Farewell type 'AL' Hello type 'A-LPD'

[Erik Mandaville]

I have so much grading to get done in the next two days, I decided to take a brief mental vacation from that. For those of you keeping up with the L-pad thread/information, Here is my plan:

edit: I will work on the values to get them right, since there is going to be some interaction of the series connected L and C in the band-pas section. The easiest thing to do would just be install the L-pad after the autoformer, but that's not what I necessarily want to do. There may be a better way, but some value changes of capacitance and inductance will be needed.

Erik

[Erik Mandaville]

Here is what I'm going to call the type A-LPD. Getting into this last night I realized I was calculating for low pass section inductor -- too sleepy from the day, but this is what it's going to be for a trial run. As is shown, the L-pad comes AFTER the crossover (autoformer included), and is used exclusively for midrange volume control. I would really like to completely re-design the network, with series L and C in the band pass section, where the required coil will be more in the range of .50mH and the series connected capacitor around 30uf, or so. I just wish I had the means of testing the response when all is said and done -- which with me will probably never be the case. I need to get my hands on a good on-line crossover calculator, since I am using an ancient graph, based on relationships of inductance, capacitance, driver impedance, and desired frequency of reactance. It works, but is maybe a little more crude than what can be found today.

For those of you who would like to try a very easy way to control the output of your midrange horn -- and in this case (thanks to a couple of suggestions humbly made) -- without significant change crossover frequencies -- this would be a method you might find useful.

What is shown is an AA-to-A with and L-pad. I am not going to go nuts with expensive capacitors right now.

Erik

[AnalOg]

Eric,

Did you say you were an Art Teacher, stick to it, Your photo skills suck!!

Tom

[Erik Mandaville]

Holy smokes! does someone know how I can shrink that down a bit!? I need to bring back home my camera from school. It works much better for me with this.

[Erik Mandaville]

LOL! Yeah, I have trouble with my wife's camera, but the one at school does a decent job.

This is Wolfram's GG preamp, before I decided on using the same kind of input level control that Mark D. uses on his great Peach preamp. All the wiring on the right was removed and redone. That center potentiometer had one section completely expired, and had to be replaced.

[Erik Mandaville]

Let's see if this is better...

Ugh -- still looks like crap. Way too fuzzy, sorry about that. At least you can see the basic layout of the parts.

[Deang]

"I would really like to completely re-design the network, with series L and C in the band pass section, where the required coil will be more in the range of .50mH and the series connected capacitor around 30uf, or so."

Here you go. Courtesy of John Albright. To build these "my" way costs close enough that one might as well buy some ALKs. It's the only thing that's stopped me from offering them.

[Erik Mandaville]

That's not my design, it's someone else's, just as ALK's. This is straightforward, and looks fine. Once basic crossover points are established based on known driver impedances/behaviors, certain elements will remain the similar among a number of different designs. Certainly there will be small differences, but I could do it MY way for much less than what someone else might charge -- and so could lots of people with a little practice. Crossovers are not difficult to make. My mom soldered together a complete radio by herself. All one has to do is get some encouragement, and given some confidence in their own abilities -- which they may never become aware of if always told it will be too difficult, or that soldering takes surgical expertise (which it absolutely does not). It's easy, and can be mastered in a weekend if there is a will to do so.

BTW: How does one control the output on the midrange in the above network? What I have in mind seems easier -- to me...

Erik

[Deang]

O.K. Erik. I think everyone knows by now how EASY it is to build and solder a network together. I mean, you mention it in over half of your posts. When I referred to "my way", I was talking about the use of expensive capacitors. You know, most can tune up their own engine and change their oil, or paint their own house, do their own plumbing, etc. -- but do they? Sometimes it's not because someone lacks the skill-sets, but simply because they just don't have the time to mess with it. My DIY thread in mods sure hasn't slowed down my orders any.

John's network has the correct series L-C in the passband that you were looking for -- I was trying to be helpful.

[Erik Mandaville]

You're right, I do mention it often -- in order to balance the seemingly prevailing belief that soldering is some sort of mystery. I try to encourage self-reliance and confidence rather than dependance on others. Sometimes that dependence (or just trust) IS the result of simply not wanting to take the time, such as in building an amplifier -- which I in fact mentioned to you, Dean. BTW: Did you see the offer I made to you concerning the loan of a great little amp for the time it would take you to build your own? If not, that offer still stands. You said you would have to be without tunes, and I was trying to be helpful in letting use one of my amps for the time it took you to build one. I'm assumming you've read the posts in your need for a new amp, which is where I left that for you.

Erik

I like the auto light bulb protection on the tweeter. That's a neat idea.

[Erik Mandaville]

And, if you have a look in an earlier post of mine in the same thread, I also said I will send you the punches you would need (which are NOT cheap) to build whatever design you thought you might like to try. That offer still stands, as well.

Erik

[mikebse2a3]

Eric

hopefully this is a resized picture of the AA to A with L-Pad picture you posted.

mike

[Erik Mandaville]

That is indeed much better, Mike. Thank you for doing that for me.

Have a good evening,

Erik

[Deang]

I saw the generous offers, and thanked everyone for them -- this included you.

I don't build my own amp(s) for the same reason many probably don't build their own networks -- no time. I basically work three jobs. I do 50 hours during the week, as well as work 2nd shift Saturdays and Sundays. I also spend a few nights a week rebuilding, or building networks to further supplement the income. The decision Deb and me made to quit her $45,000 a year job and home school the kids wasn't an easy one -- but this is what I have to do to make it work for all of us.

I sure don't have a problem with you encouraging people to do things themselves, but I do have a problem when you infer that people are wasting their money when they use me. Sure, you've never come out and said it straight-out, but people aren't stupid -- even me.

[mobile homeless]

Welcome to the Mandaville Paradox...

[Erik Mandaville]

"but I do have a problem when you infer that people are wasting their money when they use me. Sure, you've never come out and said it straight-out, but people aren't stupid -- even me."

This has been jerked completely out of context. There have been numerous times in the past where someone had indicated they wished they had the ability for a small amount of DIYing. You have also openly indicated on several occasions that soldering is not as straightforward as some have made it out to be. It's just that sort of thing that could possibly prevent someone from undertaking a project that would otherwise might be a very rewarding experience. If you read a my post a little more closely, I also said that someone might just prefer to defer the work -- for whatever reason they may have. That is entirely a personal choice. That the crossover you illustrated above should cost nearly the price of an ALK, in my opinion, puts it beyond the reach of many who might otherwise be interested in it; and is the primary reason you indicated for not making it available.

It's possible to make a very decent sounding and good performing network with less expensive parts, and one can have the added enjoyment of building as a project for themselves.

You mentioned that you don't build your own amplifiers. May I ask if you came into the world building your own crossovers? Dean: We have all mentioned at some point in the past that there were occasions where any surplus of time might be more constructively spent doing things other than defend our PP or SET amplifiers here on this forum. In the same time it has taken each of us to go through the thinking and composing and typing required to submit a post, we could have punched a couple of holes in a chassis, soldered together several connections, secured a couple of power supply filter caps...that sort of thing. I strongly disagree about the time issue. Choosing how to spend one's small amount of personal time is a personal choice, and is different from the availability of time.

If my inference was that people are wasting their money (which is actually their very own personal choice and decision and no business of mine) on buying alreadly built crossovers from you, it would logically stand to reason that my suggestion for you to try your hand at amplifier building (along with tools I would loan you to make it easier)is an underhanded way of telling people they are wasting their money on buying products from the many sellers of audio electronics and electronic kits. In an effort to 'help' generate business in another way, I have suggested that you possibly consider providing 'kit versions' of your crossovers. This would help promote sales, as well as give people an easier in-road to doing a fun project for themselves.

I didn't come into the world building amplifiers, either. I would submit, however, that if the interest were strong enough, a re-juggling or reorganization of time available could put it quite easily within your reach. If one were to add up the thousands of posts we have scrawled into this electronic forum over the months and years, I think we would find the equivalent of many, many hours that could have otherwise been spent on a project completely of our own making. I suggested one of JFL's amps because I know from experience they are damn good sounding amplifiers. I also pointed out(some time ago) that this latest on-line DIY project, co-authored by KH and Jeff, was an outstanding way for people to start what I KNOW would result in a fine sounding amplifier. I rather think that it was not their intention to imply that people would be wasting their money on buying an already built PP2A3 amp project (Hi, Kelly), but to help make a very good product more affordable than it would otherwise be -- and hopefully foster an interest in very satisfying DIYing at the same time.

Twist what I have said into whatever shape you want -- it won't change the essence of the message.

[AnalOg]

Erik,

Wow, are you sure you're an Art Teacher!

Tom

[Born2RockU]

I can step up and gladly state that ERIK Mandaville is so much more then that.

We can start w/ ...a great honest friend !!

[Born2RockU]

[3dzapper]

Both these individuals deserve to be commended. Both for their contributions to the education of our youths each in a different way and their willingness to share with us all their expertise. In another thread, in another section of the forum, Dean gives a beautiful step by step instructional essay on xover rebuilding for budding DIYers. Erik is always sharing his experiences, good and bad, in hiswell written easy to understand manner.

Because I admire and respect both of them, I humbly ask them to take their dirty linen private and work out whatever. Let's keep this Christmas merry.

Rick