Turtlerock Forum

So I recently picked up the Magnatec clone of the EQP1A from Steve (despite telling myself I had to stop buying gear).

I've never owned a good valve EQ before so it was a real eye-opener. And now I'd like at least 3 more to put together a tasty 4 channel all-valve signal path.

Anyway a friend builds point-to-point valve hi-fi amps, and so he's both capable and willing to give this a whirl.

Does anyone know of a decent EQP1A design (that features components which actually exist in the mortal realm)?

There's quite a few out there, prodigy forum has a few and I'm pretty sure Myles on here has built a few, maybe pm him?

Drip eletronics

There's also a good schem, layout and parts list to build a point to point Pultec going around. I imagine the Magnatec and others are v similar to this. If I find it ill post it.

drivebystudios wrote:Drip eletronics

Nice. PCB and build manual with bill of materials.

Here's the link if anyone else is interested.
http://dripelectronics.com/index.php?op ... &Itemid=36

Alistair wrote:There's also a good schem, layout and parts list to build a point to point Pultec going around. I imagine the Magnatec and others are v similar to this. If I find it ill post it.

Cool - I'm also digging through GroupDIY (Prodigy) looking for something P2P but no luck so far. Let me know if you find anything.

There's plenty of interesting stuff here....

http://danalexanderaudio.com/Indexer.htm

Cheers

I have a pair that Myles Mumford built, based on the Gyraf re design for DIY.
Very, very nice. They are used on every session somewhere, and are always on the stereo buss when mixing.
I hope I never have to part with them.
Cheers,
Paul

With Myles being in Swaziland, the option of getting him to build one is probably out, sadly.

The Gyraf one looks sweet, and I've since found the schematics and BOM for it.

Regardless, I'm hoping Myles gets on this thread at some point and shares his wisdom.

Your wish is my command!

The pultecs that Paul has are straight Gyraf builds, it's a well documented build with a bunch of options and is a very easy build. It's not point to point but I really don't see how that is good or bad. Most of the info is on gyrafs site but you can also get loads of info from groupdiy. The build is also pretty cheap (depending on options) and because it is not a kit you can put in a variety of extras if you like, stepped gain control for recall and precision matching, different transformers (lundahls, jensens, cinemag, st.ives, etc) smaller casing (you can get a stereo in a 2ru if you wire the pots/switches off board), precision components, extra frequencies, independent switching of the low freq cut and boost. and the list goes on.

My next pultec build will be a stereo solid state with stepped switches for all controls, trimax transformers and matched hand wound inductors. Will probably set me back around 6-800 including case. Valve set would add about 200 to that price.

Drip stuff gets a good wrap by builders but is realistically very similar but for a much higher price.

See, if you say Myles' name 3 times he will appear.

Hey Manning,

Just a few ideas.... of which i'll get around to building when i free up some time / cash..

http://www.groupdiy.com/index.php?topic=50848.0

This guy has designed a complete set of pultecs on pcbs.... no wiring - looks pretty straight forward. For what it is worth, Colin is a pretty highly regarded engineer - the units should be pretty good.

Another approach is to go for a pair of solid state pultecs (like the lang) - using an api / melcor gainblock for make up gain. These are 500 format. Not stepped switches, but they do have extra freq points.. quite cheap too...

http://www.groupdiy.com/index.php?topic=48328.0

These should be pretty straightforward builds - they are well documented, and both designers have done a heap of testing / research into making them sound right..

happy hunting..

h.a.r.r.y.a.r.v.a.n.i.t.i.s

Here is the site I mentioned- very thorough and good info, plus you can pay $10 and get even more info and photo build guide.

http://www.recproaudio.com/diy_pro_audio/pultec_eqp1a.htm

I've built a pair of the Solid state eqs for my 51x rack but barely finished them before heading to swaziland so didn't really get a chance to check them out. They were a very easy build though and the documentation was excellent.

I really think your best way is to pick either a kit or go for a "choose your own adventure" ( my money is with the choose your own adventure) as the EQ circuit is very simple (and you can choose a few options depending on which way you go) and then you can pick your own makeup amp (original valve, gyraf SRPP valve amp, solid-state, neve, etc) to suit yourself and then case it up in something that says custom for me.

Here are a few more options:

http://www.groupdiy.com/index.php?topic=43413.0

http://www.groupdiy.com/index.php?topic=43429.0

http://www.groupdiy.com/index.php?topic=37324.0

http://www.groupdiy.com/index.php?topic=37324.0

http://www.groupdiy.com/index.php?topic=16761.0

http://www.groupdiy.com/index.php?topic=37850.0

That should be enough to keep you going for awhile...