ECN Forum Forums Technical Discussion Electrical Theory and Applications A taper or B taper, which is it?

I read this the other day until I got a headache! http://www.edn.com/article/520749-I...alizer_filter.php?cid=NL_UBM+Electronics
Notice that nobody made any comments.

Then I thought of your project Trumpy, and thought you might want to add some tilt to it.
Joe

Joe,

I like that filter!!!
Kind of looks like 1/3 of a Parametric Equalizer.

Mike,

I have a similar problem regarding personal Projects (the "Not Work Related / Fun Projects"), being that there is always some pressing task, which comes along right after I begin working on something non-work based!

Kind of sucks about the Plywood - more appropriate, the 'lack-of' Plywood.
Is MDF also difficult to obtain?

-- Scott

Scott,
Now if he had only come up with the Excel spreadsheet so that we could just plug and chug! I know, I know, There's probably already an "App for That!" I have absolutely no use for that filter but it might be a fun way to try out those digital pots I bought without having a use for them. (One of the ones that stores the last count in NOVRAM on power down.)
Joe

Hi Scott,
I got the plywood late last night, however with my hectic work schedule (think coming to the end of the "fitting season" here), it's going to be a wee while before I have saw-dust on my workshop floor.

A couple of weeks back, I managed to get the PCB loaded:


The green wires are all earth points taken back to a common ground and will be tied via a crimp lug to mains earth on the body of the case.

Mike,

The PCB looks sweet! Nice Soldering work on the Ground Leads, too!

Maybe you will get Snowed in at Home; severe enough to allow 3 days of paid vacation..., which could be more like Power Amp / Enclosure Construction time.
Several Gallons of Fuel, an adequate Genny, and an understanding Spouse would be perfect!

For me and others North of the Equator, the Season is inverted as would be Winter in the Southern Hemisphere is Summer here.
Two Weeks after the Summer Solstice, the hot stuff kicked in with a vengeance!

Three Heat-Related outages were experienced since the Vernal Equinox (March 20-22), with Two occurring since July 1st!

One of the Outages was due to a Primary Feeder failure on a Pole, located 2 Blocks away.
The ACSR Conductor failed at a Dead-End Insulator, and that Single Ungrounded Conductor fell to a freshly paved Parking area below!
I was not there to witness the Fireworks, but judging from the Flash Points, and the actions of the Security Guards standing near the downed Conductor, it must have been sparky and loud!

When the PoCo re-closed the Breaker (attempt to "blow free" the fault issue) , the resulting "BOOM!!!" was loud and clear at my House!

Outage lasted about 3 Hours.

Anyhow, keep us informed to the progress!

-- Scott (EE)

These chips sure do make building amps easy. I remember building my first audio amp with tubes. It was probably about 5 watts output with more like 20-30w in, just to keep the tubes warm.
That LM3876 is rated at 56W

Yeah Greg,
I have quite a large heatsink in mind for this project and if all goes well, it shouldn't even be running anywhere near rated wattage.

I have to agree in saying that these chips do make building an amp pretty easy, especially with a minimal amount of field components.
When I first decided to buy this kit, I checked out the LM3876 chip to see what it's parameters were, for the dollar spent, this seemed like the best value for money.
Although I would have loved a valve (tube) amp, I'd still be in the design process and this kit was a means to an end.

I suppose the next part of this project will be placing the toroidal transformer, getting the bridge rectifier and filter capacitors mounted to the base of the case and then wiring them up.

Guys,
I'm in two minds about the speaker enclosure, what I've decided on is 4 x 8" drivers, I bought a bass port tube and some foam to go inside the enclosure.
I've got enough plywood and timber (for the sub-frame), to make the box any size I like.
It's the actual dimensions that have me really up in the air, I mean you could probably make the box any size you liked (as long as the speakers fitted), but speaker enclosure design is not something I've had a lot to do with.

Any thoughts there fella's?

Then you are going to be looking for crossovers ;-)

I did this some years ago and ended up with some pretty nice speakers but they were big honking things that I had a problem finding a place for.
They did not make the trip into my new entertainment center.
I gave them to a church here that got robbed and lost all of their audio equipment.

What voltage is that amp running on?

Cross-overs?
Why?
Although I can sort of understand what you're saying, I've never actually needed them before.

This amp is powered by 230V mains, fed into a 160VA transformer that has 2 x 25V secondary windings, that will be wired in series to give a 50V center-tapped output fed into a bridge rectifier.
This then feeds 2 x 2200uF 63V electrolytic capacitors, giving 2 balanced supply rails of +/-35V

If you are building a speaker box with multiple speakers you really want to split out the highs, mid range and lows.