Author Topic: Tube DI Project  (Read 11289 times)

Whoops

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Tube DI Project
« on: November 29, 2008, 01:18:44 PM »
Hi,
since I've used the Aguilar tube DI that I wanted to do a Tube DI box.

This DI sounds amazing but at $450 it was way out of my budget, and I'm sure its possible to build the same circuit or similar for much less.
Now that aguilar discontinued them, its a good time to try a similar project, based on this unit.

Also the lack of an organized and complete tube DI project on prodigy pro led me to post this topic.

if anyone is interested in this project and helping out, I can take high resolution pictures of the aguilar inside and components,
maybe someone could help me do the reverse engineering work and trace the schematic. The circuit looks quite simple.

Its one 12AX7 , there and input transformer and the power supply transformer, the rest is regulator, resistors and capacitors.

it was mentioned in another post that the Aguilar DI was similar to a jensen schematic, I will try to source that. that would be a big help.
« Last Edit: March 05, 2009, 05:04:32 PM by Whoops »


Gus

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #1 on: November 29, 2008, 01:30:07 PM »
Copy

  A DI is easy stuff do a search here, jensens site and look at some members sites, Tube phantom powered DI, solid state Di.... 

  12ax7?




Whoops

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #2 on: November 29, 2008, 05:58:06 PM »
Thanks, I will investigate.
« Last Edit: December 27, 2008, 11:38:39 PM by Whoops »

pucho812

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #3 on: November 29, 2008, 06:38:36 PM »
yes they do sound good. You know what though, there is nothing special to those. I had one apart once. It looked pound for pound like the jensen tube DI schematic.

build that and you will be happy...

also note we tend to not clone units in current production. There are some exceptions to the rule because some circuits have been reissued like the 1176.

here is the schematic you seek.

http://www.jensen-transformers.com/as/as021.pdf
Every mic has a purpose it might be a door stop or a hammer, but every mic has a purpose.

Whoops

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #4 on: November 29, 2008, 10:21:00 PM »
Thanks a lot Pucho,
I will check the schematic and start to build one of those.


The aguilar DI is discontinued now. So we keep the good standards.

Anyway there's a lot of projects going on on this forum that everyone is raving about that are currently being produced.
Like the SSL Bus compressor, Neve 1290 (Neve 1073 DPA), API 312 ...
« Last Edit: December 10, 2008, 02:26:59 PM by Whoops »

Svart

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #5 on: November 29, 2008, 10:26:51 PM »
Actually no there aren't.

The Gssl isn't an exact copy, it's based on the idea behind the mixbus compressor but it's not a direct clone.  The rack version that SSL sells is somewhat different than either the Gssl or the real Mixbus design.

The other stuff is being built by companies other than those that initially designed the devices.  Essentially all of those are clones too..
Welcome to the GroupDIY leper colony! when something falls off, we just replace it with a tube!
occupation: General Electron Mayhem

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http://www.theopiumdenproductions.

Whoops

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #6 on: November 29, 2008, 10:37:12 PM »
Thanks Svart,your help was precious.

Checked with Aguilar, the DB900 is discontinued now.

they don't offer any DI anymore
« Last Edit: December 10, 2008, 02:24:47 PM by Whoops »

Whoops

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #7 on: November 29, 2008, 11:00:19 PM »
was checking the Jensen Schematic, it doesn't seem too complex.

is the input already prepared to receive Hi-z instrument signal?

shouldn't the output be a Balanced Mic out instead of Balanced Line out?

How hard would it be to build a power supply for this circuit?

This schematic doesn't seem to be similar to the Aguilar circuit. The Aguilar uses one 12AX7 and the output is Mic level.

« Last Edit: December 29, 2008, 04:07:38 PM by Whoops »

pucho812

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #8 on: November 29, 2008, 11:52:29 PM »
hmmm I just caught the balanced line out... Maybe the Aguilar has only 1 tube. It's been so long since I used or had one in shop. They are solid though. the output of the jensen is 600 ohms. so it would be a line out. if you really want to run it so the level out is mic level... check the the output level and build in a balanced attenuator to drop the level down to that. If you really want to pimp it put in a switch between the output transformer and the XLR. The switch could then switch the attenuator in or out of circuit. Thus having line level or mic out level. You then could go directly into a daw if you so desired or through a mic pre then into the daw or whatever you use as a recording device.

just a thought...

as for a PSU... because of the tubes in use and such could most likely get away with a PSU design  that is used in a fender amp. the plate voltages are 250 DC and you can run the heaters off AC. Look at the mila schematic for a PSU and I think that would work nicely. Allthough don't take my word for it. I am sure someone around here might have a more simple idea.
Every mic has a purpose it might be a door stop or a hammer, but every mic has a purpose.

Whoops

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Re: Cloning Aguilar Tube Direct Box DB900
« Reply #9 on: November 30, 2008, 01:33:54 PM »
Yeah its strange,
maybe the related Jensen schematic is a different one, since the one in your link is a Line driver.

the aguilar specs are:

Specifications:
Input Impedance: 12.8 M ohm
Balanced Output Impedance: 880 ohm
Unbalanced Output Impedance: 150 ohm
Noise: -98 db
Distortion: .025%
Bandwidth (balanced into 600ohm): 10 Hz to 40 kHz +/- .5db
Bandwidth (unbalanced into 10K): 10 Hz to 100 kHz +/- .5 db
Unbalanced level out: Unity
Balanced level out: -20.5 db
Tube Compliment: one 12Ax7
Output Transformer: Jensen DBE
Operating Voltage: 100, 120, or 230 VAC


So it doesn't even use the same type of tubes, it uses only one 12AX7. And the output seems to be a Mic output and not Line.

Searched on the Jensen website and couldn't find any other schematic on thos subject.
« Last Edit: December 01, 2008, 09:20:27 PM by Whoops »


Whoops

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Re: Tude DI Project
« Reply #10 on: December 15, 2008, 10:52:05 PM »
Had some time today to take some pictures of the Tube DI guts.

the circuit itself looks quite simple, although the PSU looks a bit more trickier.

take a look at the photos



« Last Edit: December 15, 2008, 10:54:22 PM by Whoops »

Whoops

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Re: Tude DI Project
« Reply #11 on: December 15, 2008, 10:53:56 PM »








Whoops

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Re: Tude DI Project
« Reply #12 on: December 15, 2008, 11:00:13 PM »
The Transformer says:

8581
Made in USA

I'm trying to find it in the Jensen website.

I'm preparing a diagram with the parts on the Tube PCB.
if someone could help me draw a schematic that would be great because I don't really know how to do it.

from the power supply there 4 wires going to the tube PCB and 1 wire is goes to the "star ground"
I measure those 4 wires, it seems one is 12volts, another 17volts, and the other 2 seem to be connected to ground. Not sure if I measured it correctly though.

The tube is an 12AX7 WA and it has the Aguilar logo.


if anyone recognizes these circuit from a jensen schematic please let us know where we can check it.

thanks


emrr

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Re: Tube DI Project
« Reply #13 on: December 15, 2008, 11:11:35 PM »
8581 is more like a Reichenbach / Cinemag part #.
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g

Whoops

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Re: Tube DI Project
« Reply #14 on: December 15, 2008, 11:25:49 PM »
It's totally possible.

Although the Jensen transformers usually have a "8xxx" number close to the "Made in USA"

like in this pictures


« Last Edit: December 15, 2008, 11:48:31 PM by Whoops »

Whoops

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Re: Tube DI Project
« Reply #15 on: December 15, 2008, 11:29:04 PM »
This DI looks like a twin brother:

http://www.alphaton.com/english/products/di-1000-e.htm

http://www.johnhardyco.com/AMB-DIDetails.html

they're "Discontinued/No longer available" also
« Last Edit: December 15, 2008, 11:41:07 PM by Whoops »

Whoops

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Re: Tube DI Project
« Reply #16 on: December 15, 2008, 11:34:52 PM »
Aguilar DB900 Top View



AMB Tube-Buffered DI



Demeter - Tube Direct

« Last Edit: December 15, 2008, 11:52:58 PM by Whoops »

okgb

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Re: Tube DI Project
« Reply #17 on: December 15, 2008, 11:38:40 PM »
I posted a couple of schematics in a past thread , but the demeter is similar too , easy to use a CF stage in front of the xfmr
use one half for gain  [ although that will invert the signal ]
biggest trick is finding a pwr xfmr small enough for the case
do it ptp
o.k. can't find them so far but search here
[ oops seems i emailed them to you pucho when i didn't know how to post
still got them ?
« Last Edit: December 15, 2008, 11:47:15 PM by okgb »
GKB Audio / Greg Boboski

Whoops

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Re: Tube DI Project
« Reply #18 on: December 15, 2008, 11:56:28 PM »
I posted a couple of schematics in a past thread , but the demeter is similar too , easy to use a CF stage in front of the xfmr
use one half for gain  [ although that will invert the signal ]
biggest trick is finding a pwr xfmr small enough for the case
do it ptp
o.k. can't find them so far but search here
[ oops seems i emailed them to you pucho when i didn't know how to post
still got them ?

Hi,
found the Demeter also, they all seem to have a similar circuit , is it like a well know schematic or something?
even the layout is the same between all 3.
it would be great if you could find those schematics, on even the thread.

thanks a lot

emrr

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Re: Tube DI Project
« Reply #19 on: December 16, 2008, 12:12:13 AM »

Although the Jensen transformers usually have a "8xxx" number close to the "Made in USA"


ah, that would be a date code then, if on a Jensen.  I see now the DBE was listed in the specs, so that's likely it.
« Last Edit: December 16, 2008, 12:32:38 AM by emrr »
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounded g


 

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