EH Echoflanger layout finished, Layout inside.

[nelson]

ahhhh, so a gain recovery stage needs to be tacked on.

[nelson]

Cheers for mentioning that britt, I have updated the file.

[dj_death]

Thanks for the explantion Paul .
As i see in this circuit the output is out of phase with the input. That means that even at bypass mode the signal will be inverted. Also the input
impedance of the circuit is 100K,(the 100K at the inverting input of IC1A is the input impedance at an inverting op amp) which is low for guitar signals.

This can be solved by changing the connections at IC1A to make it a non inverting amplifier.This can be done easily by removing the 100K resistors which connect at IC1A pins 1,2. Place a jumper to connect pins 1 and 2 in the place of the 100K which was removed. Remove the 0.047uF capacitor which connect to pin 3 and replace the 100K which connects
to pin3 with an 1M resistor. Finally use a jumper to connect the 0.1uF cap with pin 3 of the ic. The jumpers can be placed to the empty pads of the components that were removed.

This an image of what i mean



Now we have a non inverting phase circuit with 1 Meg input impedance. This may even solve  the problem of volume drop when the effect is true bypassed. I don't know if this mod will change the character of the effect. But i think that it will not cause any additional problems like cancelations at the signal adders of feedback, blend etc.

It can also be modified to provide a little gain if the volume drop insists.

John

[nelson]

Thanks John!


Thats one possible mod to add to the file.

Stereo outs is another idea  


I wonder why it was designed with such low input impedence and inverted phase.

[nelson]

a 1M anti popping resistor would be a good idea too.

[dj_death]

Right Paul, pulldown resistors are always welcome. This mod will make some difference, ihope :? . SA571 can be used in place of the NE570, i am right? Did you verify any of the unknown components? I'm sure that all of them will be found at the testing procedure.

John

[nelson]

AFAIK SA570 replaces NE570, SA571 replaces NE571.  There arent any "unknown" parts in this, all of the out of production components are available at smallbear, banzai etc.

[dj_death]

Thanks Paul. I mean the resistors and capacitors that are unclear in the schematic.

John

[vanessa]

I loved my old poly-chorus. The thing I did not like about it was the very short delay time.

If this thing could be modified to be able to increase the delay time, like a Memory-Man or close this thing would rock!

Can it be done?

It would be the total all-in-wonder!

[nelson]

Thanks Paul. I mean the resistors and capacitors that are unclear in the schematic.

John

Sorry John, misunderstanding :roll:

I will verify the unclear components when my polychorus arrives, should be about 1 1/2 weeks or so.


Re: Vanessa


ToneB had the idea of adding another 1024 stages of delay to increase the slapback delay time, I for one wouldnt know where to start on doing that.

Perhaps someone with a bit more knowledge than me can chime in and come up with a way to do it.

Could it be as simple as a switch changing the wiring of one of the SAD1024's to place the two 512 stages in series rather than in paralell?

That way it would effectively double the delay time....  :?

Personally I am more interested in it for the flange and chorus....Would be icing on the cake to get longer delay time though.

[nelson]

I bought an original EH polychorus...
150 bucks.....

it uses an NE571

[dj_death]

Paul you said you bought a polychorus which is the same circuit with the echoflanger. What are your conclusions about the part numbers? NE570 are equivallent to SA571 and NE571. As for the extra delay in slapback mode the second SAD1024 is wired as a 512 stage, the first SAD1024 gives full delay.

John

[nelson]

When I opened it up, the only differences between it and the echoflanger are the use of an NE571, a redesigned PCB, looks less "curvy".  I think the pinout is diff on the NE570... I havent had time to really examine the circuit. I will verify the components that were unclear on the schem. I still have to draw the second page of the schematic on the echoflanger project PDF.

The double track on the polychorus imo isnt meant to be a proper delay, it is meant to just increase the thickness of the guitar, hence the name double track. It is an expensive enough build without adding another BBD to it. I wouldnt mind modding this and both the clone theory for stereo, although I dont know how.


On a side note.
I did re-do my EH clone theory layout.... its available at zero the hero's site. Fits in a 1590BB and can be battery powered, check it out.

If you are building the Echoflanger and want me to verify anything on the polychorus, drop me an email hempathy at hempathy dot org dot uk. Or just to discuss anything, feel free.

I am really busy with work/uni commitments, but I will do it.

[MartyB]

Nelson that is one beautiful layout!  GREAT job.

[chicago_mike]

WOndering if this is verified and how to mod for MN3007 BBD's and the like

[gena_p1]

Here is the layout.

it is NOT verified, the schem is not even half drawn, consult the factory schem in the meantime. i havent even written up a parts list for it yet.


please post any comments suggestions for mods etc here.

Feel free to email me with them too.

Enjoy everyone.


http://www.auaj24.dsl.pipex.com/EHEchoflanger.pdf


Paul Nelson

Link dosn't work
Locking non US IP addresses?