Neve 1290 build completed!!

[madriaanse]

Hi Dan,

Could you wire the EZ1290 w/o the Go Between and see how that goes? If it still has the same symptoms without it, I would suspect a solder bridge on the last set of switch pins, or some incorrect resistor values.

HTH,

M.

 

[danjpiscina]

Thanks Martin, I'll give it a shot.

Dan P.

 

[djn111]

Hi,

Digikey link works fine, it only gives one resistor, and disgard the rest hits.

DJN

 

[SIXTYNINER]

thanks djn111
47H-ND  - resistor hyperlink:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Cat=66690&k=47H-ND

Found this post about "Styroflex" capacitors
as Neve placed in original

somebody can post a "large" picture ,
that show well
the position in the pcb where "Styroflex" caps are placed ?

also found this suggestion (only for who is not much "expert")
Polystyrene Capacitors
This type is rarely used now. Their value (in pF) is normally printed without units. Polystyrene capacitors can be damaged by heat when soldering (it melts the polystyrene!) so you should use a heat sink (such as a crocodile clip). Clip the heat sink to the lead between the capacitor and the joint.

Here the post about :

I've got a European BOM jpeg put together with all the manufacturers parts numbers from the original Digikey ect BOM
at the above links for the EZ1290, it's missing the following 6 items which I can't find @ farnell
rswww or Banzaieffects??
c10 Polystyrene    Digi-Key 399-4493-1-ND   CAP 1500PF 50V 5% CER AXIAL KEMET
c11 Polystyrene    Digi-Key 399-4480-1-ND   CAP 680PF 50V 5% CER AXIAL KEMET
c3 Polystyrene    Digi-Key 399-4511-1-ND   CAP 4700PF 50V 5% CER AXIAL KEMET
c5 Polystyrene    Digi-Key BC1045CT-ND   CAP 330PF 50V CERAMIC C0G 5% VISHAY
C1 Polystyrene   Digi-Key   1003PHCT-ND   CAP 50V 180PF AXIAL CERAMIC C0G VISHAY
Phantom LED   Digi-Key   L10021-ND   LED RED 1/4" HOLE 5V PANEL CML 5102H1-5V
Also the following resistor values seem to only be available in Carbon Comp / Metal Film @ banzai??
R10    Digi-Key 91QBK-ND    91 OHM 1/4W 5% CARBON FILM N/A ?    
R6   Digi-Key   4.3KQBK-ND   4.3K OHM 1/4W 5% CARBON FILM N/A?
From another Forum:
"Styroflex is a registered trademark from BASF.
When used in capacitors, whe are talking about polystyrene"
0.001µF  =  1nF  =  1000pF
C10 - 1,5nf
http://www.banzaieffects.com/Styroflex-1-5nF-pr-21165.html
C11 - 680pf
http://www.banzaieffects.com/Styroflex-680pF-pr-21161.html
C3 - 4,7nf
http://www.banzaieffects.com/product.php?productid=21168
C5 - 330pf
http://www.banzaieffects.com/product.php?productid=21158
C1 - 180pf
http://www.banzaieffects.com/Styroflex-180pF-pr-21155.html
No Benefits in using 5% carbon film at all, let's stick with the higher quality 1% Metal film:
R10 - 91R Metal Film
http://www.banzaieffects.com/product.php?productid=16968
R6 - 4,3K Metal Film
http://www.banzaieffects.com/product.php?productid=17033
Gotta love Banzai
Phantom LED   Digi-Key   L10021-ND   LED RED 1/4" HOLE 5V PANEL CML 5102H1-5V
-don't be too strict with this kind of stuff, this is very specific , it's a matter of taste. You can use any Led you want or not even use one at all.
endless possibilities.

 

[briomusic]

Hi Group,

when I built my EZ1290 I thought I wouldn't need a PAD, as the lowest setting on my LTD-1 has been fine for even the loudest close-mic'd drums. But today I had to swap for a different pre because the toms were distorting. However, rather than adding an additional pad switch, I would just like to make the lowest setting less sensitive, even though this would give me a bigger jump (more than 5db) between this setting and the next. From looking at the schematic it seems I would have to make R6 larger (more attenuation) and R18 smaller (less resistance to ground) - but by how much? trial and error? simple formula?

thanks in advance for all help.
briomusic

 

[madriaanse]

Hi Briomusic,

Your thinking is correct, but it's not the approach I would take. I think you'll run into gain staging problems with too large of a gain step between position 1 and 2. How about making a barrel connector with a 470R-120R-470R U-pad (put the 120R on the male XLR side): http://www.markertek.com/Cables-Connectors-Adapters/Audio-Connectors/XLR-Connectors/Switchcraft-Corporation/S3FM.xhtml

Or you can use a DPDT switch (added to frontpanel) to accomplish the same thing, see:
http://www.jlmaudio.com/JLM%20GO%20Between%20PCB%20Schematic.pdf

HTH,

M.

 

[lsskmki]

Hi there,

finished my pair of 1290s on saturday after a looong (14hour) work day to finish them. Phew!  I tried to make these the best pres I have, so I carefully measured and selected all caps. I used polystyrene for most smaller valued caps and panasonics fm series for electros.  Carnhill in/out.

It seems all the work was really worth it as comparison with digi003 internal preamps revealed the 1290s being a lot smoother and just generally more pleasant sounding when recording electric guitars (clean/distorted).
I know it was kind of clear from the start that the 1290s would sound better, but I was still surprised by how big the difference was after all.

Many thanks to Madriaanse for great documentation and providing the base (pcbs) for this!

 

[madriaanse]

Nice!! I like the black panel, black knobs look a lot! It's very: http://audio.kubarth.com/fairchild/Fairchild.jpg

I also love it when builds work perfectly right away! Really nice job!!

M.

 

[gerardmanvuca]

I am finally starting the process of buying the parts for this project after having owned the boards for a couple of years. Money has been tight!! 

                I was wondering if standerd 3 way XLR cable would be usable for the conection between the JLM ac/dc box to the rack? i see in the BOM it sais to get a 4 way xlr connector,  but from wat i can tell there is only +24v, +48v and 0v coming out from the power supply....right? 

 

[briomusic]

Believe me, it's worth spending the extra few quid on a 4 pin and never worry about accidentally plugging the PSU into an audio input or output....

of course the actual cable can be three way with one pin not connected.

I am finally starting the process of buying the parts for this project after having owned the boards for a couple of years. Money has been tight!! 

                 I was wondering if standerd 3 way XLR cable would be usable for the conection between the JLM ac/dc box to the rack? i see in the BOM it sais to get a 4 way xlr connector,  but from wat i can tell there is only +24v, +48v and 0v coming out from the power supply....right? 

 

[gerardmanvuca]

Believe me, it's worth spending the extra few quid on a 4 pin and never worry about accidentally plugging the PSU into an audio input or output....

thats wat i thought. just wanted to dubble check that a 3 way cable was all that was needed. I am defo ordering a 4 way socket as i would probably be the first to plug the power straight into the wrong plug.

 

[briomusic]

hey madriaanse,

thanks for this advice. I have jlm gobetweens on other preamps, I was hoping to get away without a pad on this one.... :
I quite like having the phase swap on the output to avoid getting pops when phantom is on. I might just stick a permanent pad on the output, as I quite like the sound when the preamp is driven slightly harder. probably only needs a 5-10dB pad as it is really just the very occasional peak. :-\

out of interest....why would there be gain staging problems? the additional BA183 is switched off at those low gains - if I understand the circuit correctly - and there is no feedback loop either at that setting.

cheers,
briomusic

Hi Briomusic,

Your thinking is correct, but it's not the approach I would take. I think you'll run into gain staging problems with too large of a gain step between position 1 and 2. How about making a barrel connector with a 470R-120R-470R U-pad (put the 120R on the male XLR side): http://www.markertek.com/Cables-Connectors-Adapters/Audio-Connectors/XLR-Connectors/Switchcraft-Corporation/S3FM.xhtml

Or you can use a DPDT switch (added to frontpanel) to accomplish the same thing, see:
http://www.jlmaudio.com/JLM%20GO%20Between%20PCB%20Schematic.pdf

HTH,

M.

 

[evilcat]

Hi Madriaanse !

Do you still sell PCB for your 1290 project ?
How much would cost one board+shipping ?

Thanks, regards,

Ben

 

[stitch-o]

Hey kats,
I have some trouble-shooting I'm doing and I thought I'd see if anyone has ideas before I put the rack back on the bench:
-The right channel is very low gain...almost nothing at all. Maybe a bad solder point?
-the left channel gets a static noise that crackles after about 5-10 minutes of the 2 pres being turned on. Is there a ground scheme I'm missing?
-The last two clicks of both channels throws either channel into oscillations. I've moved the transformers as far away from each other as possible but to no avail here...

I kut some vocals with the left channel before it started cracklin'-> very nice!!

 

[audiovisceral]

Hi Madriaanse !

Do you still sell PCB for your 1290 project ?
How much would cost one board+shipping ?

Thanks, regards,

Ben

I just e-mailed asking. His reply:

Boards are $20 each. Shipping for any amount of boards is $6 USA, $8 international. I can take payment via paypal: martin_adriaanse [at] yahoo [dot] com

Bought two myself an hour ago. 

 

[snipsnip]

-the left channel gets a static noise that crackles after about 5-10 minutes of the 2 pres being turned on. Is there a ground scheme I'm missing?

I have a very similar issue to this. Ive hardly been in the studio since completing my build, so assumed it was a loose connection somewhere. Would be interested to see peoples thoughts on this issue.

-The last two clicks of both channels throws either channel into oscillations. I've moved the transformers as far away from each other as possible but to no avail here...

Have you wired up all your shields correctly?  I made some mistakes in with my shields which caused some oscilation issues.

Also, you need to have the circuit (use the hole near the 5k trimpot) grounded to the chassis. This removed the last piece of oscilation for me.

Jake

 

[evilcat]

@ audiovisceral : Thanks ! I've e-mailed him too for one channel, I can't wait to started it !!!

I'd like to put it in the same case than the S800 EQ, and though to use only one PSU : the 5 rails from JLM audio may work, isn't it ? +24V for the EZ1290 and +/-18V for the S800.
What power transf should I have for this ?
I'd like to have a "link/split" switch in order to have the preamp then the EQ in serie, or the preamp and the EQ separate. Does a 4PDT could works for that ? (assuming that I would only switch the hot and cold pins, not the ground)
Thanks to all for your advices.

Ben

 

[stitch-o]

-the left channel gets a static noise that crackles after about 5-10 minutes of the 2 pres being turned on. Is there a ground scheme I'm missing?

I have a very similar issue to this. Ive hardly been in the studio since completing my build, so assumed it was a loose connection somewhere. Would be interested to see peoples thoughts on this issue.

-The last two clicks of both channels throws either channel into oscillations. I've moved the transformers as far away from each other as possible but to no avail here...

Have you wired up all your shields correctly?  I made some mistakes in with my shields which caused some oscilation issues.

Also, you need to have the circuit (use the hole near the 5k trimpot) grounded to the chassis. This removed the last piece of oscilation for me.

Jake

Thanks Jake!
I knew there must be a ground-point for each channel but I never connected it.
Now, are you referring to the standoff hole on the corner of the PCB next to the 5k trimmer?

Still don't know about the static crackles or low right gain but I'll have some time on the bench today when my lil Stitch-lit goes does down for a nap.

Thanks again and Cheers!

 

[snipsnip]

The crakles an odd one, please do let me know if you figure anything out.

And yes, from memory the standoff hole near the 5k trimmer is connected to the ground, so I connected that to chassis. That resolved the last of my oscillation worries, which I think was also in the last 2 clicks.

Also, I know its a simple thing, but check the polarity of your wiring in and out of your input transformer, if you get hot and cold mixed up you would most likely get a very low signal.

Cheers
jake

 

[stitch-o]

Also, I know its a simple thing, but check the polarity of your wiring in and out of your input transformer, if you get hot and cold mixed up you would most likely get a very low signal.

captain obvious says "Doooh".
I changed a lot of the wiring and I have the pin 10 and pin 11 mixed up on the bunk channel.
I'm sure I woulda got it eventually but you just saved me hours of troubleshooting.

Thanks Jake!

I'll keep updating about the crackle...

EDIT: Snip, I owe you at least 3 beers. That was 2 problem birds cured with one internet reply.
Now, on to the crackle...
Cheers!