Dual EZ1290 build complete

[solderspongebob]

Well, after starting it two years ago, and being stumped by a smoking resistor, I've finally cracked it this weekend and completed my dual EZ1290 preamps:

PSU based on a few different circuits (doubler for phantom power taken from a Symetrix schematic!) and an anti-thump relay board hastily added after nearly popping an earphone!

A BIG thankyou to madriaanse for this fabulous project, and to Colin at AudioMaintenance for stocking the transformers in the UK and to all other members who have answered my fault finding questions.

It makes all my microphones sound much more expensive than they are (as I don't own any Neumanns this is a big plus for me).

 

[bruno2000]

Very nice!  That's a lot of stuff crammed into a small package.
Best,
Bruno2000

 

[solderspongebob]

Very nice!  That's a lot of stuff crammed into a small package.

I did think at times that I should've gone for a 2U case, but after sketching it out in AutoCAD I found a way to fit it all in. Tightest part was the inside height - those Shroff cases are really tight for that.

 

[SimonB]

Looks good. Where did you get those knobs?

 

[solderspongebob]

Looks good. Where did you get those knobs?

They're Elma knobs, from Farnell:

http://uk.farnell.com/elma/023-4510/knob-grey/dp/1209777

 

[snipsnip]

thats really nice!!

So are those boards at the front your own take on the go between?

 

[erikb1971]

oh man Iam afraid to ask this  :-[ :-[ :-[ .... I have ordered all parts for my first diy project, the dual 1290, but......

Iam having troubles finding the right wires... with al the different types and indications.. it is somewhat confusing to me... could anyone please help me with some explanation and tips of the farnell wire filters:

Manufacturer (any preference)
Conductor Size AWG: what size do I use for different connections?
Conductor Area CSA (is this not the same as above, but in different system
Voltage Rating ?
Conductor Material: any preference?

I already have bought microphone cable, so Iam looking for cable for the non sheilded bits...

I also noticed that some people twist their wires together... why and where to do that?

Thank you!

 

[solderspongebob]

So are those boards at the front your own take on the go between?

Yeah, pretty much. They are mainly to reduce the amount of wiring between the switches, but due to the tight layout of the case, I couldn't fit the JLM (or Igor's board) in.

I already have bought microphone cable, so Iam looking for cable for the non sheilded bits...

For the mains connections, I just strip the individual wires out of spare mains cables (ever bought equipment that comes with an IEC cable with a different plug on the end? perfect for stripping out!).

For power to the boards (0v, 24v & 48v) I actually used the same audio cable I bought as it was small diameter and had red and blue cores (I used the drain wire for 0v, red for 24v and blue for 48v) - you might be fine using your mic cable for this if the diameter isn't too large, otherwise things might get a bit bulky.

Typical stranded hook up wire is 7/0.2 (7-strands, each 0.2mm dia) which can carry currents of up to ~1.4A, 16/0.2 (up to ~3A), 24/0.2 etc. etc.  I think people generally twist the wires together when the pair carries AC, as this helps cut down on stray fields being radiated (but please don't quote me on that!).

 

[ChrioN]

Nice job. I see you had to plan the sh*t out of it to make it all fit. Looks very pro!

 

[letterbeacon]

Looks great!  Where did you get the heatsinks for the transistors from?  Did you have to do anything to get them to fit in the 1U?

 

[funkymonksf]

What space did you use for the terminals on the EZ1290 PCB? Your build is clever and clean! Good work?

-Brice

 

[deuce42]

Yes this one is a nice build. May you enjoy many hours of recording with it.

 

[madriaanse]

Yes, awesome work! Love the Wima caps throughout! Best, M.

 

[kante1603]

A very nice build-congrats!!!
But where´s adam?

Udo.

 

[Di_Sousa]

Amazing build,
congratulations for your work!

 

[solderspongebob]

Looks great!  Where did you get the heatsinks for the transistors from?  Did you have to do anything to get them to fit in the 1U?

The heatsinks are from Farnell: http://uk.farnell.com/fischer-elektronik/akk-127/heat-sink-to-3-14-c-w/dp/4621360 but they don't make much surface-area contact with the transistors; luckily they don't seem to get more than a little bit warm during use, and fit nicely in the case with a few millimetres to spare (the TO-3 transistors are on 6mm standoffs).

But where´s adam?

LOL! I might use that name for the next project (might be an 1176 - I'm not confident enough to tackle the D-LA2A yet, but PCB awaits).

 

[saxmonster]

I am looking to build this or a 1073 but not finding the kits or list of stuff to buy.  Where do I go to find them, I looked in the meta but found nothing.  I will keep digging.  About how much does this project cost as well as a 1073 model.  Just trying to get an over all price idea before I just into this stuff.  Just wanted to see if someone would answer me before I were to find it.  There is just so much here I get burried in just reading other stuff, hahahahah.

Thanks
Scott

 

[mulletchuck]

@saxmonster
check out Colin's ez1073 project with front panels/cases from ddt.

http://www.audiomaintenance.com/acatalog/AML_Products.html

ddt's thread for his front panels/cases is in the white market. 

 

[letterbeacon]

Try searching for 1290 instead of 1073.