Neve 1290 build completed!!

[okgb]

And an extra gain stage in the 1290 i believe
where Geoff Tanner maintains the 1272 was never intended
as a preamp , although if you don't design it for max gain , seems to work fine?

 

[Phazinhead]

Hi everybody

Thanks for your explanations ! In fact, I should tell something before asking more things... in fact I'm not interested buy Mic input ('cos i don't use mic at all), I only need line and Hi-Z inputs .... but maybye this have no interest to put so much money in a Neve for only line/Hi-Z preamp ?

However, the EQ section of the 1073 or 1084 could be interesting, to have a very good preamp with a very nice EQ .. in any case it can only be better than my VST EQ plug-ins :green:
so, I'll contact Audioforge (I know him from a french music forum) to know if he still have some neve PCB.

... but a stupid question : Why use so expensive rotary switch .... instead of using a very good pot ? It coul be cheaper, let choose exactly the frequency you want to process.. no complex wiring and resistor soldering... but I know that purist will tell me it doesn't respect the original Neve .. OK OK .. but it coul reduce the cost and add some using flexibility maybye .. wha do you think about it ?

 

[Bluzzi]

If you only need line stage then look at maybe a THAT line driver design. Do a search here to find more info.

If its only the NEVE EQ you want its possible but I would not start with one as there are many more that are far simpler and cheaper to build.

jim

 

[Phazinhead]

Salut Jim

Ok, I understand what you say

But, i'm actually building some API 312 preamp (Fabio reliquia) and I find it sound really great, so, to my ears :green: ... and I like this kind of stuff, building myself something, to have something different, good sound (... and maybye to tell me it is "API" or "neve" thing -joke).

But you're right, I agree with you when you say I could find other EQ project , easier and cheaper, as Calrec EQ maybye... but I would like to do something great, and this Neve preamp and EQ could fit.
The problem is that I don't know exactly today how it will cost, how much time it will take to achieve... so this is why I'm asking thoses questions. What is interesting IMO is to have the musical EQ and the trafo sound ... I don't care if it has Neve-style pots, or rotary switchs as a real neve .. you know what I mean, I just want to get what "does" the sound, I don't mind of the rest, it is only for the pleasure of my ears :razz:

But if it cost over 500$ for just have a "one pot" preamp to set the sound level.. or a 1500$ EQ for only ears pleasure... yes I agree, this is absolutly ridiculous :green:

 

[madriaanse]

Hi Phazinhead,

If you need a DI, pad, phase etc. I'd just get a JLM Go Between and use that with the EZ1290. Pls see:
http://www.jlmaudio.com/JLMDI.htm

That'll make it easy. You can order your PSU and Go Between all from the same place.

With Audiomantenance selling the trafo's for cheap, you can probably build a channel for around $300. Everybody should at least have a couple channels of Neve IMO... Call me biased. :green:

All the best,

M.

 

[Phazinhead]

Hi madriaanse !

thanks for the links ! intersting :grin:

... but in fact I just need a DI imput, I don't wan't have phase, pad and phantom power (because I don't need it).

But the EZ1290 is just a preamp ... I only have nice preamp with my API312 ... get another preamp doesn't interest me really and the interest of building a 1073/1081 or 1084 is to have a very nice EQ !

 

[madriaanse]

makes sense; sounds like this is not the project for you. Have you checked out Igor's EQ? It really looks great:
http://www.groupdiy.com/index.php?topic=23968

Let me know if you ever start tracking live drums!! :green:

All the best,

Martin

 

[Phazinhead]

Mmmm intersting, thanks madriaanse ! very nice and easy to make EQ I think. it is nice, i've already have a bunch of Bur brown Op amp .. do you have an idea of the cost for a stereo one ? ( I think not more than 100 euros.. for electronics parts.. )

Yes, I know my aim is not very clear ... the fact is that I'm student and havn't illimited money, no illimited time and not as good ears and monitoring system as you, or as a real sound engineer !
If I do this project it is only for my pleasure, to learn more with electronics, for the pleasure of having something that sound really big and beautiful ... even if is for recording my samplers or my bass guitar :green:
I know this project is expensive, it takes time to be correctly done, but ...I should do it this project in all his globality

More seriouly, I could use the neve preamp/EQ to record some friends, who are playing guitar, battery, saxophone, violin and who sing ..

Let me check some little things before continue to ask stupid questions here :green:

 

[ChuckD]

Those Grayhills switches are $32.02 USD each ! Wow that is crazy for a switch. Also the lead time is 6-7 weeks from Arrow electronics.

Maybe we could get a schematic of the switch hookup so a suitable sub could be put in it's place? Any chance of getting something soon?

Thanks

-ChuckD

 

[Bluzzi]

Its a 3 gang switch so it will be harder to find. I don't think you need schematic. Just wires from terminals to the PC board. If I'm wrong someone let me know.

If you think thats expensive try Elma switches!

I just don't like the 7 wks waiting period though.

I'm going to try Elma. I'd rather pay more and get it quicker. Also it may be fun to try a 24 position switch. Although the resistor values for all 3 gangs might be over my head right now. Anyone have any thoughts on that?

jim

 

[ChuckD]

OK I found a solution!

71BDF30-03-1-AJN
Rotary Switch, 1/4" shaft, adjustable stop, PC mount, 30°, 3 deck, 1 pole/deck, non-shorting


Or :

71BD30-03-1-AJN
Rotary Switch, 1/4" shaft, adjustable stop, 30°, 3 deck, 1 pole/deck, non-shorting

http://lgrws01.grayhill.com/web/images/ProductImages/J-31-44.pdf

The second one is the same only the non-PC version
And is in Stock in North America at Allied Electronics for $24.00

Just go to http://www.alliedelec.com and search for 71BD30-03-1-AJN

It is there and they have 25 of them.

From the PDF above you should be able to figure out the corresponding wires for each I think???

-ChuckD

 

[madriaanse]

You can certainly wire a solder lug rotary to my boards, but I think after wiring one you'll probably be kicking yourself for not going with the PCB mount version. You also have to use shielded wire from switch to PCB and vice versa to avoid oscillations and noise pickup; this makes it even more of a hassle.

On the other hand I fully agree that Grayhill's a pain to deal with. I have done an alternate layout of my PCB for an Elma Type 08 switch (08-3114). But there's several things I don't like about this switch. It's got a weird size/shape shaft and no nut to screw it to the panel. (okay, that sounded a bit odd). I do like the bigger pin spacing of the Elma, and the fact that it's an Elma.

If anyone's got any recommendations for an easily available, high quality PCB mount 3X12 rotary I'm all ears and I'll probaby do a layout for it. I'm not looking for cheap/cheesy. $35 for a high quality 3 deck rotary is not bad.

All the best,

Martin

 

[Bluzzi]

Yeah, I think I'll wait for the PCB mount one. Although what I don't like about PCB mount is that it forces you to place the switch according to the PCB layout.

Do you really think there would be oscillation going on if the wires from PCB to switch are about 3 to 4 inches long?

So on second thought if that length of wire won't be a problem I would go for the alternate switch.

An Elma is always nice, but then why not try and get a 24 position Elma going for next PCB revision? More resistor values to figure out I guess, right?

Also I think many of us are wondering iif we can't easily turn the 1290 into a full 1073 by adding the EQ part the way you have done the 1290 (in 1 board)?

(sorry for all the questions in a row)

jim

 

[madriaanse]

Hi Jim,

RE: wiring the switch: you might be okay if you use short wires and keep wires carrying high level signal away from wires carrying low (mic) level signal, but I personally wouldn't mess around with it. Using the PCB mount is the way to go IMO.

A 24 position would be nice, but I haven't been able to find a 24pos PCB mount rotary. Only 12 pos.

It would be very easy to use my PCB with an EQ section. If I remember correctly (pls correct me if I'm wrong), the EQ is switched in between P and L of BA183AV. It would make a lot of sense for somebody to design a "EZ1073-EQ" - an integrated 1073 EQ section only. Then you could just jumper that over to my EZ1290 boards with only two wires to make a complete 1073.

All the best,

M.

 

[ChuckD]

Yes an EQ section would be very cool ...

-ChuckD

 

[Bluzzi]

OK, not wanting to give myself extra headaches I've decided to stick with the PCB version.

The audioforge boards may be the answer to the EZEQ.

jim

 

[ChuckD]

no phase, no pad, no trim, just 5db steps - all I need. I did this to keep cost down.

Any way of adding these off board?

1. Phase would just be a double pole double throw switching the +/- signal on the output transformer correct?

2. Pad ? isn't that a 20db atten? So could taht be done with a simple resistor on the output switched into the circuit?

3. Trim.... Suggestions?

4. Also could you tell us how the ticks on the Gain switch look. My guess is 12 ticks at 5db each starting 0 in the first (most counter clockwise) position. 0-5-10-15-20-25-30-35-40-45-50-55


Thanks! looking forward to finishing this one up.

-ChuckD

 

[madriaanse]

Hi Chuck,

For phase/pad, just use a Go-Between:
http://www.jlmaudio.com/JLMDI.htm

Trim I'd leave out. I don't like the sound of potentiometers in the signal path, but if you have to have it, please see:
http://musiciansgig.com/ez1290/trimmer.pdf

Gain is 12 steps, 5dB per step, from 20 to 75dB of gain.

All the best,

Martin

 

[ChuckD]

Thanks!

It might be cleaner to add a resistor network in that spot instead that way you wouldn't get noisy pot syndrome. But a high quality pot would be good enough I think.


I didn't want to purchase another add on besides the JLM power supply. I already looked at the Go-between.

I think for this project since it already has the 48 output it would be better just to add these in myself. Really I don't need PAD but Phase is often nice.

I think my assumption is correct about that. Phase can be shifted 90 but swapping the +/- on the input of the output transformer.

Anyone want to clear this up for me?

-ChuckD

 

[madriaanse]

Hi ChuckD,

Phase can be shifted 180deg by using a DPDT before the input tranny or after the output tranny - pls also see:

http://musiciansgig.com/ez1290/phase.pdf

Or... you can ask your intern to make you some mic cables and most likely a few of them will be out of phase :green: :twisted: :green:

M.