Neve 1290 build completed!!

[adam1176]

on the pcb, near the pot, there are 3 holes for a 180 pF cap. Does it matter which holes I use? It looks like the traces lead to different areas from each hole. Anyway I'd like to get this right.

Who here knows?

Thanks!

 

[adam1176]

ohhh and... I'm not sure where to place the fuse. I haven't seen it in any of the pictures in this thread. Of course that doesn't mean it's not there. Any help is appreciated.

Thanks Guys!

 

[desol]

on the pcb, near the pot, there are 3 holes for a 180 pF cap. Does it matter which holes I use? It looks like the traces lead to different areas from each hole. Anyway I'd like to get this right.

Who here knows?

Thanks!

I only see two holes on my cards. Did something change?

Your gonna probably want a couple fuses. One on the hot main to the switch, and one one the secondary of the transformer going to the power supply. That's what i did anyway. Cheers.

 

[MatthewF]

Hi everyone, I've finally got two channels of this pre up and running and they're sounding fantastic - thanks Martin for such a great layout, high quality PCB and top notch documentation!

I included an impedance switch, wired as per the original Neve schematics, in order to provide another tonal option with certain dynamic mics. I've also added an insert point, just before the trimmer. This should provide a good place to insert an eq, such as those currently offered by Bluzzi and Igor. I had the front panel done at Schaeffer - if anyone's interested in something similar I can share the file.

Here are a few pics:

Sorry for the lens distortion!

Knobs are from Elma.

There's that lens distortion again, makin me look fat!

All that shielded cable is Belden 1508A. Its great stuff to work with - the foil screen is bonded to the rubber sheath, so it all comes off with one shot of the wire strippers, leaving just the twisted pair and drain wire.

Signal path electros are Vishay BC. Other caps are LCR polystyrene and Multicomp tants. (Don't buy Kemet tants - the leads aren't long enough!)

Right, now to record some music!

Cheers,

Matthew

 

[wolfgang]

Congrats!!!!

Very nice build!!!!!!

Have fun with it!!! ;D ;D ;D

regards,
Wolfgang

 

[Whoops]

Amazing work,
congratulations.

Can you provide some info on how you did the Impedance switch?

thanks

 

[madriaanse]

Wow MatthewF, this is a top notch build - really fantastic work! This is how the pro's do it!

I hope you get some great use out of it!! Ya liking that tone?  ;D

Martin

 

[madriaanse]

on the pcb, near the pot, there are 3 holes for a 180 pF cap. Does it matter which holes I use? It looks like the traces lead to different areas from each hole. Anyway I'd like to get this right.

Who here knows?

Thanks!

I only see two holes on my cards. Did something change?

Your gonna probably want a couple fuses. One on the hot main to the switch, and one one the secondary of the transformer going to the power supply. That's what i did anyway. Cheers.

Hi Adam/Desol, on the V2.3 PCB's I added an extra hole for the 180pf to accommodate wider footprints. One side connects to pin 7 on vtb9045, and the other side connects to one of the two holes that connect to 0V.

Just fusing the ACDC per my instructions is sufficient

Best,

m.

 

[MatthewF]

Thanks for the nice comments!

Ya liking that tone?  ;D

Oh yeah, for sure! I've not had a chance to use it in a proper session yet, but just messing around with a few mics has got me pretty excited about some of the sounds that could be had, especially with a screaming loud rock singer...

Can you provide some info on how you did the Impedance switch?

Sure, its wired exactly as shown in the original Neve schematics (which can be downloaded from the AMS website). Here's a portion from the front end of the 1084, showing how its done with a DPDT switch:

Note how the switch changes the configuration of the primary windings between series and parallel. The former configuration yields a higher input impedance than the latter, thereby offering two different loading conditions which can be of interest when using certain dynamic mics.

Matthew

 

[desol]

Just fusing the ACDC per my instructions is sufficient

I had some weird experiences choosing the right location for the fuse. I put a 1.5 amp fuse on the hot line coming into the switch to the primary; the acdc is rated at 1.5 amps. Then, during the build, something shorted at the acdc. Fuse on 115v primary(switch) did not open. Power supply smoked. So, added 2nd fuse to secondary going to powersupply. That fuse then opened. Found problem...and fixed....but ended up with two fuses as working solution? I'm assuming the transformer isolated the excess current draw to the secondary only, causing the powersupply to smoke...but left the primary fuse untouched?

I'm pretty sure i asked Joe at JLM about this too, but i can't quite remember.
I wanted to only use one fuse...but that didn't seem to protect the circuit and myself completely.
I don't know, everythings working ok now, but i'm still somewhat confused over this.

 

[madriaanse]

Ahhh, the sweet smell of burned electronics.  with a 1.5A fuse you'll blow the bridge if something goes south. Those 1N4007's are only rated for 1A. The LM317 is rated to 1.5A and will crowbar if there's a short. Best to use a 1A fuse before the power transformer.

M.

 

[Whoops]

Can you provide some info on how you did the Impedance switch?

Sure, its wired exactly as shown in the original Neve schematics (which can be downloaded from the AMS website). Here's a portion from the front end of the 1084, showing how its done with a DPDT switch:


[/quote]

Thanks Matthew,
it was just to check if I have done it right.

I'm still amazed with your unit!

 

[Johndcx]

T :Very nice work,I am thinking of doing the same with Igors 69 eq with it...

 

[Eddy]

Hi Martin

I receive all the PCB today  and nice PCB printing and very quick shipping

I'm really happy  ;D

I'm working in a Recording studio for PostProduction in France

I have a lot of schematics (All SSL 5000G+/Neve Serie 51/Studer Stuff Ect...)


Best Regards
Peace
Ed

 

[adam1176]

I missed the aluminum stand off's in my part order and i really don't want to pay all that shipping for a $3 order. Also I can't find ones small enough in my local stores.

Is there any reason a simply nut wouldn't suffice?

 

[snipsnip]

Yeah, you can just use a nut if you'd like.

Jake

 

[ilfungo]

ciao Marin
Have you recived my payment for
2 x EZ1290 PCB?
When you ship them?
Thanks

 

[adam1176]

I missed the aluminum stand off's in my part order and i really don't want to pay all that shipping for a $3 order. Also I can't find ones small enough in my local stores.

Is there any reason a simply nut wouldn't suffice?

or two nuts stacked and soldered maybe?

 

[bruno2000]

How hot do the 2N3055s get?  The ones I built barely get warm.  How about yours?
Thanks!
Bruno2000

 

[statzern]

Yeah same here - not hot at all.

Now the LM317s are another story...