Enhanced Pultec - short questions before project start

[barthman.de]

OK, summer is gone, evenings indoors are getting longer and longer, my last marathon run is on 30.10.16  in Frankfurt, so I have time to think about a new electronics project. There is some heavy metal, which should fabricated to a new (old) product. Here some original parts next to new parts from Sowter:

The HS56’s and the holy HS29 lounging around for many years in my treasury chest. Now the time is ripe to build two tube based Pultecs (EQP1 - point to point wired).  8)

Some questions to discuss:

Which inductors should I  buy?
I think about to build the Pultecs with enhanced filters.  When I look on the original schematic the passive filter section is „independent“ from the tube part, isn’t it?

So the old input / interstage transformers will work with another filter section than the original EQP1a - section - right?

For enhanced filter setting I need 312 / 155 / 78 / 39 / 26 / 0 mH inductors (matched pair would be fine). There are different types on don-audio.com. Are there differences in the sound?

Thanks for sharing your experience.




 

 

 

[lukas]

Here we go: http://www.vintagewindings.com/products/VintageWindings%20EQ-1A.html  , i have one, but don' try yet...build with oryginal spec.

 

[AusTex64]

Here we go: http://www.vintagewindings.com/products/VintageWindings%20EQ-1A.html  , i have one, but don' try yet...build with oryginal spec.

I tried several inductors and also measured a Pulse Techniques unit. I found the Carnhill inductor is the closest to the original in frequency centers and filter slopes.

 

[barthman.de]

Nice inductors but how is your opinion to build in more frequencies? Will this work with the Triad HS 56/ HS 29 tranformators?