Quayhog

Pultec EQP-1A
« on: July 19, 2016, 03:17:01 PM »
I'm getting ready to build up a pair of Rainton's EQP-1a chassis.  I've managed to acquire all of the specialized parts with the exception of the HS-29 interstage transformer 20k-80k with its 1:2 ratio.  I have several possible choices I've acquired over the years but none have the 1:2 ratio of the original.   
Which would make the best substitution?

Langevin TF412B 20k-60k (1:1.82) estimate (no CT)
Triad HS-27 15k-60k (1:172),  NOS
UTC A-18 15k-80k (1:2.3),  NOS
 Halldorson H4000 15k-60k (1:1:172)

These all have suitable frequency response, I'm not sure of db ratings.


vari-mu

Re: Pultec EQP-1A
« Reply #1 on: July 19, 2016, 06:11:58 PM »
  I think   Triad HS-27 15k-60k (1:1.72),  NOS  !!!

Quayhog

Re: Pultec EQP-1A
« Reply #2 on: July 19, 2016, 09:32:20 PM »
The HS-27  is my preferred choice too. Trouble is I only have one and I have a pair of chassis coming.  I'm thinking build one project with Triads and the second one with the UTC.  I have  UTC A-20 600:600, and a Triad HS-56.  The S-217d are Cinemag reproductions.

Quayhog

Re: Pultec EQP-1A
« Reply #3 on: July 19, 2016, 09:40:15 PM »
I need to disqualify the Halldorson and the Langevin. They are designed for single grid circuits.  They are otherwise nice transformers awaiting a project.

Re: Pultec EQP-1A
« Reply #4 on: August 07, 2016, 04:22:27 PM »
What inductor do you plan to use?

mikeyB

Re: Pultec EQP-1A
« Reply #5 on: August 24, 2016, 07:33:00 PM »
colin at audiomaintenance.com has the pultec clone parts made by carnhill
making better music!


 

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