8 Channel, 3U NEVE 1073 completed

[snipsnip]

Hi madrianse,

My 2 channel project is close to finishing now... just need to wire up the xlrs to the transformers / boards / switches etc. Thanks so much for great boards and great documentation.

One thing im not 100% on is the input section on the board. As per your photos and the assembly guide, there are 2 connections from the input transformer to the board. However, on the 2.1 boards, there is an additional hole, between the power and input sections. Does this need to be wired up?

Thanks

 

[wolfgang]

Hello!

I think this is just a 0V Test point for measuring!

wolfgang

 

[madriaanse]

I think this is just a 0V Test point for measuring!

Correct!

M.

 

[mmmyesm]

Just paid for four 1290 pcbs... figured I'd drop a line here too.

 

[snipsnip]

Hi Man... need a little more help

Ive got one channel working fine, but one channel makes no noise. A quick visual check looks likes everythings right. Ive got power to the board...just no sound!

ive knocked up a diy signal tester but not 100% sure how to use it. Ive got 1 leg in ground and another making the circuit. When I touch pins 8 or 7 on the output transformer i get a signal, but when i touch pins 1 or 3 i dont. However, this is the same on the working channel. I cant seem to get a noise prodding away anywhere on either channel. The only difference I can find on the output transformer is that on the dead channel I get a signal if I touch the jumper between pins 2 & 4. The noise is a higher pitch than the test tone. One the working channel, I get no noise touching this jumper.

Any ideas ???

Thanks again (the working channel sounds nice!!) ;D

 

[madriaanse]

Hello,

How are your voltages?
http://www.musiciansgig.com/ez1290/transistor_voltages.pdf

so on LO1166 you have 2/4 and  6/7 jumpered, right? pin 1 goes to the pad marked 1 on the board, pin 3 goes to the pad marked 3 on the board? Shield's only connected to the board and nowhere else?

M.

 

[snipsnip]

ive got the jumpers in, and the transistor going to the correct the pads on the board.

Just took some rough voltages. They are in the right ballpark, but a little off. Power at the board is only measuring 23.5v at the moment though.

Do I need to get these a bit more accurate?

Thanks a lot dude! 

 

[madriaanse]

Say, you don't happen to have an oscilloscope laying around do you? (That way you can trace the signal through the mic pre and figure out where the fault lies). Also, try reheating some of your solder joints.

m.

 

[snipsnip]

Thanks man... no I dont have a scope unfortunately. Only the signal tester for now  :'(

 

[madriaanse]

I would highly recommend trying to score a cheap one (sometimes under $50) on ebay, craigslist etc. A good scope and signal gen. are indispensable.

Best,

M.

 

[snipsnip]

Thanks dude... I will try and pick up a scope when I see one for a good price.

I have done some more tests (seems I was using the signal gen incorrectly).

I can trace the signal up through the board to the area with the 4700p cap. The signal reaches one leg of that cap ok, but doesnt come out the other leg very strong. There is no singal at all on the 82u's.

Knowing this was the problem area, I tested the transistor voltages again and they are way off.

4, 5 & 6 are all fine. I couldnt easily measure 3 so i havent got that result now. 1 & 2 are as follows:

1)
C - 1.2
B - 0.0
E - 0.0

2)
C - 0.5
B - 1.2
E - 0.5

Does this make any sense to you?

Thanks for your help!
Jake

 

[snipsnip]

Im trying to figure this out on my own in the absence of assistance from the almighty creator

Does anyone know where 'm' on the schematic comes from?

It seems to form the part of the circuit im having issues with. the 68k resistor is fine, which makes me think there is an error in the part of the circuit leading to the 68k... but I cant figure out what it is from the schematic.

All help very much appreciated!!

Cheers
Jake

 

[snipsnip]

Ah, m is +24 right?

Just a little development.... my working channel is no longer working, dont seem to get a signal on the output of the input tranformer anymore!!!!

Look forward to hearing from you genius's!!  :-*

Jake

 

[madriaanse]

Hi

Im trying to figure this out on my own in the absence of assistance from the almighty creator

Haha, I'm flattered, but "almighty duplicator" is probably more appropriate. ;-)

Anyways, can you measure the DC voltage on pin 1, 2, 3, 4 of LO1166 and report your findings? Did you try reheating all solder joints on the output section, and the 12R/1W (near the +24 connection)?

Best,

m.

 

[madriaanse]

Ah, m is +24 right?

Just a little development.... my working channel is no longer working, dont seem to get a signal on the output of the input tranformer anymore!!!!

Look forward to hearing from you genius's!!  :-*

Jake

Hmm, try different gain settings and see if it only does that on certain settings. Also, how's the PSU doing? Still putting out +24?

M.

 

[snipsnip]

Hi - thanks for getting back to me.

forget the issue on my working channel... the carnhill has died!!! Bizarre, but when i swapped it with the other one it works fine. I'll see if AML will do me any favors on a new one.

When i realized m was +24, I measured the 12r resistance. on the working channel i got approx -160, but on the broken channel i got approx 12. This made me think it was isolated form the circuit so I dropped a new resistor in, but no joy :'(

I will take the measurements of TR3 and get back to you.

(p.s - the 68k isnt fine..this was a mistake from me... its late here in the uk! : )

Thanks again!!

 

[madriaanse]

Hi snipsnip, any luck sorting out the problem?

M.

 

[mkoz]

Hi Martin,

Great boards, many thanks for the effort. Three questions:

1) Is there a preference for a particular make of 2N3005? Motorola or ST or On or something else?
2) Is there a preferable Hfe range for BC184Cs and 2N3055?
3) Does the Grayhill switch chosen for this project -that AudioMaintenance sells- have an adjustable stop to prevent it from going around the clock?

Also some of the Digi-Key codes in the BOM seem to lead to an irrelevand part number, so it would be good to check them just to make sure.

Thanks.

B.

 

[Nele]

Hi Barish,
Some quick answers about my almost finished 2-channel build:

1) Is there a preference for a particular make of 2N3005? Motorola or ST or On or something else?
2) Is there a preferable Hfe range for BC184Cs and 2N3055?
3) Does the Grayhill switch chosen for this project -that AudioMaintenance sells- have an adjustable stop to prevent it from going around the clock?

1. I used ST's
2. Don't think so. I just grabbed what I had lying around. Just be sure you use BC184C's, not BC184L's (different pinpout).
3. Yes. It comes with stop-adjust pins which you can insert yourself. It even comes with a sticker so the pin won't fall out.

adios,
Corneel

 

[mkoz]

Thanks for the replies Nele, vey much appreciated mate.

Regards,

B.