Wild Burro Betsy OB Build

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Happy New Year to all of you.

I have also orderd a pair of Betsy's and wait (impatiently :) ) for their arrival. Got inspired by Fleawatt's posting in the Bottlehead forum.

Here is my question: Has anyone tried a JE labs baffle with the Betsy's? Why or why not?

Thanks for your opinions.

Michael

Here is one thread on it:
JE Labs open baffle advice?

Paul recommends it as well:
Wild Burro Audio Labs - Fullrange Speakers - The Betsy & Betsy-K Drivers

BTW my drivers get here tomorrow!!

Has anyone have any suggestions about dampening the back of the baffles? Would just adhesive cork board work, or should I do something else?

Dan
 
From just listening tests long ago, the various cork products I tried were all too hard to be of any use beyond decorative, so switched to thick felt or jute carpet padding, which worked well, but I still preferred the old fashioned way of loosely fastening an acoustic fiberglass insulation 'blanket' over the rear of the driver and covered with a double knit or similar cloth to contain it to make it act similar to a very low Qt [lossy] box.

GM

edit: the driver need to be covered with cheesecloth before adding the insulation.
 
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OK -- project update.
An externally hosted image should be here but it was not working when we last tested it.


Baffles are built and BetsyKs are installed. DIY Cat5e speaker cables built. I'm only using 2 of the leads in the Cat 5 per side to add a bit of resistance to tame the HF response.

Amplifier is a Class D TPA3122 based on @cervelorider's reco. I have it powered by a 12v SLA battery. It sounds amazing!

An externally hosted image should be here but it was not working when we last tested it.


They speakers sound really good on most things -- but I've noticed that on certain instruments, mainly solo piano this happens (listen to the distortion/resonance in the last few seconds of this video):
Distortion Issue with BetsyK driver

That little amp can certainly drive them to a perfect listening volume (I've been listening between 25-33% volume on the pot) -- and I love the battery powered setup (right now I am either using my iPad/iPhone as a source or my turntable. The turntable setup rocks, perfect match for this amp and speakers).

I did end up swapping out the piano hinges for a black duct tape/regular hinge solution, as I thought that this was causing the resonance. In retrospect, I would not recommend the piano hinges at all for a project like this. They are too expensive and way too many screws.

To cure the resonance/distortion issue with this driver, I tried the following:

1) Removed both piano hinges (as I thought they might be rattling).
2) Taped up hinges first and then installed new hinges (2 per side, 2" medium hinge).
3) Switched drivers on baffles. (left for right) -- to see if it was the baffle or the speaker.
4) No matter what I did this is the distortion I get. I checked the interconnects, the speaker terminals the wires. The VC is not rubbing. It seems to only manifest itself on piano, but only on this speaker (the other speaker does not have this distortion. It's the oddest thing.

I am open to any ideas or thoughts you may have, especially since only one speaker is doing on it, no matter what baffle I install it on.
 
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He switched the driver from the left side to the right side and the distortion issue followed the driver. If it were the amp, it would be safe to say that the distortion would be channel specific. Right or left. Am I missing something?


Just to factor everything else out, I would also try another amp. Not that I don't trust the little class D amp (built one myself :)), but I would recommend to make sure.

Best of luck and keep us posted.

Michael

_______________________
Michael's Project Page
 
He switched the driver from the left side to the right side and the distortion issue followed the driver. If it were the amp, it would be safe to say that the distortion would be channel specific. Right or left. Am I missing something?

Yes, I agree. If it were the amp, the distortion would be on the right channel, and would have been present on the swapped driver if that were the case, I would think.
 
BTW here is the updated parts list on the baffles, since I made the build changes:

Baffles:
8 x 2" Zinc Narrow Hinge: $15.92
16 x 8-32 x 1-1/4" for Speakers: $3.54
16 #8 Lock Washer: $1.18
16 #8 Steel Flat Washer: $1.18
4 x 12x48 Stain Grade Pine: $47.76
2 x 16x48 Stain Grade Pine: $25.94
QT Clear Shellac Zinsser: $13.78
3M Tough 2" Black Tape: $6.98 (plenty of roll left, for hinges)
Frost King 3/8" Weather-strip: $2.57
Total for the baffles: $118.85

BetsyK drivers: $130 (110+20 shipping)

Speaker Cables: Free (had the Cat5 lying around).
Battery for amp + charger: $34.99 Amazon
Class D Amp: TPA3122D2: From Jerry's Electronics -- here


Total for the project so far: ~ $310 or so.
 
BTW here is the updated parts list on the baffles, since I made the build changes:


Speaker Cables: Free (had the Cat5 lying around).
Battery for amp + charger: $34.99 Amazon
Class D Amp: TPA3122D2: From Jerry's Electronics -- here


Total for the project so far: ~ $310 or so.

Don't forget your amp was modded with Elna Silmic II 470uf 50V caps. They do make an improvement from stock in my opinion. Each cap (4 total) is $2.15 plus shipping.
Elna Electrolytic Capacitors RFS Series
Nice job assembling such a nice system without a huge outlay in costs! :cheers:
 
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Joined 2012
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BTW here is the updated parts list on the baffles, since I made the build changes:

Baffles:
8 x 2" Zinc Narrow Hinge: $15.92
16 x 8-32 x 1-1/4" for Speakers: $3.54
16 #8 Lock Washer: $1.18
16 #8 Steel Flat Washer: $1.18
4 x 12x48 Stain Grade Pine: $47.76
2 x 16x48 Stain Grade Pine: $25.94
QT Clear Shellac Zinsser: $13.78
3M Tough 2" Black Tape: $6.98 (plenty of roll left, for hinges)
Frost King 3/8" Weather-strip: $2.57
Total for the baffles: $118.85

BetsyK drivers: $130 (110+20 shipping)

Speaker Cables: Free (had the Cat5 lying around).
Battery for amp + charger: $34.99 Amazon
Class D Amp: TPA3122D2: From Jerry's Electronics -- here


Total for the project so far: ~ $310 or so.

How did you choose the TpA3122 amp from Jerry's Electronics? And how do you like it? Why is this better than a Sure prebuilt from PE? I am looking for a compact amp to put inside a speaker cabinet.
 
I have no experience with the Sure prebuilt from PE. The Jerry's Electronics with upgraded caps was a recommendation from @Cervelorider. I figured I'd give it a shot before jumping in a purchasing a SET. I am VERY happy with the sound and I love that I can battery power the whole thing.

@Cervelorider was very helpful in provided recommendations and selling me an amp with upgraded caps that he assembled. I am very grateful that he was willing to do that as I am not yet comfortable soldering a kit up like that yet.
 
Cervelorider can probably clarify then, but I imagine it has to be the quality of the input/output caps that makes a difference as the stock ones that come with the Sure are not the best for musicality. Looks like a fairly simple build though. An option is to replace caps on the Sure and save the build time.

I'll message you the differences (many) as I don't want to hijack danvprod's speaker thread. Btw, I will solder a 3112 board at no cost for anyone who wants one, but doesn't have the tools or desire to sling solder.
 
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