8 Channel, 3U NEVE 1073 completed

[benlindell]

are you turning the gain of the channel all the way or almost all the way up?

 

[zmgwg]

all the way, I can get it to 22.6 with many many turns but then it comes back to 22.4 as it seem max i can get. Its like that on both of my channels. maybe its problem with how transistor is mounted but then I shouldn't get any voltage instead of slightly to low, right? 

 

[zmgwg]

ok you were right, I have 22.6 after readjusting power supply. one channel working, but another have really low gain with transistor voltages different than working channel. input transformer and wiring is ok. 2n3055 is ok. checked all the components except polystyrene that have marking anther them, can it be something elst? there are no shortings and I've reheated all the wiring joints

 

[benlindell]

ok you were right, I have 22.6 after readjusting power supply. one channel working, but another have really low gain with transistor voltages different than working channel. input transformer and wiring is ok. 2n3055 is ok. checked all the components except polystyrene that have marking anther them, can it be something elst? there are no shortings and I've reheated all the wiring joints

I had the same problem, ended up being an incorrect resistor, triple check compared to the working channel and check all the caps, especially their orientation.

 

[sgenevay]

Hey MicDaddy !!!  

i just wanted to ask you something about your  Neze 1290-4 Rack front panel ....

What color did u use exactly ? cause it's not looking the same on all pictures u have post...     is it a RAL color ? or anything else ?

Thx for your answer.
Best.

Sylvain

 

[MicDaddy]

You'd have to ask dandeurloo about that, as the cases are the ones he sells in the WhiteMarket.

They are real nice and worked perfectly.

I too would like to know which RAL color it is so I can powder paint the front panel to the PSU chassis I made, right now it's black and I'd like it to match.  I just haven't gotten around to shoot an email asking.

Sorry I couldn't be more help.

 

[madriaanse]

is anyone using metal standoffs for pcbs? I cant find any non conductive solution and I dont want too mailorder it [unless i'll have to...]

Using metal (conductive) standoffs is a bad idea for the EZ1290's. It will short the top left mounting hole (0V) to Case Ground, which is not the end of the world, but not a good idea either. For proper star grounding, low hum, low interference, use plastic or some other insulating standoffs. If everything's wired correctly there should be 10 Ohms resistance between the rack case and 0V on the EZ1290.

M.

 

[desol]

I've reinterated this many times in the thread as well Martin...and even pointed out another reference from the designer of the power supply. Now i just leave it up to people to read, believe or disbelieve.

 

[zmgwg]

is anyone using metal standoffs for pcbs? I cant find any non conductive solution and I dont want too mailorder it [unless i'll have to...]

Using metal (conductive) standoffs is a bad idea for the EZ1290's. It will short the top left mounting hole (0V) to Case Ground, which is not the end of the world, but not a good idea either. For proper star grounding, low hum, low interference, use plastic or some other insulating standoffs. If everything's wired correctly there should be 10 Ohms resistance between the rack case and 0V on the EZ1290.

M.

I came around it by installing standoffs [from the 2u build] to top cover and not the bottom and now it sits nicely in 1u.
there's something wrong at 91r in my not working channel, it shows 0 resistance compered to working channel and all the parts are the same and measure the same until that point. I guess I'll switch that resistor and see what happens

 

[band_master]

took my ez1290s for a test run the past couple nights at my studio...sounds incredibly excellent. thanks martin!!!

 

[MicDaddy]

Nice build band_master, where'd you find the knobs for the trim?

 

[MicDaddy]

I just wanted to reiterate the importance of the 'trim' function  (at least for my own personal uses)

Recently I sold my big heavy clunky analog mixer and opted for a single RU interface to handle the routing.

Using the EZ1290s on the front end, I don't miss the faders as I'm able to dial one extra step of gain than needed, and then fine dial with the trim.  It may not be necessary for every builder to incorporate, though personally I would be lost without it.

The 1290s sound so good. 

 

[sr1200]

Was in a session last week and was using my dual EZ for drum overheads, and noticed that one of the channels was a bit "off" gain wise.  Besides the baising, is there any way to calibrate these things? 

 

[spase]

where i can find this boards?

 

[Andreas Pfeiffer]

I have problems in the high frequencies, they are too low.
Attached is a picture from measuring a pink noise.
Output is measured at the output of logic´s test oscillator (Left analyzer). Input is measured from the soundcards input (Right analyzer)

 

[sr1200]

Could be a cap value issue somewhere in the signal chain? If you're sure you didn't mess up any values in the build...

[list type=decimal]
[*]Was the unit biased properly?
[*]Might wanna try and match the gain as well for comparison purposes. 
[*]Send the pink out into another pre, and see if you get the same response (if so swap cables and try again)
[*]Send the pink out and directly back into the sound card and see if you get the same response (if so, it's new sound card or cable time)
[*]Balancing act?  Are you using an unbalanced cable anywhere in the signal chain?
[/list]

I'm guessing since you're going in and out of the same card there's no clocking issue.

 

[Andreas Pfeiffer]

1-Yes
2-I did
3-If I don`t go through the amp the curves are equal
4-If I don`t go through the amp the curves are equal
5-No

 

[sr1200]

Im thinkin you may have to look at the board then and verify that all the caps that are in the signal path are the right values. 
Might want to check to see if the cap on the output TX is right first and work back from there.
When I get in the studio tonight, ill do the same test using the PAS analyzer and post my results so you have a comparison of sorts.  I would expect SOME coloration, but nothing to that degree.

 

[Andreas Pfeiffer]

I will do this today, but I need a pic of the bare PCB to check the values.
The cap on the output TX is 10nF.
Also I forgot to mention that my other preamp (1272 hotrodmod) doesnt have this rolloff, also I dont use a Di box, The EZ 1290 is directly connected with my soundcard...

 

[Andreas Pfeiffer]

Ok, I think I found the mistake, instead of a 180pF cap on the input transformer a 39nF found its a way onto the board  :
I have no idea how this was possible!