8 Channel, 3U NEVE 1073 completed

[Whoops]

This wiring for the trim-pot should be ok !

I also want to know how a 600R Termination on the OT would affect the sound.
Read somewhere that on the old consoles the modules were loaded with 600R and now we are running the modules in 10K gear.
Could somebody explain pro and cons for terminating with 600R? Is it necessary?

best regards,
Wolfgang

this is actually interesting...

 

[desol]

'Quick' search at Geoff Tanners site:

http://www.auroraaudio.net/dcforum/DCForumID1/506.html

 

[wolfgang]

Just wire the pot and leave the 10k resistor offboard. if you look at the pcb you will see that point "P" is connected with the backside of the 10k resitor.

regards,
Wolfgang

 

[madriaanse]

1- 100p instead of 180p accross the input transfo.
Is that to extend the top end??  This clone utilize the same input transfo than the ez1290.

Yes, it would increase bandwidth - at the possible expense of increased ringing.

2- 22uf tant instead of 10uf tant in front of the first bc184 of the input and output section.
Is that to extend the low end??

Hmm, I'm not so sure. It could possibly increase stability; this could mean lower THD at expense of bandwidth. Or perhaps it was done to be more resistive to DC offset. I would be interested to hear SCA's reasoning for this, or perhaps ask Geoff T.

3- They suggest to put a loading resistor (620R) on the output.  If im going directly into my soundcard that have a 24k input impedence when balanced, should i care about putting a loading resistor??
I'm asking this because i've just notice that inside my api 3124, there's a place to put an ''optional 1k loading resistor''!!

As always, Geoff Tanner's info is GOLDEN (thanks Desol for posting):
>Hi Geoff,
>
>I have got a Neve 32074 with the BA283 and LO1166.
>Should LO1166 always be terminated with 600ohm?

No, not "always"... if your set up is relatively small and you don't have long cable runs on the output, you won't need termination on the output.

The terminations come into play when the cable on the output presents a sufficiently high capacitive content to the load of the transformer that will resonate with the leakage inductance in the transformer to produce a high frequency peak and would be seen as ringing on a square wave or sibilance on a voice or music signal.

Then a 600 ohm load would damp that effect though you might experiment with a scope and a square wave to find the optimum load... which might be higher, like two or three Kohms.

-----------
That said, I'm not sure "improving" these preamps is at all necessary, but that's a personal choice and a bit of experimenting is always good.

Zach, did you get that trimmer worked out?

M.

 

[YLab]

Thanks for your anwser Martin, really appreciated!

By the way. i've just received my pc boards, and they look fantastic!!

Thanks again.
Hubert

 

[basementmedia]

Hey madriaanse,

are you still selling PCB's?
I'd want to built a 8 channel Version like yours...

Would be great to get this sound into my DIY collection which seems to be never completed AARGH ;-)

Greetings

Daniel

 

[madriaanse]

Hi Daniel,

Sorry I missed your post, I do have more PCB's available. Please email me at: 1290preamp [at] gmail.com.

Best Regards,

M.

 

[nikonet]

;D
Hello !
i found my noise problem: i move the transformer outside the case

the PSU didn't make good job:
20v instead of 24v, so i use the 48v regulated to 24v .
I dont need 48v for this préamp, but i would like to know if it's possible to correct this problem: i would like to use it for other préamp.......

and a last question, how many préamps can i use with one PSU (PSU-2448 from fivefish)

thanks a lot every one , i think i'm going to be totaly addict!!!!

 

[desol]

From the looks of your powersupply, i'm thinking 2 channels.

30va / 24v =1.25A

If i remember correctly, Martin recommends 500ma per channel.

D.

 

[Whoops]

I'm putting a trim pot in my 1290's.

I would like to have a rotary fader , with a center detent for 0dbs.

What brands and models would you advise?


I've searched for Penny and Giles RF11 but it costs 120€.

I can Buy PEC from Banzai, but couldn't find any rotary fader there, just normal pots. the same for CTS

Vishay Spectrol can't find an easy European store.

 

[zachs]

What are the differences with a rotary fader instead of of a pot?

I still need some high quality pots for my 4x 1290s...

 

[Whoops]

center detent for 0dbs.

 

[desol]

Rotary fader(r11) is the way to go...but ya gotta pay the price.

One could always rig up a fader pack with used faders....they're pretty affordable on the market...but take up rack space. Then's there's the way that everything gets wired into the faders. I have two seperate preamp packs...6 in ea...both these types would connect to the fader differently. Still thinking about how to wire this up properly.

 

[Whoops]

unfortunately  I can't afford to pay  240€ for two R11.

Is there any other rotary fader alternative?

I would like to have 0dbs at the 12'oclock position, do I need a rotary fader to do that or any Pot would do the job?

I was seeing a 5K Log PEC, it costs 15€, much more affordable. It just feels strange for me not having a centre detent (if that's the correct name)

 

[madriaanse]

I would like to have 0dbs at the 12'oclock position, do I need a rotary fader to do that or any Pot would do the job?

I was seeing a 5K Log PEC, it costs 15€, much more affordable. It just feels strange for me not having a centre detent (if that's the correct name)

I think you might have the wrong idea. The trimpot is an attenuator only, and so all the way clockwise would be 0dB, and it's down from there - all the way to -Inf.

P&G or bust baby!!

M.

 

[Whoops]

I think you might have the wrong idea. The trimpot is an attenuator only, and so all the way clockwise would be 0dB, and it's down from there - all the way to -Inf.

maybe I'm getting confused.

I attached a picture showing what I would like,

in number 1 the pot has a centre ident at 12oclock position where it says 0dbs.

number 2 it's exactly the case you described all the way it's 0dbs.


is it possible to have a pot that acts like the example in picture 1?


I searched for alternatives to the P&G 120€ pot,
what do you think of these ones?

http://www.banzaieffects.com/PEC-MIL-MO-LOG-5k-pr-26690.html

http://uk.farnell.com/vishay-sfernice/p11vyn-5k0-10-l/potentiometer-5k-log/dp/1141609?_requestid=236522

 

[zachs]

That Vishay looks nice...

 

[R3]

madriaanse if your not too busy PM me when you get the chance, I've been trying to get ahold of you for 2 or 3 weeks but your box is full.
-Richard

 

[zachs]

I PMed you his email.

 

[nikonet]

hello Martin, i received 4 pcb 3 days ago

thanks; thanks; thanks!!!!