THD Analyzer Test of the Subwoofers

[Ethan Winer]

If I could put a 60Hz notch filter in there, I could possibly read with more accuracy.

I have a notch filter distortion analyzer I designed and built in the 1980s, and it still works (last time I used it a few years ago). Here's the R-e/p magazine article that describes it:

http://www.ethanwiner.com/distort.html

See Figure 4. If you think this would be useful, let me know and I'll bring it over some night this week.

--Ethan

 

[Ethan Winer]

Ah, sorry for the false hope. I was confusing my RTA and distortion analyzer. I realize now that you'd have to change the analyzer circuit slightly to tune it to notch out 60 Hz. You're welcome to do that though if you'd like. It'd be easier than making a notch filter from scratch.

--Ethan

 

[Mark (Basspig) Weiss]

Ah, sorry for the false hope. I was confusing my RTA and distortion analyzer. I realize now that you'd have to change the analyzer circuit slightly to tune it to notch out 60 Hz. You're welcome to do that though if you'd like. It'd be easier than making a notch filter from scratch.

--Ethan

I'm chasing after 60Hz hum that is 80dB down now. Flipping the ac line cord plug on the mic preamp bought me another 15dB of hum reduction.
Thanks for the generous offer though!


(BTW, did you and Kal get the invite for the meetup here at the end of the month?)

 

[Ethan Winer]

I'm chasing after 60Hz hum that is 80dB down now. Flipping the ac line cord plug on the mic preamp bought me another 15dB of hum reduction.

Yeah, a line-level notch filter probably won't do much for that.

(BTW, did you and Kal get the invite for the meetup here at the end of the month?)

I don't know about Kal, but I got your invitation. It's a little early in the day for me, and I'm not much of a "get-together with many" person. But I may show up. It's on my calendar, anyway!

--Ethan

 

[Mark (Basspig) Weiss]

Just hit 'reply to thread' and wiped out everything I typed here...

Not much a line filter will do. At any rate, I have multiple means of measuring and interpreting data.



We'd love to have you at the shindig. Even if for just an hour, toward evening. This will be an all-day and into the night event. Some folks are driving up from other states and staying in hotels for this.

 

[Ethan Winer]

We'd love to have you at the shindig. Even if for just an hour, toward evening. This will be an all-day and into the night event. Some folks are driving up from other states and staying in hotels for this.

I'm planning to come by later in the afternoon.

--Ethan

 

[Mark (Basspig) Weiss]

Fantastic!

 

[Ethan Winer]

Also, since you wanted to know how many people to expect, Elli is coming with me too. We'll get there around 5:00 pm or so. Looking forward to seeing you again Mark.

--Ethan

 

[Mark (Basspig) Weiss]

Super!

I've been organizing the lab and getting equipment in order.. picked up a non-working curve tracer and started repairing it. Needed some new caps in the power supply mostly and there's a problem with some of the voltage ranges in horizontal and vertical step gain, but as long as the curves of the DUT fit on screen, it works great. I plan to do a couple demos of capacitor distortion and vacuum tube filament voltage effects on 3rd order distortion, as part of the 'lab' portion. You'll miss dinner, which is being served around 3pm, but I'm sure there will be lasagna remaining, as my recipe makes a lot. Anyway, there will be eats available throughout the day/eve.

Gonna be a fun day! 3 others confirmed, some coming from as far as PA.