rainton's True To The Original PULTEC EQP1-A chassis kit discussion thread

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

rainton

Well-known member
Joined
Mar 26, 2011
Messages
651
Location
Southern Germany
I know some of you have been waiting for months now but now I can finally start the feeler for my  authentic Pultec EQP-1A chassis.  :D

It's been a long way and a lot of work to get to this point and I'm excited to know what you think!

This chassis is designed as close as possible to the vintage original - meaning: with the right components you will be able to recreate an original Pultec to an extend not possible before.

But let me show you some pics so you know what I'm talking about:


This is my finished prototype in the rack:

11t0gfm.jpg


The almost finished unit outside of the rack:

nei2pd.jpg

from the back: as you can see the layout is exactly as the original - in this pic the only difference to a vintage one is the Sowter output tranny...yet  8)


118oqba.jpg


Since I didn't want to build just another clone but a recreation of the  vintage EQP-1A I did a lot of research to find and use original components throughout the entire build. Here's a peak inside (output tranny still missing in this shot)


2i87l37.jpg

Here's a closer look at the filter units mounted to the back of the EQP-1A. Here's an empty filter box as provided with the chassis:

29sd5e.jpg


And here's a finished filter unit:

ebc707.jpg


The front panel color was a little tricky to decide on since there were at least half a dozen different grey tones that were used for the Pultecs  ranging from a rather greenish gray to the enamel blue-gray.
With a little help of Frank @ frontpanels.de I went for a color which he found out was very close to the blue-gray used in many EQP1-As. The front panels will be powder coated RAL5009 and silk screened.
Other than my prototype the logo on the front panel will not say "Pultec" but only "program equalizer EQP1-A" since "Pultec" is a protected trademark.

The rear of the chassis will most likely be a slightly bit darker than my prototype, since I spray painted it with a varnish that gave me exactly the hammer finish grey tone I was looking for, but unfortunately all paintshops I called so far told me this color was not available for industrial production anymore. There's still one company on my list but for now I'd go with a dark grey hammer finish powder coating which is also very close.

All cutouts on the back are made for the original transformers so far but:

a) I'm open for discussion
b) I will offer adapter plates for the most requested transformers (as some of you may know I have done with my LA2A chassis project before which worked great)


In addition to the chassis I want to offer an "all-knobs included" option. I made a deal with don-audio.com if I buy enough of the Dakaware Pultec knobs he can give me discount of almost 40%!!
So with this "all buttons in" option one of the big boost/attenuation  and also the frequency selection knobs will cost only roughly 7 Euros ea. instead of 11.50 Euros ea.
That makes a huge difference considering you'll need 7 of them altogether.

Ok that was the good news - now the "bad" news:

This will not be a cheap project - due to several facts:

- all parts of the chassis incl. the filter units need to be powder coated (other than e.g. the LA2A where only the front is powder coated)
- the filter units and 2 of them: these little boxes are pretty expensive for their size because they need to be spot welded, threads inserted etc. 
- a lot of individual parts


As always: the more we are the cheaper it gets ;)

For 10-19 chassis it'll be 270 Euros ea.
For 20-39 chassis it will be 250 Euros ea.
For 40+ chassis it will be 235 Euros ea.

The knobs kit with original Dakaware knobs will be 56 Euros

consisting of:

5x boost/atten knob
2x large freq. selection knob
1x power knob
1x chicken head knob for attend. selection


ONE MORE THING...

Thanks to forum member Deepdark I found out that Cinemag is indeed doing a technically exact replica of the unobtainable Peerless S217D output transformer!! It's not listed on their website but they do have it!
I talked to David @ cinemag and he confirmed he used 100% original material, L12 lams and he invested a lot of money to make it happen. The only difference is basically the color of the varnish, it has lead wires instead to terminals and the mounting studs are positioned slightly different. But given the fact it is electronically 100% identical to the original and also from outside looks very very close it is the best option available in terms of sound and look.
Usually the Cinemag S217D is 225 $ ea. but if we find more than 11 people the price will go down to 180$ ea. :)
So I think I might this be the standard OT cutout on the chassis...

I will start a dedicated feeler for the Cinemag S217D group buy tomorrow and as soon as I did I will post the link here and also post a link to this thread there so everybody interested in one or the other will have the chance to become aware of both...

This feeler will be opened for a limited time only - I'll update the thread ahead of time before I close it.

Ok guys I'm excited to hear your thoughts!  :)
Martin


Group Buy List:

nickhepfer (2) PAID
Floti (2) PAID
Quayhog (2) PAID
Shaker-her PAID
kosi (2) PAID
LeRoux (2) PAID
Craig  PAID
bancho (2) PAID
SimonDemon (2) PAID
Bobbi (2) PAID
jpharaoh (2) PAID
fishdrop PAID
rainton (2) PAID
 
That's really awesome!

I'd take:
- 2x case
- 2x knob set
- 2x adapter plate set (for Sowter IN + INTERSTAGE + OUT)

Again, thanks for this great project and your effort to make it happen!  ;D

Cheers,
Nick
 
Thanks guys!

I just launched the feeler for the Cinemag S217-D transformer:

http://groupdiy.com/index.php?topic=62081.0

I hope we can get enough people together to make it happen :)
 
Good Job !

- I'll take 4x set of knobs (Need to replace mine ... perfect timing)

Thinking, to get 1 or 2 chassis...

Best !
Jay
 
Hi Martin,

I'm in for 1 chassis, 1 transformer, the knobs kit.

I basically want to build one unit.

Huge thanks

James
 
2 chassis and knobs for me.
I  received an LA2A and 2 psu chassis yesterday and the quality is outstanding !
 
kosi said:
2 chassis and knobs for me.
I  received an LA2A and 2 psu chassis yesterday and the quality is outstanding !

Thank you so much!
I will leave this feeler open until we have at least 20 chassis together, so we can get a cheaper price.
We're counting 13 or 14 if I counted right - so I think we'll reach 20 soon!

 
If someone's interested, GDIY member" wannabe" is selling HS56V for 280 USD/pair. (plus paypal and shipping)
He still has 8 of them. Here's the thread

http://groupdiy.com/index.php?topic=60346.msg765348#msg765348

His name is Michael  and he handles the sales and inventory of orphan audio, which belongs to Ken Hirsch, owner and designer of Quad Eight and Electrodyne as well
 
I will take 1 chassis 1 knob set and 1 output transformer
If the feeler gets above the 40+ may consider a second order
Thanks for the hard work on these projects
 
Hey guys,

We're at 15-16 chassis at the moment, so I'm sure we'll reach 20 soon. But I would try to not stretch this feeler too long, because there's gonna be some lead time until the chassis and also (for those who want one) the Cinemag trannys are done,  so how about we close this feeler 15th of April?
 
Gentlemen we still need to talk some details:

- My own prototype had the cutout on the back for the original Chicago PCC-55 power transformer, but the group buy chassis should have the cutouts for something easier available such as a Hammond power transformer.

-  the original Pultec doesn't have an IEC socket, but the power cables is hardwired to the chassis. My prototype was build the same way, but maybe you prefer to have a modern IEC socket for a detachable power cable?

I would to the audio transformer cutouts for: Triad HS56V on input and the Cinemag on output and offer adapter plates for Sowters. What about the interstage transformer? My prototype was made for the original Triad HS29 but it's very hard to find!

Let me know what you think guys! :)
Martin
 
Hi there,
I can speak only for myself:
I bought 2 HS56 and will participate in the Cinemag / Peerless deal.
In the moment, I plan to buy the Sowter interstage 9330.
 
rainton said:
Gentlemen we still need to talk some details:

- My own prototype had the cutout on the back for the original Chicago PCC-55 power transformer, but the group buy chassis should have the cutouts for something easier available such as a Hammond power transformer.

-  the original Pultec doesn't have an IEC socket, but the power cables is hardwired to the chassis. My prototype was build the same way, but maybe you prefer to have a modern IEC socket for a detachable power cable?

I would to the audio transformer cutouts for: Triad HS56V on input and the Cinemag on output and offer adapter plates for Sowters. What about the interstage transformer? My prototype was made for the original Triad HS29 but it's very hard to find!

Let me know what you think guys! :)
Martin



Hi Martin :)

regarding the power transformer I'd go for the Hammond.
The IEC is a great idea since it is more flexible!

But for the IS transformer cutout I'd chose the Triad + adapter plates for Sowter; just because of the overall original layout by default  :)

Cheers!
 
Ok great.
So let's do it with IEC socket ok?
Many vintage units had the fuse holder in the front  - left from the power switch, just like my prototype unit.
But if you want to go for the original look this only makes sense if you can find the original fuse holder with the red inlay.
I found one for my prototype but it was pure luck and I didn't even find a model number on it - so it'll be hard to find it again...
I just saw it on a picture in an auction and bought it ;)

Anyway - the reissue has it on the back. Should we also place it on the back?
 
nickhepfer said:
Hi Martin :)

regarding the power transformer I'd go for the Hammond.
The IEC is a great idea since it is more flexible!

But for the IS transformer cutout I'd chose the Triad + adapter plates for Sowter; just because of the overall original layout by default  :)

Cheers!

Agree with above ideas, and putting the fuse holder on the rear.
Thanks
Neil
 

Latest posts

Back
Top