Beginner's Luck

[DanP]

Folks on this forum have been very kind to answer questions, so I thought I would report something that might interest others.  I've enjoyed audio for many years and I have played a number of instruments, so I knew that sooner or later i would like to experiment with a SET amp and single driver speaker.  I started modestly by purchasing an already assembled, older SEX amp.  I paired it with a single driver, bookshelf speaker from a well-known manufacturer, but I was not impressed.  The speaker did not have much depth or weight and the folks on this forum explained that the early SEX amps were a bit bass-shy as well.  However, I did hear a very nice midrange, so decided to make my own single drivers.  I had a pair of 30 year old Proac Tablettes in which both tweeters had died, but the cabinets were still beautiful. The cabinet volume would work well with the Fostex FE103En, so I cut some new baffles and dropped in a set of these speakers.  It took some experimentation to determine the right amount of cabinet damping.  I ended up using 1 sheet of sound damping foam from Parts Express (part#260-516).  It also took a bit of experimentation to determine the right port length.  I ended up with a bit of a bass bump at about 90Hz, but this turned out to work great with the SEX amp.  Last I put a bit of felt around the speakers since I did not try to flush mount the speakers. I am using a small sub and put the speakers on plinths close to the ground, angled up and about 10 inches from the wall. The speakers did not take nearly as long to break in as others have suggested.  The effect is magical with the SEX amp.  I have a fairly small, lively room and output has not been an issue.  Not sure if this was beginner's luck, but if it is, I'm happy to have lucked out.  Thanks for everyone's help.

[Natural Sound]

Great story, Dan! Its fun to experiment like that. Especially when the experiment has such great success like yours. I'd love to see a picture if you have one.

Quick question. Which of the earlier S.E.X amps do you have? Is it a pair of monoblocks or the stereo S.E.X. with a volume control up front?

http://www.bottlehead.com/smf/index.php/topic,4188.0.html

[Clark B.]

Congrats! 

I have been fortunate enough to have a few cases of beginners luck with some of my older custom speaker designs and I can really share the sentiment. 

Granted - Even the old bottlehead sex was a great amp and mine still stands up to the best desktop amps from others (except the 2.1 C4S!).  It is phenomenally chilled out and relaxing to listen to.

I used to make speakers with the 103En driver and I liked them alot.  they were able to get surprisingly loud and not totally break up or sound very harsh.

I ended up landing on the FE83En however because of my unique priorities.  They have about the same frequency range but just don't get as loud as the 103En do.  I found that most of my own listening and others' listening (every day, not at dance parties and such) were well within the volume range of the 83En, and they just had a very pleasant overall character. 

I'm so excited to see folks like you still discovering the magic of fullrange/SET systems.  Keep enjoying, it only gets better with time on the drivers!

Best,

Clark

[DanP]

I think this amp is about 5 years old.  It is a stereo amp with the volume control in the front.  I love having the inputs and the speaker terminals on the top deck instead of in the back.  I use anti cables which are not easy to work with and it is great being able to see the connecting terminals easily. I also like having the headphone jack (although this is not the self-shorting one) because I use headphones to evaluate components that produce small sonic changes, such as interconnects. I have attached a pic of one of the speakers.  The reason the felt is cut at odd angles is so it would fit under the speaker grill.  My source is an Oppo BDP-95 which I have nothing but good things to say about.
Dan
PS may not let me attach pic.  I'll try again.

[DanP]

Tried multiple formats but was unable to attach picture. Program said the attachment was too large.

[DanP]

Clark,
Thanks for your kind words.  Your speakers helped serve as an inspiration for my attempt.
Dan

[Paul Birkeland]

Tried multiple formats but was unable to attach picture. Program said the attachment was too large.

You can generally just decrease the resolution of the picture when you take it (be it on the phone or with a camera).

[adamct]

Depending on your image editing software, you might also be able to reduce the "quality level" of the JPEG. Try selecting a quality level around 60-70% for substantial file size reductions without readily noticeable image artifacts.

Best regards,
Adam

[Clark B.]

Clark,
Thanks for your kind words.  Your speakers helped serve as an inspiration for my attempt.
Dan

Thanks, Dan.  I'm honored that I contributed to your inspiraton to try out small FR bookshelfs.  On a side note, with the speakers you'd bought from that company (whatever they were), if they were decently sized FR drivers, you can count on a potentially significantly long break in time - and the difference in sound can be HUGE.  For instance, on the FE83En, at around the 40-50 hour mark they can sound their worst... and then at 100 they start to settle down for the long haul and really start to make bass.

I recently noticed, for instance, that when I was running a line array of Orcas - some with well broken in drivers and with some brand new, that there was (measured visually) a 2-3 fold difference in excursionrelative to which driver I was looking at.  The broken in ones simply moved more air even thought they were getting EXACTLY the same power levels.  Its food for thought about FR drivers in general, and especially for the larger ones (with bigger surrounds/spiders to break in).  I've started putting solid hours on our pieces until they ship.  It really helps to get people down the road a few miles before you let them take the wheel.

Cheers,

Clark

[4krow]

As much as I enjoy building electronics, Speakers have to be by far the most amazing/disappointing projects ever! And the driver that you mentioned is one that I have to admit has the kind of midrange detail that I hope for. I also have ended up with single driver speakers. Mine are from Decware. I have no plans to change, and the only regret is that I couldn't have found them sooner! Congrats on getting the best as soon as you did.

[DanP]

Another try at attaching photo.

[Grainger49]

Dan,

I think you have your Orca upside down. 

[DanP]

Funny, but as I told Clark, when I heard the raves that his speakers were getting and I looked at the driver and cabinet dimensions it gave me confidence to give it a try.  But in all seriousness placement of the driver was one of the biggest issues I wrestled with.  The location of the bass driver in the original Proac speaker was a bit lower, but they had to make room for the tweeter and the port.  I toyed with having all 4 distances to an edge of the cabinet different, but in the end I kept the speaker centered left to right and just increased the distance from the bottom edge of the cabinet a bit.  The port is at the top, but I did listen to the speakers upside down, and didn't think it was better, and possibly was worse.  The thing that really surprised my was the cabinet damping.  I decided to start with none and actually found the sound to be pretty good.  I then tried placing 1 piece of eggcrate mattress foam at the back of the cabinet.  This completely sucked the life out of the speakers, so I decided I had better try something designed for listening and not for sleeping.  I placed one piece of acoustic foam against the back of the speaker and this smoothed the sound out while allowing the speakers to still sound alive. I also placed some thin foam on the surface of the speaker magnets, but I really have no idea if this created any sonic improvement.  The other surprise for me was comparing the SEX amp to a traditional 60 watt tube PP amp with KT88 tubes.  Very difficult to describe the aural experience in words, but I suspect folks on this forum will understand why I prefer the sound with the SEX amp.  However, as I mentioned in my first post, the SEX amp did not sound good with the commercial single drivers I tried first, so I think there is some sort of sweet spot where the speaker and the amp compliment each other and I consider myself lucky to have found it relatively quickly.
Dan

[Clark B.]

Dan,

What's going on here is: Parallelism between amplifier and speaker design.  Using low watt output, Zero NFB Single Ended Triodes is the greatest "parallel" to using low watt input, Zero BSC, Single fullrange drivers.  All is connected with a single uninterrupted piece of wire (even considering the OPT's).  The maximum life with the minimal total energy produced.  And the compromise here is that you really can't get things ultra loud with this path (unless you can tolerate a rising frequency response which I can't).  I personally like to just kick back and relax when I listen to my speaker system and I know other people who do as well so I think that there's a bit of a common-hood in our personalities as listeners going on in the BH/single driver community.

Cheers!

-Clark