I have managed to install and uninstall a TC9FD or 3FE25 with the front aperture glued in place. But it is not ideal and you will end up damaging the aperture in trying to remove the driver later. I would use drywall screws onto a stack of foam core "cleats" glue to the inside of the front chamber. maybe 4 on the sides and one extra screw at midpoint on the top. Definitely use screws if making aperture out of wood. Thin 3/16in Luaun ply bonded to foam core can work too.
I am still blown away by the MK 0.4X w/ TC9's. Can listen to them all day long at the computer and never seem to get ear fatigue. I'm powering them with a cheapie TDA7297 with improved caps, fed by a roland interface to my laptop. To try for a larger, similar sound I built the 0.53X w/Dayton PA130-8's. Powered by a couple of TDA8932 boards with no mods and fed by a heavily modded and sweet acurus preamp. Even tho many hours are piling up, this system seems to grate on my ears. Something wrong in the midrange, especially 1K to 4K Hz. I keep wanting it to smooth out to no avail. I've now put them at the computer connected to the TDA7297, so I can A-B them to the 0.4X TC9 set. They defenitely provide some of the larger sound I was going for, but the subtle ear pain is also there. The hobby has its grip on me. I want to try a better 5" (or thereabouts) driver. I like the MK 0.53X box; but would consider an XKI, or a Pensil, or even a Frugel-Horn Lite (if I can foamcore it!). What would you suggest? Listening room is about 225 sq ft with low ceiling and I prefer acoustic instrumental jazz.
Bonjonno,
I wonder if your ears are especially sensitive to the circa breakup 5-7kHz peaks of PA130-8? The TC9FD is very smooth relatively and benign in this region. So one thing to try is adding a passive notch (RLC) filter to bring down the peak.
You can calculate such a filter here:
mh-audio.nl - Home
For example put in 6kHz center frequency, and have a 2kHz bandwidth with 8ohms, you get a parallel RLC with 0.6ohms, 0.125mH, and 5uF filter.
Conversely, you can change the baffle board on the 0.53x to install dual TC9FD's in parallel and that will have same smooth sound signature of the 0.40x but +6dB more sensitive.
You might like the Tang Band W5-2143 in an XKi or one in a Karlsonator that is 0.58x scale in height and depth and 0.52x in width (that is optimum, but it may work quite well to your satisfaction as a straight swap in your existing 0.53x box). For an XKi, the dimensions are posted in that thread.
That W5-2143 is VERY smooth - like unbelievably smooth response.
https://www.parts-express.com/pedocs/specs/264-958--w5-2143-spec-sheet.pdf
I wonder if your ears are especially sensitive to the circa breakup 5-7kHz peaks of PA130-8? The TC9FD is very smooth relatively and benign in this region. So one thing to try is adding a passive notch (RLC) filter to bring down the peak.
You can calculate such a filter here:
mh-audio.nl - Home
For example put in 6kHz center frequency, and have a 2kHz bandwidth with 8ohms, you get a parallel RLC with 0.6ohms, 0.125mH, and 5uF filter.
Conversely, you can change the baffle board on the 0.53x to install dual TC9FD's in parallel and that will have same smooth sound signature of the 0.40x but +6dB more sensitive.
You might like the Tang Band W5-2143 in an XKi or one in a Karlsonator that is 0.58x scale in height and depth and 0.52x in width (that is optimum, but it may work quite well to your satisfaction as a straight swap in your existing 0.53x box). For an XKi, the dimensions are posted in that thread.
That W5-2143 is VERY smooth - like unbelievably smooth response.
https://www.parts-express.com/pedocs/specs/264-958--w5-2143-spec-sheet.pdf
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xrk, thanks for the suggestions. I didn't know about the peaks. Since I'm using a PC based system, I can fool around with the EQ using Peace and Equalizer APO. I'll report back with the results.
Do you think that dual TC9FD's can deliver a tone as impressive as the more expensive drivers in that range, i.e. TB or MarkAudio?
Do you think that dual TC9FD's can deliver a tone as impressive as the more expensive drivers in that range, i.e. TB or MarkAudio?
The dual TC9FD is quite impressive sounding, but lacks a little Sd compared to a W5-2143. If you are sensitive to peaks and like smooth drivers, the MA A10P may not be your cup of tea (called a 6in driver but Sd is smaller than Tang Band 5in driver).
Here is an A10P frequency response. It is plotted on a insane scale (-10dB to +110dB scale to reduce the visual impact of such peaks), but those peaks are of order 6-8dB at 4khz and 6kHz.
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Hey we are running a similar setup! 0.4x Mini with TC9, a laptop as the source, and TDA7297 amp. I am running an old MacBook Pro, digital out goes to Muse Audio DAC (4xTDA1543 parallel), then to the preamp and to the amp.
[url=https://flic.kr/p/Z4z8Cv]
And I totally agree with you, this setup is so balanced, I never get ear fatigue. Right now I feel my room is the biggest constraint, and I will just have to live with it now. The speakers and amp are more than adequate for me.
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If you're considering a Pencil, have a look at the TABAQ.
I know X made a foam core version of it.
I love mine.
Here's the latest, using an iPad and the treble reducer EQ setting, but could be done easily with a small BSC circuit of 1mH and 8 Ohms in parallel.
The TABAQs are on a wall to help the bass get that curve... off the wall, the 60-ish Hz range drops by 3dB.
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A Tabaq is a long mass loaded TL design and sounds very balanced when appropriate BSC circuit is used. However it has low efficiency due to BSC and no real bass gain. The Karlsonator on the other hand actually has enough bass gain to compensate for the -5dB falloff of the baffle step loss. Thus, no BSC is needed or used. So for comparison, a Tabaq with a 91dB 3FE25 will lose -5dB in sensitivity due to BSC so has about 86dB down at 80Hz. Whereas the 0.40 Karlsonator will maintain about 90dB down to 80Hz - enough to give it a rich sound. The Tabaq digs deep though maybe 55Hz - but is softer. When used with a less sensitive driver like a TC9FD, Tabaq will be 81dB sensitivity.
Easy Peasy
xrk971- I finally got the parts and assembled Juma's Easy Peasy Cap Multiplier. My hands were shaking through the whole soldering process. Luckily none of the delicate parts smoked. I'm running an HP 130 watt 19V laptop SMPS into the cap multiplier into a TDA7297 into MK 0.41X's w/ TC9FD18's. Like you said it would, the bass has improved. It's actually hard to believe the sound that is coming out of a few dollars worth of parts and 3.5" speakers. Just listened to Jaco playing on Joni Mitchell's version of Goodbye Pork Pie Hat; it was a visceral, life affirming experience and I was grinning like a kid with an ice cream cone. Two cones. You mentioned also a block of 20 or so 1000 uF cheap caps for added zest. Are they just wired in parallel? And then where do they go in the circuit exactly? Thanks again for the great guidance.
xrk971- I finally got the parts and assembled Juma's Easy Peasy Cap Multiplier. My hands were shaking through the whole soldering process. Luckily none of the delicate parts smoked. I'm running an HP 130 watt 19V laptop SMPS into the cap multiplier into a TDA7297 into MK 0.41X's w/ TC9FD18's. Like you said it would, the bass has improved. It's actually hard to believe the sound that is coming out of a few dollars worth of parts and 3.5" speakers. Just listened to Jaco playing on Joni Mitchell's version of Goodbye Pork Pie Hat; it was a visceral, life affirming experience and I was grinning like a kid with an ice cream cone. Two cones. You mentioned also a block of 20 or so 1000 uF cheap caps for added zest. Are they just wired in parallel? And then where do they go in the circuit exactly? Thanks again for the great guidance.
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The cap array is all in parallel and goes in between the cap multiplier and the amp. Make a high current bus using solid core 12ga copper (Romex is good). Solder the 20 x 1000uF caps to the thick bus. Connect amp power leads to the bus via 16ga to 18ga copper stranded wire. The cap multiplier is needed to reduce any hum from mains. If you did not have hum then not needed. But cap Mx also provides a gradual ramp up soft start so no speaker pop from turn on.
The cap array allows use of cheap caps with typical 60mOhm ESR. 60mOhm/20 is now a 3mOhm cap ESR. That acts as essentially an infinite reservoir of charge (for a short period) so that the output transistors are never current starved. Bass impact goes way up.
You can also buy the Folsom TDA7297 PCB which has a built in cap array (Destroyer OS recommends use of Panasonic OSCON low ESR caps). So he uses fewer more expensive caps ($2ea x 10) vs my cheap bag of 50 for $3 from Aliexpress.
Here is Folsom amp for 7297:
Folsom DIY7297 Amp & Antipole PSU
Here is a photo of a 16 unit cap array with 12ga bus for a small class A headphone amp.
The cap array allows use of cheap caps with typical 60mOhm ESR. 60mOhm/20 is now a 3mOhm cap ESR. That acts as essentially an infinite reservoir of charge (for a short period) so that the output transistors are never current starved. Bass impact goes way up.
You can also buy the Folsom TDA7297 PCB which has a built in cap array (Destroyer OS recommends use of Panasonic OSCON low ESR caps). So he uses fewer more expensive caps ($2ea x 10) vs my cheap bag of 50 for $3 from Aliexpress.
Here is Folsom amp for 7297:
Folsom DIY7297 Amp & Antipole PSU
Here is a photo of a 16 unit cap array with 12ga bus for a small class A headphone amp.
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