8 Channel, 3U NEVE 1073 completed

[USIEL]

thank you whoops ,
channel 3 is working  great now  ....made the classic elco polarity mistake 
i'll check and measure  channel 4 again and again.......

thanks for your time !

 

[JW]

Okay,

Maybe this is voodoo territory, but polystyrene caps are "polarity sensitive" as Martin says in the build documents, but only to the extent that it's slightly better shielding for the cap to have the foil side connected to ground (unless they're used where one side isn't connected to ground in which case it doesn't matter) Correct?

Well, numerous of these styrenes are used where connected to ground in this circuit.

Does anyone know how to determine the foil side of a polystyrene cap? I can't for the life of me see it with my eye. (I happened to order the Xicon polystyrene caps from Mouser but they came as radials not axials.) Oh well. I don't really care about that, just how to see or determine the foil side of the cap.

 

[Whoops]

it's slightly better shielding for the cap to have the foil side connected to ground

Yes, but maybe marginally minimal better,
these are really small caps, inside a metal box

(unless they're used where one side isn't connected to ground in which case it doesn't matter) Correct?

Wrong.
Foil side should always connect to the lower impedance part of the circuit.

It really doesn't matter in this build,
It's more relevant inside Tube Amplifiers where the film caps can be quite big (bigger area for noise induction) and can be next to heater wires or other internal source of noises.

Does anyone know how to determine the foil side of a polystyrene cap? I can't for the life of me see it with my eye. , just how to see or determine the foil side of the cap.

Easy:

http://lmgtfy.com/?q=how+to+determine+foil+side+of+caps

 

[Potato Cakes]

The four channel version that I built years ago uses polystyrene caps and I paid no attention to the position of the foil. All the channels are quite and sound awesome. Depending on the quality of your test equipment, you might be able to measure some type of difference, but as Whoops pointed out it would be marginal and I doubt you would hear a difference. Just put them in there and make sure you don't overheat them.

Thanks!

Paul

 

[JW]

Looking for a good 4 channel power supply for this one (w/ phantom hopefully) Five Fish ain't emailing back. I'm not sure, but one of the JLM ones might be a switching supply (?) Can't tell. Don't take my word for it. But anyway, any recommendations? There's a lot of options for 2 ch's. Not sure about 4.

 

[Potato Cakes]

JLM Powerstation is linear but has a switch on it to go from 240v to 115v. The JLM TREX and TREX2 with the 840w SMPS is switching. Both options will do 4 channels. It's listed on each product page on this website.

Thanks!

Paul

 

[madriaanse]

Hello friends,

Since this project has been ongoing for such a long time I wanted to make the PCB design file for this board open source.

Gerber file:
https://s3.amazonaws.com/EZ1290/EZ1290V26.zip

Design spec for PCB house:
Board size: 6.5 x 3.75" (165.1 x 95.3mm)
Material: FR4
Min hole size: .3mm
Gold fingers: No
Finished copper: 1oz
Board thickness: 1.6mm (.062")
Solder Mask: Green
Surface finish: HASL with lead
Layers: 2 layers
Min track/spacing: 6/6mil
Silkscreen: White
Via process: Tenting vias

I did want to point out that it's  still cheaper and easier to order boards direct from DIYRE if you're building 4 channels or less and they deserve our support:
https://www.diyrecordingequipment.com/collections/parts/products/ez1290-preamp-pcb

All the best,

M.

 

[Whoops]

Hello Martin,
thank you so much for your work and for the kindness in providing the pcb design

 

[Asiandude]

i’m  about to finish 2 channel of EZ1290 next week waiting for the Transformers and Grayhill switch from AML...
Thanks a lot to this forum for more topic support.

 

[JW]

Hey guys ,

Regarding the grayhill switch for the version of the board that I have (V2.4)
has the 71BDF30-03-1-AJN footprint.

I see mouser has nearly the same exact switch: the 71BDF30-03PAJN
In fact it has an "alternative part number" in the specs on the mouser site that happens to be 71BDF30-03-01: https://www.mouser.com/ProductDetail/Grayhill/71BDF30-03PAJN?qs=sGAEpiMZZMvNbjZ2WlReYhndqMY8foDI9yruO910dJc%3D

I cannot tell what the "p" is for in this part number.  No mention of it in the grayhill literature that I can tell (attached)

Anybody know if the "PAJN" switch will work? Or how to decode the difference? Bummer to have to order from Audio Maintenance because my old man just got me a gift certificate to Mouser.

 

[Potato Cakes]

For what ever reason, I think Mouser has the wrong link for their Grayhill switches as those are binary and not for the 1/2/3x6/12 71 series version that are that part number. This is the data sheet you want:

http://www.grayhill.com/assets/1/7/Rotary_71.pdf.

Thanks!

Paul

 

[JW]

Thanks Paul
That's the same pdf document I attached in the last post. What I mean is I'm not seeing what "P" means anywhere in that document.

At the end of the part number 71BDF30-03-1-AJN
the "1" stands for poles per deck, the "AJ" stands for adjustable stop and the "N" is for non shorting.

But there's no mention of a part number with a PAJN suffix in the grayhill document. However, there's the part at mouser (71BDF30-03PAJN) with an "alternative part number" listed as what I want, the 71BDF30-03-1-AJN

The ultimate answer is just to buy one I guess.

Are you saying the "PAJN" switch at Mouser has the wrong literature linked to it, but might otherwise be the right switch? Or are you saying the "alternative part number" is just a 'similar' part recommendation and not a substitute part number, and the "PAJN" switch is wrong altogether?

 

[Potato Cakes]

If you click on the mouser link then click on the data sheet you get the binary version and not the attached document. Not sure why.

Thanks!

Paul

 

[Potato Cakes]

You should be fine with that switch, especially since they list the exact part number from the BOM as an alias in the product description. Grayhill may have added a designation but haven't updated their product literature yet.

Thanks!

Paul

 

[madriaanse]

Hello Martin,
thank you so much for your work and for the kindness in providing the pcb design

You're welcome and thank you for helping others build their mic pres! This is what I really love about this forum.

I can confirm that Mouser part # 706-71BDF30-03PAJN  (71BDF30-03PAJN ) works. I've used these myself. They did use the wrong product image on their website.

Good luck with all the builds!

M.

 

[Asiandude]

I just finished 2 channels of EZ1290 and both of them introduce a pop sound between 50db into 55db gain or click # 6 to 7 position  on gain switch  it’s normal or not? I just wondering any of you have the same problem? Any feedback would be appreciated.

 

[Asiandude]

Does the pop sound is activating  the 3rd gain stage between 50 into 55db afterward? Regarding Neve 1272 at 50db and 1290 got the extra gain stage start at 55db so ...

 

[Potato Cakes]

This is not normal. Unfortunately. You're going to have to start checking over your soldering and component placement. Look at the schematic and find were stage 2 and 3 interact and start there.

Thanks!

Paul

 

[Asiandude]

I”be checking every thing 3 time before soldering and after and find no faults and no shortage as well. The PCB is Martin Ver 2.6 EZ1290, so they labeled components placement very well documented as you could read miles away. This it’s very strange so far for me as I’ve built all Hairball Audio 1176’s, Lola Mic Preamp, Elements Preamp, and many Capi-Gears 500 series modules without any problems first time powered its up. My soldering skill is very professional as I’ve been doing it’s at least 20 years with good  temperatures controlled soldering station, so could the pop sound between click #6 into 7 position (50db into 55db) cause by a faulty components or switch?

 

[Potato Cakes]

Are your switches shorting or non-shorting?