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Betsy impedance plot

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music soothes the savage beast
Joined 2004
Paid Member
I searched and searched and found none. Can anyone tell me why are there no impedance plots with frequency response graphs for Betsy on Wild Burro Labs page?
I found none on diy forum either, except perhaps one in Karlson, which is not relevant for me. On other forum I found link, but it did not work.
Thanks, ed
 
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GM

Member
Joined 2003
Yeah, 'slim pickins'.........

GM
 

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music soothes the savage beast
Joined 2004
Paid Member
thanks for replies

d to the g, my post was not to critisize your lack of measurement system
my interest is in flattening the impedance peak
some report lowering the distortion, as you have probably seen in the posts about current drive

GM, thanks! that is very useful, second graph that is, first one is my own fr response measurement of betsy-wow
I wonder why I missed that second plot, I searched everywnere
 

GM

Member
Joined 2003
GM, thanks! that is very useful, second graph that is, first one is my own fr response measurement of betsy-wow
I wonder why I missed that second plot, I searched everywnere

You're welcome!

Oh well, that's what happens when one just saves without taking the time to document the 'who/what' of it.

Dunno unless it's because it's for the 'K'............ Then again, it's one of Freddy's, so he may have sent it to me as we once did a fair amount of audio 'bench racing' via email.

GM
 
music soothes the savage beast
Joined 2004
Paid Member
Thanks d to the g! Its my clone of Marantz LS-85. I just like the look of the original Marantz. I will to speaker stands later, just to make it look sleak. Right now I am not using subwoofers with Betsy, only as a stand. But eventually the subs will be added.

Yesterday I was playing with Holm Impulse, and it measures pretty well (sounds darn good too). I will post some fr responses.

I believe this is pretty good place for Betsy...after whizzerectomy and dustectomy it measures flat 50Hz to 5 kHz, which is amazing. Plus nice phase plug gives it nice rolloff without much breakup. I am running Betsy wild, no inductor, and only one cap from 5 kHz up on ribbon. So far.

I did some distortion curves by Holm Impulse, and it measures well, except the rising distortion towards low frequencies. I am not sure if that can be helped by LRC filter, or not. Problem is that values for cap and coil are quite high. I can use bipolar electrolyt, those are cheap, but I do not have the coil at hand to try it. It would be interesting to see if LRC filter will have an effect on lowering the distortion or not though.

Here is how the filter should look like:
Series Notch Filter

Re = 5.7 Ohms

fs = 50 Hz

Qes = 0.945

Qms = 4.567


Parts List

--------------------------------------------------------------------------------
Capacitor
C = 591.11 uF
Inductor
L = 17.15 mH
Resistor
Rc = 6.879439456973944 Ohms
 
You're welcome! Yeah, impedance compensation down in the LF is no inexpensive tweak and why I prefer the pioneer's way of using a TL to damp it down. If you have a separate pre-amp/amp, then of course you can use small values across the amp's input.

That, or go digital and use a damping resistor and/or inductor to lower its typical 'bite'/'sharpness'.

GM
 
...after whizzerectomy and dustectomy it measures flat 50Hz to 5 kHz, which is amazing. Plus nice phase plug gives it nice rolloff without much breakup. I am running Betsy wild, no inductor, and only one cap from 5 kHz up on ribbon. So far.

I did some distortion curves by Holm Impulse, and it measures well, except the rising distortion towards low frequencies. I am not sure if that can be helped by LRC filter, or not.

I wonder if these are made by Eminence............. they at least use to be pretty good about making low volume sales. That, or maybe WBAL will consider either adding a new model or doing a buy.

Never had the tools back then to do much in the way of measurements, but seems like you'll be trading one type of distortion for another and all things considered, I personally prefer modest speaker distortion over large cap 'ringing', so at the least they would need damping resistors.

Seems like all this added inductance, series resistance would tend to 'suck the life' out of a high Qt speaker.

GM
 
GM, are you discussing a buy of the whizzerless betsy? It's not something that I normally have but I've done batches of them before. The "official" Betsy wow has a dustcap, but could just as well go without if someone is adding a phase plug.

Also, please shoot me an email. I'd like to get a full res copy of that impedance plot.
 
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music soothes the savage beast
Joined 2004
Paid Member
Never had the tools back then to do much in the way of measurements, but seems like you'll be trading one type of distortion for another and all things considered, I personally prefer modest speaker distortion over large cap 'ringing', so at the least they would need damping resistors.

Seems like all this added inductance, series resistance would tend to 'suck the life' out of a high Qt speaker.

GM

Only one way to find out. Once I get the parts to make the RLC filter, I will measure/listen before I add it on, then measure/listen again and see if there is a benefit or no. Its easily reversible, just remove the filter. Problem is I need to find out what else to order from PE.

Both, Tony Gee @humblehomemadehifi (Netherland) and Troels Gravesen @diy loudspeakers (Denmark) use the RLC filters a lot. Maybe because they have free parts or they promote purchase from sponsors, or perhaps there is a benefit to it. As I said, only one way to find out.
 
GM, are you discussing a buy of the whizzerless betsy? It's not something that I normally have but I've done batches of them before. The "official" Betsy wow has a dustcap, but could just as well go without if someone is adding a phase plug.

Also, please shoot me an email. I'd like to get a full res copy of that impedance plot.

Hmm, so Ed's plot is actually for the whizzerless version and it's called the 'wow'?

Mine is only 71.5 kb and to me doesn't look any better blown up than the one I posted. Try Freddy, I saved it as a gif: 'Betsyksolderz'

http://www.diyaudio.com/forums/private.php?do=newpm&u=35726

GM
 
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