EQ diy

[analogical]

Hello to all, my first post.

Reading thru the threads here I notice that little is talked of concerning diy eq's, at least not with the type of passion the LA2A and 312 threads have been getting, ie, BOM's, .pdf's and pcb group buys, ect.

I'll confess that I know nary a thing about IC's or how to properly read a schematic, and to top it off I am brand-noob at this site, so I will try not to bore y'all with other posts until I am sure my questions have some meat to them. Ok, so that said, the question:

I am purchasing a pair of SCA N72's and want to add an eq stage once I get done building them and could use any advice concerning this. What pairs up well with them? I mean a neve eq would, duh, but I mean is there a diy solder by number EQ out there that I can add to my signal chain?

Thanks,
don

 

[rafafredd]

Reading thru the threads here I notice that little is talked of concerning diy eq's

LITTLE TALK about EQ? Man, read again and read more. There´s massive material on EQs out there in the old threads.

Active, Passive, Active tube, parametric, graphics, gyrators, inductor actives, simple tone controls, inductors DIY, Pultec, Calrec, API, sontec, amek, neve, it´s all there.

:thumb: :sam:

 

[analogical]

all i meant is that I see no BOM's, .pdf's and pcb group buys. I'll keep looking.

 

[rafafredd]

OK, I think N72 by SCA are great, but if you want a neve mic preamp and an EQ, why don´t you go for the great style DIY:

http://www.linear-recording.com.au/neve.htm

http://www.linear-recording.com.au/neve2.htm

There it is.... all the info you need for complete 1073 channelstrips.

 

[clintrubber]

[quote author="analogical"]all i meant is that I see no BOM's, .pdf's and pcb group buys. I'll keep looking.[/quote]

Nice G-Pultec PCBs available from Gustav, see the Black Market.

 

[craigmorris74]

I would definitlely like an separate 1073 style eq that could be inserted into your existing 1272 or 1073 circuit. A lot of people already have these pres, so it would be cool to have the eq as well.
Also, could it be possible to just build a separate 1073 style eq?

 

[pucho812]

Yes Craig it is possible...

 

[analogical]

Thanks for the link rafafredd. appriciate it.

Also thanks to clint, I Have yet to go into blackmarket. lemmie see.

 

[analogical]

[quote author="rafafredd"]OK, I think N72 by SCA are great, but if you want a neve mic preamp and an EQ, why don´t you go for the great style DIY:

http://www.linear-recording.com.au/neve.htm

http://www.linear-recording.com.au/neve2.htm

There it is.... all the info you need for complete 1073 channelstrips.[/quote]

quoting from the site you sent me to:

"Would I do all this again? Nooooooo fu*****g way. Please don't email me questions about it, everything you need to know is in the drawings that exist all over the web. That's how I made it. It works, the one above works perfectly. There are one or two minor errors, if anyone actually makes this and can't figure them out I will help you. It is a couple of traces and a couple of jumpers that need fixing."

Ok this is not my idea of community diy goodwill, but oh well, he worked hard on the project, he dont have to be nice, he deserves to be left alone about it... but.. i don't think I would jump headlong into a project like this when he admits that there are some mistakes and also provides no bom or premade pcb's. I'm just not that confident yet. thanks anyway.

Update**

He also says in his site that his knockoff does not sound like the 1073. To paraphrase, he says it sounds different, but better than other stuff in the industry.

 

[soundguy]

some thoughts on a BOM-

good for a newbie perhaps but you should consider that many of the component selections are a personal taste thing and can leave you with a box that sounds so different from another that you'd think it was a different circuit. This is especially the case when selecting capacitor types for EQ sections.

as far as community goodwill is concerned, its not an easy project to build with or without a bom or anything else.

One thing you might consider is searching through the many pultec threads on this board. What you could do is build the passive section of the EQ and stick an appropriate output transformer on there which will allow you to use your N72's for make up gain. I know this has been discussed in the past here. This would be considerably easier than trying to do the same thing with a 1073 style EQ and the circuit is simple enough that you could easily build it point to point. There is absolutely no reason to require a PCB to make a pultec EQ even if it is your first project, you'll be able to wire the eq section point to point really easily.

if you do it that way, you get a pretty classic eq happening and you can use whatever mic pre you want for makeup gain. one option to consider.

dave

 

[analogical]

Thanks Dave for the reply.

I have to build the N72's first but then I'll have a go at the pultec.

Still, the pultec is not really what I had in mind. I'm into a solidstate thing first, I want to pair the N72 to a perfect companion that colors the sound in as 'neve' a way as possible. It's also a sound vs. size thing- I'd like to add on something small- make it modular enough to use as a buildingblock to a full framed mixingdesk, not a rack of U19's. That would come later.

Craigmorris has my vibe here.

 

[soundguy]

so far as the sound of neve EQ's go, Ive personally felt for quite a long time now that the raving that goes on over neve EQ's is really raving over the amplifier stages driving the transformers in which ever EQ you happen to like, the EQ in and of itself isnt the most magical thing in the world. Very cool, sure, but the hype is sorta misplaced IMO. I think you could feed just about any EQ circuit into a 283AV style circuit and come away with a very "neve ish" sounding EQ so long as you use the appropriate output transfomormers.

What you could do with the pultec is just build the filter section and instead of building a line amp stage, just put a 600:150 transformer on the output (I think the filter is 600 ohm output) and then just plug that into your n72 to make up the gain. If you did this you could build the box incredibly compact.

You could really do this with any passive eq design out there, using the pultec is just for convenience as there is a ton of documentation and the specific inductor is available for purchase from 1 or 2 companies, so the parts arent difficult to find.

As you build more mic pre's over time, having a passive eq box like this is quite handy as you can change your make up gain tone in a snap. I have a pair of langevin 251 passive EQs that I use like this, I always intended upon building them into a box with a dedicated makeup amp but its really convenient to be able to plug them into this or that preamp and totally change the tone of what the eq is spitting out the speakers.

dave

 

[CJ]

Yeah, same thing with the Pultecs, people running a signal thru just for the line amp, no eq at all.

 

[Svart]

ok so I can't seem to find any info on those inductors in the 1073.. I must be dumb or something..

 

[craigmorris74]

OK, screw it, I'm going to buid the Pultec eq section. Is anyone sure that a 600:150 output transformer would work (not saying you don't know what you're doing, dave, just want to make sure before I order something.) I have an Ampex tube pre that would probably work well for make up gain, as well as a N72 and A12.
Craig

 

[craigmorris74]

Oh, and would I need to use an input transformer? (see previous post)