[Diamondj421]

Greetings,
I'm about to pull the trigger on a DIY Pultec but am having a hard time deciding between two options. The Analog Allstars 500 series was also in the running but I think I'd rather have a rack mounted unit (or two). That being said, I've been looking at Don Audio's Classi PEQ which seems to run about $450-$500.  Any one that's completed a G-Pultec; what was your total price after completion? The G seems to be a more common build, but has anyone out there had experience with the Classi PEQ?  I'd prefer that Classi since it's solid state but if the price is right on the G-Pultec, I could be swayed. Also, are there any other solid state Pultecs out there that I haven't found yet.  I'm fairly new to the entire DIY thing so I'm not looking to seek out individual parts from multiple sources and then build from a schematic.

Thanks in advance!
Jeff

[Potato Cakes]

I did the Classi EQ and put it in one of the Collective 2U Pultec cases. I then P-touched the frequency labels as they are different and more of them. I sounds really good. I did a 1:2 for the output transformer as opposed to the 1:1 option they have plus I used their RM inductor. It sounds very nice and is comparable to the EQ that's with the Retro Instruments Powerstrip. The guys at Don Audio where also very helpful with their support. If you're new to DIY I would recommend this option.

Thanks!

Paul

[leitmo]

I strongly recommend Classi EQ from Don Audio. Aaron is a really nice guy to deal with. He knows his products and they are very high quality.

Building a Classi EQ is a "painting by numbers" kit. You can add Don Audio's solid state gain make up using NE5532 or use your own tube circuit, DOA, etc

I used different switches for Low Boost and Cut, and added a switch for Peak/Shelving Hi Boost just to have more options

I really love two things about this EQ:
- Bass is massive: you can boost a ton without sounding muddy..
- High boost never sounds harsh

Here's the thread of my building:
https://groupdiy.com/index.php?topic=60942.msg772047#msg772047

[Diamondj421]

So far, I've ordered the PCB (w/caps, resistors, etc.), the Classi PEQ gain stage kit, pots and switches. I'm stumped when it comes to inductors and/or transformers. In fact, I just started buying the parts that were listed under the EQ so I'm kind of doing this research thing backwards.  Other than what I've purchased, what do I need to make the most accurate representation of todays solid state EQP-1a3.  What would put me in that area? Don Audio's custom stuff, Lundahl LL5402 or Edcor XS1100, etc? I've been reading up on as much information as possible but it's a lot to take in. HS56V, interstage transformers... I'm lost.

[leitmo]

So far, I've ordered the PCB (w/caps, resistors, etc.), the Classi PEQ gain stage kit, pots and switches. I'm stumped when it comes to inductors and/or transformers. In fact, I just started buying the parts that were listed under the EQ so I'm kind of doing this research thing backwards.  Other than what I've purchased, what do I need to make the most accurate representation of todays solid state EQP-1a3.  What would put me in that area? Don Audio's custom stuff, Lundahl LL5402 or Edcor XS1100, etc? I've been reading up on as much information as possible but it's a lot to take in. HS56V, interstage transformers... I'm lost.

Congratulations for your purchase, you won't regret.

You can find lot of info about EQP-1a3  just googling.

The original one used 2520 DOA as gain make up amplifier. I don't think it used interstage transformer. What I'm sure about is that Classi EQ doesn't allow to install it. Input and output balance/unbalance can be done through transformers/opamps. I used 2520 for input balance to unbalance, 1731 for gain make up and 2503 CAPI output transformer for unbalance to balance.

[Potato Cakes]

So far, I've ordered the PCB (w/caps, resistors, etc.), the Classi PEQ gain stage kit, pots and switches. I'm stumped when it comes to inductors and/or transformers. In fact, I just started buying the parts that were listed under the EQ so I'm kind of doing this research thing backwards.  Other than what I've purchased, what do I need to make the most accurate representation of todays solid state EQP-1a3.  What would put me in that area? Don Audio's custom stuff, Lundahl LL5402 or Edcor XS1100, etc? I've been reading up on as much information as possible but it's a lot to take in. HS56V, interstage transformers... I'm lost.

This inductor for more of the character you desire.

https://www.don-audio.com/Inductor-Classi-PEQ-312mH155mH78mH39mH26mH

 And since you're just starting out in DIY, if focus on just making it work before doing mods and tinkering with the project. It can be overwhelming being immersed in all the research and info you can find for the circuits you want to emulate if you are new. Just get  one working following the build instructions as is, and with your gained knowledge you can proceed with tweaking the circuit to your taste.

Thanks!

Paul

[Diamondj421]

That's actually a really good idea. There are so many options out there that it's getting even more confusing. I was about to do the XS1100 (2:1 600:600) on the input and output and then the XSM15K/600 (5:1 15K:600) as my interstage transformer.  I wasn't sure if I needed that or the XSM600/15K though. What's the difference? Another option for interstage, would be the Carnhill VTB2424M (20k:80k).  Any simple explanation as to what all of these damn numbers mean would be incredibly beneficial. Thanks so much for your help everyone!!!

[Potato Cakes]

That's actually a really good idea. There are so many options out there that it's getting even more confusing. I was about to do the XS1100 (2:1 600:600) on the input and output and then the XSM15K/600 (5:1 15K:600) as my interstage transformer.  I wasn't sure if I needed that or the XSM600/15K though. What's the difference? Another option for interstage, would be the Carnhill VTB2424M (20k:80k).  Any simple explanation as to what all of these damn numbers mean would be incredibly beneficial. Thanks so much for your help everyone!!!

If you are going to do the Classi, you only need a power transformer that comes with the Gainstation kit. The transformer on the output is only an option. The balancing in and out are all done electronically with the Gainstation. This is the easiest way to build this guy.

For all your parts go here:

https://www.don-audio.com/Classi-PEQ-Filter-PCB-Passive-Equalizer

When ordering select the inductor of choice (EF for color, RM for HiFi), and include the All Caps, Gainstage kit, Case, and Knob set options. That will get you everything thing you need to build it and equalize sound. Once you make that work then you can start adding other options like transformer output, etc.

Thanks!

Paul

[Pusch3l]

I remember when Aaron handed the PEQ PCB over to build a unit. After some thoughts about the Gainstage i went with Jakobs SRPP Stage from the GPulteq and 2 LL5402 and never regret the decision! its Plug and Play and im more of the tubeguy.
Debugging the pot-wiring was a bit time-consuming and adding the 20K Hi-Cut (Beta-PCB  ) but thats fixed now.
The EQ sounds warm and never harsh and i use them as much as possible.
Downside of my version is that the bypass switch is just a fancy Knob with no function, but thats fine to me
I cannot remember exactly my costs per unit but i think they where in the 600€ because of the SRPP Stage but if you look around in the Black Market or on E*ay you will find Lundahls in good shape for a good price and its worth a shot!
I will stick with the SRPP Stage on the MEQ i have laying around.
If you want to go with Jakobs GPulteq i can help you out with a frontpanel and ready built filter pcbs
Greets

Some pics i did during the build:

[Diamondj421]

Very nice! I actually ended up going with 2 of the Sowter 3603s. They're similar to the HS-56 so I'll see how they work and keep everyone posted.

[Diamondj421]

How long did it take for you to get your orders? Like I said, I ordered my PCB and parts for it on January 9th and still haven't recieved anything. Should I be worried?

[Potato Cakes]

The holidays seems to backlog a lot of stuff. I just received an order I recently placed. Have no fear! Or maybe just a smidge.

Thanks!

Paul

[Diamondj421]

Just got everything today and there is no BOM or instructions for the gain stage. Can someone send me a list of where the resistors go? I've used a picture and process of elimination to put all of the capacitors on. Actually even a close up of the gainstage would help immensely!

[Diamondj421]

So, I got most of it figured out. Looks like I'm missing a few capacitors so I just ordered those from Mouser. How did everyone mount their LEDs? Just right to the gainstage PCB? There has be a better way.

[Potato Cakes]

Just got everything today and there is no BOM or instructions for the gain stage. Can someone send me a list of where the resistors go? I've used a picture and process of elimination to put all of the capacitors on. Actually even a close up of the gainstage would help immensely!

Email Aaron and he'll send it to you.

Thanks!

Paul

[Diamondj421]

Did anyone have issues with their Classi Pultec's being too quiet? If so, what was the fix?

[Potato Cakes]

How quiet? It's supposed to have a -6dB drop with the circuit engaged to allow for EQ boosting and not overload the Gainstage. I initially had a -10dB drop, but I think I had a misplaced resistor on the Gainstage.

Thanks!

Paul

[Diamondj421]

I wish. We're talking -24dB. Is your gain stage the Classi solid state?

[Potato Cakes]

It is.  Do you have the correct output when it is bypassed?

[Diamondj421]

I put a 20k trim pot in at R5 and dropped the resistance until the EQ curve hit zero. Bypass is at -44dB though so something is obviously wrong.