Pultec EQP-1A ideas needed ???????

Hiya im thinking of maybe making a DIY Pultec
This is for my PC based DIY home studio heres the ruff set up

Solid tube vocal mic {for now} into choice of DIY tube mic pres,main 3 are V72,RCA BA21A & Mccurdy AU300 these seem to have lots of level
then into a DIYed BA6A,LA2A or AM864u limiters
then into Maudio delta break out box & into Delta sound card to cakewalk

thing is I always have loads of level to get rid of the V72 & BA21A pre & BA6A & AM864U limiters all have 10:1 balanced T attenuattors on the outputs
or if I use the LA2A the make up is only on about 2 of 10 notches

now im thinking of adding the Pultec EQ,Iknow the Pultec adds no extra gain but what im thinking is do I need to biuld the amp part of the Pultec & adding another 3 transformers, could I just insert the passive EQ part somewhere in my chain ??
any ideas ??

also got me thinking in this situation do I need all the transfomers in the chain too, the vocal can end up going thru six or 9 with added Pultec,I do like the sound of iron tho & some of the transformers keep the level down too,any ideas on this too.


would love to hear any ideas ,thoughts on this lot, many thanks from Gary O.

You could build the Gyraf version which only uses two x-formers, or, just use the filter section without a line amp and see if you have enough level left over. The Pultec hacks about 16 to 18 db. You could tweak the filter section to only chop about 10 db if you wanted, like the MEQ, which has about 12 db if I remember corectly.

If you just use the filter section, you coud use two cheap 600:600 x-formers, or go with unbalanced output and use one 600:600 input x-former.

Unfortunately, a lot of the reasons people like the original Pultecs is because of all that cool iron. Triad HS-56 is killer, Triad HS-29 is just crazy good and expensive/rare and the Peerless S-217-D is awesome and expensive/rare.

Three killer chunks of nickel.

hi CJ

that's what I plan to build for the future... a passive pultec and a g9 for gain makeup...

In all my other projects I used lundahl trafos... I already bought some oeps for the g9 and for the pultecs I want to use sowter replacements...

what transformer would you suggest as output transformer
for the passive pultec?? 600:600 or something like the sowter 9330 2,5k/10k ??

sorry for the long url, but it should work...


http://www.sowter.co.uk/cgi-bin/sh0...OWTER_PRO_VINTAGE_TRANSFORMERS_6.html#a36#a36


thanks,
mat

Hi CJ and Matthias, so the amp inc irons is big part of the Pultec sound then ?
I was thinkin I could make the filter section 1st & try it in my voice recording channel I reckon id still have plenty level ya know, then make an amplifier section later.
Yes I was wondering about the Gyraf 2 transformer version ,how it might compare to the Pultec 3 tran original, also I seem to have come accross different schematics for the Pultecs make up amp ?
As Matthias says Sowter have trans to replace the original irons do you know how they sound compared to the triads & peerless ?

Thanks guys .....Gary O.

I used the Sowters in a DIY Pultec and they sound transparent.

I guess you could step up the output signal a little.
2.5K:10K would probably be fine.

Come to think of it, a 600:600 on the output might load down the filter too much.
What's the HS-29, 5K/20K pri imp?

Hey CJ, what the fundamental differences between the HS-56 and the HS-66? As you know the 66 is what I'm using.

The 66 is the same. Just less shielding, which actually might be an advantage on the high end.

Not actually heard a Pultec original are you saying with its original iron it would sound more coloured [dont no if thats a good word} perhaps more flattering than the Sowtered version??

Cheers ....Gary O.

I built mine using Gardeners input and line transformers & the sowter line amp output transformer. The main reason I used Garddeners was because at the time I had a few around & they were roughly the right ratios. I`ve never compared it with the real thing, but I do like the sound of it.

I think its right that it will only sound like a Pultec with the right transformers, but that doesn`t mean it will sound bad with other ones. Just different (maybe).

Yeah I agree the filter must be huge part of the sound add a good amp & iron it must sound nice.
I was thinkin of makin the filter & experimenting with the make up amp of me LA2A.

the question for me is... why should I use a transformer that sounds "clean" ...?? then I could also use a good burr brown opamp ??

@ cj

what output transformer would you recommend
for a passiv pultec that's connected to a G9 ??

thanks
mat

hmmm, good idea using the G9 for gain makeup...

Also, since the g9 have lots of gain, would be possible to put 2 gyraf eqp1as in series for having more bands? well using a eqp1 amd meq5 would be better...

Synthi

Also, since the g9 have lots of gain, would be possible to put 2 gyraf eqp1as in series for having more bands? well using a eqp1 amd meq5 would be better...

Click to expand...

If you`re after scalpel like control then maybe its worth considering some of the other eq projects also i.e Sontec or Calrec. That is of course if you don`t have a phobia of using tramsistors & op amps.

hmm..., I really have some phobia to opamps...

Also after trying the gyraf pultec I`m in love with the sound. For surgical eq I use the 495s and 491s in series and also some software: voxengo glisseq and sonalksis eq, I`m now after that valve character, just like the peq1a , but a couple of extra bands and I`ll be real happy :grin:

Best Regards,

Synthi

Update..... made the passive part of Pultec EQ with no transformers worked well until I blew 2 inductors, well I think thats what happened so will be ringing RS soon.
Think im gonna knock up a point to point version of the Pultec make up amp out of bits that are laying around.
Is this the correct schematic to work from ??

http://www.purpleaudio.com/pdflib/PultecEQP.pdf

Cheers.
And was thinking about the iron do lundale do some equivilants of all or any of the originals or just Sowter, slightly concerned about the Sowters sounding transparent...

Many thanks............... Gary O.

Have you checked this thread?

http://www.groupdiy.com/index.php?topic=228

More stuff:

http://home.earthlink.net/~cayocosta/diy_files/eqp_1a/

Very nice job a proffesional looking unit well done Ron, I enjoyed checking that out the amp circuit you used is the original push pull I think, thats the one I want to do & I see you used Sowter tranformers im trying to find out if lundal do them too, ive made the filter like Jakobs redesign due to lack of 7 way switches & im useing cheap inductors from RS for now.

Thankyou for that................Gary O.

Very interesting thread. I'm also about to make a Pultec. I want to make something like Steffen's Pultec, only with transformers as in and output stage.

I ordered a DIY inductor kit from Conrad. Here's a description, again by Steffen, on how to do it.

Now I only have to find meself a multimeter which meassures inductance.....