Hot Rodded Bottlehead S.E.X.

H

HF9

New member
I completed my third Bottlehead kit last night. The next one will hopefully be the DAC when that comes out :)

Here's my Bottlehead S.E.X. Kit featuring:


  • MagneQuest Transformers
    C4S Upgrade
    Cardas / Kimber / Neotech wiring
    Film power bypass caps
    Cardas RCAs and copper binding posts
    Neutrik locking plug
    Kiwame and Shinkoh resistors in a few places
    Teflon tube sockets and PCBs
    Vintage pilot light
    GoldPoint stepped attenuator

LL


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Full build details and more photos are available at: http://www.diyaudioblog.com/2011/03/bottlehead-single-ended-experimenters.html

 
Bryan, that looks great!

I particularly like the way you mounted the big caps on standoffs instead of letting them flap in the breeze.
Once you get accustomed to the sound, try a pair of 'coin base' Sylvanias....they're the best I've heard so far.

Mike
 
That is awesome!  And speaking of awesome, that is pretty awesome power wire coming to the IEC connector.

Can you give a little background on the AmpOhm Caps?  I'm a cap junkie!
 
Thanks for the compliments as always fellas ;) Mike, I've always been a sucker for Sylvanias, I'll have to track them down.

Grainger, the power wire was some leftover Vampire interconnect wire I had in the tool-box, it's a nice healthy gauge, 20 or so IIRC with a braided copper shield. The AmpOhm caps are highly rated from the Humble Homemade HiFi test. They're no longer in production, and TheTubeStore is the only place that stocks them in the U.S. with dwindling supplies. They have a variety of types, including aluminum, tin and copper in both paper and wax. They are ridiculously sized though, as you can see ;) Prices are good compared to other boutique caps.
 
I got to have a listen to this yesterday, Eileen got me a replacement set of RCA tubes, and I had a pair of Sylvania coin-bases arrive from another supplier. Sound is really excellent, even before burn-in. No lack in the bass department, a nice powerful sound with just enough detail.
 
Bryan, you continue to amaze with your DIYer skills. One day I will have the monies to see if you would be willing to build a kit for me. Maybe if I sold the HifiMAN HM-801 and HM-602 units I could have $$$. Enjoy the fruits of your labor.
 
Thanks Miguel! Building had been on my bucket list for a while, it's something that I always envied that other people could do. I finally decided to try it with a MiniMAX last June, and it's become a really enjoyable hobby :)
 
Beautiful build. In my opinion the best S.E.X. ever! You have a real talent my friend!
I have a couple of questions:
1. Where did you get the thin leather for the OPTs? Do they offer different colors?
    How did you install the leather and get a tight fit? I have tried threading thick
    ribbon around the bobbins and thru the frame but tying it off just made a mess.
    I was hopeing to paint the bobbins but Mike on the Magnaquest forum strongly
    discouraged me from painting the bobbins.
2. I really like the way that you mounted the big caps. It appears that you have a
  small piece of plastic mounted on top of the 2 inch posts. Are these screwed or
  glued into the post? Where did you purchase them?


        Thanks!

        James
 
wylymon said:
Where did you get the thin leather for the OPTs? Do they offer different colors?
    How did you install the leather and get a tight fit? I have tried threading thick
    ribbon around the bobbins and thru the frame but tying it off just made a mess.
    I was hopeing to paint the bobbins but Mike on the Magnaquest forum strongly
    discouraged me from painting the bobbins.
Click to expand...

I've done a few this way. You can get the leather at Michael's art and craft supply stores. Just cut it to size and glue it on with 3M 77 spray or similar. It doesn't have to be one continuous piece. Just cut one for each side of the transformer, long enough to extend into the gap between the coil and lams at each end.

Another interesting approach is to use the flocking kits they sell. You paint a thick paint onto the coil and then you "spray" synthetic fibers of the same color onto the wet paint. I did a bunch of these with Mike several years ago, custom cobalt trannies with black flocking and polished and lacquered brass channel frames, and printed labels with the customer's name.
 
Doc B. said:
wylymon said:
Where did you get the thin leather for the OPTs? Do they offer different colors?
    How did you install the leather and get a tight fit? I have tried threading thick
    ribbon around the bobbins and thru the frame but tying it off just made a mess...
Click to expand...

I've done a few this way. You can get the leather at Michael's art and craft supply stores. Just cut it to size and glue it on with 3M 77 spray or similar. It doesn't have to be one continuous piece. Just cut one for each side of the transformer, long enough to extend into the gap between the coil and lams at each end.
Click to expand...

Yup, that's what I did. I remember stumbling upon the idea here on the Bottlehead forums from one of your posts Doc. I bought a small piece of leather on ebay and trimmed four pieces, then used some adhesive to keep them in place. The guy had a number of colors, all natural though. Very interesting rust finish on the metal Doc, I tend to like the texture of rusted metal when I see it used in modern art.

The plastic pieces screwed on top of the aluminum standoffs are from PartsExpress, they are in the zip tie section :) http://www.parts-express.com/pe/showdetl.cfm?Partnumber=080-512
 
Hey there Grainger.....I'm running some of the ampohm aluminum in oil in my dynaco mark iii's as interstage caps and some of the polyester in oil and aluminum as interstage in my  own S.E.X. amp.  In both circumstances I'd highly recommend them.  A lot like mundorf silver/oil.  They are great at pulling out the context of the recording location such as is the case in live performances.  I listened to Leonard Cohen's "I'm your man" tribute CD the other night and was just floored....felt like I had a sense of the recording space.  They are hard to get hold of as ampohm has unfortunately gone under.  I have a couple of the polyesters I can't wait to use in my Klipsch Forte midrange crossover.  Trying to decide on whether to pick up while I can a set of 2.2uF while I can as I'm finally on the path to putting in the upgrade iron.  Anxious to see what both do.

BTW...great job HF9....looks awesome!
 
Japhy said:
Hey there Grainger.....I'm running some of the ampohm aluminum in oil in my dynaco mark iii's as interstage caps and some of the polyester in oil and aluminum as interstage in my  own S.E.X. amp.  In both circumstances I'd highly recommend them.  A lot like mundorf silver/oil.  .  .  .  They are hard to get hold of as ampohm has unfortunately gone under.  I have a couple of the polyesters I can't wait to use in my Klipsch Forte midrange crossover.  Trying to decide on whether to pick up while I can a set of 2.2uF while I can as I'm finally on the path to putting in the upgrade iron.  Anxious to see what both do.

BTW...great job HF9....looks awesome!
Click to expand...

I guess I better look into these quick before they have gone the way of Black Gate.
 
That would be a good call. There's only the one supplier in the U.S. and it's pretty typical for them to run out of certain values. I did read another review that the Mundorf Silver/Oils are slightly better, but the AmpOhms are quite a bit cheaper.
 
HF9 wrote:

    I was hopeing to paint the bobbins but Mike on the Magnaquest forum strongly
    discouraged me from painting the bobbins.

I always thought this was ok as long as you used poly paint.

Was there ny particular reason given as to why?

I've got my MQ nickel OPTs for my s.e.x. all prepped and the channel frames painted gold and just waiting to apply a glos black finish on the bobbin and coil.  The paint is VHT high gloss quick-poly.

I also thought I've heard of others painting their transformers, so can anybody confirm this?

Thanks,

Jim
 
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