RST28F and DC130A Foamcore Homage to LS3/5A

[tubemax]

Hi xrk,

Nice amps, are those CPU heat sinks?

 

[xrk971]

Yes, surplus Dell Precision T7500 LGA 1366 Processor Heatsink 0T021F. These can handle big Class A load with a Noctua fan.

 

[tubemax]

I see, smart use of cheap aluminum - they look nice, I also have some vintage Apple G5 Heat sinks that are waiting to be used in some amp...

 

[moutik2]

Hi, speakers and crossover ordered to make a nice center and surround channels with FAST10F/RS225 main left and right.

 

[xrk971]

Hi Moutik,
Great! Looking forward to see how your build goes. Are you making your own XO boards?

 

[moutik2]

hi, yes i'll do on small piece of wood .

do you think it's an heresy to built it in 18mm mdf like your Fast 10f/rs225. there's not the good dimension at my local store (only medium in (6, 10 and 18 mm) and keep the 18mm will be a strong box. Of course i'll keep internal dimension.

(i've aps aeon ( APS AEON - Zikinf ) in my studio for music recording an listenning and they are building like a tank).

after , i think i'll try your amp as i can soldering until smd and i begin to understand electronic schematic. i'd love to try a class A but step by step ...

 

[hifijim]

So I forgot... what does FAST stand for? what does WAF stand for? I know both involve a full range driver which is augmented by other drivers .... ???

 

[ewollowe]

Fullrange Assisted Subwoofer technology (or some such)

Wife Acceptance Factor

Edit: A lot of folk prefer WAW now, Widerange and Woofer, it's more accurate.

 

[moutik2]

So I forgot... what does FAST stand for? what does WAF stand for? I know both involve a full range driver which is augmented by other drivers .... ???

hi, here the link of the post :
10F/8424 & RS225-8 FAST / WAW Ref Monitor

 

[Scottmoose]

The FAST term is (praise be) dwindling, since many of the drivers employed for LF support aren't actually subwoofers, and it further implied that subwoofers are 'technology' while for some reason other types of drive unit don't qualify. 😉

 

[xrk971]

hi, yes i'll do on small piece of wood .

do you think it's an heresy to built it in 18mm mdf like your Fast 10f/rs225. there's not the good dimension at my local store (only medium in (6, 10 and 18 mm) and keep the 18mm will be a strong box. Of course i'll keep internal dimension.

(i've aps aeon ( APS AEON - Zikinf ) in my studio for music recording an listenning and they are building like a tank).

after , i think i'll try your amp as i can soldering until smd and i begin to understand electronic schematic. i'd love to try a class A but step by step ...

Yes, 18mm MDF will work. I would still try to make the removable front baffle mounted with the screws like shown though. The use of the thinner 9mm plywood and braced with a frame of hardwood (beech or white oak in my case) has been said to give the LS3/5A type box some of its sound signature. But hard to say how important that is to the overall sound.

 

[xrk971]

Maybe WAFT is a good one as it combines the pun of the WAF but is actually
Woofer Assisted Fullrange Technology. The technology being applied to the system as a while and not one particular driver(s).

Although Fullrange Assisted Woofer Technology (FAWT) could be interesting or funny depending on how you say it. 🙂

 

[Scottmoose]

Being a simple soul I just call them 2-ways. 😉 The fact that most happen to have a lower crossover frequency than many contemporary loudspeakers (but far from uncommon until ~the late '60s) is neither here nor there in that sense. But as noted, I have a simple mind.

 

[xrk971]

2-way is definitely correct anyway you look at it. 🙂

 

[Sashi]

Hi XRK,
I'm very interested in trying out your design.
Unfortunately the DC130A-8 woofer has run out of stock where I live.
The shielded version DC130AS-8 is available,though.

Could you please take a look at the specsheet?
https://www.daytonaudio.com/images/resources/295-300-dayton-audio-dc130as-8-specifications.pdf

Do you feel it could work out,perhaps with minor tweaks?
To me the FR curves look pretty similar but I'm not very good at spotting the details.

regards,
Sashi

 

[jmascreen]

2-way is definitely correct anyway you look at it. 🙂

Is it possible to go ported with this design also the shielded woofer a direct drop in?

 

[xrk971]

Fs is 57Hz vs 53Hz, Qts is a little higher, sensitivity is within 0.2dB, Yes, the shielded woofer should be close enough. I have not tested it myself but give it a try.

I would not port this speaker. It has plenty of bass for it’s intended purpose and the group delay is kept in check. If you port it, the dynamics and timing of bass vs mids and highs will not be as good. The other way to do this is to put it in a TL as shown in this thread. That will preserve the timing of the group delay.

 

[jmascreen]

I will go with the original design and drivers, do you have the crossover components parts express code?

 

[xrk971]

Here you go - you want minimal effort I see. 🙂

Crossover Part Numbers from Parts Express (per speaker)

L4 = 5mH 18ga #275-141 qnty 1
L1 = 0.1mH 20ga #257-568 qnty 1
C2 = 4.7uF MKP #255-020 qnty 1
C3A = 10uF MKP #027-114 qnty 1
C3B = 1uF MKP #027-410 qnty 1
R2A, R4 = 12.5ohm #006-12.5 qnty 2
R2B = 1.0ohm #006-027-101 qnty 1

C3 = C3A+C3B
R2 = R2A+R2B

It looks something like this:

Or this if you have exact custom values 🙂

 

[jmascreen]

Yes this time very minimal last time with pmc clone using rs180 anf rst28f still figuring out the best crossover

Thanks for sharing seems the tweeter is off stock