Neve style 500 series mic pre 1290 1073

[andre tchmil]

really?

so the bottom two (spaced away) pins are the magnet coil in the relay yea?
and the switching switches the two 'common' connections to the opposite adjacent pins... i dont see what this is doing on the board.

i've not used relays before, only transistors so this is helpful.

some people just never stop posting dumbass questions do they!

Hi Kebeb, it's just come to my attention that I drew the link as looking from above the top PCB, not the bottom like the jpg suggests.  So to stop confusion, I'm just saying link both sides now. 
eg.

Did you clock this?

Does this mean we can bypass the delay circuit if the pre operates at +24v ?
What else needs to be done ?

 

[nielsk]

My question too, I have left out all parts labeled "dly", is there anything else I need to do other than jumper the relay? I get 24V to the fuse , but not to the DC jumper
ALSO! I am running on a test jig, do I need to jumper -24 to GND on the edge conn?

 

[canidoit]

Hey canidoit

Yeah I had read your thread before, you had around 7 Momhs between those goldfingers if I remember correctly.
Therefore I found it so strange that my resistances are so much lower.. :s My NV73 sounds amazing though.
What are pins 12,13,14 for maybe ? On another forum I have read those are -15V, ground and +15V ?

So does anybody have an idea why my resistances are so low ?

Oh I see, you are doing the 51x 24volts version?

 

[Mr.Franky]

Oh I see, you are doing the 51x 24volts version?

No, 500 (API) version.

 

[andre tchmil]

Nielsk and I , we're obviously both talking about the 51x 24V version

 

[nielsk]

Yes, I am building it 51x (24 VDC)
So I have jumpered the relay as shown, still no voltage. I get +24 on the big (fuse) jumper, nothing at the little (Converter board) jumper, nothing at the relay jumpers.
I must be missing something simple here, and could use some direction as this is getting frustrating... with no PCB drawing to trace it is very difficult to figure out what is going on.

 

[onlymeeee]

I wouldn't recommend leaving out the dly parts of the main PCB despite doing 51X as the relay has a couple of pros.. mutes output until ready etc. and is a bit easier on inrush.  Having said that.. if you are leaving them out.. yes all you need to do is the jumpers on the relay .. nothing else. 

So you've done the two jumpers for 51X shown? http://www.thedonclassics.com/images/24v_operation.gif  



Pin marked +16V (where the small converter board would normally go) is connected directly to where the big jumper is..  all that jumper does is connect either to +24V rail.. or +16V  (depending on whether small jumper or big)  so can't see how you can have 24V on one end.. but not the other.    Pictures maybe could be helpful.

Hey all


I'm currently testing my NV73 and everything (still at 'testing before starting it up') seems to be as it should, except for the goldfingers.
PIN 14 should have a high resistance to PIN 13 and 12, but in my case I don't have a high resistance.

PIN 14 to PIN 13 has 430 kOhms-ish
PIN 14 to PIN 12 starts at around 35 kOhms and keeps dropping when connected to the multimeter.

Does anybody have an idea of what the problem might be ?

That's fine. Several thousand ohms is a high resistance! It's just a check on the rails to make sure there is no short.  You don't want a short on the power rails!

 

[nielsk]

By little jumper I mean the one by the DC-DC converter board connections.
After jumpering the FILT1 (oops!) I now have 24 VDC where it should be, and I see audio going into C1C &C8A  nicely (depending on gain switch position), and nothing after that. No action in the op amps.
I have the 24VDC ground from the bench supply connected to pin A (1) & pin P(13) of the edge conn.
I have checked over all parts and solder joints...NPF
Any ideas?

Later (many hours..)
I finally figured it out! It is using pin 5 as the power ground! Yikes, that took me  WAYYYYY to long (pin 5 is usually used as the audio ground)

 

[Mr.Franky]

Oh ok, fantastic !
Thank you very much for your help! So now I can truly say that my NV73 build was great and more importantly, it sounds great ! Really love it! I'll be buying several more when I have some spare money.

A happy newyear still

 

[bruno118]

Hey all


I'm currently testing my NV73 (this is my first DIY kit).
I read on page 31 of this forum that the PIN 1 and 3 of output transformer must not have a resistance to the ground.
In my case, when i check this values, I read several MOhms and this numbers are changing slowly? And when I repeat this, the values and not the same...

I notice that I have no link between the GND and the chassis on the goldfinger (pin 1 and 5). Is it correct because some of you have made their test using the chassis of the box?

But when I try between the pin 13 and 14 on the goldfinger, I read 17,52 MOhms... This is correct, right?

Where is the problem?

Thanks

 

[MagnetoSound]

In my case, when i check this values, I read several MOhms and this numbers are changing slowly? And when I repeat this, the values and not the same...

Those are pretty high readings. You could be reading the resistance of your fingers if they are touching the probes.

 

[Marcocet]

Okay: new problem that I can't find any reference to. I just pulled these things out of the closet to try and get them going. However once the DC-DC converter reaches 22v for a couple seconds it starts switching off. When it drops to about 9v it turns back on. Over and over, really fast. And I can't track it down. Any advice?Is there a schematic for that part of the circuit?

 

[onlymeeee]

Okay: new problem that I can't find any reference to. I just pulled these things out of the closet to try and get them going. However once the DC-DC converter reaches 22v for a couple seconds it starts switching off. When it drops to about 9v it turns back on. Over and over, really fast. And I can't track it down. Any advice?Is there a schematic for that part of the circuit?

Do 2 units have the same symptoms?
Is it a stable +-16V rail from the power supply in?
Some pictures of the small DC-DC boards might give a clue.. if any transistors are upside down etc.
The problem is probably on the DC-DC board. Check resistor values.. cap/diode/transistor orientation.

If it's same symptoms on 2 units, then it's probably not a component fail or short. So should be able to spot on a pic.. probably orientation or wrong value part put in.

 

[fazeka]

I finally got around to building this over the last week. But my 5k trimpot is not effective in changing the voltage from 23.92 volts to 22 on the 2N3055. In fact it only adjusts it down to 23.72 volts... anyone else experience this?

 

[andre tchmil]

I finally got around to building this over the last week. But my 5k trimpot is not effective in changing the voltage from 23.92 volts to 22 on the 2N3055. In fact it only adjusts it down to 23.72 volts... anyone else experience this?

24V version ?

 

[fazeka]

Yes... Did I misunderstand something?

 

[andre tchmil]

I have 3 preamps on my bench with the same behavior. 8)

 

[fazeka]

I tried replacing the 2N3055 as pacemaker. No dice.  :'( I'll keep looking...

 

[andre tchmil]

I tried replacing the 2N3055 as pacemaker. No dice.  :'( I'll keep looking...

ok , let us know if you have solved it.

 

[buildafriend]

Hey I am pretty close to ordering a pair of these kits but I would like affirmation of there being decent replacement parts available. Does any have a mouser cart saved with a correct bill of materials? there are a few parts that are nearly outdated or back ordered. thanks regardless!