Building a S.E.X. kit from 1999- missing iron and other questions

li303ve · 3231

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Offline li303ve

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A friend of mine recently bought a pair of S.E.X. mono amps from a garage sale, which he has given to me. I would like to build the kit, but I am having trouble determining exactly what it is that I have, and what I'm missing. This will be my first DIY electronics project, so I'm feeling a bit overwhelmed trying to sort everything out.

In terms of documentation, I have the S.E.X. Manual rev. 2.0, a ParaS.E.X. Upgrade Manual, and a ParaS.E.X. packing list dated 5/31/99. Is this kit for the original S.E.X., S.E.X. 2.0, or ParaS.E.X.?

It looks like most of the parts are there-- resistors, caps, switches, screws, terminal strips, tubes, tube sockets, chassis, wood base, jacks, etc. In terms of transformers, I have two boxes marked "Power xformer PGP-8.1." According to the parts list, I appear to be missing the output transformers and chokes. Are there any inexpensive transformers I can buy that will work with this design? I am also missing two of the retaining clips for the tube sockets, and both fuse holders, but I assume these parts should be easy enough to find.

Any guidance is greatly appreciated.
« Last Edit: August 15, 2013, 10:34:29 AM by li303ve »



Offline Paul Birkeland

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For a first time build, this is way, way, way too much to take on.  Without actually sitting down and physically looking at what you have, it's very difficult to determine the correct course of action.

For output iron, you will need Magnequest TFA-204's, that would be the best place to start.

-PB

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Joppa

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Basically I agree - it's pretty hard to know what you don't have! But given the documentation on hand, it's probably a ParaSEX, the last of many versions. The best way to confirm this is to go through the packing list, and note what is missing plus what is left over.

In this Legacy Products sub-forum there are several threads started by "najo49" who acquired an original SEX monoblock pair that needed some work. For more perspective, it would be worth your while to review them. Post back with any questions.

If my guess is correct (ParaSEX with PGP8.1) then I recommend some changes to the circuit and instructions for improved reliability and performance. The changes depend on which of several choices are made; the TFA-204 series feed modification is probably the simplest but there are several possibilities.

Paul Joppa


Offline li303ve

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Thank you both for the input. I checked the packing list, and the kit I have does appear to be the ParaS.E.X. with PGP 8.1. The capacitors I have correspond to the ParaS.E.X. packing list rather than the S.E.X. rev. 2 manual. There were no leftover parts, but I am missing the following:
- tube socket retaining rings (have two, missing two)
- inline fuse holders (x2)
- parafeed choke/transformers (430V039C10) (x2)
- parafeed output transformers (50-130) (x2)
- filter choke (C7X filter) (x2)

I'm starting to see why this project would be too much to take on for a beginner. It seems like I will not be able to get transformers that will allow me to build the circuit as described in the assembly guide. Using alternate iron and modifying the circuit accordingly is something that I just don't have the knowledge to attempt. I'm thinking I should probably pass the kit on to someone who can do something with it, or wait until I have the skills and knowledge to work with it myself.

On the bright side, I also got an already built Foreplay and a complete Anticipation kit. At least I can get my feet wet by building and installing the Anticipation.



Offline Paul Joppa

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Cool - the Foreplay will be a great experience, pretty much guaranteed. Get it working if it isn't, then get used to the sound, then put in the upgrade - you will learn a lot and have fun doing it.

The iron-less kit will be great for someone - the PGP8.1 is a Magnequest product, very nice. And - if you review the threads I mentioned - you'll see that a moderately advanced experimenter can do some interesting things with the kit using currently-available iron. The same chassis plate and power transformer was even used for the high-end Afterglow, Paraglow, and (with some extra holes) B-glow amps. All those things have a long history of mods and refinements.

We don't maintain a formal archive of recommended versions, but there are several on the board who remember - at least, remember a few things!

Paul Joppa


Offline najo49

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I would gladly take them off you hands. Send me a pm. Jann Olsen

Jann Olsen, [email protected].  Lowther medallion 2 with pm2a./ extended foreplay lll,/EROS phono /Grado ref/ SOTA star Vacuum SME V, /  45 amp direct coupled,c4s,mQ nickel  / paramour  2a3 w MQ iron /Original SEX monos /Jena Cables /heathkit wm6a/ proAc Tablette 50 sig , with push pull