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Speakers for bottlehead Sex amp

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Last Xmas I purchased a bottlehead sex amp kit for my son in law as a joint project. This year I would like to procure some small speakers for the Sex amp to be used in near field as desktop speakers.

I have read the rave reviews for the Blumenstein speakers, which I can afford, but would prefer to build our own.

I have seen the plans for several speakers based on the Fostex FF85wk...the uFonken, the uFonken plus, and the Harpoon. We have rudimentary carpentry skils, so the uFonken SET might be too difficult.

Dave, since you seem to be "the man" on this subject, I would appreciate any guidance on this decision. Do you have any experience/feedback using any with a sex amp?

I have no problems paying for the plans. Are any of those mentioned available as flat packs?

Thank you,
John
 
I’ve owned / built quite a few boxes for the 85, and would suggest the uFonken plus for a first time project, particularly for a near field/desktop application. Dave may have some flatpack kits for these that I know are a pretty easy build. IIRC, they are maple veneer faced Baltic Birch type plywood, which if not contaminated with glue seepage during assembly n takes clear top coats like lacquer, shellac or waxes very nicely.

The closest to the type/power level of the SEX amps that we’ve heard driving smaller Fostex speakers would be the old Paramour monoblocks (2A3). You might want to consider the slightly larger FF105WK, for which there should be several similar enclosure designs - my favorite of which is the Woden Baby Lab - I forget for the moment what it’s called. While this series is physically larger than the micro / milli-Fonkens, for my money they deliver deeper bass extension.
 
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crisb,

Thx for your input. We were thinking these would reside on his desktop rather than on separate speaker stands, so I doubt we'd want to exceed the size of the ufonken plus.
If flat packs are available, great. If not we can handle to carpentry needed. I suppose Dave will weigh in at some point.
 
frugal-phile™
Joined 2001
Paid Member
Chris poked me, i’m here.

The uFonkens give outstanding performance, perhaps just piped by the Alpair 5.2 (in the same/different venting boxes). I do have uFonken, uFonkenPlus & uMar-KenPlus flat-paks.

Nearfield, the lowish sensitivity is probably not a real issue.

To gain a few dB you couls go with the FF105wk, which also goes a bit lower, but at the sacrifice of a box 2x as large and a tiny bit of mid/top fidelity.

One interesting driver that gets good reviews and is a but more efficient yet is the Faital 3E22. I have a set of uMar-Ken modified for this driver (but i am a bit cautious havingbeen burned by recomendations by the same group). It will have to sacrifice some bass to get greater sensitivity in the same size box. It is also a cheaper driver.

dave
 
Dave,

I'd like more information on the available flat packs and required drivers/parts (I understand you sell them as well) for either the ufonken or ufonken plus. What is the best way for further communication...here, PM, or by visiting Planet 10?

I would need all the necessary items in time for xmas.

Which would you recommend between the standard and plus ufonken?

Thank you,

John
 
FYI,

I contacted Dave, who was very helpful. I ordered a flat pack and drivers for the ufonken plus. I look forward to building them with my son-in-law after Xmas.

Thanks to Chrisb for his input and for poking Dave.

I now have another question. My son in law’s birthday is in March and I am already considering another project for us...building a small sub to compliment the ufonkens plus. So, I am looking for suggestions for that. I would again like a diy instead of prebuilt.

I saw on the bottlehead forum where one had paired his ufonken plus with a Dayton plate amp and 8 inch driver in a sealed box. Would that be the ticket?

Thanks so much for any input.

John
 
Even some of the 6 1/2” woofers would be worth considering, and you’d improve overall performance even more so if you’re able to implement a HP filter on the Fostex - say around 100Hz or so. But as I recall, the S.E.X. amp is an integrated, so absent an upstream master volume control, that’d be a bit tricky to implement.
 
Thinking about this a bit more - it might be worth posting a query on the Bottlehead forum, or by direct e-mail to either Paul or Dan as to whether it’d be possible to add a pre-amp level output - i.e before the output stage. Provided your source(s) have sufficient output, that should allow insertion of HP filter via adjusting value of existing coupling caps - or adding additional lower value caps in series with bypass - to effectively achieve a PLLXO. I did exactly this about 15 yrs ago on a pair of Decware Zen C amps to bi-amp a custom DIY build (Heil AMTs and bipolar Fostex woofers now long out of production) and it worked like a charm.
 
Chrisb

Yes,

I did post the same question on the bottlehead forum under the speakers section.

I appreciate your suggestion, although honestly, I only vaguely understand what you are saying.

As neophytes, I don’t think we’d want to tamper with the stock design.

John
 
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