, we decided to not drill any holes.

Volker did match the rear hole pattern for my VP-preamps when he did the little 51x proto card edge boards.

What ever you guys think. I will gladly post the dim's at least for the 2 rear holes. Sometimes the front holes need to be moved entirely depending on the faceplate layout, components and so on.

 

[michal_k]

I will gladly post the dim's at least for the 2 rear holes. Sometimes the front holes need to be moved entirely depending on the faceplate layout, components and so on.

Please do, perhaps one day you'll order L-brackets with drilled mounting holes and then it may be handy.

m.

 

[JAB]

very nice

about the holes for mill-max sockets:

Instead of putting them on the board, maybe you could do a sub-board that would have holes for mill-max, and then short tracks to connect these to standard sized holes/pads. The idea being that the builder could connect the sub-board to the mainboard with pins, or even old clipped leads, and could put the DOA socket(s) anywhere on the main board. Would make the board even more flexible for comp / eq builds.

The sub-board could mount almost flush to the main board, and could probably have the same footprint size as the opamp. Could be useful to folks wanting a DOA on their non-51x vero projects, too. Hell, you could even put in tracks for a DIP package opamp on the same sub-board, just in case.

Anyways, no matter how you address the DOA pins, I'll be in for some of these.

 

[dmp]

- what is optimal drill and pad size for DOA sockets?

The datasheet states mounts in min .089" hole.
http://www.classicapi.com/catalog/images/gallery/opamps/150.pdf

- is spacing of the pins/sockets the same for DOA and Hi-Z plugins?

No, the footprint is different.
http://www.classicapi.com/catalog/images/gallery/HiZ-Plug-In/HiZ-PlugInPCB-Specification.pdf

 

[michal_k]

thanks dmp, the mighty google helped me to find those papers before and here it is, rev. B

I decided to include holes for DOA sockets in the board rather than making additional PCBs. First of all it's cost effective and secondly, they don't take a lot of prototyping space.
So it can take up to three DOAs(who would want that many anyway) or two doas + hiZ plugin.  ;D

 

[dmp]

Cool!
Now, a thought. Should V+/gnd/V- be run to the DOA pins?