Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #20 on: November 05, 2009, 03:34:34 AM »
.... is yours true stereo, or dual mono?

This surprised me. Can an eq be true stereo or dual mono? I get the distinction when talking about compressors, but on an eq, I dont - unless youre only refering to wether the controls are shared for both channels or not. Id like to know.

Gustav


Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #21 on: November 05, 2009, 03:47:57 AM »
Well I really go crazy finding the right freqs to accent things. I mostly try to mic it that way. But a good EQ would be awesome. Such as a 550. Then I wouldn't have to spend so much time. I like to track it the way it should be. Or close. Saves a lot of time having it where ya want it. And are usable for mix a second time... Rack mount!

John

Couldn't agree with you more on the "record it the way it should be" mentality. My attitude towards eq (when tracking) is to use it to get the sound of the eq more than anything so building an eq without character would be a waste of money for me (i can do that in pro tools)! the 550's have a great sound, even if you're just shelving 3db @ 10k it's beautiful.

snipsnip

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #22 on: November 05, 2009, 05:10:41 AM »
.... is yours true stereo, or dual mono?

This surprised me. Can an eq be true stereo or dual mono? I get the distinction when talking about compressors, but on an eq, I dont - unless youre only refering to wether the controls are shared for both channels or not. Id like to know.

Gustav

I guess 'true stereo' was a bad turn of phrase on my part. I mainly meant dual control... like you may have on a stereo desk channel.

Im no expert in either electronics or audio engineering either, just a hobbyist, and am currently building a dual mono pultec, personally this suits me fine as I mainly want it for processing kick and bass at the same time, but was just intreagued by the OP's use of the word 'stereo' and wondered if there was something I was missing.

Boards are really nice BTW gustav .....only thing was I had to drill out the holes for the ECC88 sockets as they were very small, but I dont want to de-rail this topic  ;)

Autophase

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #23 on: November 05, 2009, 05:48:51 AM »
for me its gotta be the pultec, I'm definately going to do one after the GSSL.
I master most of my own material, having a pultec in the chain really would improve my palette.

iangomes

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #24 on: November 05, 2009, 09:25:55 AM »
looking at the 550A schematic, it looks pretty easy, no? Other than the dual concentric switches of course.

I'd build the 550's. the A's have more freq selections (harder to build). also I think the 550's sound better. those are a great all-around rock 'n roll eq! can't get enough of 'em.

i wonder why a 550 hasn't been on gdiy yet - It's pretty popular. Are there copyright issues at work here?
I actually have never seen an original 550 without the suffix A or B. I wasn't even aware that they exist! :-[
« Last Edit: November 05, 2009, 09:38:27 AM by iangomes »

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #25 on: November 05, 2009, 03:29:30 PM »
i wonder why a 550 hasn't been on gdiy yet - It's pretty popular. Are there copyright issues at work here?
I actually have never seen an original 550 without the suffix A or B. I wasn't even aware that they exist! :-[

Oh they exist. They're the originals. The 550A's are the newer versions. Here's my pair. I'm hoping to have 8 some day!


iangomes

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #26 on: November 05, 2009, 04:15:39 PM »
wow, wonderful! now where's that darn schematic?! haha

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #27 on: November 06, 2009, 05:45:35 AM »
I mainly meant dual control... like you may have on a stereo desk channel.

Cool. I only asked because I was wondering if there was some sort of summing of the signals going on in a stereo eq.

Boards are really nice BTW gustav .....only thing was I had to drill out the holes for the ECC88 sockets as they were very small, but I dont want to de-rail this topic  ;)
:)

Gustav

helterbelter

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #28 on: November 06, 2009, 06:31:30 AM »
Speaking A*P*I....

I'm currently busy with many projects, but one of them is some kind of rebuild of a dual 15 band graphic EQ, into a dual 15 band 560.
The graphic EQ that I have is a low cost old unit, belonged to a local radiostation. I used this EQ years ago for soundshaping of distorted guitars. It's very easy to use, but the sound gets degraded, and that's also the reason why I haven't used it anymore. There were also a couple of sliders broken, so I had to use a screwdriver for setting these sliders, haha. This week I have repaired the sliders (replaced the sliding part with new ones, because I couldn't find sliders with the same taper and size).

Anyhow, the beauty of  this EQ,  is that the filters are built the same way as the 560, including the slidertapercurve and value. So, the only thing needed, is to replace the line amp, which currently consists of a few 4880 opamps. I have bought the parts for getting it A*P*I. a pair of gar2520's, 6 LF356 opamps, C's 'n R's. I do have a pair of Jensen outputtransformers, similar to the 2503 outputtrannies, but they probably don't fit in the enclosure.  Maybe I'm going to use a pair of Lundahl's instead. But I still have to design a PCB for it.

I'm curious what the result will be.

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #29 on: November 06, 2009, 03:01:25 PM »

I'm currently busy with many projects, but one of them is some kind of rebuild of a dual 15 band graphic EQ, into a dual 15 band 560.


COOL! I LOVE the 560. Great on kick, guitars, vocals, etc. Here are some shots of a new one. I guessing the older models don't have (as many?) ICs in them. Seems pretty much as complex as the 550, given that the dual concentric knobs are replaced with what are effectively small faders!







helterbelter

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #30 on: November 06, 2009, 07:17:13 PM »
Hey, that's nice man !

I haven't seen close up pics of the 560 yet.

Most of the IC's (the 4580's) are used as active inductors. 3 opamps are LF356's, which are for the line(pre) amp, together with the DOA.

Nice...

I might harass you soon with questions about components, hahaha. Especially the Silvered Mica's is what I'm curious about.

Funny thing, the sliders look exactly like the ones in my graphic eq (which are Alpha W-curve 50k. The original 560 uses S-curve sliders.)

drpat

Re: If you only had one DIY eq you wish to build, which would it be? New
« Reply #31 on: November 11, 2009, 05:35:27 AM »
...
« Last Edit: September 18, 2010, 06:44:55 AM by drpat »
I use the LA2a on very hot signals like lead vocal.

iangomes

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #32 on: November 12, 2009, 09:38:29 AM »
does anyone have the original 550 schematic (maybe even the 560 too!)?  I'd really like to mess around with the schematic and tinker with the idea of putting a board together

Biasrocks

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #33 on: November 12, 2009, 12:57:32 PM »
does anyone have the original 550 schematic (maybe even the 560 too!)?  I'd really like to mess around with the schematic and tinker with the idea of putting a board together

I have the schemos and related info for the original two opamp 550A and the 560 eq. PM me and I'll forward them.

The board is the easy part, from the looks of the schematic these eq's need three 5x12 dual concentric switches.
If you're doing the "B" version add one more to the pile.





That's a lot of bread-e-o....  :o

550a's go for around 1K, so that leaves some room.

Mark
« Last Edit: November 12, 2009, 03:22:46 PM by Biasrocks »
http://SharktankPro.com

"I'd rather use an SPX90 than a UA plugin....." Joe Barresi

helterbelter

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #34 on: November 17, 2009, 05:11:56 PM »
Speaking of A#P#I, does anybody here have an Eagle library file for the 2520 ?

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #35 on: November 17, 2009, 05:38:35 PM »
I've had only limited experience, but the Calrec PQ15 is killier sounding pre/EQ.  That's a new favorite.  They're just so hard to find.  So is the money to purchase them when they do come up for sale.  ;)

Harpo

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #36 on: November 17, 2009, 05:44:05 PM »
Speaking of A#P#I, does anybody here have an Eagle library file for the 2520 ?
this one maybe ?
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.  -Douglas Adams

helterbelter

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #37 on: November 18, 2009, 04:39:08 PM »
?!?

When I open it, it shows an empty editor....

Or is it just a hint that I have to make it myself ?

Harpo

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #38 on: November 18, 2009, 08:25:44 PM »
When I open it, it shows an empty editor....
? Its a library file. Download (maybe rightclick save_as, if windows has a different application registered for this file extension) and put it in your ..\eagle\lbr folder.
A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.  -Douglas Adams

Re: If you only had one DIY eq you wish to build, which would it be?
« Reply #39 on: November 19, 2009, 03:43:33 AM »
There aren't many schematics of high end mastering eq's out there, so it would be cool to do one. Unfortunately most of the eq's I'm thinking of (manley massive passive, gml 8200/9500, sontec/iti eq’s, maselec mea-2, great river maq2nv, canesong ibis…) are still in production, so it’s more or less out of the question. Kinda sad for us :-\


 

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