EH - Clone Theory ( versions )

Professor SourTone · Post by **Professor SourTone** » 18 Mar 2008, 09:21

This was brought up on another forum, and in researching I found this page. I have two old Clone Theories, an earlier one with red graphics and an "edge" switch, and a later one with chorus/vib-vib/flange switch instead. I like the red one better, with the edge "on" always.

This site says they have different chips. It says the earlier version is based on the SAD1024 chip, and the later one on the MN3007. Is this so? I can dig them out and have a look, of course.

http://electroconducive.googlepages.com/ehxclonetheory

EHCloneTheory.pdf: EHX Clone Theory project files; (165.81 KiB) Downloaded 381 times

analogguru · Post by **analogguru** » 18 Mar 2008, 09:40

There were two versions, the early one from 1977 with SAD1024A and the 1980 version with MN3007.

They are similar but from a schematic viewpoint they are totally different - not only the BBD has been replaced, the complete circuit was reworked.

guts are always welcome, especially since I don´t trust the EH-1317 (SAD1024A) factory schematic.

analogguru

Professor SourTone · Post by **Professor SourTone** » 18 Mar 2008, 09:42

WilCo

andregarcia57 · Post by **andregarcia57** » 26 Feb 2009, 20:43

hum... great!

Professor SourTone · Post by **Professor SourTone** » 26 Feb 2009, 23:21

Sorry, forgot - will attempt this w/e

nelson · Post by **nelson** » 27 Feb 2009, 16:27

Professor SourTone wrote:Sorry, forgot - will attempt this w/e

I'd love to see them too.

Professor SourTone · Post by **Professor SourTone** » 01 Mar 2009, 16:04

Vib Flange version

Edge version

Professor SourTone · Post by **Professor SourTone** » 01 Mar 2009, 18:38

Oddly enough the edge version has the MN3007 and the board layout looks similar to my uneducated eye.

analogguru · Post by **analogguru** » 02 Mar 2009, 01:12

Oddly enough the edge version has the MN3007 and the board layout looks similar to my uneducated eye.

Thats not very astonishing. The edge version is from the end of 1979 and the other is from mid 1980.

Thanks for the pictures. Here is a different version, maybe the SAD-version.

Professor SourTone · Post by **Professor SourTone** » 02 Mar 2009, 08:42

That's interesting - so there appear to be 3 versions

SAD with Edge
EH 3000 MN3007 with Edge
EH 3000 MN3007 with VibFlange

borislavgajic · Post by **borislavgajic** » 02 Mar 2009, 10:02

thanks for great pictures

theehman · Post by **theehman** » 02 Mar 2009, 17:58

Professor SourTone wrote:That's interesting - so there appear to be 3 versions

SAD with Edge
EH 3000 MN3007 with Edge
EH 3000 MN3007 with VibFlange

Are the slide switches in your units wired the same? Maybe you have a transitional unit?

Professor SourTone · Post by **Professor SourTone** » 02 Mar 2009, 18:17

They can't be wired the same because the functionality is different. There do seem to be a couple of extra caps on the trace side of one of the circuit boards. Unfortunately once again I do not have the units with me...

theehman · Post by **theehman** » 02 Mar 2009, 18:37

Professor SourTone wrote:They can't be wired the same because the functionality is different. There do seem to be a couple of extra caps on the trace side of one of the circuit boards. Unfortunately once again I do not have the units with me...

I think those caps are on the back of the board due to space reasons.

V1nce69 · Post by **V1nce69** » 10 Nov 2013, 08:22

I own a vintage Clone Theory that is an EDGE SAD version.
Here are some pictures of its guts:

: outside view

: inside view

: the board, rear side

: the board, front side

: original EH1317 schematic

May be these can be of some interest to all of you.

Vince

Scruffie · Post by **Scruffie** » 09 Jan 2014, 18:19

Having traced through those MN3007 units above (they are both wired the same for the edge switch so I don't know why they sound different but the edge one is just a transitional model) I think i've discovered that both Tom Boy and subsequently Nelsons schematics are incorrect, here's what i've got so far;

This applies to the Nelson schematic;
No - C19
No - C20
No - C7
C22 - 560pF
C17 - Possibly 220nF?
R33 & 34 - 220k
5k Cancel Trim (No R10 & 11)
C8 - 100nF

R21, 22 & C14 wrong, R22 (160k, maybe 150k on the other unit) and R21 (1k?) with switch pole coming from the center, R21 goes through 100nF to ground.

Output, Pin 7 through 1k? (switch pole connects here) with ?? Cap to ground in to ?? Output cap with 100k pull down.

If anyone has a unit that can help confirming all the cap values and those 3 questionable resistors that'd be a help in getting a correct schematic.

phibes · Post by **phibes** » 10 Jan 2014, 15:01

Email me Scruff, I got a SAD1024 unit.

Scruffie · Post by **Scruffie** » 11 Jan 2014, 02:52

As far as I can tell, this is now 100% correct for the MN3007 version except for the values of C5 & 6 which I have left as 680pF for now as the original has a cap labelled 412 and I cannot confirm what the actual value is, both 412pF and 4,1nF seem like very odd values.

Vib Flange Switch is shown incorrectly, 2nd half should be in N.C position and the input opamp should be U1A - RC4558.

Thanks to pinkjimiphoton for confirming some values from his original units.

pinkjimiphoton · Post by **pinkjimiphoton** » 19 May 2014, 20:59

alright, ya got it done!! sweet!! i wanna build one now, cuz the other one is similar (the toppopiccione site one) but i think it's a modded small clone, not a clone theory.

the actual mn3007 clone theory is THE one to have. the sad1024 version with the "edge" switch is pretty much a "feature" that lets the full frequency of that hiss come thru...

Scruffie · Post by **Scruffie** » 19 May 2014, 22:11

pinkjimiphoton wrote:alright, ya got it done!! sweet!! i wanna build one now, cuz the other one is similar (the toppopiccione site one) but i think it's a modded small clone, not a clone theory.

the actual mn3007 clone theory is THE one to have. the sad1024 version with the "edge" switch is pretty much a "feature" that lets the full frequency of that hiss come thru...

Nah the toppopiccione one is a clone theory, only the filtering & feedback is a bit wrong, there's some unnecessary parts and a few wrong values.

But yup, got it all confirmed and eventually got hold a copy of the factory schematic, my redraw is correct.

Keep an eye on the madbean forum in the next few days too

EH - Clone Theory ( versions ) [schematic]