8 Channel, 3U NEVE 1073 completed

sr1200 said:

Kind of a silly question.  Has anyone tried to stack these on top of one another (as in have the PC boards using the same standoff locations)  Im trying to make some room in my case, and I just want to know if the transistor/heatsink on the cards get too warm to put one on top of another.  Im attempting a 4 channel build and need to commit to a front panel design in the next few days.  Im trying deparately to NOT have to use an external PS for this one.

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That should be fine. Use insulated standoffs to keep them separated, and make sure nothing touches. Also keep the transformers spread apart a little as they can start talking to each other.

M.

PS. check to make sure your transformer wiring is EXACTLY as it should be. If you wire the output backwards you will get a drop in gain.

Awesome, thank Martin, still the best sounding pres in the studio man, cant thank you enough.
Last question, for a 4 ch build, fuse rating?  Im thinkin like 3amp but i dont want to high ball it and risk damaging the boards.

Ok, I didn't populate any of my cards with sockets for the transistors.

I've seen Jim Williams post at Gearslutz about lower noise transistors Toshiba 2SC3329 BL's, and Renesas 2SC2545.  A fellow lifted the hood from another mainstream 'Neve' manufacturer for me and noted 2sc1114 inside....  any thoughts?

Is there anyone out there that did install sockets that would be willing to do a comparison?
Or better somebody that has already put this through the wringer?

I honestly cannot see how these pres can be any better  8)  but I'm always up for a good goose chase.

Before I go and unsolder each of the transistors in each of the 8 cards I'd like to ask the community for your thoughts and in your opinions is the 'value added' (less noise) would be worth the rework.

anyone can recommend good power supply kit to power 2 or more (8) pre?

2 pres use the JLM AC/DC kit
3-8 use the JLM Powerstation kit (rectified)

Transformer spec may change depending on the amount of pres as well.

I just put my 4 pres into my case (which im a little miffed at since i "thought" i ordered a deeper case)  The case is TIGHT to say the least... (id post photos but want to avoid being laughed at) question is, would putting a metal mesh barrier between the input tx's make a difference,  I have the input tx's only a few inches apart.  When i was building my 2 ch. it was mentioned that i wanted them REALLY far apart (how far "REALLY" is i guess is subjective).  Im thinkin a conductive screen like material (similar to what putting chicken wire around larger devices does).  Any thoughts or am i just being paranoid?

sr1200  my advice is dry fit them and take a listen.  FWIW my output iron is side by side, winged mounting hardware nearly touching one another.  The input iron are only a few inches apart from themselves.

See this post for idea of the orientation/spacing. http://www.groupdiy.com/index.php?topic=22828.msg563186#msg563186  The input iron rests directly under the pcb where the audio in pads are located.

...another FWIW, I've seen some of these (very Brave) guys cramming 8 pres into unbelievably tight spaces.  You can dig through this thread for photos (desol, sgenevay, Govinda Doyle, madriaanse himself) to get an idea of how close some of them are mounting transformers, though I think some may have used some type of MU shielding etc... 

http://www.musiciansgig.com/neeb/2inside.jpg

http://www.groupdiy.com/index.php?action=dlattach;topic=22828.0;attach=6647;image 

http://www.groupdiy.com/index.php?action=dlattach;topic=22828.0;attach=6902;image 

http://desmond.imageshack.us/Himg839/scaled.php?server=839&filename=dsc02842z.jpg&res=medium

Yeah i got way more clearance than some of these.  I am hoping to power it up tonight and see whats up.  Gotta mock out a face plate for it first though.  My go betweens and trim pots need to be mounted otherwise they're just kinda... hannnngggin out. lol

Thanks mic for the pic list, some really nice wire jobs on there!  Mine's gonna look like the wire section at home depot expoloded.

Well i fired her up last night and Channel 1 & 2 (stacked were PERFECT) channel 3&4 not so much.  Im def. going to have to move the power supply outside of the case   the 2 channels on the right side of the case were humming like a ... well, something that hums a lot lol.  when i took the input and output txs out of the case all were silent.  So, now i gotta fond some of that alarm wire (5 lead i believe since I'm using 2 separate 24V channels, the 48v the 0v and the case ground)

Gonna be a drill-tastic weekend for me

Been a while since I've jumped on the site, I figured I'd better update the progress on my 8 channel 1073 build (just like martin's). So far so good! I torpedoed the 1w resistor on the powerstation when I was building channel 1, it seems it arced with the secondary leads of the toroidal. I wonder what my face looked like when I heard my newly-built PSU sizzling! I cleaned up the PCB and rigged up the new resistor for the 48v and I was back up and running. Then I built channel two, ran into some issues, as usual, double-checked all my solder points and discovered one of the jumpers on the input tranny had broke loose, so we were getting very weak and noisy signal. I had channels one and two up and mounted for about two months before I started work on 3/4, I picked up two pairs of transformers from hairball audio instead of the carnhills, and no regrets! I did a shootout in one of my classes with six different pre's, and I couldn't hear a difference between channels 1(carnhill) and 3(hairball). I had one little idiot mistake with channel four, but both of those channels were installed and up and running with zero issues (very exciting!). I ended up ignorantly grounding one of the leads for the input transformer and phantom power wouldn't work, but we tracked that down and fixed the issue. I've got four channels up and running and winning mic pre shootouts! Thanks go out to everyone on this site, I've stalked this thread for several months educating and troubleshooting! It's very exciting to have my first build up and running, I'll post up some pictures soon!

Finished the build for my 4ch unit.  They sound AMAZING (as expected).

Hey sr1200, after calling around quite a bit I found the cable at a theater installation place.

believe it or not, I found it at a home depot near my house.  they sold it for $0.44 /ft. It works great, but not very flexible since its not stranded wire.

Finished 2channel unit (or so I thought). Other channel works&sounds great, the other one doesnt.
Visually everything seems to be ok, I've checked parts and will check them again

Main problem was, when I tried to adjust bias the trimmer had no effect -voltage (3055 to gnd) remained near vcc ~23,5V.
And line-N(Vcc to BA183NV) voltage(after r51) was something like 3V.
So trimmer was busted- I replaced it with 2resistors (as voltage div.) since i had no replacement in hand..
that got bias to 22.8V but still N-line was low.

I measured voltages lifting one part at a time, so when I lifted one leg off, the voltage rise up to normal;
r51->c4->r13->collector of tr5 where i gave up.

any clues?

Sr1200 did you get the Pad, 48V, Phase from Jlmaudio?

Manu

Yeah, I've used em in 6 channels now, they're awesome!  JLM also makes a VU buffer that I've used in a pair as well.

Sr1200, I want to try building this Neve clone.

So to be clear could you tell from who did you get all the Parts :

PCB?
CASE?
PSU?

Thank you,
Manu

If you go to page 1 of this thread, everything is pretty much there in the BOM.

The only "add ons" I did were the JLM audio GoBetweens for the phantom/pad/phase since its all in a nice pretty package.

If you're doing more than 2 channels, go with the Fully rectified JLM Powerstation (not the AC/DC as stated in the BOM).  The power tranny will also be different (if you check a few posts back, I asked about the correct tx for the powerstation, and someone pointed me to the Lindberg which has been great)

1 AC/DC is good for 2 ch.

I've been told you can get up to 8 on a single Powerstation. (I wont go more than 4 though... I like headroom)

Sr1200 Thank you so much for your quick and nice response !

I will surely get all the parts and get on building a 2ch unit.
I would like to also build some Trident Clone. Maybe the powerstation could power them all at once and i could get 4 channels in one rack (2neve, 2 trident).

Thank you !

If the voltages required are the same for all 4 you might be able to do that.  I'd tend to keep em separate though.  Makes trouble shooting a lot easier, and a cramped case is never fun to work in.