DIYRE EQP5 Passive Equalizer Kit - 500 series SS Pultec

The GAR opamps certainly have a color to them. I've got a bunch of them, and if I'm going to work on something that needs to sound really retro'sh I'll pull the EQ's and put them in. Most of the time though I really love the sound of Scotts 1731's. If you're using the vintage output you only need to swap out one of the IC's, but it most certainly makes a difference in the sound. OPA2134's are drop able to drop in, but the new generation Burr Browns are by far my favorite.

It just converts SOIC chips so they can be fitted into DIP8 sockets. You can get them on Ebay for hardly nothing. Now, the soldering for this is somewhat delicate and you need a really small tipped iron, but honestly maybe after one screw up or even after your first one you'll be good to go, nothing to it. They just don't make some of the better sounding IC opamps in DIP8, especially the newest generations, they have just forgone that footprint, so it's just a way to get the sound of those new opamps into units fitted with DIP8 sockets/footprints. 

Aha....thanks for the education.   But you probably need decent eyesight and exemplary soldering skills too.....    I pass on the surface mount stuff!  <<thumbsup>>

I think I'll pass on those unless you can get the opamps pre soldered in.

SWEET!!! Thanks Blackdawg!!  


OK. NOW we're talking'!!!!!!!!! Yeah, $14 is totally worth it. Now I must research opamps..... :-) Is the OPA1612 the class favorite at this point?

And of course, the next question becomes - which IC is the one to replace if you're using the FE transformer based output?  IC1 or IC2?

Wait, so are we saying that different IC configurations sound different or just that different footprints allow different DOAs to be used?

I would go with the OPA1612. It's going to be the faster one and the 1642 is a Jfet input, so you're going to get a little different response there. You could order both and see which you like best. I use both in circuits and it's really just about which you prefer, both are excellent. I'm not sure which IC it is, but throw in another 1612 there and have the option of bypassing the FE out and using pure SS front and back. 

I say go with the OPA1612 because it's the purest and fastest so it's going to deliver an extremely open and clean bit of gain into the EQ, from there when you twist and turn you're going into using the DOA, but the frontend and backend amps work in harmony. I like the frontend to be nice and clean and the backend to be where the color is happening. Most designers out there will tell you the 5532 in a circuit like this is perfectly fine, but use your ears and put them into play and you'll get why having that frontend IC really fast and open. That's at least what I came to find when I was dialing in mine.

Also depending on what you're using these for, the Q adjustment is pretty important. To me these EQ's can rival some of the best SS Pultec clones, even the original's out there. I found that with a very wide Q they sound the best. 

Thanks for your thoughts Jerome!!

On the Q, are you dialing it in by ear or measuring the bell? I haven't had enough play time on them yet. Still waiting for parts on the 2nd one....

TFW your physics homework and the forum browsing you're doing to avoid your physics homework are talking about the same thing...

Yes you need some! Get the EQs first I'd say. The passive summing mixer is cool too, couple of vp28s on the make up gain would be dope. What I'm going to try next. The ola5 is nice too, very different optical compressor



You can match them with the two contact points under the trim pot. Just measure impedance (ohms). Keep in mind if your letter is sub par they won't ever truely be matched. I just picked up an EEVblog 121gw meter which is 0.2% accurate for most the range for resistance. My Fluke 115 is only 5%.

I went wider with mine too. Around 2k ohms I believe. 2.2 maybe..

It's also only adjustment for the high frequency boost. Other bands are not affected. 

Always on there. And second pair for drums

Well funny you should ask..

So i have a pair that are stock output Trannys and IC opamps. And a pair with 2503L Output trannys and stock IC op amps(NE5532P)

For output opamps I have mainly used Brads Rogue5 Opamp. 

However..

I am in process of doing a large shootout of opamps. Right now i have the following: 

gar2520
gar1731
garAM10
gar910c
Rogue5
REDD5
SS2590
APP992e

Id like to add more to the list but this is plenty to start. That and I kind of like that they are all in the same general price point of $40 or less. I need to get some Hairball 990s in there too. 

I also plan on trying the OPA1612 in the input and probably a APP992DIP as well. 

So Im going to make a PT session for this and share it when its done. Then you'll be able to hear the difference in opamps and transformers yourself. I've only just begun this with burning in the opamps. So i don't have a ton of experience with the other opamps yet. 

I will say the Rogue5 is a great choice though. Its punchy and extended. 


So...eventually, I will have a lot to say on the opamps! haha Just not 100% yet. Hit a few kinks with a bad part in the new 2503L pair and I just got the replacement so should be starting in on the comparison this week. 

You would not be disappointed with the Rogue5s. All the great stuff of the API sound but better. Really like them. Likely be my choice for a lot of the ML2 modules I plan on building. 

You're right I need to do the 990s. I'l order some today.