Alternate transformers for MEQ-5

[Quayhog]

The Triad HS-50 as used in the Pultec MEQ-5 is rare and expensive when found.  I've committed to one of Rainton's chassis kits.  Is there a consensus on an output transformer that will work as a similar and adequate replacement? I have some nice output transformers but would require a 3U chassis.  Would Altec/Peerless 15095 work?

I need to start my search soon.  The research goes on.  The 600:600 input should not be a problem.

 

[emrr]

You won't find a consensus.  26dBm headroom will be the hard part to find, the spec otherwise is very common.  The Edcors will do 26dBm +, though not a nickel core transformer.  The Altec won't do that level, but will the Pultec circuit?  Do the research on that part. 

 

[gridcurrent]

Would Altec/Peerless 15095 work?

the 15095 is  also employed as an output transformer in the Altec 1567a.
the Edcor WSM 15k:600 performed very well for me.
the Pultec MEQ circuit cannot do over +20 dBm.

 

[rainton]

According to Sowter, their 1290 output transformer should also be a good replacement:

http://www.sowter.co.uk/specs/1290.html

It has a max output level of +24dbu

 

[Quayhog]

There must be some other options for the output transformers.  The rare HS-50 is probably way overkill in this circuit.  It exceeds all of the other components, from the tube era specifications that you might have in the signal chain.

The HS -50 is spec'd to 26dbm, the UTC A-24 as used in the LA-2a specs out at 15 dbm, this HA-133 at 22dbm,  the Altec 15095 with its mu metal can is at 15dbm.
The Triad B-6300 used in the Ampex recorder must spec as well as the the HA-133 since both were used in the same Ampex circuits.

I'm looking to find the specs for Bogen T-165.  It's a littler header to find specs and schematics that use it.  The ones I've seen use a 12AX7 or 6SN7 to drive the transformer.  The search for alternatives goes on.

 

[moltenwok]

What about the Jensen JT-10K61-1M

 

[AusTex64]

I had opportunity to extensively compare two Drip Pultec builds that were identical except for transformers. One was all Sowter, the other has UTC A-20, UTC A-18 and new Cinemag S217D repro. I expected a lot more difference between the two units, but they were very very close in sound, THD and freq response. A lot of people would not be able to tell the difference in a blind test, including me. I dare say the Sowters have a vintage sound. Which is great news to me, now feel I don't always have to chase vintage iron and the associated prices to get good sounding, good performing transformers that can stand up to the iron of yesteryear. I am definitely more of a Sowter fan now from a sound standpoint.

So the Sowter 1290 Rainton suggested looks like a pretty good alternative to me.

 

[Quayhog]

I'm still waiting for the chassis.  To get the project going I will use the Altec 15095. I suspect that in a blind test it would indistinguishable from the original, all else being equal.  Using an octal socket wouldnt prohibit the use of an original HS-50.  The hole for the octal is about the same as the hole required for the Triad.

The next hard to source is RV4 spec 2.5K REVERSE Log/audio pot.  I have lots of useful DIY parts to trade for one or two.

 

[vitopower]

How did this turnout?  What did you use for i/o xformers?