NEW: authentic style LA2A, Pultec EQP-1A, MEQ-5 & Ultimate Mic-PSU chassis

Hey folks,

just recently I a fellow GDIY member pointed out that this page is completely out of date.
Before I explain everything in every detail - long story short:
I have my own website and all my projects are available there - most of them have been updated tremendously compared to what you see below. Meaning screen printed backpanels, custom made powder coating - color sampled from vintage units, the Pultecs have a massive 5mm (13/64") thick front panel, the LA2A has a 2-piece back chassis now just like the vintage units, anodized etc.

Check up-to-date information on all projects on: www.analogvibes.com

Thanks

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LA2A style P2P chassis V2:

front:


back:


all parts of the kit:



finished unit from the inside:




finished unit in the rack:



The front of the chassis is powder coated RAL7035 light grey with black silk screening,
the back of this new V2 version consists of a 2 piece aluminum chassis - just like the vintage units.
This make the build much easier because the entire wiring can be done on the open L-frame back&bottom part of the chassis.

It features all holes and cutouts necessary to build an authentic LA2A style compressor without any further modification, drilling etc...

The chassis is designed for the original UTC HA-100x input and UTC A-24 output transformers,
but I also offer adapter plates for UTC A10 input transformer and Sowter in- and output transformers.

The VU-meter cutout fits the Sifam AL39-WF meter as well as the "Teletronix" branded replacement
meter available at don-audio.com in Germany and IMS in the US.

All chassis screw holes are threaded for extremely easy assembling and the chassis also features
vintage style thumb screws for fastening the front panel -  just like the vintage units.



The adapter plates are 7.50 EUR each

Here's an extensive package put together by fellow forum member Gambaholic which includes a BOM, an excellent
graphic layout of the components inside the chassis, schematics and HQ pics - it's almost foolproof

http://www.mediafire.com/download/ley4pm3tcam3iam/LA2A_to_Z.zip


chassis discussion over here:  http://groupdiy.com/index.php?topic=59538.0


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PULTEC EQP-1A style P2P chassis:

front:



back:



back with mounted filter units:



my finished prototype:



my finished prototype from the back:



Other than my prototype on the pics the chassis available here feature cutouts for XLR in & out instead
of a screw terminal and also a cutout for a IEC socket (in my prototype the power cable was hardwired
just like in some vintage units)

In addition the main chassis the kit includes 2x filter boxes to be mounted to the back of the main chassis
(as in the original unit) to house the filter sections of the EQP-1A.

The front panel is powder coated blue-grey - very close to the original color and silk screened.
The back and the filter units are powder coated in a rough dark grey color - similar to the hammer finish
of the original units but much more hit and scratch resistant.

Like the LA2A style chassis the EQP-1A style chassis sports all necessary cutouts to build an authentic tube
equalizer without any further drilling or modification. The chassis is designed for the original Triad HS-56 input
and HS-29 interstage transformers and for the newly available Cinemag S-217D (authentic Peerless S-217D replica)
transformers.
However there are adapter plates available for the use of Sowter transformers.

Here's a graphic layout of the components within the chassis and filter units - it shows that building one of these gems
is not really as difficult as it seems

http://www.mediafire.com/file/2b8py0igkenkh7l/Pultec_EQP-1A__layout_rev1_31.pdf

And here's a  paper by Chris Preston of vintagewindings.com about "facts and fiction about the Pultec EQ"
Great information about filter caps etc..: http://www.vintagewindings.com/tech%20swag/Pultec-Facts-&-Fiction.pdf

And many people have asked for it - FINALLY a BOM with some additional infos on parts
If you find any mistakes please let me know:
http://www.mediafire.com/file/zfeckxx7jeo1jfg/raintons_Pultec_EQP-1A_Parts_List_rev.1_2.pdf

The price for one complete chassis is 299 EUR (+ VAT if applicable) and includes:

- main chassis
- front panel
- 2x filter boxes



The adapter plates for input, interstage and output transformers are 7.50 EUR ea. (+ VAT if applicable)

discussion over here: http://groupdiy.com/index.php?topic=62061.0

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PULTEC MEQ-5 style P2P chassis:

The chassis is built pretty much the same way as the EQP-1A style enclosure - here's some pics of my finished prototype:

front:



back:



from the other side:



Like the above mentioned chassis this one also sports all necessary cutouts to build an authentic tube
equalizer without any further drilling or modification. The chassis is designed for the original Triad HS-56 input
and HS-50 output transformers.
However there are adapter plates available for the use of Sowter transformers and with little modification other vintage
transformers should fit the Triad HS footprint.

Other than my prototype the chassis available here features cutouts for XLR connectors instead of the terminal strip and a cutout for a modern IEC power connector instead of the hard wired power cord.

Also for the MEQ-5 I made a graphic layout of the components within the chassis and filter units - it shows all connections inside this wonderful piece of gear. If you follow it exactly it shouldn't be too difficult to end up with a wonderful sounding EQ

http://www.mediafire.com/file/cn5t2z828h8n6ax/raintons_MEQ-5_layout_rev1_2.pdf

BOM:

http://www.mediafire.com/file/7bpp4bbu540412h/raintons_Pultec_MEQ-5Parts_List_rev.101.pdf

Again all this is made to my best knowledge, but nobody's perfect - if you find a mistake please let me know and I'll correct it asap.

The price for one complete chassis is 249 EUR (+ VAT if applicable) and includes:

- main chassis
- front panel
- 1x filter boxes


The adapter plates for input, interstage and output transformers are 7.50 EUR ea. (+ VAT if applicable)

discussion over here: https://groupdiy.com/index.php?topic=63443.0


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Ultimate Mic PSU chassis:

blank chassis:






inside:





laser engraved dividing panel that shows the shapes & names of pretty much all tube mic projects available, so you
know where to mount the pcbs :




included in the metalwork inside the chassis are integrated mounts for the pots needed to adjust the supply voltage - here's a close up:




There's also cutouts for measuring plugs, so you can tilt the PSU to the side, connect your DMM and
dial in the right supply voltage from the front with a screwdriver as shown in the pics below:





The final chassis also includes the mount + optional cutouts for a second pot needed for some tube mic projects...

finished PSU (for a U47 in this case):





The Mic PSU chassis is made from solid steel,  powder coated with a hammer finish and comes with:

- 4x rubber feet
- beautiful and sturdy leather handle

One Mic PSU chassis Kit is 115 EUR (+ VAT if applicable)




here's the discussion thread for the Mic PSU chassis: http://groupdiy.com/index.php?topic=61160.0

For orders please go to:
www.analogvibes.com

and please include your location so I can calculate shipping.

This is my first WM thread, so I if you have any suggestions or questions please let me know

Thanks
Martin

Wow!
Beautiful work, and that PSU looks like an authentic oldie, only a bit more robust. *applause*

Me thinks my 47 project needs one of those puppies to round out the acoutriment.

Is there room in the architechture for installing a pattern selector switch?

Thank you,

John

headstack said:

Wow!
Beautiful work, and that PSU looks like an authentic oldie, only a bit more robust. *applause*

Me thinks my 47 project needs one of those puppies to round out the acoutriment.

Is there room in the architechture for installing a pattern selector switch?

Thank you,

John

Click to expand...

Hi John,

of course

Since not all mic projects need the pattern switch on the PSU I didn't want to have a huge 10mm hole in chassis that probably sits there unused.
So I came up with a different idea:

In the position where the pattern switch goes I designed a tiny hole 0.8mm. It's located in the middle above the XLR and binder connectors (the spot where you would actually expect the pattern switch )

With the the hammer finish of the chassis you don't see it if you don't know it's there - but it's there. Here's a close up:



And IF you need a pattern switch you just use a drill to enlarge the hole.
No measuring to find the right spot, no pre-drilling etc.  8)

Inside the chassis the dividing panel is not centered, so there should be enough space for a
rotary switch (unless you want to use one of those big military ceramic switches )

hope that helps
Martin

Any thoughts about doing the MEQ5 to complete the set mate

moltenwok said:

Any thoughts about doing the MEQ5 to complete the set mate

Click to expand...

Yes
How about that?
http://groupdiy.com/index.php?topic=63443.0

I think the leather handle is a lovely finishing touch

Nick Froome

added a graphic layout which shows the Pultec EQP-1A component layout within the chassis.
It's my first revision, but if you follow it exactly it should be a foolproof instruction to wire up an authentic EQP-1A
with my chassis

Mic PSU chassis shipped to Sweden

I'll update the thread with a graphic layout of the component inside the chassis for the LA2A build soon...

A plug for Martin on this stuff. I bought 2 LA2A cases in the group buy and they are excellent.
-GLT

gltech said:

A plug for Martin on this stuff. I bought 2 LA2A cases in the group buy and they are excellent.
-GLT

Click to expand...

Thanks Glenn - I'm glad you like them!

added the long awaited BOM for the Pultec EQP-1A project including some very useful infos about the original components.
Also I added the link to an extremely interesting paper by vintagewindings' Chris Preston with even more great infos about the components used in the original units

have fun 

Alright guys stock is getting low on the Pultecs - only 6 kits left so far of which 2 are reserved already.
8 LA2A style chassis left of which 1 is reserved already. Mic kits I still got a couple more - 15 kits left.

BTW: I added an extensive all-inclusive package for the LA2A build put together by fellow forum member Gambaholic (thank you so much!!) This package includes pretty much everything you need to know when building an authentic LA2A replica - BOM, schematics, HQ pics and  a beautiful graphic layout of the components inside the chassis.

If you don't manage to build a proper LA2A style comp with this package you should probably look for another hobby  ;D

running out of chassis guys  ???

2x mic PSU chassis kits shipped to Equador
5x mic PSU chassis shipped to  the USA
1xLA2A style chassis + 2x EQP-1A style chassis shipped to France
1xLA2A style chassis shipped to Australia
2x EQP-1A style chassis shipped to Belgium
2x EQP-1A style chassis shipped to the USA

another LA2A style chassis shipped to Southern-France
and also another Mic PSU chassis shipped to Northern-France

Pultec EQP-1A style chassis  SOLD OUT for now...

Hi Martin,

It looks like from the pictures you have a place for 2 pots for adjusting the B+ and H+, but only one pot seems to come to the front with a slot to adjust with a screwdriver. Any reason you didn't make both pots accessible from the front panel with a small hole? Also, is there a hole on the bottom for the other pot to be adjusted without opening the unit? I can't tell from the pix.

Love what you did, however!  ;D

Best,

Mike

Edit: realized there were 2 pot holders

Phrazemaster said:

Hi Martin,

It looks like from the pictures you have a place for 2 pots for adjusting the B+ and H+, but only one pot seems to come to the front with a slot to adjust with a screwdriver. Any reason you didn't make both pots accessible from the front panel with a small hole? Also, is there a hole on the bottom for the other pot to be adjusted without opening the unit? I can't tell from the pix.

Love what you did, however!  ;D

Best,

Mike

Edit: realized there were 2 pot holders

Click to expand...

Yes, you're right Mike, there are two pot holders.
The first one makes the pot accessible from the front with the cutouts for the measuring jacks accessible from the bottom  and the other one makes the pot accessible from the bottom with two extra optional cutouts for measuring jacks - also on the bottom.
Optional in terms of that the cutouts are pre-cut for the most part but not completely.
So if you need them, you just have to burst out the metal at the according (pre-cut) spots but if you don't need them you won't have two gaping holes in the bottom.

That was also the reason why we had one pot pointing downwards making it accessible from the bottom, while the other one is accessible from the front:
Not all tube mic projects need the 2nd pot (i.e. U47), but all of them need the first one.
And we didn't want to ruin the looks for those who only need one pot

Martin

It all makes sense.

Thanks!

Mike

1x LA2A style chassis going San Francisco,
1x Mic PSU kit going to L.A.
1x Mic PSU kit going to Northern-Germany


The bad news is now I'm running out of all kinds of chassis and Pultec EQP-1A style chassis are sold out completely.

The good news is - since I received so many requests:  a new run of EQP-1A style chassis will be coming in the middle of November.
So PULTEC STYLE CHASSIS BACK IN STOCK IN APPROX. 3-4 WEEKS 

Martin

What would be nice would be an exact list of the PCB's that the Ultimate PSU chassis supports. I read through this whole thread and the feeler thread and could not find one definitive list, just a smattering of items here and there. Just a suggestion!

Does this fit the Chunger/Matador PCB?

Thanks; I already ordered and am waiting in anticipation to getting an awesome case! Thanks Martin!!

Mike