jsteiger

Hi everyone,

Volker aka [silent:arts] and myself have been working on something kind of new the last month or so. It is what we have been calling a “plug-in” HiZ for Direct Inject applications. Our thought is to have a standardized footprint for a small PCB, which can contain many different HiZ circuits for different applications.  The idea is to be modular much like the 2520 DOA concept. Volker has authored the footprint/layout, which is on a board measuring 28mm X 28mm. The board shall contain 6 Mill-Max pins exactly the same type as we all have been using for our DOA projects.

Our thought is that anyone designing, building, etching or whatever…a mic preamp PCB, can incorporate this footprint and use for Direct Inject. This really opens up some great possibilities.  8)

As of now, Volker has a good ole passive, transformer version which has the standard Jensen JT-DB-EPC footprint to it. For other passive options, we have the wonderful Ed Anderson hard at work designing and creating his very own DI transformer. Ed was pretty excited about the idea when I emailed him. He said he had thought about a DI transformer in the past but wanted to do something very unique. I wait with baited breath.  :P

Next we have an IC version. This is a circuit that Volker has come up with. There are a few different versions of this out there already…but now we have one for our “plug-in” format.

And that brings us to the multiple FET versions. Volker has many already drawn up. I will let him post what he has done. We have contacted a few of the guys who have used these type circuits in their projects already. Like Peter Purpose and Fabio. Both have given their blessings to publish the circuits in our new format. An email has been sent to Dan Kennedy and we are anxiously awaiting his response to utilize his already published circuit.

The HiZ Plug-In will run on a single voltage rail. Someone building a standard API style preamp may want to run the HiZ off of the +16V rail. Someone building a Neve may want to run on +24V. A person who has the new GDIY 51x rack may want the option to run on either.  ;)

As you can see, there are loads of options and possibilities.

Here are the basic specifications for the PCB from Volker.


One of the main reasons this came together was the new VP312 board that I was working on. I wanted to utilize the 51x option like the possibility of the higher voltage rails. I sent Volker my Gerbers to see how I made the voltage switchable and so on. He replied back, “Looks good but you are missing the DI option”. I explained my thought for the VP312 PCB and how the DI would not fit for some of the various alternative uses I have planned. I told him my next project would have to be the VP312DI. I also expressed the desire to inject the HiZ signal before the input transformer not directly before the DOA. Most seem to do this and it is just great but I wanted something a little bit different. I wanted something more conventional like similar to using a standalone DI box. Volker said, “Have you thought of a FET circuit like Dan Kennedy uses? The Neve type DI could sound really cool and different in front of the API preamp”. I suppose you can figure out the rest of the evolution.

This is what I have come up with for the VP312DI. I am using an auto-switching method to de-energize a 12V relay which is triggered by opening the normalled sleeve/ground connection on a ¼” mono PCB jack. I have also made the +V for the HiZ Plug-In switchable between 16V and 24V. I thought this would provide some nice options. The relay circuit is zener shunt regulated to 12V off of the +16V rail so this way it will still function if the PCB is clipped to operate in a standard 500 series rack. The relay will be a TQ2-12V. Cheap and reliable.


Cheers all, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.


[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #1 on: February 05, 2010, 01:38:18 PM »
bad timing, have to have some steak first ;D
too much happened in one day, and I want to have the files ready for Lukas.
it is still friday (but I have to eat something first to compensate the champaign) ;D ;D ;D
will post later
Volker

jsteiger

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #2 on: February 05, 2010, 01:51:23 PM »
bad timing, have to have some steak first ;D
And beer!
Quote
too much happened in one day, and I want to have the files ready for Lukas.
Yes and hurry. What have you been doing?  8)
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

ultra-alex

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #3 on: February 05, 2010, 04:17:36 PM »
you guys are awesome...

livingnote

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #4 on: February 05, 2010, 05:43:04 PM »
Me too I had a bit too much on my plate of late - so cheers, take your time.
Quote from: emrr
F-in' hook some Sh*t up and see if it catches on fire
Living Note Studio

ChrioN

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #5 on: February 05, 2010, 08:19:11 PM »
nothing on my plate, but tons of beers running through my system  ;D
"All PCB traces are curved to emulate the electrical response of point-to-point wiring" -Drip

[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #6 on: February 06, 2010, 04:35:47 AM »
here is a preview of the different HiZ Plug-Ins we have developed right now:

HiZ-TX1

passive, for Jensen JT-BD-EPC or Cinemag CM-DBXPC transformers

HiZ-TX2

passive, for Pikatron ÜP3096M wired in reverse (thanks to Ed Anderson for the tip)
if there is enough interest I will buy a bag of 50 pieces for a good price.

HiZ-FET1

exactly the same Sir Peter uses in his LAZ MPA
we have his permission using it, thank you Sir  :)

HiZ-FET2

this is based on the circuit Fabio Baumann uses in his Reliquia 1272
he can't remember from where he had got it, but gave us the permission for using it. thanks! :)

HiZ-FET3

a modified version of the Jensen AS004 application note

HiZ-FET4

this is from the Dan Kennedy schematic floating around. tried to contact him asking for permission, but still waiting for an answer.

HiZ-IC1

a more or less own design but similar to this

just to show you (won't be released):

Joe stated out he is still selling his IC based DI kit, we will respect this.

however, everybody is invited using this HiZ Plug-In format, either as a footprint in your project, or to provide us with more Plug-Ins ;D ;D ;D
I'm really curious to try them all out!
« Last Edit: February 06, 2010, 06:52:32 AM by [silent:arts] »

alexc

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #7 on: February 06, 2010, 06:40:58 AM »
Hats off to you guys for a most excellent product realization.

For my part, I find DI variants to be fully half the fun of diy preamps.
I think you have covered all bases.

Well done.

Cheers
I ping therefore I am

livingnote

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #8 on: February 06, 2010, 07:08:12 AM »
Rock N' Roll! It's Partytime  ;D
Quote from: emrr
F-in' hook some Sh*t up and see if it catches on fire
Living Note Studio

jsteiger

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #9 on: February 06, 2010, 10:32:10 AM »
Volker,

I really would like to try one of those Pikatron's. Are you gonna get one or 2 for proto testing?

Got all the pins and sockets BTW.  ;)

I will send Dan an email and point him to this thread.

Cheers, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.


[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #10 on: February 06, 2010, 01:05:59 PM »
I really would like to try one of those Pikatron's. Are you gonna get one or 2 for proto testing?
I have two here for proto testing, will send you one.

Got all the pins and sockets BTW.  ;)
great :)

wtmnmf

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #11 on: February 06, 2010, 01:18:11 PM »
What about including some mounting holes in the standard for securing heavy boards with transformers? Or if that is a tight squeeze, then maybe specify some holes/slots on the main board for threading some zip ties through. Otherwise you will have to make the selection of transformer permanent, and also deal with the inevitable solder joint failures, especially on vertical PCBs.

[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #12 on: February 06, 2010, 01:31:28 PM »
valid point.

just do it like Sony did it in the old days when they have been using 990s:
leave one socket out, solder that pin directly.
very easy to desolder.

except of the Jensen / Cinemag Plug-In (right now) I doubt all others would fall out,
but the Jensen / Cinemag is already tight (one resistor soldered on the bottom of the PCB).
no place for a screw.

jsteiger

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #13 on: February 06, 2010, 01:43:33 PM »
And also, the Mill-Max sockets that we are using are a very tight fit when seated. It takes some force to install and remove a DOA, especially the first time around. I can't say how it will be after many, many plugging and unpluggings. I don't see them working their way loose if the rack is stationary. If toting a lunch box around, I think something should be done to help secure the transformer based Plug-Ins. Zip-ties would be an easy solution that many pro gear manufacturers seem to use freely.

Cheers, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

tv

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #14 on: February 06, 2010, 03:17:52 PM »
Neat and tidy.

But - where's the SansAmp plugin board?
If you sprinkle when you tinkle, please be neat and wipe the seat.

[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #15 on: February 07, 2010, 05:35:54 AM »
But - where's the SansAmp plugin board?
it is up to you doing one ;D ;D ;D

files have been send to Lukas for etching some prototypes :)

jsteiger

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #16 on: February 08, 2010, 07:42:33 AM »
Volker,

I will be ordering a Jensen JT-DB-EPC for our proto listening tests later today. Should I make it 2...1 being for you? I have been saving up since they are about as costly as a trafo comes.  ::)

BTW, also sent a note to Dan K.

Best, Jeff
Visit the CAPI store at http://www.capi-gear.com

CAPI is not affiliated with, endorsed by, or sponsored by API.

zayance

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #17 on: February 08, 2010, 07:53:06 AM »
Thumbs up, Really nice, can't wait.

zayance

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #18 on: February 08, 2010, 09:44:14 AM »
By the way [silent:arts] are you using solidworks to buil the 3D images?

[silent:arts]

Re: [silent:arts] & classicapi developing a new “Plug-In” HiZ DI format
« Reply #19 on: February 08, 2010, 12:39:14 PM »
I will be ordering a Jensen JT-DB-EPC for our proto listening tests later today. Should I make it 2...1 being for you? I have been saving up since they are about as costly as a trafo comes.  ::)
Jeff, I already have one (expensive) Jensen, two Cinemags (cheaper) and Pikatron (cheapest) for the passives.

By the way [silent:arts] are you using solidworks to buil the 3D images?
no, I use the build in function of Target where I design my PCBs.
have to write loads of the 3D models myself  :-[


 

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