DIY Pultec EQP-1A Layout and Pics

[CJ]

Cine,ag probably uses a stck mu can with dimensions their stuck with, since those cans are expensive and hard to source.
The original was potted in wax from what I hear, and sits in that sheet metal cage at the back of the chassis.
I am suprised nobody here has a vintage Pultec.
But why pay 2000 bucks when you can build it right here!

 

[mesmer]

I'm in LA, so I can rent one next mix I get and have a look under the hood.
Peter

 

[CJ]

Now that would be awesome!
Take some pics if you can.
Especially inside the extra enclosure.
You will have to un-pot the inductor to see it, so obviously thats out of the question.
But you could measure the dc resistance of the inductor, which would tell us a lot.
Take your time. Been waiting for 3 years anyway.
cj

 

[drpat]

...

 

[ChrioN]

The links in the beginning of the thread are broken

Please does anyone have them?

 

[Bluzzi]

Chrio - I have them but since they were first posted by Cayocosta I am not sure what the proper way to proceed here is.

I imagine he may have decided to remove them for a reason or maybe the server is inactive?

Cayocosta - Can you let us know if its OK to pass them around?

Jim

 

[tim-burns]

hi there
my first post and i'm already getting needy! i love this site! i'm new to diy so i will probably need help from my ever useful tech but i want to build a couple of eqp-1a's (i thinkn they call this get some one to help you to DIY :wink: !)
still no links to the pultec schematics.... i've read most of the stuff on the other links, which seems to be politicly resolved.... but no working links. i'd love to build a couple of these. i'm from the uk so sowter txrs look good. but i'd like the origional layouts... if pos?

cheers guys
T

 

[Bluzzi]

It would seem from another thread (LA2A) that Cayacosta does not want his layout copied or passed around. But the schematics are around if you do a search. Its just that Cayacosta had done a nice P2P wiring drawing. One for the LA2A as well. For some reason he decided to pull everything off the internet.

Jim

 

[tim-burns]

thanks jim!
i'll keep looking around!
T

 

[Sender]

Is anyone rehosting the original pictures?

 

[CJ]

Not at the moment.

 

[acrossen]

Drpat,

Would you be so kind as to measure one of your original EQP-1A cases to provide the group with the depth?

I'm going to order a Par-Metal case for my clone, and would like to match the original size (3RU, but how deep?).

Cayacosta used the 14-19053G which is 5" deep. That's probably close.

Thanks!
Andy

 

[Bluzzi]

Just in case no one noticed Cayocosta's link is up.

http://www.recproaudio.com/

So I guess its OK to use now.


jim

 

[supaheef]

[quote author="Bluzzi"]Just in case no one noticed Cayocosta's link is up.

http://www.recproaudio.com/

So I guess its OK to use now.


jim[/quote]

Nice Site. Are you planning on releasing details on the Redd47? Would be very keen to get that one happening. The Revolver is an excellent name, too.

heath.

 

[Bluzzi]

Its not my site, its Cayocosta's. I used his layout and my LA2A turned out great (other than a hum that was wire routing and fixed by simply moving one).

jim

 

[acrossen]

Here's another thing I don't get about the original Pultec EQP-1A. Maybe Patrick or someone else can clear this up for me.

Do the two sheet metal cages on the rear house only the inductor? Why so big - just for the wax potting? Why split into two - different frequencies in each?

In building a repro, I want to be sure that a) my little Cinemag CML-150MT (or equivalent Sowter, etc.) serves the same function as what's in those cages, and b) building repro cages and potting my inductor in one of them would be entirely superfluous (David Geren at Cinemag seems to think so).

Thanks for the help,
Andy

 

[drpat]

...

 

[acrossen]

Excellent, that makes sense to me now. The filter circuitry was proprietary and hidden in the cages. The inductor then, I assume, is just to the right of the lower cage.

Thanks Patrick.

 

[Jeff5]

This is an old thread, but I couldn't find any more appropriate recproaudio pultec threads.

I'm trying to find out if the .002u capacitor in the 2013 recproaudio parts list (labeled to be in the "Filter Low A1" section) is correct. I can't find this cap in the layout or the schematic. I've been looking for quite a while.

If anyone can help I appreciate it. Thank you.