Neve style 500 series mic pre 1290 1073

[Neil]

Hi David / all.

Can some one tell me where to find R11A 33K on the main PCB? ive looked and looked and i cant find it! driving me crazy...

if there is a pic of the silk screens that would be much apprciated too.

best
Pete

It's in the line of resistors that are above the output transformer (in-between TR5A/T5A transistor and C12A).

Neil

 

[user 10827]

Thanks Neil,

Id stuffed it already, thats why! cheers

Pete

 

[onlymeeee]

I think I've discovered what's happened with the mouser basket.. not disastrous, but a bit annoying...
I added the project to my basket last week to purchase some, and as some things were out of stock, I changed them in my basket or took them out completely ... BC184Cs etc..     However, it was reflected in the saved project for some reason.  So anyone that's ordered from it, hasn't missed out as such too much, as the stuff was out of stock and I don't think had a replacement available anyway...  
Until I change it, use the copy paste method from the googledoc general bom.

Thanks

For silkscreen layers and wiring guides, I've done these...
topsilk
bottomsilk


Also, has anyone come across a magical 33k resistor that appears to have nowhere to go?  I got that too but left it in the basket just in case!  Have since seen it came from the first version which still had the cap and resistor used on a 1073 for an unbalanced output

 

[funkymonksf]

Hey David,
I had a couple questions about your first build of the 1290 with the carbon comps.. I am thinking of doing the same, but I've hit a couple road blocks and wanted to know how you avoided them. Firstly, I can't find all the values listed in the bom, did you just use the closest value or hmmm, What did you do? And second what brand did you use or did just use any brand that had the value in stock?

Any help or suggestions would be great

Thanks
Brice

 

[funkymonksf]

Also the wiring guide... what is the two wires for on the back? Is it connect the trimmer to the switch or am I an idiot. DOOR #2!!

 

[user 10827]

Hi David,

thanks for the silks and wiring guide, im just about to finish and that all makes perfect sense.

In fact I have to say how well thought out this whole project is, from the circuit drawings to the PCB layout and physical fittings, how you work all that out, well very clever..well done and thanks!

Best
Pete

Funkymonksf : that single wire on the back connects the 2nd amp to the output amp..thats all..

 

[onlymeeee]

Hey David,
I had a couple questions about your first build of the 1290 with the carbon comps.. I am thinking of doing the same, but I've hit a couple road blocks and wanted to know how you avoided them. Firstly, I can't find all the values listed in the bom, did you just use the closest value or hmmm, What did you do? And second what brand did you use or did just use any brand that had the value in stock?

Any help or suggestions would be great

Thanks
Brice

Hi, I used http://gb.mouser.com/Search/Refine.aspx?Keyword=66-RC07 for carbon comps

I've got an early parts list from back then if it's any use.. don't use it as a definitive list though as I can't remember if I ordered everything or if I had some in etc.  (I see there's some notes next to a couple which will need to be changed)

rough bom of carbon comps

Also the wiring guide... what is the two wires for on the back? Is it connect the trimmer to the switch or am I an idiot. DOOR #2!!

To take the signal from input amps to the output amp in the most effective way

 

[onlymeeee]

Hi David,

thanks for the silks and wiring guide, im just about to finish and that all makes perfect sense.

In fact I have to say how well thought out this whole project is, from the circuit drawings to the PCB layout and physical fittings, how you work all that out, well very clever..well done and thanks!

Best
Pete

Pete, you're FAR too kind! Glad to hear you're nearly finished... it's a proud moment seeing them done and amplifying!

David

 

[Grooveteer]

I finally had some time to play with my finished NV73.  

SM7B > NV73 > EQN > Drip LA2A almost made me sound as if I could actually sing! (not really, but it did sound just like a good recording of bad singer)

Thanks David!

Cheers,
G

 

[onlymeeee]

I finally had some time to play with my finished NV73.  

SM7B > NV73 > EQN > Drip LA2A almost made me sound as if I could actually sing! (not really, but it did sound just like a good recording of bad singer)

Thanks David!

Cheers,
G

Good stuff!
Just the mic now you need to diy hey!

 

[funkymonksf]

After some research I think that I may be using Vishay Dale metal films on these guys. I know resistor aren't to crucial, but I had a couple questions that maybe someone can answer. The CMF 55 series comes in weird values I.E. instead of 510R they offer 511R, instead of 56K they have 56.2K... My question is.. Does this matter or make much of a difference or will be fine as long I get as close to the value as possible..

The other question is I notice on David's mouser order some of the 1 WATT resistors (on the bom) are 1/2 W on the order form. Is it alright to use to use 1/2 watt instead.

Stupid newbie questions. I'm learning..

Thank you,
Brice Conrad

 

[user 10827]

Brice,

for one, these Neve circuits are not too critical for the most part, but also be aware of the resistor tolerance you are using or advised to use, this is a good guide idea of how close the value of the actual resistor is said to be by the manufacture and the circuit would operate under.

so 56,000 ohms with a 1% tolerance is 560r variation, so your 56.2k or 56,200 ohms is only 200 ohms out of the suggested value, well with in the value needed or suggested by the circuit, so perfectly fine.

make sense?
Pete

 

[funkymonksf]

Thanks for that. So even if it's a little out of the range it should be okay for this circuit. like 27.4K being 40 OHM from the 1% of 27OHMs?  I am having a  hell of a time figuring this out. I was still curious about the wattage. I see some parts call for 1W in the schematic, but in the mouser order they are 1/2W. So does this not matter too much either.

What is the resistive tolerance to this neve circuit any how?

Thanks,
Brice

 

[user 10827]

Hi Brice,

If i understand you correctly, then 40r additional to your 1% at around 27.4k is no biggie at all.

Also it's worth noting, with out going into to much complexity, resistors come in set classes or decade values, it would be impossible to make them at every possible value, so IIRC this would generally be e12 or e24 range, so when a designer works out his or her values needed for the circuit, often they will just choose the closest to what matches in that class. of course if more precision is needed then they can move to a different range.

google it up, plus the Meta here will have all this and explain it far better than I.

don't go crazy over it, it will work! Also your 1/2W will be fine here too..at least this is what i've used and its just fine.

 

[onlymeeee]

regarding resistor tolerance, Pete's summed it up.  I think the original resistors were 2% tolerance so I'd say use 2% as a guide, in which case, all the ones you mention are ok.

Also caps are 20% tolerance so take that into account when looking at modern values compared to Neve specified values.

In regard to wattage.. what resistors are they?  I can only see one which is the 10R which just ties everything to ground and not much voltage drop happens and as such lower wattage is fine.

 

[funkymonksf]

thanks to you both for helping me. I've got an order from digikey coming in with the dale resistors. Much appreciated. One more and I'll stop for a few days.
On the picture of the wiring on the bottom I see two connections for each wire the 0V and P but the next connection there is only P. Where does the 0V connect to? Do they connect together?

 

[user 10827]

a picture is a thousand words..but you only connect the screen one end, at the 0v end.

http://www.thedonclassics.com/nv73topsilk.jpg

http://www.thedonclassics.com/nv73bottomsilk.jpg

 

[funkymonksf]

ummm... Do I win a prize for the most obvious and dim question? Like another kit or something? thank  you pete

 

[Neil]

Not until I'm done asking all of my questions and have a couple passing audio! 

 

[pacemaker]

Hi Guys,
i might be able to get some spare marconi bar knobs for this preamp,
in blue red and maroon,
anyone's interested ?
don't know price yet, i will ty to get them as cheap as possible
regards,
Francois