Driver and enclosure for 4 watt amp, 12x12 room, moderate volume chamber music?

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zenga123

Member
2010-12-01 2:50 pm
Upper range probably isn't that important, since my hearing isn't good there. But I would love to be able to be able to hear the instruments in chamber music reproduced realistically in the midrange and lower. What would be a good driver/cabinet (or open baffle) combination for someone with basic woodworking skills?
 
Hi zenga123

check out the fostex fe126en advised cabinet on the spec sheet.....I think its about optimum(by winisd figs anyway) and it's simple to build...I'm working on a variation at the moment to compare with a MA Alpair10 that I put in a similar cabinet.....

if it is a SET you have and the hum levels are not great then the 166/126 will expose...I mention this because it disappoints some people....

Ed
 
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Hi zenga123

check out the fostex fe126en advised cabinet on the spec sheet.....I think its about optimum(by winisd figs anyway) and it's simple to build...I'm working on a variation at the moment to compare with a MA Alpair10 that I put in a similar cabinet.....
if you're talking about the hybrid BR/"BLH" fir the FE126E, optimum would not be the term I'd use to describe it. I built a pair several years ago for previous model of 126, and can think of at least 4 DIY (and one commercial ) BLH designs that vastly outperform it in every respect.

if it is a SET you have and the hum levels are not great then the 166/126 will expose...I mention this because it disappoints some people....

Ed

very true that
 
I believe Ed's talking about the bass reflex box tucked away at the bottom of the page rather than the BH/BR hybrid.

oops - but provided space is available, still think there are better options for this driver or the FE166 than the BR boxes


Yes it is a SET amp, the Decware Zen SE amp. I think a 94 db driver is recommended.

Thank you for the suggestions, I will do some reading on the drivers this afternoon.

The Decware is more like 2W and really likes a 2 ohm load.

dave

I've heard older versions (circa 2003-5) of this little gem, an in stock trim ( i.e. not the "EX" OPT) it's quiet enough for full range drivers like the FE126E in horns or "Horns" or systems with AMT1 tweeters. Due to the interesting method in which the OPT float off ground, it can be bridged in mono for the approx 4W level, albeit with an increase in noise that might not be acceptable in some systems, or for listeners with sensitivity in the upper ranges.

It certainly punches above its weight class and as Dave says doesn't at all mind the lower impedance loads of multiple drivers in parallel.


Even a pair of Mark Audio or Alpairs probably wouldn't belabour it, so a wide range of options would be available - which begs the question - how much floor/shelf space is available. (in other words my first suggestion might be the Castle MicroTower with CHR or EL70)

This is after all not a huge space, and as someone else posted recently - "we often forget how loud 90dB SPL really is"
 

zenga123

Member
2010-12-01 2:50 pm
The room is my study, bookshelves can be moved around, so space or what the cabinets look like isn't a problem.

The amp was made 8 years ago but has been stored for a few years. It probably wasn't matched with suitable drivers before, and the living room space was probably too big for it. I really should use it, at the time I collected some very nice tubes for it. This time I want to make speakers just for this amp, and for chamber music in this smaller room.
 

zenga123

Member
2010-12-01 2:50 pm
I just talked to someone at the lumber yard, asking about Birch plywood, and he says that as a side business he gets drivers from parts express and builds speakers to sell. He said he'd do the cabinets for me for $50 each, which includes the cost of 3/4" void-free birch. Seems like a good price.

I found the micro-tower plans at Planet10. Are those the same as the Castle? Would the Zen amp run a pair of FE126E or EL70 per box?
 
I just talked to someone at the lumber yard, asking about Birch plywood, and he says that as a side business he gets drivers from parts express and builds speakers to sell. He said he'd do the cabinets for me for $50 each, which includes the cost of 3/4" void-free birch. Seems like a good price.

dirt cheap, if you can confirm quality of previous work - go for it

I found the micro-tower plans at Planet10. Are those the same as the Castle?
"Castle" is the nick-name for the version with second driver top mounted.
(left hand pair below)

138650d1250013844-mark-audio-chr-70-application-thread-microtower-comp2.jpg


Would the Zen amp run a pair of FE126E or EL70 per box?
The Zen would drive 2 of either per channel just fine, but the microtower is not the best box for 126 - (they really want some type of BLH), but killer with the EL70 and SET or low power EL84 P/P - with your Zen amp, wire them in parallel.
 
2 EL70 in parallel will bring the impedance into the range where the Zen is at its best, and the 2nd driver gives 3 dB more efficiency (89 dB). That coupled with what seems that in practise, people are getting away with less power than we'd guess possible. A good case in point was when Don (aka Doorman) went from 92 dB FE167eN to 82 dB CHR-70eN and is perfectly happy with his 3.5 w amp in a room much larger than yours.

A single Frugel-Horn Mk3 with FE126 would give you 92-93 (but at 8 ohms, where Zen foesn't do quite as well), and now that you have someone to build them, the more complex build won't likely be an impediment.

And if you want crazy, a stack of 4 FH Mk3 (per side) with FE126 has been discussed (98-99 dB/w)

dave
 
For a smallish room, and the subjective power of the little Zen amp (both circumstances with which I've had some experience) I'd suggest the Castle microtowers, or even a dual forward facing design such as we heard the EL70's in a little Parts Express box at Bob Reimer's. Maybe Dave has a picture stashed somewhere - a pretty nondescript looking but not sounding box - kinda like the Zen amp.

Any of numerous single or dual rear or front mouthed horn designs with Fostex FE126En or FE166En could certainly fill the room with more volume than it sounds like you'll ever want, but they do have placement / listening distance issues that the others mentioned above wouldn't.
 

zenga123

Member
2010-12-01 2:50 pm
I would be interested in seeing the plans for the dual forward facing design for the EL70's. That is how I have my speakers set up for movies in the living room, 2 x 2 forward facing Audio Nirvana 8's in a large BR towers driven by a Parasound amp, and it works nicely for its purpose, though maybe missing a bit of what I would call musicality. (My computer set-up is a bit more eccentric: a 30 watt Parasound Zamp v3 driving 2 10"x18"x22" BR boxes I recently put together with Radio Shack FR drivers I bought 10 years ago for maybe $15. I'm surprised at how non-awful they are, especially considering that the stuffing is just odds and ends of fabric and foam I put into the bass ports now and then.)

I like the plans for the Castle microtowers, though I have to say the single driver wall mounted box has a lot of appeal since I have two cats, and I am sure the first thing they would do is try to make a bed in the top firing driver.

Are there any independent assessments of the EL70's that someone can point me to?
 
I would be interested in seeing the plans for the dual forward facing design for the EL70's. That is how I have my speakers set up for movies in the living room, 2 x 2 forward facing Audio Nirvana 8's in a large BR towers driven by a Parasound amp, and it works nicely for its purpose, though maybe missing a bit of what I would call musicality. (My computer set-up is a bit more eccentric: a 30 watt Parasound Zamp v3 driving 2 10"x18"x22" BR boxes I recently put together with Radio Shack FR drivers I bought 10 years ago for maybe $15. I'm surprised at how non-awful they are, especially considering that the stuffing is just odds and ends of fabric and foam I put into the bass ports now and then.)

I like the plans for the Castle microtowers, though I have to say the single driver wall mounted box has a lot of appeal since I have two cats, and I am sure the first thing they would do is try to make a bed in the top firing driver.

Are there any independent assessments of the EL70's that someone can point me to?


Well to be honest, I think the "design" for Bob's dual driver system was simply a matter of 3/4 or 1 cu ft Parts Express pre-finished box and standard port per whatever software he used. It sounded quite fine.

Dave has a very thorough set of plans for a lot of permutations of all sizes of the Mark Audio drivers available by subscription.

As for independent assessments of the EL70s - probably most of the "reviews" will be by builders at forums such as this, so exhaustive technical measurements by testing labs and/or purplish prose descriptions of finished systems by "accredited reviewers" may be hard to find :rolleyes:
 

zenga123

Member
2010-12-01 2:50 pm
I guess I wasn't clear when using the word independent. My concern isn't "exhaustive technical measurements by testing labs and/or purplish prose descriptions of finished systems" with a "Rolls Eyes (Sarcastic)" at the end, but rather that thing you said before that, the actual builders experience with the drivers, builders who aren't selling the drivers in some way. I have done a few searches on google without luck, I will try further.
 
The Decware is more like 2W and really likes a 2 ohm load.

dave

SE84B Zen Triode from High Fidelity Engineering, budget single-ended amplifier - home listening test

Hi,

Whilst its allegedly stable into 2 ohms it would be the first ever single
ended amplifier I've heard off that "likes" a 2 ohm load. It simply won't.

Output will be current limited and around 0.6W into 2 ohms, 1.2 W into 4
assuming the standing current is set for maximum output into 8 ohms. No
way ever would a single ended valve amp be optimised into 2 ohms, possibly
6 ohm, they nearly all are optimised into 8 ohms, the bridged specification
implies 8 to 9W into an unspecified, load, I'd say this is greater then 8 ohm.

The fundamentals of single ended amplifiers absolutely preclude
what you are saying, none of them like low impedance loads at all.

Here is a good design with all the basics and measurements :
http://asinus.dk/Asinus_Elektroakustik/Home_files/cb-amplifier_8wse.pdf

rgds, sreten.
 
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