8 Channel, 3U NEVE 1073 completed

[CJ]

where's the mix buss? :grin:
dang nice job.

 

[madriaanse]

Hehe, Thanks CJ! Funny you mentioned a mix buss. I was actually just thinking of building one of NYD's summing thingies with some nice P&G faders.

outoftune: yes, the PSU-2448 looks like it'll work fine.

ffaudio: I'm almost out of PCB's, but I'll get more made in the future.

Thanks!!

M.

 

[ffaudio]

[quote author="madriaanse"]

ffaudio: I'm almost out of PCB's, but I'll get more made in the future.

Thanks!!

M.[/quote]
Okay, as long as you'll still be making them I'll be happy.

 

[ChuckD]

Hey I trying to design my frontpanel for this 1073DPA clone or whatever you want to call it.

Is this correct?

Thanks!
Just waiting for my swicthes but other then that I think I am almost done.

-ChuckD

 

[Siegfried Meier]

Hey Chuck,

I think if you're using a Grayhill there's only 12 positions and that's it. No?

Sig

 

[ChuckD]

Yes I am using the standard Grayhill.

From What I thought postion 0 = 0 then it starts at 20 db and goes up 5 db from there hence my meter showing 20-70 with 11 ticks total???

Right?

-ChuckD

 

[madriaanse]

Hello ChuckD,

Check out this picture for the correct switch layout. There are 12 positions; from 20dB to 75dB in 5 dB increcements. So there's 30 degrees between each switch position, and a "stop" between 75 and 20dB. The stop is there so you don't accidentally switch from 20dB to 75dB - which could lead to musicians hurling headphones and other objects at you in similar fashion to early man attacking a mastodont.

Hope this helps,

M.

 

[madriaanse]

Also, since most people are building 2 channels, I've uploaded a basic 2U, 2ch front panel design for this preamp. It's a Front Panel Express file. (http://www.frontpanelexpress.com/)

This panel will bolt right up to the Circuit Specialists' case specified in the BOM. It should be pretty easy to adapt to a 1U, or a Par-Metal case as well. Pls see:
http://musiciansgig.com/ez1290/circuit_specialists_2u_panel.fpd

M.

 

[Slenderchap]

The following are now available from the on-line store;

VTB9043 - GBP 16.58 each
VTB9044 - GBP 14.88 each
VTB9050 - GBP 14.91 each

Prices exclude feight and VAT [if applicable]

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

Colin
www.audiomaintenance.com

P.S. There are only 25 of each in stock .... so expect to be disappointed if you hang about.
P.P.S. VTB9057 & VTB1847 are also in stock and will appear in the store shortly.... VTB1148's are now back in stock.

 

[guavatone]

I missed this M.

Nice one.

or, uh... 8

-Like the neve grey!

 

[RedNoise]

Up!!!Very nice looking 8 Pré!! :thumb:

 

[gar381]

Really Nice Build!!! :thumb: :thumb: :guinness: :sam:

I'm going to have to try a build of these one of these days.

Love the knobs. Reminds me of the ones
maxwall had about 3 years ago.

GARY

 

[vertiges]

Hi Martin,

:shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: (<--8 of them :green: )

Congrats !!! :thumb:

eD

N.B. : I would be interested in buying two EZ1290 PCB. I emailed you.

 

[madriaanse]

Hey thanks for the kind words guys!! It was a fun project that has taken the sound of the studio to a new level. (was using Millennia Media HV-3 before, always felt like something was missing).

I've actually built 24 channels of EZ1290's since I first posted this thread - two 8ch boxes and four 2ch boxes.

But if I had to do it all over again I would have built six 4ch, 2U boxes; would have been SO much easier.

Take care,

M.

 

[vertiges]

[quote author="madriaanse"]24 channels of EZ1290's.[/quote] :shock:

You're completely addicted !!! :wink:

eD)))

 

[RedNoise]

waow!!!! :thumb: :thumb<--only 2 of them , sorry! :green: )
Did you do the pcbs yourself?? :?:

 

[Bluzzi]

I finally got around to start finishing my 2 1290s. I was getting a loud hum on one and the other was not passing audio.

3nity came down today and he found a few un-soldered points on the board that wasn't passing audio. So that one now is fine although a bit noisy but not unusable. These pups have a hell of a lot of gain!

The other one still has a hum/buzz. We've tried to move the board, and even the input XFR. I haven't tried moving the output and its at 90 degrees offset from the quiet one's XFR. I will try that next but I doubt its that.

I doubt its AC leaking from the Power Supply as then both boards should have the same problem, which they don't.

I'm going to keep trying things like removing the toroidal XFR from the case, moving the output XFR's position. Verifying all parts.

If any of you have any suggestions as to what to try to find the culprit let me know.

I really want to also thank 3nity who came down to my place after a long day at work and spent hours with me on finding solutions. 3nity your the best man!

Thanks to Madrianse, even with some hum I can hear the 1290s are going to be great! I'm hearing a thicker and punchier pre than I'm used to (John Hardy mostly and its fantastic too but another species from these).

So guys please, give me some ideas!

Jim

 

[madriaanse]

Hi Jim,

Congrats on one finished pre!! Let's see if we can get the other one to play nice.

To start:
-Is the pre with the hum closest to the PSU transformer?
-Moving the toroid OTB is definitely a good idea
-Pay EXTREMELY close attention to grounding AND shielding. It has to be **exactly** like my assembly guide, or you can run into all sorts of problems.
-Can you post a pic of your layout?
-Any ripple on the DC rails? Can you measure any AC on the DC rails?

Let me know how it goes!!

All the best,

M.

 

[Bluzzi]

Hi madriaanse,

Thanks for the encouraging word but I'm not out of the pile of .... yet.

Yes the noisier one is closest to the toroid. By the way the Power Toroid is a big one. I need to drive 2 1290 and 2 MP-2 GR.
Also I must say moving the PCB twice as far from PT than the less noisy one resulted in no perceptible noise loss.

I'll double check the assembly guide again just in case!

I'll post a picture this weekend.

I haven't checked the DC with an oscilloscope yet. 3nity and I were quite tired after 3 hours sitting on the floor with our legs crossed debugging the pres. It took another 3 hour to get the blood circulating again. :wink:

I have to mention also that on both pres, I have the wiring for the 48v phantom hooked into the XLRs up to the switch but not to the power supply. Maybe its that but again I have to wonder why it would affect one and not the other.

Its 60/120hz hum for sure so I'm sure its grounding.

Thanks again for stepping in. Just replying gets me off my ass to get this finished!

Jim

 

[madriaanse]

Hi Bluzzi,

Just wanted to check in and see how it's going with the troubleshooting? A littlebit of white noise at higher gain is normal with these mic pres (Neve haze?), but there should be no hum.

Take care,

M.