8 Channel, 3U NEVE 1073 completed

[MicDaddy]

@MicDaddy
Mine was like that too, they work fine, however, you might need a little bit of wiggle room for when you get the heat sink on there.  I had to bend those caps slightly away from the heatsink so they didnt touch.

;D   I already installed with that in mind, heat sinks will be here today so we'll see how well I did judging the foot print

edit: They fit just fine with heat-sink 532-501503B00

 

[beatnik]

Hi there,

I have almost finished building two channel of this pre. However, I have some questions about the output transformer.

I am using Ed Anderson EA-1166. Since they already come with unshielded wiring, how to proceed? Cut the wires and solder shielded wire directly to the transformer, or can I use the unshielded wiring without noise problems?

And about the 0.01uF cap and 1K5 resistor on the secondary. I have to put them or they are specific for Carnhill transformer?

Thanks in advance

 

[desol]

Keep the transformer close to the pcb and wire to the board...then run shielded from x-former to xlr.
Keeping things neat and plenty of space from input wiring.

Yes, i would think you still need the termination.

 

[madriaanse]

Hit a snag, as I'm populating cards I don't see anyone else using axials for C4, C6, and C7  Electrolytic 100uF 25V.

I purchased MAL213836101E3  which is an axial package and I see all the builds on here using radials....  where did I go wrong?  I've double/triple checked BOM against digikey/mouser/allied and they tell me axial package....    are the VishayBC axials I have ok to use for these 3 designators?  See attached photo...

Hey Micdaddy, you may have to mount the bottom axial cap upright to clear the heatsink. Basically stand the Axial on end on the bottom through hole.

Best,

M.

 

[letterbeacon]

I've also noticed that the BOM is calling for axial caps, but in the photos there appears to be radials.  Does the PCB call for radial or axial?

Thanks!

 

[MicDaddy]

I've also noticed that the BOM is calling for axial caps, but in the photos there appears to be radials.  Does the PCB call for radial or axial?

You can use either, I used what the 1290BOM24 called for MAL213836101E3 (axial) and was able to fit them fine.  

 

[MicDaddy]

..another angle.

 

[letterbeacon]

Great, thanks!

 

[madriaanse]

Nice! what heatsink/standoffs are you using for 2n3055?

Later,

M.

 

[MicDaddy]

Nice! what heatsink/standoffs are you using for 2n3055?

Later,

M.

Heat-sink 532-501503B00  from Aavid Thermalloy (via Mouser), I did notice the footprint looks a tad smaller than what I've seen on others' boards (look smaller overall).  Hopefully the 2N3055 will stay cool.

For the standoffs I cheated and used a pair of 6-32 zinc plated nuts, stacked, using 1" 6-32 machine screw to secure, with a 6-32 locking nut on the bottom of the pcb.  I checked for good continuity prior to soldering, and was sure to put a nice bit of elbow grease on the locking nuts.

 

[sgenevay]

btw Desol !! 
I finally changed my ACDC wiring..
as joe has validate this way to plug with the TE62085 Transformer for 220v Countries..
with that i removed all V- parts of the board, have set it to tripler, and shortcut the C8... then add 4x 4007 under the board on the specified places...
i'm building my new power supply like this to power 16 Channels with 4 ACDC....  seems to be fine.
But as Joe said.. The first wiring that Martin gave was enough too for 4 boards normally...

In other way....

i can't choice the correct finish for my new preamps racks ...    i'm between anodized and powder coated...    and i can't understand which is the better looking one... the stronger one...
if someone can tell more about this... Thx a lot.

Sylvain

 

[desol]

btw Desol !!  
I finally changed my ACDC wiring..
as joe has validate this way to plug with the TE62085 Transformer for 220v Countries..
with that i removed all V- parts of the board, have set it to tripler, and shortcut the C8... then add 4x 4007 under the board on the specified places...
i'm building my new power supply like this to power 16 Channels with 4 ACDC....   seems to be fine.

Great sgenevay! At first i thought it was strange too...but i took the time to suss it out with Joe and i'm glad i did. It's the better way to run jlm power for this application. I'm sure there are better supplies period...but this setup is fine...and Joe's a good guy.

I think i personally would like the anodized finishes better, but that's just me.

This is how i did mine: (still trying to find knobs)  :

 

[mica]

I've just finished a 2 ch version, with JLM PSU and Go-between kits. I had tested the PSU and adjusted it to output 24V/0/48V as it should and connected everything, but when i turned on the phantom on the second channel: BAM! a puf of smoke and the 47R 1W resistor (right next to the JLM logo on the PCB) on the PSU fried, as in completely black! Im not sure if it was a coincidence, but im pretty sure it was when i turned on phantom on both channels at the same time..  I not that great at electronics, but could someone give me a pointer on what to look for when debugging?

thx

Michael
Denmark

 

[mica]

.. also a pic of the (almost) finished unit
Thx for a great project by the way!

 

[evilcat]

If I remember correctly, the 47R 1W is a protection resistor for the phantom cicuit. Mine burned too when I accidently did a shortcut between +48V and another rail or ground, I don't remember...
Anyway, check your solderings, shortcuts in the phantom area. Hope it'll help. Good luck.

Ben

 

[sr1200]

I've done something similar (twice... didnt learn my lesson the first time).  Make sure the JLM power supply is not using metal standoffs.  For some reason you can hook up the ground wire fine to it without problem but as soon as you try to use metal standoffs... bam.  (just my experience, using both the old style of JLM PS's and the new)

 

[sgenevay]

Strange.... i'm using metal standoffs on all versions of board... as said on Jlm website... that let use less wiring in the box... and i never had any problem on 1W res cause of that...  ???

 

[evilcat]

Strange.... i'm using metal standoffs on all versions of board... as said on Jlm website... that let use less wiring in the box... and i never had any problem on 1W res cause of that...  ???

Yep ! Same thing here

 

[mica]

Thx guys. I got it sorted out.. There was a short on the go-between kits phantom switch on ch 1. Its up and running now, just need to adjust it... I stuck with the metal standoffs, and it seems fine. will post hi-res pics as soon as it's 100% done

 

[mica]

OK, trying to do the BIAS adjustment: add a 1 KHZ tone to input untill clipping.. My Ch 2 is lower in volume that Ch 1 for some reason, and the waveforms look very different:

Ch1:

Ch2:

Could someone point me in a direction on what to look for?

M