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6DJ8 Tube Crossover [message #39688]

Thu, 02 January 2003 02:51

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

I've put the Spice model online for the π implementation of the 6DJ8 tube crossover. You'll need OrCad's version "PSpice" to run this model, and you'll need to install the libraries contained in the distribution file. It's a pretty big distribution, to tell the truth, but it has the advantage of allowing you to work directly with the schematic. OrCad was originally written for PCB layout, so you can layout a circuit board and have fiberglass made with it too.

First, download "PSpice" and install it, and then download the 6DJ8 crossover model. Inside the crossover distribution file, you'll find another archive called "Tubemods.zip" which must be installed and configured before the model will work.

http://www.pispeakers.com/Tube_Crossover.gif

Active implementation of π compensated crossover using 6DJ8 tube

First, second and third order networks can be formed by configuring the circuit to use one, two or three poles. Components R15/R16 and C10 are similar to R1/R2 and C1 on the π passive crossover networks. This is the HF compensation section of the circuit, and values may be modified for different amounts of compensation. You'll also notice the addition of resistor R17 in the LF circuit, which damps the filter and improves response. All other component designations follow those used by Steve Bench in his crossover circuit.

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Re: 6DJ8 Tube Crossover [message #39689 is a reply to message #39688]

Thu, 02 January 2003 03:11

spkrman57
Messages: 522
Registered: May 2009

Illuminati (1st Degree)

Wayne,
Would like to see if anyone out there will provide kit form or finished built product for those of us who don't have the time to build. Sounds like a good thing though. Keep us informed.
Regards, Ron

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Re: 6DJ8 Tube Crossover [message #39696 is a reply to message #39689]

Thu, 02 January 2003 12:16

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

Check out Gary Kaufmann's PCB:

http://www.the-planet.org/images/pcb-1.jpg

The traces correspond to Steve Bench's crossover, which is what the circuit is based on. Steve says that Gary's board has room for the extra components, and you can see from the photograph that there are what appears to be prototyping holes just under the tube location. I haven't confirmed this to be true, but since there are only four additional parts, I expect that it will work quite well. My circuit is the same as Steve's, except for the additional components R15, R16, R17 and C10, used for tweeter compensation. The Spice model makes it easy to tailor the crossover and configure it for response curves that suit our needs.

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Wayne.... [message #39697 is a reply to message #39696]

Thu, 02 January 2003 12:27

Garland
Messages: 269
Registered: May 2009

Grand Master

At some time would you be able to specify the components on Gary Kaufman's boards for use with My Theater 4's. I'm fair at soldering but no good at working with computers, downloads, etc. Dave Cope and I are ordering a batch of boards from Gary and hope to have something working in the not too distant future. (That is, "with a little help from our friends")

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Four π implementation [message #39698 is a reply to message #39697]

Thu, 02 January 2003 13:00

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

I'd be happy to make a recommendation for the configuration of these boards for your Theater Series four π Speakers. Give me a couple of days, and I'll have it for you.

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Re: Four π implementation [message #39702 is a reply to message #39698]

Thu, 02 January 2003 15:09

Rusty Iron
Messages: 3
Registered: May 2009

Esquire

Hi Wayne,
I already have the board for Steve's crossover which I got from Gary and I'm also interested in setting it up for the Pi4. Would certainly appreciate receiving your response also when you have it worked out.
Regards,
Russ Stevens

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Re: Four π implementation [message #39703 is a reply to message #39698]

Thu, 02 January 2003 17:12

Garland
Messages: 269
Registered: May 2009

Grand Master

"You da Man!"

Thanks as always!

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Re: Four π implementation [message #39794 is a reply to message #39703]

Wed, 08 January 2003 16:30

Wayne Parham
Messages: 18787
Registered: January 2001

Illuminati (33rd Degree)

Here are lists of component values:

For an Altec 811 or other horn with collapsing directivity:

R1 - 1M
R2 - 1M
R3 - 1M
R4 - 91K
R5 - 100K
R6 - 100K
R7 - 22K
R8 - 1M
R9 - 89K
R10 - 18K
R11 - 1.3M
R12 - 1.3M
R13 - 22K
R14 - 1M
R15 - 3.3M
R16 - 3.3M
R17 - 220K
C1 - 0.22uF
C2 - 2200pF
C3 - 0.01uF
C4 - 270pF
C5 - 0.22uF
C6 - 2200pF
C7 - 2200pF
C8 - 2200pF
C9 - 0.22uF
C10 - 15pF

For a Peavey CH-3, Eminence H290 or Martinelli horn:

R1 - 1M
R2 - 1M
R3 - 1M
R4 - 75K
R5 - 83K
R6 - 83K
R7 - 22K
R8 - 1M
R9 - 150K
R10 - 33K
R11 - 2.2M
R12 - 2.2M
R13 - 22K
R14 - 1M
R15 - 3.3M
R16 - 3.3M
R17 - 220K
C1 - 0.22uF
C2 - 1600pF
C3 - 6800pF
C4 - 200pF
C5 - 0.22uF
C6 - 1000pF
C7 - 1000pF
C8 - 1000pF
C9 - 0.22uF
C10 - 10pF