looking for opinions and info on original S.E.X. kit

[sl-15]

i have the chance of buying an original sex amp kit. i think it is from mid 1996 and came as two monoblocks. i did a lot of reading in the VALVE magazine archive. from my understanding the original sex kit could be bettered quite a bit with upgraded output transformers. it looks like it really changed the frequency response and output power to the better. but i am unsure if the kit ever came with these transformers or if they had to be ordered as an upgrade and if they might be still available today?i am trying to figure out if i want to give these stock amps a shot even if the upgraded transformers are not available anymore. do some people here still use or have their original sex kits? i guess i am looking for words of encouragement and some more info so i can make up my mind. i guess one of the strong points is that it is an experimenters kit and gives one endless possibilities of tinkering around and learning? thanks for any input.

 

[Paul Joppa]

The transformer most often mentioned is the Magnequest TFA-204, and all but the very earliest OriginalSEX amps were drilled for mounting that transformer. Bottlehead never supplied it directly; but you can still purchase them from Magnequest  http://www.magnequest.us/

There are of course other mods that look desirable from today's perspective. The amp went through a number of variations, so any advice on modifications beyond the transformer transplant would start with identifying what you have. A clear photograph of the underside and topside would be a good place to start!

My personal OriginalSEX amps have not been in use for more than a decade, but they was sounding good when I replaced them. They have a guitar amp output transformer with 5K impedance for which I modified the power supply and the operating point of the tubes. The last time I actually wrote down anything on upgrading the amp was in 1997, it's in the October VALVE.  They are not exactly detailed instructions! In that article you will see the first time I suggested converting the monoblock to stereo; that was the genesis for the current SEX amps, first introduced nearly a decade later.

 

[sl-15]

thanks for the reply paul. i am actually looking at an original kit- unassembled. so i will have all the fun of putting it together and then following all the different update paths. thanks for clearing up the transformer question it is good to know that those are still available.

 

[najo49]

i bought a set of originals a few months ago. Keep them they are a lot of fun and they snd great too. I have done the mods paul mentioned and the c4s too, There a 3 issues of valve that are a must. vol 4 no. 9 vol 6 No 1 and 1 more that if you are interested I can give it to you, its the one with brainiacs sex changes article in it.

 

[sl-15]

hi najo,
i just wanted to check in if you got my PM from yesterday. i went ahead and got the original sex amp kit. although i was second guessing my decision i am now really excited about them. i am not sure what version i will be getting but i think it is one of the very early production runs. i am planning on going through the suggested upgrades one at a time. not sure yet if i eventually want to invest in the magnequest transformers, he still sells them and they go for $150 a piece. anyways the more i look the more information i find out there but it seems rather confusing not having my kit yet. because you just went through all these uprades already it would be nice if i could contact you for advise and tips if i need it. i downloaded all the valve mags already and the articles that you pointed out are helpful. where is the one that you mentioned with brainiacs sex change article? thanks