6 dB per Octave Passive Crossovers

[mah]

FWIW

RE: Absolute nonsense - drlowmu - Tube DIY Asylum

[RonSSS]

I'm thinking about the wires that connect the woof terminals to the voice coil....oh my god, think of the length! And they are COPPER!

I'm screwed.....it's all for sale now........

[Altec Best]

Yes, this is Dr. LowMu elsewhere. I tried to be a bit diplomatic earlier but Jeff fails to see that others don't agree with his methodology. He's on a self proclaimed hiatus from his usual posting spot and can't stop putting his ideas out there, in this case here. His posts are inflammatory and by the tone of his first question I would say that he's trolling.

Thanks for pointing this out.. I will be on alert !

[SD-50]

Here's a crude schematic of the XO I've been using it for past year, rather satisfied with it so far. Arrived at this design after much trial and error; a great deal more error. The cabs themselves received much TLC before work began on the XOs. Cabs heavily braced; Horns each damped with 10lbs of non-drying modeling clay. Cabs sport 10in wings; horns also have side and top wings.
The throat and interior of the horns were buffed with sandpaper to remove surface imperfections caused by welding splatter.
I used decent, but not exotic components in the XO, foil inductors, metal film resisters, and surplus PIO caps bypassed with smaller values.
The amp used is a Simaudio Moon i-5080, Jolida CD-100, and an early Oracle Delphi with a Zeta arm and Koetsu Blackline Gold cartridge
Just about everything I?ve learned and applied to my Altecs was acquired from members of this site, so do appreciate any additional insight on my design.
Thank you.
Cheers

[mah]

The Seas ER18DXT ported two way uses 6db/octave crossovers but not Altecs.

[LowOhms]

Attachment 1739

Here's a crude schematic of the XO I've been using it for past year, rather satisfied with it so far. Arrived at this design after much trial and error; a great deal more error. The cabs themselves received much TLC before work began on the XOs. Cabs heavily braced; Horns each damped with 10lbs of non-drying modeling clay. Cabs sport 10in wings; horns also have side and top wings.
The throat and interior of the horns were buffed with sandpaper to remove surface imperfections caused by welding splatter.
I used decent, but not exotic components in the XO, foil inductors, metal film resisters, and surplus PIO caps bypassed with smaller values.
The amp used is a Simaudio Moon i-5080, Jolida CD-100, and an early Oracle Delphi with a Zeta arm and Koetsu Blackline Gold cartridge
Just about everything I’ve learned and applied to my Altecs was acquired from members of this site, so do appreciate any additional insight on my design.
Thank you.
Cheers

Hello SD-50.

I really appreciate you following-up as you said you would, and I am delighted to see your crossover schematic and description.

I have taken some freedom, and in the interest of sharing information with you and others, have converted your Parallel crossover to a Series crossover. Some contend Series is even better sounding, but I have no direct experience with this quite yet. In the first order ( 6 dB / octave) mode, one uses the same exact parts in Parallel and Series, very convenient !!

What is fascinating to me is the similarity between what you selected by trial and error by ear, and what Larry D. Moore selected over a number of years by ear also. Larry wrote up the hilarious story of his A7 experiences in issue number 6, of his UltraHiFi Times magazine, some years ago.

Should you (or any ALTEC enthusiast) care to be sent a copy of Larry's A7 write up, please email me at drlowmu AT gmail.com, mentioning this Altec Forum, and your moniker, and I will send his A7 crossover article promptly to anyone as an email attachment.

Cheers and thanks for contributing,

Jeff

NOTE: To clearly see the two Series A7 schematics, right click, and select " Open Link In New Window ". Click on plus / enlarge.

[LowOhms]

Yes, this is Dr. LowMu elsewhere. I tried to be a bit diplomatic earlier but Jeff fails to see that others don't agree with his methodology. He's on a self proclaimed hiatus from his usual posting spot and can't stop putting his ideas out there, in this case here. In the past Jeff has written that he can hear the difference between a cathode resistor of 10 ohms difference. I asked whether that was hot or cold without a response. His posts are inflammatory and by the tone of his first question I would say that he's trolling. His experience goes way beyond most posters and if he's asking about Altec, he's owned them before or has personal experience with a variety of drivers. His current favourite speakers are by a friend of his that uses 604"s.

Hi Zelgall,

You have gotten a few things correct, and you have also made several rather important errors. I do not have the time to spend, nor frankly the inclination, to accurately respond to your writings.

If you would like to contact me privately, I will be happy to email you, so you can re-post about me to others 100% factually. I certainly would appreciate you doing that. Thanks.

Sincerely,

Jeff

[mah]

drlowmu hears volts: RE: Biasing a 300B amp - by ear? - drlowmu - SET Asylum

I hear sound pressure variations.

[zelgall]

Hi Zelgall,

You have gotten a few things correct, and you have also made several rather important errors. I do not have the time to spend, nor frankly the inclination, to accurately respond to your writings.

If you would like to contact me privately, I will be happy to email you, so you can re-post about me to others 100% factually. I certainly would appreciate you doing that. Thanks.

Sincerely,

Jeff

Jeff, you are correct. I did misquote you and it was due to my poor memory. My apologies. It was about 8 years ago but that's not an excuse.
It was a grid stopper that was in question and it wasn't that you could hear a 10 ohm difference, it was .05 ohms.
This is the relevant post from DIY tube Asylum:

Posted by drlowmu on October 4, 2004 at 07:59:39
In Reply to: Question for Doctor Low Mu posted by Vinnie on October 4, 2004 at 03:00:21:

Hey, if I had one you could duplicate, I'd send it off to you but I don't.
I can tell you, by ear, I very much like 115.00 ohm grid stoppers on that tube, and a 2A3. ( 114.95 ohms minimum, to 115.00 maximum, using a Fluke 8060A ).

My current P-P 6B4G amp is basically a globe 27 ( 227 ) AC ( cap ) coupled to a UTC A-18 as a splitter driver trannie, to P-P 6B4G's and into a pair of Dyna ( ST-35, SCA-35 ) output trannies, real sleepers.

But the amp's two B+ supplies are real low in DCR, employ eight 5Z3's, double tube regulated ( series ) and would be a nightmare for you to try to duplicate, as would the multiple L/C/L/C & current sourced DC Filament supplies. Its on four chassis. Got the mental picture??

Jefrf Medwin

[LowOhms]

Hi Zelgall,

Thank you, very nice !! I actually remember someone ( you ) eight years ago asking me about hot and cold resistances. Wow.

I shall give you my delayed answer - today !!

Since its a grid stopper, ( and not a power dissipating plate or cathode resistor ), the grid stopper would dissipate very MINOR power (heat) and it would be most subject to the ambient temperature rise of the amp, below deck. I am an amateur, and had no way of accurately measuring that.

Thank goodness, I had a couple of 4 1/2 digit Fluke 8060As working well back then, to measure things. Also, anyone can compute what happens when you place 1 MEG Ohm resistor across a 120 Ohm resistor, as a minute fractional change.

( IIRC) each mono amp had 22 regulators on them ( 16 for the filaments and 6 regulators for the B+ ) so "everything" was locked down good and tight, and it allowed me to make esoteric listening differentiations, that likely, no one in audio had ever had the opportunity to do.

Zegall, how do you think I felt when people intimated I was crazy and lying ?? Not so nice at all. When my Kansas City audio buddies HEARD that P-P-P 6B4G amp in their homes, they named me "drlowmu".... from that day on !! WE knew it was the best thing we all had ever heard. The darn ( " Zediker " ) solid state B+ regulators would blow regularly, and it became a nightmare for me to keep it going, so it got retired. An all-out FUN triode amplifier to design, build, and experience.

Since 1988, I have heard better amps, the super expensive MBL amps are wonderous to me playing their cost prohibitive MBL Radialstrayler omni speakers. For tube amps, I easily most-respect the Serious Stereo 2A3 DC amps' performance playing Altecs, over anything anyone else has built. YMMV, just my opinion, very subjective.

Good news, long-time Forum member SD-50 and I are now comparing ideas on "6 dB" crossovered A7s. He MAY even try a SERIES hookup next !! We maybe will learn things, from his work and listening. Great !

Jeff