Gchang (straight chang) with FE206E questions

[mymindinside]

Hi all,

I have been sitting on a pair of FE206E's for a couple of months now, and have finally decided to build them a home. Have decided on the Gchang because it is within my skill level to build, and most people who have built one have been happy with it. i was a bit concerned because i have the FE206E and not the FE207E that it was designed for but have decided to take the plunge. I will add the recommended 4 ohms series resistance and hope for the best.

This brings me to my first question: what power rating should this series resistor be? is 10W enough?. Also is it better to use a non-inductive part here?

My second question is regarding the 'holey brace' that is the recommended form of brace. i don't have a router so cutting circles for me is not easy at all. what brace can i use without having to cut circles?. would two vertical strips of wood (say 1" x 1") crossed by two horizontal strips work? something like a tic-tac-toe grid.

This is only my second build, in my first i just soldered the internal wiring to the speaker lugs, i have read in some build threads that this is not advisable since it can melt the voice coil, and also because it makes the speaker tougher to remove (to adjust stuffing etc). what method of connection do the gurus prefer?

Quite excited about the build, have been meaning to try out a full range build for a long time now...will post build photos as they come...

Thanks in advance for any help...

cheers,
mymindinside

[rjbond3rd]

Howdy mymindinside,

How come G-change and not Sachiko? Just curious! FE206E and FE207E really have absolutely nothing in common except the physical size, in my mind.

[mymindinside]

I was quite keen on the sachiko,.. from what i have read it is a very good design. what went against it was that in one thread scottmoose (i think) said that they needed a fairly large room to work their best, and did not sound great when placed close to rear and side walls. unfortunately in my room i will have to place them about a foot and a half (max) away from the side and rear walls...
also they are a fair bit bigger than the Gchangs.

I was quite concerned about using the FE206E in this cabinet but then i read Bobtrancho's half chang thread and he seems to be quite happy with this driver.

what do you guys think

mymindinside

[Jim Shearer]

I built a pair of HC's like Bob T using the FE206e driver. Very pleased w/ the results. You can try the resistor alone, but I used a BSC with a 5.5 ohm R and 1 mH air core inductor. I use Mills non-inductive resistors:

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The holey brace can have holes of any shape, just so long as they make up about 40% of the area. You can cut them with a jig saw or whatever.

Cheers, Jim

[mymindinside]

Hi Jim,

Glad to hear that the cabinet - driver combo worked out well for you.
I take it you used 12W resistors.. That is what i thought the rating ought to be, just wanted to make sure. good to hear about the brace as well. will have some kind of rectangular holes in the brace.... thanks for the help

right now the only amp i have is a lm3886 gainclone. i am thinking of building a F2 (current source design from Nelson Pass)...has anyone tried either of these with the FE206e in the changs?

[planet10]

G Chang & Curvy Chang have about the same room requirements as Sachiko... Using them with FE206 will alow placement closer to the wall. For a smallish room where you can't get far enuff away from the box for the 2 mouths to integrate, you might be better with Half Chang.

dave

[mymindinside]

Hi Dave,

its an honor...

My listening distance will be about ten feet from the speakers and they will be roughly the same distance apart.

I was just worried that being too far back into the corner (one and a half feet from rear and side walls) would make the Sachiko's bass a bit boomy and overwhelming. from what i understand of your post, the same 'corner problems' will affect the Changs as well. in that case i might go ahead and build the Sachiko.

my interest in these designs has been to experiment with a sound which has the least correction circuitry (EQ, BSC) in the signal path. As i understand, the Sachiko does not need a BSC because the cabinet is 'self correcting'.

Cheers,
mymindinside

p.s. Dave, i cant access the frugal-horn website today, is it a problem on my end or is the site down?

[planet10]

Originally Posted by mymindinside

My listening distance will be about ten feet from the speakers and they will be roughly the same distance apart.

That is sufficient.

I was just worried that being too far back into the corner (one and a half feet from rear and side walls) would make the Sachiko's bass a bit boomy and overwhelming. from what i understand of your post, the same 'corner problems' will affect the Changs as well. in that case i might go ahead and build the Sachiko.

It is a better fit to the driver... if needed you can always make an "anti-BSC" filter to reduce bass.

dave

p.s. Dave, i cant access the frugal-horn website today, is it a problem on my end or is the site down?

It is a problem at my end. An ID 10 T Error which i am headed into to town to fix right now.

[mymindinside]

Well,
the man has spoken
Sachiko it is.
Big thanks to everyone for the help

already bought the plywood though, it is 18mm and not 19mm
will just correct it while glueing up i suppose

cheers,
mymindinside

[planet10]

We only get 18mm here too, so at some point i need to draw an 18 mm one. You can either just use the mid-line or if you want to get anal, redraw to keep the passages the same size.

dave