Neve 1290 build completed!!

[bluezplaya]

Got it! Had to put a little more elbow grease in the dremeling process :wink:

 

[madriaanse]

Nice! :thumb: On the newer V2.1 boards the trace in question is replaced with a jumper; works out a tad easier. :grin:

How are you liking your 1290's w/ 31267 so far Adam?

Take care,

M.

 

[bluezplaya]

I like them a lot!

 

[bluezplaya]

Any more boards available? I could use 2.

Thanks,
Adam

 

[madriaanse]

Thanks Adam! Invoice sent. :thumb:

M.

 

[3nity]

Hey Martin.
How loud is there a Hiss on the 1290?
Thanks.

 

[madriaanse]

Hi 3nity,

Like all 1073/1290's, these preamps have some hiss ("Neve haze"). They are not dead quiet, but the hiss shouldn't be distracting unless you're recording quiet sources with ribbon mics. The noise floor specs can be improved somewhat by hand-picking BC184C's for highest HFE (especially the first one in the darlington config), but I never bother.

HTH,

M.

 

[3nity]

thanks.

 

[mtw]

Hi Folks,

I'm getting ready to mount the transformers in the case and, having never done a full DIY build before, don't know how careful I need to be about placing the input and output transformers. I've got the toroid on the opposite side of the case, about 4 inches away from the nearest channel card, but does it matter how close the audio transformers are to each other?

 

[promixe]

[quote author="mtw"]but does it matter how close the audio transformers are to each other?[/quote]

Page 11 of this thread at the bottom:

The HF oscillation probably/usually comes from either:

.....

b) having the input transformer too close to output transformer

So, this particular statement partially answers your question. I THINK it's okay to have both output transformers pretty close to each other. It's the input where things are most sensitive...

 

[madriaanse]

You'll want to keep some space between the input/ouput transformers. It's not as critical as keeping the power toroid away, but don't put them right next to each other. Here's a pic of a BAE layout:
http://www.brentaverill.com/mm/products/big/1073mod_inside.jpg

HTH,

M.

 

[mtw]

Thank you both for your answers! :thumb:

 

[promixe]

Martin, quick question for you:

Earlier you said you "safe-estimated" the current draw being 500mA per channel on the EZ1290 boards. It seems way way too much of a draw, since I think even the original 1073 with full EQ section draws about half of that (at most)... Would you say it would be safe enough to have 1A for 4 channels of EZ1290 in one chassis? I mean, we're not talking about absolute precautions here, just something that is "good enough" and is not gonna blow up in the next several years. =)

I'm thinking about using a single PSU2448 from Fivefish to power 4 channels of EZ1290s... Is it an absolute "no go"?

Thanks!

 

[matta]

[quote author="promixe"]Martin, quick question for you:

Earlier you said you "safe-estimated" the current draw being 500mA per channel on the EZ1290 boards. It seems way way too much of a draw, since I think even the original 1073 with full EQ section draws about half of that (at most)... Would you say it would be safe enough to have 1A for 4 channels of EZ1290 in one chassis? I mean, we're not talking about absolute precautions here, just something that is "good enough" and is not gonna blow up in the next several years. =)

I'm thinking about using a single PSU2448 from Fivefish to power 4 channels of EZ1290s... Is it an absolute "no go"?

Thanks![/quote]

The problem is not the idle current (well not that it is ever truly 'idle' being Class A) but the inrush current.... 4 1073's can easily draw an amp on power up.... it doesn't hurt you to have a bigger supply, if the juice is needed, rather have it than not.. a stitch in time saves nine...

Matt

 

[Di_Sousa]

Hi,
this is a great project. Simply amazing.

I will build 2 of these soon.

Could I use BC547C instead of BC184C? 

http://www.banzaieffects.com/BC547C-pr-16574.html

Also about the switch, could I use this one?
its 1/4 the price of the Grayhill

http://banzaieffects.de/Rotary-Switch-2-level-2x1x12-pr-20274.html

thanks for your help

 

[madriaanse]

Hello Whoops, I would highly suggest sticking to the BOM; you'll be a much happier person!  ;D

M.

 

[SaMpLeGoD]

Hello Whoops,

When you order the Carrnhill's trafos from www.audiomaintenance.com , they have the Grayhill rotary switch too
For the BC184's I think i have some extra... PM.

Cheers,

Eddie  ;D

 

[Di_Sousa]

Hello Whoops, I would highly suggest sticking to the BOM; you'll be a much happier person!  ;D

M.

Thanks mate, I will stick to the BOM and I have to say that I'm a happier person already!!!!!!!!!!!!!!!


EDU - will send you and email, have you seen my last one?

 

[SaMpLeGoD]

Hey Whoops,

Yes I did! thanks for the photos!
Cheers,

Eddie

 

[Di_Sousa]

There's any way of having the option for Hi-Z or Low-Z like in the Neve 1073 DPA ?

you can select between 300 ohms or 1200 ohms, this is quite usefull for ribbon mics and also to change the charecter in normal dynamic mics.

would it be hard to do? what's the standard impedance of the EZ1290 is it 1200 ohms?