8 Channel, 3U NEVE 1073 completed

Thanks Martin for the part number. Maybe I have an out of date BOM, C9 shows on the BOM Digikey PN. P4922ND which looks to be a 10000pf ceramic.

Ok so updates on mine!

Finished the board and the go between. I Have to do the 2 transformers and do my rack. All went well on this side.
Also finished the power supply, but after putting it in the case and screw everything, i power it on (after i already tested it without the case and fixed the voltages at 24 and 48) and smoke and flames was coming out of it!

I found out that there was a short between the case and the board because the 10r burned out as the 47r 1w. So what I did is use plastic screws to fix the LMs to the case to be on the safe side and it worked (as someone told me to do so). So a suggestion, either use plastic screws or heatsinks for your LMs. Now i replaced the two resistors and it works perfectly  ;D

Anyways hoping to finish it this week and to try it! (have to record vocals and acoustic guitar wednesday). Everything seems fine now. I ordered two but will start with only one as I'm short on free time right now.

Here's a picture of my second completed build!

Sounds amazing, thanks to madriaanse for all the help!






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Joelv, great look man, I like the racked PSU. Where'd you get those knobs if I may ask?

Thanks!

e-mail [email protected] and ask for the "Red Neve Knobs"


-Joel

nice work joelv

Whats that think blue wire youve got that appears to be attached to pin 1?

Thanks
jake

The blue wire goes to the LO1166 shield on the PCB.

Ahh, OK - so you attached the transformer end of the shield to pin 1..... anyone else doing this? I gathered Pin 1 could be left disconnected.

Cheers

If you don't mind me asking, how much did the whole project run you?

@ snipsip - correct, you could also leave Pin 1 disconnected.
@ mattyblue - around $1600 CAD (I have a lot of left overs though)

snipsnip said:

Ahh, OK - so you attached the transformer end of the shield to pin 1..... anyone else doing this? I gathered Pin 1 could be left disconnected.

Cheers

Click to expand...

I'm running the full shield on the output. You don't have to but...
Just be careful with the ground loops i'm guessing...

beautiful job!

can you post pics of the psu too?

Ive had my pair in bits for a few weeks as I coundnt resolve my darned crackle.

I built it into a new case with a couple of tiny changes:

1) I used an M4 bolt to connect the audio ground to the case, avoiding any extra / messy wiring.

2) I used the fivefish PCB's for input transformer, with molex headers. I was personally convinced this was the cause of the crackle, as the thick mic cable would be under some degree of tension, and the little pins never seemed like a solid connection to me. (BTW I wanted to use screw terminals, but had already soldered the molex to the pcb, and the PCB to the transformer.... once that PCB is on it doesnt seem to want to come off, and those transformers are prone to failure if you overheat the pins... so decide on your connector of choice before soldering anything! )

3) I added an extra pair of input XLR's which were not hooked up to phantom power. I use this unit for a pair of mics and my mix bus (after a pad that takes it down to mic level). Now I can have both hooked up and I dont risk blowing my Alphalink up by accidentally sending +48 to it.

I missed having these around... they sound amazing!


Thanks again martin
Jake

DAMN - after poweing up properly to use in a session, I have crackle in my left channel again.

Did anyone every make any proper headway with resolving theirs?

I have my LM317 heatsinked to the PSU case. All wiring looks good. Crackle is intermittent on the left channel, with or without phantom turned on.

Appreciate your thoughts - really want to start using these properly but its unusable at the moment

Jake

Hi Jake,

One forum member resolved the crackle by *really* tightening the screws that hold 2N3055. These need to be very, very tight. (you are using metal screws right?) Also, reheating the solder joints for the rotary switch may do the trick.

Let me know how it goes!

M.

Cheers martin - I'll give them both a go! 

Hey martin,

I think tightening those screws has worked. I'll give it a bit more time, but so far so good.

I have a slightly odder problem after my rebuild that i cant quite figure out.

I used 4 input XLR's and only connected phantom power to one pair. both wired to the input tranformer making use of all 4 conductors in my mic cable.

The other 2 connecters are used for my mix bus, which has already been padded to mic level.

Both pairs of XLR's work as I can get a level when i patch my mix bus in using either pair, but the odd thing is I cant get get a mic signal to register. I have measured correct phantom power is getting to the mic.. so im totally bemused.

Me and a friend share a scope, so I will get that back and do a few more investigations of my own, but an ideas at all what this could be? Im totally stumped.

Thanks a lot

Hi Jake,

Can you confirm that: +48V from PSU is split and connects to:
A: 6K8 resistor -> XLR Pin 2
B: 6K8 resistor -> XLR Pin 3

So you should measure +48V between pin 1 and 2, pin 1 and 3, and 0V between Pin 2 and 3. Sometimes people (read: I mistakenly swap pin 1 and 2 because they are mirrored depending on whether it's an input or output.

Also, trying this mic/mic cable combo with another preamp just to be sure might be a good idea.

M.

hey martin,

I had checked the mic and cable with another pre and all was good.

What you said made me reexamine my switch wiring though (which I was trying to make as tidy as possible), and I think I may have managed to parallel the 3k9 along with the phantom feed.

I had measured 4.8v at the mic, but thought in my haste that was 48v. Im off to bed now, but im pretty confident I can get it working now.

Thanks for your help (again) dude... always appreciated!