EH Deluxe octave multiplexer ...almost

[hank reynolds 3rd]

Hi All,
I've drawn up a layout for this pedal, and sent it on to someone else to put it in the gallery...I was just wondering if the 1048 can be replaced with a 13700 ,using the buffer thingys on that chip instead of the darlington option (or use the opamp on the 13700 and the two transistors externally)...
I got the idea from the tonepad site ,for the small stone...would the resistor value be the same (as I'm guessing the trans?resistors ar simulating the internal ones on the 3098/1048??)

This pcb is all done except for this one bit, The boards kinda big but I'm guessing the ideas above should kinda work,I just don't fancy breadboarding this thing!!!

Ta in advance

Sam

[StephenGiles]

You may be able to change the CA3094 (EH1048) for a 13600 with some changes in the circuitry around it. I would save sleepless nights by finding some 3094s because that is the baby used in the original design. I thought Smallbear had some.
Stephen

[nelson]

smallbear has em for $4.95.

Bill

I put the layout and hand drawn schem up on webspace as you asked. I made the files a little smaller for ease of download, 700kb instead of 1.86mb for the layout. I believe the 2N4302 can be replaced with 2N5458?.


http://www.auaj24.dsl.pipex.com/edolayout.JPG      <----layout


http://www.auaj24.dsl.pipex.com/hdschem.gif         <----Hand drawn Schem



I have friend who owns a deluxe octave multiplexer and I am going to ask him to scan the board. Depending on which layout is smaller I will make a computer generated project out of them. It would be good to modify the existing EH board for replacement of the CA3094,  however for my personal clone I wouldnt mind paying the 5 or so bucks.


edit: it is the 2N5458 that can be subbed for 2N4302

[aron]

I have an Octave Multiplexer, but not the deluxe version.

[hank reynolds 3rd]

Howsabout a scan of the standard multiplexer??  :wink:  :wink:

I might go with the ca3094's then...Cheap enough and i guess it saves hassle...was just thinking of a workaround and quick replacements if those chips ever die...
Thanks for posting it Nelson, I've also drawn a pcb for the original Zipper filter last night ...two lm324/tl084's and 3 fet's....I'll post it off if i can get to the scanner (I use the local library and can only get 1hr per visit,and someones using it right now...dammit!!!)

Cheers

Sam

[hank reynolds 3rd]

Plus 5 dollars works out at around £2.50, so I think that seems like a good option (plus smallbear has the 2n5458's aswell)...
It's payday tomorrow aswell!! I got a busy week ahead methinks ...Mulitplexer,Clone theory ,Zipper and Some of the Metal Studding for cheapo Diy boxes  (on the GEO site )is in order !!!
Bueno!!

Sam

P.S: there's scope for a few mods aswell, (i'm guessing here)like changing the 470k in the fuzz section to a pot for variable gain, and maybe a tone stack (bmp/rat/swollen pickle??), also seperate pots for straight signal and octave going into an opamp at the output (output buffer???)..As you can see,My theory is crap, but my perseverance usually gets me results!!!

[nelson]

if you are using my clone theory layout make sure you have the most uptodate one, I changed it recently thats my next build too, I have every part but the fet. I am actually going to work out the stereo mod, the delay pot mod and the blinking LED mod and add pads on the PCB for them before i build it.

Having the option to route the octave signal to a seperate stereo out would be a good idea for a mod on the octave multiplexer aswell as the others you mentioned.

[hank reynolds 3rd]

Hi Nelson,
I've drawn up my own layout for the clone theory as I'm using the sad1024 version,but I've spliced in the vibraflange switch aswell...cheers anyways..This along with the multiplexer and the EchoFlanger are all on my up and coming list, but I found the time to draw up a layout for the zipper filter the other night...Check your inbox if you fancy posting it...

Cheers

Sam

P.S:whats the delay pot mod for the Clone theory???

[nelson]

I am thinking the resistor coming off the CD4047 can be replaced with a pot aswell as changing the cap, much the same way that changing the resistor to a pot on the CD4047 in the small clone can alter the delay of the BBD. In effect being able to get flanging all the way up to slapback delay, although the low pass filtering on the clone theory wont be nearly enough for slapback.

[Zero the hero]

Finding a way to sub a CA3904 would be cool: I'vo got a couple of EH schem I would trace, but avoidinig using this part since it has been discontinued while ago...

[StephenGiles]

Since the 3080 has also been discontinued it must be the LM13600 or equivalent that needs to be substituted for the CA3094, but in no way are they the same so surely some serious additional circuitry is required to make the 13600 act in exactly the same way. I had a lengthy explanation of the 3094 from Joe Truchess, an EH designer who worked at EH UK back in 1980 who told me that one of the reasons that EH used that chip was that no alternative existed, including the 13600, because it doesn't behave in the same way. So, if someone cares to prepare a 13600 mod circuit he'll be a hero!!!
Stephen

[Zero the hero]

a bit disappointed... the korg guitarsynth is in my wishlist, but it's almost entirely based on CA3094...

[nelson]

http://www.auaj24.dsl.pipex.com/Zipper.jpg


There you go man


Enjoy.

I really cant decipher the layout, if you make a PNP graphic and layout let me know I will host it.