S.E.X. kit temporarily out of stock pending updates

[Doc B.]

Last week we found out that the output transformer that we have been using in this kit for several years has unexpectedly been changed by the manufacturer, rendering it useless for this application. Our remaining stock of these transformers has now been committed to orders and we are suspending sales of this kit until we have updated it to use the Bottlehead OT-2 output transformer currently used in the Stereomour kit. This update has been planned for some time, so we are simply having to do this a bit sooner than anticipated. The update will require a price increase. However the performance increase will more than justify the difference, bringing the stock S.E.X. kit much closer sonically to one that has been updated with the MQ iron upgrade.

[Maxwell_E]

Would a current S.E.X. owner be able to purchase a set of the Stereomour OPT's once the transition is complete?

[JC]

I'm curious about that, too.  Also, will it still be possible to use the stock plate-loading choke, or will that need to be changed as well?

[Doc B.]

We are planning to build the updated S.E.X. prototype in the coming week. I will activate the order button as soon as we are sure it's all going the way we plan, and if it's all good we hope to be shipping in about 3 to 4 weeks.

[Doc B.]

PJ and I spent a full day working on the S.E.X. 2.0 prototype for the assembly manual yesterday. It's about 2/3 complete and going together nicely. If things keep moving along well I hope to sit down with Eileen and run our cost figures in the next day or two so we can work out the pricing. Once we have that together I think we can begin taking orders for the first run, which will have an estimated 4 week lead time.

The new kit will have the following improvements:

the big update is that the output iron will be the same as used in the Stereomour. With this iron one should experience much better bass performance than the old Specos gave. The output transformers are connected as transformers rather than autoformers and they can be wired for 4/8/16 or 32 ohms.

the PT-7 power transformer has a single high voltage secondary that will feed a pseudo dual mono supply, and an improved internal shielding arrangement. There is a center tap on the heater secondary. We will also sell this transformer by itself for DIY projects. HV secondary is rated 150V and 70mADC when configured into a voltage doubler supply and the heater secondary is rated 6.3V 3.5Arms. It is the same form factor as the PT-3 and PT-5. No pricing yet.

the power supply is simpler to build and this should reduce the assembly time.

the hookup wire is now two colors to ease tracing the wiring if troubleshooting is needed

the headphone jack is the shorting type that will cut the signal to the speakers when you plug in headphones

the mounting hole for the volume pot has been slightly modified to accommodate a Goldpoint attenuator, for those who wish to update the stock pot on their own.

[corndog71]

Could you guys put together a kit to update the older sex kits to the newer shinier version?
I would be interested in it.

[Paul Joppa]

Could you guys put together a kit to update the older sex kits to the newer shinier version?
I would be interested in it.

I'm sure Doc would be thrilled to have your money (!), but I don't think any of us would actually do it - there is no real benefit to you. For sonic improvements, the main thing is the transformer and plate choke. I still recommend the Magnequest upgrade iron - though I have not listened to the new iron in the SEX amp yet; the prototype is still only 2/3 done! I fully expect that the Magnequest is still going to be a bit better though - my new designs are still cost-oriented production products for our least expensive amps. They are much closer to the Magnequest parts than before, but still a bit below in measured performance, and Mike still uses better materials and has better workmanship in his products. Unless you really need the 4 ohm or the 32 ohm option, I'd go for the MQ iron. It's what I have in my personal SEX amp, and I don't plan to change it out. If you want or need them, it's possible Doc B will make them available - they do have some wider applications.

The new headphone jack has been installed by many already, and you can get the jack with instructions from Eileen. The Goldpoint just needs the hole to be enlarged a bit, and the anti-turn hole extended towards the main hole a bit - you can do this with a couple files and some patience. I see no point in upgrading to a more easily built power supply, if you have already built the dual-mono power supply!

[corndog71]

I guess I misunderstood Doc's post.  Thanks for clearing that up.

[Bones13]

I am considering the S.E.X. amp for my office setting (headphone and small desktop speakers). You have already worked out 2 of the mods I plan - the attenuator upgrade, and the shorting headphone jack.  How will MQ iron be used to upgrade the S.E.X. v2.0?  I have seen the MQ listings for OPT and chokes for S.E.X. and Paramount on the MQ site, are the ones for "Paramour" the same as the current Stereomour, now S.E.X. amp all the same?

[Paul Joppa]

Magnequest does not at this time have an upgrade option for the Stereomour.

The S.E.X. upgrades, BH-1 output and BH-2 plate choke, are the same size as the new stock SEX iron, and the plate choke has leads which allow it to be mounted on the top of the chassis.

The Paramour II upgrade plate choke, BH-6, is the same size as the stock unit but has exposed terminals which will be at the full power supply voltage, so it is NOT SUITED and DANGEROUS to use in a Stereomour. The output transformer BH-5 is too large to fit in the Stereomour chassis. We have talked with Mike, and I expect that he will make suitable upgrade parts eventually - I know he's given thought to how to design them.

[Bones13]

Thanks, that would be a possible longer term upgrade then.