8 Channel, 3U NEVE 1073 completed

Hey guys. Problems. I just finished my second channel and I am getting 60 Hz hum and also a very diminished low end response. A sine wave severely falls off below about 200 Hz.

I used shielded cable throughout. Transformer placement is not the problem (I moved them). I am running out of ideas!

Any suggestions?

I should add - the grounding schemes are the same in both channels, and they are in the same box. Power supply is in a separate box. First channel is silent, no hum, and even frequency response over a very wide range.

Cannot figure why they would be different. The wiring is even better on the second channel...

I checked the transistor voltages, and there are some huge differences. Power supply is adjusted to 23.9 V.

Transistor Voltages:
        Correct    Mine
TR1
C      3.8        6.4
B      0.9        1.3
E      0.4        .2

TR2
C    22.6      49.4 
B    3.6      6.4
E    3.1      5.2

TR3
C    22.6    49.4
B    3.1      Not measured
E    2.5      Not measured

TR4
C    3.8      7.5
B    2.4      1.1
E    1.8      3.2    - Base is not more positive than emitter

TR5
C    12.4      26.1
B    3.8      7.5
E    3.2      6.2

TR6
C    20.6      44.5
B    12.4      26.2
E    11.8      24.9


So as you can see, a lot of the voltages are essentially double their normal values.
Hope someone (help, Martin!!!!) can help me out here.

Thanks again.

is the voltage when it first reaches the board correct?

have you triple check the orientation of all your transistors are correct?

Really interested with this project. is there alternate way to contact other than email to get the PCB? Tried email him but no response...perhaps my email went into Spam folder?


or anybody has the file so I can self etch it?

snipsnip said:

is the voltage when it first reaches the board correct?

have you triple check the orientation of all your transistors are correct?

Click to expand...

The DC at the board is just under 24 V, right at 23.9....

Checked the transistors, all are in the correct orientation.

My plan at this point is to:
1. recheck all resistor values
2. remove all connections from both boards
3. connect inputs/outputs/power from "good" side into the "bad" board

That way I will know whether the problem is on the board or outside the board.

Thanks, snip.

Will post soon.

Hi Statzern,

You have some pretty far out voltages. Can you post some very zoomed in/hi res pictures of the top of your PCB and i/o transformer wiring? I would highly recommend not connecting the bad channel at this time to prevent damage. How does the good channel measure? Any solder bridges anywhere?

gemini:strange I'm not getting your email; sorry about that. did you send to martin_adriaanse (at sign) yahoo (period) com?

Best,

m.

Wow, I am really dumb.  :'(

Forget those voltages... my voltages were fine.

I disconnected both boards and connected the crap board to the trannys that the good board was connected to. Everything seems to be operating normally.

So, either I have a bad transformer (let's hope not $$$$$!) or I have bad cable.

Will post soon.

Hi M

I will send email again. I am sure I have the correct address.

Regards
G

1290 Gang,

can more people get back with reports on how their units sound? Alot of people are posting pictures of they're builds but little on how the units are working in a mix.

I have finished my first track using a dual EZ1290 for everything except the inside/close micing  of the drum shells. So the vocal, guitars bass et al went through the EZ1290 into my ISA428 a/d convertors.

I found the pres to be kinda slow and lacking in any top end. Was really concerned. Felt that the acoustic guitar needed no compression, that's how slow I thought they were.

Anyway, came down to mixing OTB with my Phoenix N16 Niceriser and whilst hittting the vocals and bass guitar with 1176 action and EQ, the rest was without EQ..........and holy moly the track sounds great ( for me ). I thought half way through that I was in a world of mush but gotta say, my recording actually sounds like a good old record.

These pres work well but by gosh are they slow. They make my tracks sound as though they have been hit by a tape machine. Is that right?

Michael

Hi Michael,

Your findings certainly reflect mine. I'll chime in with my own biased observation; these things sound more tube-like than most tube pre's. They're a welcome, warm cup of analog chocolate milk on a cold day in the digital ice age IMHO. Whenever I hear darker sounding albums like Norah Jones' Come away with me, or any of Ray LaMontagne's albums I'm instantly reminded of this tone (and ribbon mics). It's not for everyone (like chocolate milk for the highly lactose intolerant), or every style of music, but when it works.....

Take care,

m.

I noticed mine were way less bright than my modern pre's - and bright tends to sound more immediatly pleasing, but I chuck everything through them now and dial that high back in on a pultec clone where its needed. I put my pair on the 2bus for tranformer compression effect. very nice.

"Treble is overrated" - Terry Manning.

;D

Kinda seems like were just rediscovering the past.

My vintage API's are like this too. They have this kind of softness to them, that's really nice. Could have something to do with 2622. There are a couple samples of them at my link below. A couple quick tunes i did (first two) are with the API. Kinda messed the vocals due to my wonderful, shoddy old digi audiomedia 3 card with those wonderful RCA connectors. Very easy to distort with balanced equipment....even with levels wayy down.

I'm lazy, i need a new recording interface.

Hey Martin,

Just wondering, what is the purpose of connecting the one mounting hole in the driver stage to 0v?
Is the shielding plate on the back supposed to connect to this mounting hole? I guess it would even if using plastic standoffs, as the screw and nut still make contact? I was thinking the shielding plates should go to ground? Hmm..

Thanks!

Hello everyone!
First post ever!

I ordered all of the materials on the BOM metal list and there's 2 items backordered from mouser for 2 months.
Is there alternatives for these 2 items? (without affecting the sound of the preamp):
> Bipolar Transistor 2N3055    http://ca.mouser.com/ProductDetail/STMicroelectronics/2N3055/?qs=ljbEvF4DwOOO8oAO03E4Jw%3d%3d
> Capacitor 23PS118  http://ca.mouser.com/ProductDetail/Xicon/23PS118/?qs=VbcEA1k3avMBB6CatG1TDA%3d%3d

Thanks!

Update: Found parts elsewhere on the net thank you!
And Thanks deuc224 for the link

Martin told me to get this one:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=497-2612-5-ND

Heres a question. I see a 100p cap on the silkscreen but not on the BOM. Am I missing something? Is there a misprint?

hi all,
i am trying to solve a noise issue ;

i am using stereo 1073 as summing amp makeup gain. i have -83db noise  ???
surely, cant heat it unless blast my amp... but is this normal ?

to be able to get unity gain from summing mixer, i am using 5 clicks of gain (45db)...
(summing amp is passive;  the one is available here)

So the photo below shows the stop pin on the Grayhill in the 5:00 position, but the assembly instructions say to install at 12:00. Can someone clarify?

Hi Chrome heart,

Not sure why you don't see a 100p in the BOM; it's part C9, item # 23PS110 from mouser.

If you insert the stop pin at 12 o'clock per the instructions, it will be stopped after 75dB which is what you want.

Best,

M.