Hey Guys,
I am in the process of building my first tube amp, a single ended KT88 based on Alex Gendrano's design with some minor changes influenced by porkchop's design. Anyway, I'm going to need some speakers for it. My budget is 1,000 USD for amp and speakers, and I'm blowing 550 on the amp. I emailed Eric over at Tekton speakers, and he recommended his 8.1, built around Fostex's FE207E. At 440 a pair they are at the top end of my price range. My real question is, for around 450 dollars can I build something better for this amp? My woodworking skills aren't nearly as good as my soldering skills, but I know my way around a chopsaw. I'll mostly be listening in the near field, and am mostly interested in a bookcase configuration. Output transformers are Edcor's CXSE25-8-5k. Let me know what you think. Thanks!
- Andrew
I am in the process of building my first tube amp, a single ended KT88 based on Alex Gendrano's design with some minor changes influenced by porkchop's design. Anyway, I'm going to need some speakers for it. My budget is 1,000 USD for amp and speakers, and I'm blowing 550 on the amp. I emailed Eric over at Tekton speakers, and he recommended his 8.1, built around Fostex's FE207E. At 440 a pair they are at the top end of my price range. My real question is, for around 450 dollars can I build something better for this amp? My woodworking skills aren't nearly as good as my soldering skills, but I know my way around a chopsaw. I'll mostly be listening in the near field, and am mostly interested in a bookcase configuration. Output transformers are Edcor's CXSE25-8-5k. Let me know what you think. Thanks!
- Andrew
breakthastatic said:
Well, yes, with minimal woodworking skills, you certainly get better bang for your buck (i.e. a lot less than $450 driver/material cost) - although "a bookcase configuration" and any enclosure worth its salt for the FE207E could be mutually exclusive.
For near field/small room use, you might well get better synergy with the FE167, or even the FE127/ FX120. There are numerous excellent designs for any of these drivers which handily outperform the standard Fostex recommended enclosures*. While excellent value for a commercial product, IINM, most of the Tekton designs don't break any new ground.
*you could certainly do worse than the library of collected enclosure plans at
http://www.planet10-hifi.com/boxes-fostex.html
full disclosure - see the signature line below
I have a set of Tekton Design speakers which came with FE126E's, and I swapped them out for FE127eN. They are visually much better than the boxes I make myself. Eric is an excellent guy to deal with, in my experience.
The question is do you want visual appeal in a nice compact enclosure, or are you willing to do what's needed to wring out that last ounce of performance? If you want the second option, you need to big a bigger box than Eric's 8.1 (not sure of the exact volume but it looks around 25 liters to my untrained eye, whereas you can go up to 40-ish liters if you want to tune the bass response).
Regarding the bass response, it's not really how low it goes (though it will go lower in a bigger box). It's the Q of the bass, i.e. whether there's a bump, a flat response and then steep rolloff, or a slow, gradual rolloff that mates well with the tendency of rooms to reinforce the bass (room gain).
It's impossible to say what will work for you, your room and musical tastes, but be aware that a bump in the bass (high Q) can sound incredibly annoying, boomy and "one note" in some circumstances. That applies to any cabinent, not specifically the Tekton but smaller BR's do tend to have a higher Q than larger cabs, sort of by definition. Some cure this by stuffing the port, so maybe that's an option.
Regarding BSC, my Tektons did not come with a circuit, another fellow on AudioCircle did get a BSC in his. I have no complaint of course, just saying you might want to check because (a) if you go with bookshelf placement, presumably you don't want a standard BSC (you probably want none or just barely a touch depending on many factors), and (b) if you end up putting them on stands, pulled into the room a bit, you almost definitely need BSC. A smallish BR with a bump in the response is a way to do BSC without any circuit but that's tricky t o engineer (getting the bump to occur precisely where the baffle width causes the bass response to start dropping, thus achieving a flat response).
If you do get the Tekton, and if it does have BSC, ask Eric to put a bypass cap in the circuit (so the BSC attenuates above a certain low frequency, but the cap ceases the attenuation at a certain high frequency). The FE207E rolls off around 14k so you don't want to lose any of that precious high end (and a cap is cheaper than a supertweeter).
If you do decide to build your own, and you can go to 35 liters, Bob Brines' design is the champ, and you could buy a flat-pack but it would take you just a bit out of your budget so you might scale down to the 6.5" Fostex. http://www.geocities.com/rbrines1/
The question is do you want visual appeal in a nice compact enclosure, or are you willing to do what's needed to wring out that last ounce of performance? If you want the second option, you need to big a bigger box than Eric's 8.1 (not sure of the exact volume but it looks around 25 liters to my untrained eye, whereas you can go up to 40-ish liters if you want to tune the bass response).
Regarding the bass response, it's not really how low it goes (though it will go lower in a bigger box). It's the Q of the bass, i.e. whether there's a bump, a flat response and then steep rolloff, or a slow, gradual rolloff that mates well with the tendency of rooms to reinforce the bass (room gain).
It's impossible to say what will work for you, your room and musical tastes, but be aware that a bump in the bass (high Q) can sound incredibly annoying, boomy and "one note" in some circumstances. That applies to any cabinent, not specifically the Tekton but smaller BR's do tend to have a higher Q than larger cabs, sort of by definition. Some cure this by stuffing the port, so maybe that's an option.
Regarding BSC, my Tektons did not come with a circuit, another fellow on AudioCircle did get a BSC in his. I have no complaint of course, just saying you might want to check because (a) if you go with bookshelf placement, presumably you don't want a standard BSC (you probably want none or just barely a touch depending on many factors), and (b) if you end up putting them on stands, pulled into the room a bit, you almost definitely need BSC. A smallish BR with a bump in the response is a way to do BSC without any circuit but that's tricky t o engineer (getting the bump to occur precisely where the baffle width causes the bass response to start dropping, thus achieving a flat response).
If you do get the Tekton, and if it does have BSC, ask Eric to put a bypass cap in the circuit (so the BSC attenuates above a certain low frequency, but the cap ceases the attenuation at a certain high frequency). The FE207E rolls off around 14k so you don't want to lose any of that precious high end (and a cap is cheaper than a supertweeter).
If you do decide to build your own, and you can go to 35 liters, Bob Brines' design is the champ, and you could buy a flat-pack but it would take you just a bit out of your budget so you might scale down to the 6.5" Fostex. http://www.geocities.com/rbrines1/
interesting robert,
i forgot bob brines was making bookshelf speakers
http://www.geocities.com/rbrines1/Products.html
but that little FE207 bookshelf jog shows a F3 of 43Hz.
not bad eh!
i forgot bob brines was making bookshelf speakers
http://www.geocities.com/rbrines1/Products.html
but that little FE207 bookshelf jog shows a F3 of 43Hz.
not bad eh!
You may want to consider the Audio Nirvana line of drivers. I have no direct experience with them, but they appear to have high efficiencies and decent full range output. http://www.commonsenseaudio.com/
You could also go with a set of eNabled drivers from planet10-hifi. They will get the most out of the 2.5W and will be in your price range.
You could also go with a set of eNabled drivers from planet10-hifi. They will get the most out of the 2.5W and will be in your price range.
Man, I'm not the guy to ask about bookshelves...
I like going the other direction big higher efficiency speakers, low powered amps...
But since you ask; just thinking about what's been mentioned, like you already said, the FE207s just break the budget don't they? ~$195 for drivers + $295 for flat packs from Brines = $490.
Doesn't leave the $26 for the Ed Lafontaine EnABL kit either...
But we don't know what the wood working restrictions are; if flat packs weren't needed this one would still come in under budget. It's a pretty simple "box with holes in it?"
And why the bookshelf restriction--are they going on bookshelves?
or on stands?
Would something w/ the same foot print be acceptable?
I would really prefer the ML TL to the bass reflex, bass not only goes down to F3 = 35, but it's better quality...
And I like horns so much better than TLs I gave a good pair of FE206 TLs away last week...
Back to bookshelves for KT88s--
A pair of FE167 is $170; would come in under budget, even after EnABLing.
MANY possibilities, same as above, or for a little more work, a blh?
Actually, I've got a pair of FE167s stashed I'd like to try in a pair of karlsons.
or--
(as you already know, what I did,) For $200, bought a pair of 108s & a couple sheets of plywood. All simple, straight cuts, built a pair of Nagoka Swans.
Look kinda like very small bookshelf speakers on a stand w/ a box base?
I've never tried anything as powerful as a KT88 amp w/ them though...
and they're less efficient than any of the other options discussed...
Robert, are the Tekton speakers the pair of BRs you brought over w/ one EnaBLEd driver for the comparison?
I like going the other direction big higher efficiency speakers, low powered amps...
But since you ask; just thinking about what's been mentioned, like you already said, the FE207s just break the budget don't they? ~$195 for drivers + $295 for flat packs from Brines = $490.
Doesn't leave the $26 for the Ed Lafontaine EnABL kit either...
But we don't know what the wood working restrictions are; if flat packs weren't needed this one would still come in under budget. It's a pretty simple "box with holes in it?"
And why the bookshelf restriction--are they going on bookshelves?
or on stands?
Would something w/ the same foot print be acceptable?
I would really prefer the ML TL to the bass reflex, bass not only goes down to F3 = 35, but it's better quality...
And I like horns so much better than TLs I gave a good pair of FE206 TLs away last week...
Back to bookshelves for KT88s--
A pair of FE167 is $170; would come in under budget, even after EnABLing.
MANY possibilities, same as above, or for a little more work, a blh?
Actually, I've got a pair of FE167s stashed I'd like to try in a pair of karlsons.
or--
(as you already know, what I did,) For $200, bought a pair of 108s & a couple sheets of plywood. All simple, straight cuts, built a pair of Nagoka Swans.
Look kinda like very small bookshelf speakers on a stand w/ a box base?
I've never tried anything as powerful as a KT88 amp w/ them though...
and they're less efficient than any of the other options discussed...
Robert, are the Tekton speakers the pair of BRs you brought over w/ one EnaBLEd driver for the comparison?
Hi Robert, yes those were indeed the Tektons. I agree that an MLTL would sound (a lot) better than a BR. The Swans would sound vastly better and are super low-profile (and moveable).
I guess another crazy, lazy option, if ultra-compactness is required (and box-building is not a forte) would be to just go get some old boxes, find out their volume and stick some fine drivers in there, and use WinISD to calculate a port size. In that case, it might be good to have one of the drivers that are higher excursion. (The Mark Audio CHR-70's are certainly affordable, haven't had the pleasure of hearing them yet and they are of course lower efficiency than the FE207E but in a smaller cab, would perhaps do more bass -- just guessing, haven't heard them or played with them yet).
I guess another crazy, lazy option, if ultra-compactness is required (and box-building is not a forte) would be to just go get some old boxes, find out their volume and stick some fine drivers in there, and use WinISD to calculate a port size. In that case, it might be good to have one of the drivers that are higher excursion. (The Mark Audio CHR-70's are certainly affordable, haven't had the pleasure of hearing them yet and they are of course lower efficiency than the FE207E but in a smaller cab, would perhaps do more bass -- just guessing, haven't heard them or played with them yet).
I haven't heard many BRs or Aperiodics that I was impressed with actually. Merlins, can't think of anything else off hand... Kharmas can image really well, but have other problems. & they're both pretty High $.
If I were stuck w/ using a small box for some reason, I'd seriously consider a sealed one.
Easiest, and most compact, if that's a goal.
And can just add subs for bass.
I haven't heard Mark Audio's either, but only read good things about them.
AND,
If he's married to KT88, there's more than enough power for a pair of Jordan 92s. I forgot about those, but very small, and they can sound VERY nice in the right cab.
Heard a pair @ RMAF last year playing vinyl, MONO, through a big homegrown tube amp, was one of the best sounding rooms there I thought. Close to the mega-buck feastrex nessies for a fraction of the $.
Yeah, if I needed something low efficiency, for a higher powered tube amp, THAT'S what I'd build.
(oops, small & thin, but ends up floor standing again...)
If I were stuck w/ using a small box for some reason, I'd seriously consider a sealed one.
Easiest, and most compact, if that's a goal.
And can just add subs for bass.
I haven't heard Mark Audio's either, but only read good things about them.
AND,
If he's married to KT88, there's more than enough power for a pair of Jordan 92s. I forgot about those, but very small, and they can sound VERY nice in the right cab.
Heard a pair @ RMAF last year playing vinyl, MONO, through a big homegrown tube amp, was one of the best sounding rooms there I thought. Close to the mega-buck feastrex nessies for a fraction of the $.
Yeah, if I needed something low efficiency, for a higher powered tube amp, THAT'S what I'd build.
(oops, small & thin, but ends up floor standing again...)
I got my first listen to factory fresh, bone stock Alpair 10's in a pair of 14 liter semi-aperiodic boxes yesterday evening. I'll reserve judgment on the few quibbles I had with their performance compared to a reference standard FE127eN, until after several hundred hours of break-in.
For near field listening with the amount of power you could expect from the KT88's, the Alpairs could be another great candidate.
The CHR70s are a great bargain, but so far I've only heard them in mini monitor sized sealed boxes (circa 4-5 liters - certainly compact enough for bookcase or desk-top). They definitely have some limitations - primarily sensitivity and bass response, and for the experimental types, certainly respond very well to EnABL treatment.
So that's a helluva range from which to choose - 60mm to 200mm, 4~5 liters to 35+
Having said all that, if you're wary of the performance of any of the smaller diameter drivers ( FE103E/FE127/CHR70, etc), I'd look at the FE167 as a great compromise. If you can't avail yourself of a buddy's woodworking skills, Bob could probably do you a flat pack, and if you're truly using them in a bookcase or very near to a rear wall boundary, a BSC is probably not required. With EnABL treatment and phase plugs, these are very special.
For near field listening with the amount of power you could expect from the KT88's, the Alpairs could be another great candidate.
The CHR70s are a great bargain, but so far I've only heard them in mini monitor sized sealed boxes (circa 4-5 liters - certainly compact enough for bookcase or desk-top). They definitely have some limitations - primarily sensitivity and bass response, and for the experimental types, certainly respond very well to EnABL treatment.
So that's a helluva range from which to choose - 60mm to 200mm, 4~5 liters to 35+
Having said all that, if you're wary of the performance of any of the smaller diameter drivers ( FE103E/FE127/CHR70, etc), I'd look at the FE167 as a great compromise. If you can't avail yourself of a buddy's woodworking skills, Bob could probably do you a flat pack, and if you're truly using them in a bookcase or very near to a rear wall boundary, a BSC is probably not required. With EnABL treatment and phase plugs, these are very special.
Yeah the Brine flat packs will probably put me out of my price range. The speakers will most likely be going on my desk next to my computer monitor. I live in a small apartment and don't really have room for stands. Have any of you built Brine designs? If I bought the plan whats the hardest part involved (may be a relative question). Do you think I can get away with not stand mounting them? How hard would it be to open up a Tekton and put in a circuit to modify it?
chrisb said:
First comment I've seen on EnABL'ing the CHR70. If correct, this driver is killer. I may have to order the kit and give it a try.
I do have direct CHR70 experience and I only agree with sensitivity being an issue for a SE valve amp for anything but nearfield listening. The bass output is not a problem with this driver (although your amp/driver combo may not be able to reproduce it well.) My dual-chamber reflex design, which I use for nearfield, has a solid mid-40Hz F3 and is very accurate in reproduction of the lower octaves using my SS amp. Over-all, I wouldn't recommend it for your situation because of the low sensitivity.
For the kind of placement being suggested, the CHR might do the trick (and any sealed box 4 litres plus should do), but the more efficient mFonken might be a better call. With the nearfield desktop mounting, anything that produces significant bottom will likely end up with a BIG bump on the bottom.
1st tunes were played thru the CHR70eN yesterday -- using our newly minted mFonken sized sealed box (i can't see using the CHR in anything but sealed or a very large BR). I'll be a little stronger than Chris, EnABL transforms this driver.
Get your kit from Ed and just do it. If you don't feel comfortable doing your own, i can start taking orders today.
As Chris says we need to give the A10 a week or so of good breakin and then more comparison before commenting on CHR70 vrs stock A10.
What happened to the CHR bodes very well for an A10eN (and A6/A5)
dave
HareBrained said:
1st tunes were played thru the CHR70eN yesterday -- using our newly minted mFonken sized sealed box (i can't see using the CHR in anything but sealed or a very large BR). I'll be a little stronger than Chris, EnABL transforms this driver.
Get your kit from Ed and just do it. If you don't feel comfortable doing your own, i can start taking orders today.
As Chris says we need to give the A10 a week or so of good breakin and then more comparison before commenting on CHR70 vrs stock A10.
What happened to the CHR bodes very well for an A10eN (and A6/A5)
dave
HareBrained said:
more to follow, no doubt - I noticed improvement in areas of coherency, depth/spaciousness of soundfield, low level detail, etc.
Yup, driving the smaller Mark Audio drivers can be a problem for some flea-power SE amps - the combination of 4ohms impedance and at least 3dB lower sensitivity than say an FE103 (or 6dB in the case of FE127) might require at least 10watts of P/P for them to really bloom.
In my case, I preferred them overall with class A EL84 P/P triode, over the 300B or 2A3 - coarser "grain" texture, but larger image and substantially firmer foundation in the lowest octaves.
edit:
Dave beat me to the go button on the above post, so I'll just outright state that in the brief listening session yesterday, there was definitely a noticeable difference between the FE127En in milliFonken enclosure and the (EnABLed) CHR70s. Which was "better"? - that depends on the application and the listener. For nearfield use, and with the right amount of power, a lot of folks might certainly prefer the Mark Audio drivers.
I am overdue for ordering the Enabl kit too. Cold Feet.
But I wonder if there are pics of the Alpair with the treatment?
Using pen and paint on metal cone would seem difficult.
When I finally get the kit I have some practice Pioneers to fiddle with. Then up to the FE127e that has been Damar'ed already.
But I wonder if there are pics of the Alpair with the treatment?
Using pen and paint on metal cone would seem difficult.
When I finally get the kit I have some practice Pioneers to fiddle with. Then up to the FE127e that has been Damar'ed already.
planet10 said:
Erf. For those who haven't done it yet how do you not do the whole cone? I do not recall seeing anything about --- wait that was the
triad pattern yes? I recall that now but as I recall it was for the FE126.
When looking at the completed FE127 e as in here:
http://picasaweb.google.com/hpurvine/Fostex127ETreatment#
no triad pattern is showing. The two colors showing are the printed pattern and the Damar'ed FE127e.
I have been reluctant to do this because my setup just doesn't have the sensitivity nor do I figure my hearing is good enough to know one from the other.
Damar treatment hasn't done any noticeable damage. Bud's pix up there don't look like those are Damar'ed but maybe Mod Podged/ Puzzle coated. The Damar darkens the paper cone significantly as would any shellac/varnish product.
I have heeded the warning about not trying to fit phase plugs to the FE127e.
planet10 said:
These are transformed into a completely new and different driver, easily sounding like ones worth a HECKUVA lot more.
<IMO>
The downward dynamic range is brought up to Fostex levels and the soundstage gets a hundred feet added to it.
When I first heard the En process, when Bud switched between them, I described it as "turning the recording from the mono to stereo position". In no other speaker have I heard such a dramatic change with the En process as I did this week with the CHR's.
The top end is cleared up spectacular as well. Sonics wise, it was like in a 2-way, swapping a paper cone tweet to a ribbon. BUT... It's not harsh. It just gets that much more clear and well defined.
We listened to some more delicate female vocals and I could not hear their breath with the non-En. I could quite easily with the En version.
</IMO>
Cheers!
Well I got a buddy with more woodworking experience on board to help me, so I think I'm going to order the FB-20 plans from Bob and give those a shot. As long as the parts aren't ridiculous expensive, I should come in well under 450, and hopefully with a better sounding enclosure than the Tektons. Thanks for all the input guys. I'll post to let you know how they turn out.
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