I got them 95% 'finished'.
A few tweaks here and there, but they put out sound. I need to go over each joint with more PVA (I don't seem to get much in the way of bass, but that could be the tiny output transformers or lack of break in) and do some general tidying (removing the bits of glue which seeped out).
Haven't had much of a listen as I've got a hideous ground loop issue with my amp + source, and blew a MOSEFT in the control circuit... But once those are resolved we're in business!
Thanks for all the help.
A few tweaks here and there, but they put out sound. I need to go over each joint with more PVA (I don't seem to get much in the way of bass, but that could be the tiny output transformers or lack of break in) and do some general tidying (removing the bits of glue which seeped out).
Haven't had much of a listen as I've got a hideous ground loop issue with my amp + source, and blew a MOSEFT in the control circuit... But once those are resolved we're in business!
Thanks for all the help.
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Nice work! The 0.40x scale Karlsonators don’t put out a lot of bass - probably down to 80Hz or so, but the sound should sound quite full and balanced and not tinny or lacking bass. If you have any air leaks in the TL, it might prevent generation of deeper bass. You did an excellent job of lining the inside with the melamine foam. How much power do you have from your hybrid amp? Is it sort of like the Estudiante amp?
my 0.53 Karlsonators
Well folks,
My first experience with the mini-Karlsonator design. I built the 0.53X version in baltic birch plywood. There are dual Faital 3FE25 16 ohm drivers in each one wired in parallel for an equivalent 8 ohm nominal impedance. Internal damping materials are exactly per X's recommendations. Melamine foam on the interior bottom and both sides of the box. Additional melamine foam along the back up to the baffle height and on the back and both sides of the bracing near the drivers. And there's foam core board on the back side of the aperture.
The attached image is what one of them looks like. The resemblance to X's earlier posts is intentional. I built all four of them to his design.
My first listening experience was almost shocking. I'm listening to a Ramsey Lewis Trio CD recorded around 1958 titled Down to Earth. The detail and clarity is exceptional. The piano, string bass, and drums never sounded better. I'm not one for superlatives, in general. All I can say is that these are keepers.
Well folks,
My first experience with the mini-Karlsonator design. I built the 0.53X version in baltic birch plywood. There are dual Faital 3FE25 16 ohm drivers in each one wired in parallel for an equivalent 8 ohm nominal impedance. Internal damping materials are exactly per X's recommendations. Melamine foam on the interior bottom and both sides of the box. Additional melamine foam along the back up to the baffle height and on the back and both sides of the bracing near the drivers. And there's foam core board on the back side of the aperture.
The attached image is what one of them looks like. The resemblance to X's earlier posts is intentional. I built all four of them to his design.
My first listening experience was almost shocking. I'm listening to a Ramsey Lewis Trio CD recorded around 1958 titled Down to Earth. The detail and clarity is exceptional. The piano, string bass, and drums never sounded better. I'm not one for superlatives, in general. All I can say is that these are keepers.
Attachments
Thanks for the kind words.
The amp is all valve - those are PCL82s, so half a 12AX7 as driver and a de-rated EL84-ish pentode in the same envelope. As for power, I'm looking at a big 1W clean! But that's fine to sit in the kitchen...
I've added plate-to-plate feedback to get lower input sensitivity. This decision may be altered once I've let things settle: GNFB might be applied with a lower level of plate-to-plate feedback to try and get some more bass. But these transformers are definitely the weakest link here!
Great to hear that we can officially say it’s safe to build plywood Karlsonators if the proper amount of damping material is used. Thanks for the listening impressions. The speaker is definitely “a keeper”. 🙂
I think you have put in toooo much damping. Especially at the top. Looks like the damping is blocking the vent at the top. If possible, try and remove this to see if the bass improves?
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Oh darn it... Thought I was doing so well! That'll be a tough one without cutting the front off. Perhaps some long tongs...
That foam cuts easily (very brittle), a long razor blade or knife inserted through vent can remove a lot.
I got a buddy who would like a pair of speakers for his outdoor terrace restaurant.
There's a roof, but 3 sides are opened, the last wall is the restaurant wall towards the inside.
I'd like to try dual mini-ks, but I can only mount the boxes in the top corners, higher up near the roof. Angling the boxes down only bring the woofers parallel to the wall, not facing down, due to the angled mounting of the drivers.
Would it be ok to mount the boxes upside down? How would that affect radiation pattern?
Since the drivers are angled in the box, I could just mount the boxes flat on the wall, but upside down. That way, drivers would face down a bit.
There's a roof, but 3 sides are opened, the last wall is the restaurant wall towards the inside.
I'd like to try dual mini-ks, but I can only mount the boxes in the top corners, higher up near the roof. Angling the boxes down only bring the woofers parallel to the wall, not facing down, due to the angled mounting of the drivers.
Would it be ok to mount the boxes upside down? How would that affect radiation pattern?
Since the drivers are angled in the box, I could just mount the boxes flat on the wall, but upside down. That way, drivers would face down a bit.
upside down can work - draw a straight line from the driver's center which faces the widest portion of the K slot and that would be the central high frequency beam (I'm not sure of the HF contribution of the upper driver which sits back more "shaded")
Yes, I have actually tried mounting it upside down. If on wall near ceiling you can get substantial bass enhancement as if it were on floor near back wall.
IIRC, the original Karlsons were frequently corner mounted upside down against the ceiling, and it was even recommended for bars or restaurants or similar situations. It loads it exactly the same as if it were on the floor, which is a bit better even than on stands/a desk.
Freddi, X and Hyperion...
Music to my ears!
Thanks a bunch!
Looks like we will go Karlson on this project!
Wish I could get the Faital drivers over here for the extra oomph...
Any idea how the TC9s fare in VERY humid weather? Hope the cones will not get mushy over time.
Music to my ears!
Thanks a bunch!
Looks like we will go Karlson on this project!
Wish I could get the Faital drivers over here for the extra oomph...
Any idea how the TC9s fare in VERY humid weather? Hope the cones will not get mushy over time.
I have not had any issues with TC9FD due to humidity or heard of issues from others. If you are really conncerned, the TG9FD (8ohm) works well too and is fiberglass. The TC9FD although made of paper cone, seems to have a very thin shiny finish that may be a plastic or some sort of protective coating.
Would be great to get the TG9, but I would need to buy at least 2,016 units.... not going to happen!
Yes, the TC9 does have that shiny coating on them, and I'm hoping they will stand up to the 98% humidity we get almost year long... plus the salt in the air. That's where the plastic frame comes in handy.
Yes, the TC9 does have that shiny coating on them, and I'm hoping they will stand up to the 98% humidity we get almost year long... plus the salt in the air. That's where the plastic frame comes in handy.
Well, sounds like even if you could get the 3fe's, the TC9's would be a better pick anyway due to environment. Besides, at background music levels I don't think you'll be lacking at all. My Faital k'nators go louder than I'm comfortable listening.
Cool. thanks for the feedback.
As soon as the rain stops, I'll start cutting. These will have to be plywood. I have some waterproof marine ply here that will be used.
Time to give the plywood another chance, following X's recommendations for stuffing.
As soon as the rain stops, I'll start cutting. These will have to be plywood. I have some waterproof marine ply here that will be used.
Time to give the plywood another chance, following X's recommendations for stuffing.