Bottlehead Forum

Bottlehead Kits => S.E.X. Kit => Topic started by: Rayvolution on July 11, 2015, 04:41:13 PM

Title: S.E.X Manual
Post by: Rayvolution on July 11, 2015, 04:41:13 PM

I misplaced the CD for my S.E.X kit and the flashdrive I had it on fried. Is there any way I could get a copy? I want to switch from 32 ohm to 4 or 8 ohm on the OT.

Title: Re: S.E.X Manual
Post by: DDDamian on July 17, 2015, 10:53:57 AM

I think this was answered on Head-Fi?

Title: Re: S.E.X Manual
Post by: Paul Joppa on July 17, 2015, 05:39:09 PM

Here are the wiring instructions - sorry for the late reply, I had to convert from another format. The numbers are the terminal numbers embossed on the bobbin.

Note that I gave a wiring for 24 ohms - not included on the impedance switch  :^)

Wiring ==================
4K:2 ohms or 8K:4 ohms
 
positive   jumper   negative      
3,6           3-6, 2-7   2,7   
=======================
4K:4 ohms or 8K:8 ohms
 
positive   jumper   negative      
1,8           1-8, 2-7   2,7   
=======================
4K:8 ohms or 8K:16 ohms
 
positive   jumper   negative      
3           2-6           7   
=======================
4K:12 ohms or 8K:24 ohms
 
positive   jumper   negative      
3          1-2            7   
=======================
4K:16 ohms or 8K:32 ohms
 
positive   jumper   negative      
8          1-2           7   

=======================

Title: Re: S.E.X Manual
Post by: mcandmar on July 17, 2015, 05:52:09 PM

I got a question :)  What do you mean by 4K or 8K, i thought the OT-2's were 4k?

Cheers,

Mark

Title: Re: S.E.X Manual
Post by: Paul Joppa on July 17, 2015, 08:51:35 PM

The OT-2 was designed to work with 4000 to 8000 ohms primary impedance. It has four possible secondary impedances so it can work with 4, 8, or 16 ohm loads in both cases. It took me a while to make a design that I was happy with at both impedances, but it produces cost savings that apply to several Bottlehead products.

Technically, bass power handling is set by the transformer's maximum AC voltage. So for the SEX amp (8000 ohms) it handles 2 watts at 25Hz, and for the Stereomour (4000 ohms) it will handle 4 watts at 25Hz - the voltage is the same. The only penalty is that 4000 ohms the copper losses are larger than at 8000 ohms - but still only 0.5dB.