EHX - Echoflanger  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Dirk_Hendrik
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Post by Dirk_Hendrik »

GodSaveMetal wrote:
Fender3D wrote:I posted about converting MXR flanger with MN3007 on this and the other forum.
It's just a matter of adapting the schematic...

You please got an adaptation ???? for the SAD1024 to MN3007?? would you?? :mrgreen:
That took me a 1 minute search.

How about usting the search too??
Sorry. Plain out of planes.

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Post by GodSaveMetal »

For this pedal? It is no adaptation; you found it? plesase post IT!!!!!!!!!!!!!! PLEASE; PLEASE!!

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Post by Dirk_Hendrik »

gawd.
Someone made up an:

Adaption for a MN3007 to replace a SAD1024.[/i][/b]
Might it occur to you that if it works for one pedal chances are very good it works for another???

What's your perspective on electronic components? That the physics laws applying to a component are defined by the circuit? Or pehaps the other way around?
Sorry. Plain out of planes.

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Post by Govmnt_Lacky »

Has anyone verified the layout and the Project data from Paul Nelson?

Would LOVE to build this but I have not seen anyone verify it. Also, where can one find a 2M reverse log pot?

Thanks 8)

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Post by Govmnt_Lacky »

OK... found a source for the 2M rev log pot :thumbsup

Now I just need to know if anyone has input about the Paul Nelson layout posted earlier in the thread. Is it verified?

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Post by Govmnt_Lacky »

Well, since I couldn't wait... I decided to go over the ENTIRE layout from Paul and bounced it against (what appears to be) the original hand drawn schematics from here:

http://experimentalistsanonymous.com/di ... er%201.jpg
http://experimentalistsanonymous.com/di ... er%202.jpg

For the most part, the layout is correct. However, I did find some discrepancies that I will list here.

1) It appears that the SAD chip clocks and other signals are not connected as per the schematic. This might not mean anything but, it is not as per the print.
2) There are some values on the print that are MISSING on the layout. I went over the layout and I could not find C24.1 (.0022uF), C28.1 (.0047uF), R37.1 (100R), and C41 (??). These values are on the schematic but they ARE NOT in the layout.

Still waiting to hear from someone whether or not this layout was verified working. The differences with the SAD chip signal routing kinda scares me :shock:

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Post by phibes »

EH is known for having errors in schematics. Did you try comparing Paul's layout to the gut shots in this thread?
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Post by Govmnt_Lacky »

phibes wrote:EH is known for having errors in schematics. Did you try comparing Paul's layout to the gut shots in this thread?
I initially tried to however, I could not get the pictures to blow up well enough to get the info that I needed (i.e. color codes, cap values, etc.)

That is why I decided to use the original schemo that I found.

I suppose I could do the layman's check and just count up the number of resistors and caps on the schemo and compare to the pictures. That would at least tell me something :slap:

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Post by Govmnt_Lacky »

Govmnt_Lacky wrote:I suppose I could do the layman's check and just count up the number of resistors and caps on the schemo and compare to the pictures. That would at least tell me something :slap:
This is not really a good idea either as some of the components may be hidden beneath the pots. :scratch:

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Post by Govmnt_Lacky »

phibes wrote:EH is known for having errors in schematics. Did you try comparing Paul's layout to the gut shots in this thread?
After comparing the layout to the board pics, I can say this:

1) The "missing parts" that I listed earlier DO NOT appear to be on the board in the pic. That is not to say that they should not be there however, they appear to be missing from the board in the pictures.

2) The trimmer pot between the CD4049 and the SAD (IC4) is a 1K trimmer in the pics. This is different from the 100K trimmer listed on the Nelson layout.

Still getting up the guts to build this one. Also awaiting confirmation as to whether this is a working project :scratch:

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Post by phibes »

Govmnt_Lacky wrote:
phibes wrote:EH is known for having errors in schematics. Did you try comparing Paul's layout to the gut shots in this thread?
After comparing the layout to the board pics, I can say this:

1) The "missing parts" that I listed earlier DO NOT appear to be on the board in the pic. That is not to say that they should not be there however, they appear to be missing from the board in the pictures.

2) The trimmer pot between the CD4049 and the SAD (IC4) is a 1K trimmer in the pics. This is different from the 100K trimmer listed on the Nelson layout.

Still getting up the guts to build this one. Also awaiting confirmation as to whether this is a working project :scratch:
Yeah I was just gonna suggest to see if there matching parts, no need for values since there hard to see.

I don't know if it was ever verified, there's a few threads about it over at DIYSB if you do some searching. Maybe you could get a hold of Paul over there or at the e-mail in the PDF.

Otherwise, spend a day on the breadboard before committing to populating a pcb. I'd probably go off the schematic in the PDF and then reference back to the original drawings. You can use a charge pump to get the +15V and then do a voltage divider to get the +7.5V. You got a 2 SAD1024A's? You could work out any kinks when it's on the breadboard.
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Post by Govmnt_Lacky »

phibes wrote: Yeah I was just gonna suggest to see if there matching parts, no need for values since there hard to see.

I don't know if it was ever verified, there's a few threads about it over at DIYSB if you do some searching. Maybe you could get a hold of Paul over there or at the e-mail in the PDF.

Otherwise, spend a day on the breadboard before committing to populating a pcb. I'd probably go off the schematic in the PDF and then reference back to the original drawings. You can use a charge pump to get the +15V and then do a voltage divider to get the +7.5V. You got a 2 SAD1024A's? You could work out any kinks when it's on the breadboard.
I don't see an email in the pdf :scratch:

Yes, I have 2 SAD1024s that need using :thumbsup

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Post by Govmnt_Lacky »

Govmnt_Lacky wrote: I don't see an email in the pdf :scratch:

Yes, I have 2 SAD1024s that need using :thumbsup
Found the email but it is DEAD!! :x

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Post by phibes »

I'd just say hit the breadboard than.
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Post by Govmnt_Lacky »

phibes wrote:I'd just say hit the breadboard than.
I know this is sacrilege but, I am not a big breadboarding fan :blackeye

In all honesty, it is just as easy (and convenient) for me to etch a PCB and test/alter the circuit then. I must admit, I am totally inefficient with a breadboard and it takes me quite a bit of time to breadboard circuits. Take into account that this is a pretty large circuit and the breadboard that I have is fairly small and you know which way I would want to go.

I have plenty of copper clad, etchant, resistors, caps, transistors, etc. As long as the ICs dont get ruined, I will be OK. Thats what voltage checks are for!! :thumbsup

Now... electrically, the layout looks good when compared to the original hand drawn schematic (althugh it IS missing a few parts but, those parts are also NOT on the board in the pics on Page 1). Also, the layout seems to follow the pattern from the pictures on Page 1.

So, the only questions I have now are about parts values. There are several resistors with odd values (i.e. 3.01K, 6.19K, 15.8K, 46.4K, 9.1K) I am wondering if I can round to the nearest values without effecting the performance of the pedal??

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Post by phibes »

If that route works better, give it a go. How do you plan on doing the power supply? That would definitely be something to figure out before etching. If you use sockets for the chips, those will be fine. Those resistor values are odd, EH musta been cleaning house. Just use the closest to what ya got on hand. All those values are easily within a radioshack bulk bag if you don't have the right ones on hand.
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Post by Govmnt_Lacky »

phibes wrote:If that route works better, give it a go. How do you plan on doing the power supply? That would definitely be something to figure out before etching. If you use sockets for the chips, those will be fine. Those resistor values are odd, EH musta been cleaning house. Just use the closest to what ya got on hand. All those values are easily within a radioshack bulk bag if you don't have the right ones on hand.
As for the power supply, I would like to use a voltage multiplier however, I need to know the max current draw from the circuit (LT1054 will only go up to 100mA!) Worst case scenario, I have some small transformers that I could use or just order one from evilbay :shock:

As for the resistors, I already planned to use values that are close (46.4K = 47K).

Some of the "non-standard" cap values are in question though (0.004uF, 0.018uF). I think I may have some 0.0039s and some 0.015s :thumbsup

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Post by Govmnt_Lacky »

Can anyone explain to me why, on the Nelson layout, the Vbb and Vdd inputs to both SAD chips are marked as "LED?"

It looks as though they should be connected directly to the 15V input (Which also has an "LED" pad) The way this is labeled might cause one to actually connect both pads to an LED :shock:

Better yet, shouldn't the Bias voltage (Vbb) be equal to Vdd -1 volt? Why are they all connected together?

Can someone shed some light on this?

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Post by phibes »

Look at the original schematics. There's an LED going off the +15V. The other end of the LED is V1 which goes the corresponding pins on the BBD's. The layouts right, each pad goes to an end of the LED.

It looks like the schemo in the PDF got cut off so that's probably why you're not seeing it in there. You might wanna just redraw the old schematic to match the layout, those old scans are hard as hell to read too.
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Post by phibes »

Govmnt_Lacky wrote:Can anyone explain to me why, on the Nelson layout, the Vbb and Vdd inputs to both SAD chips are marked as "LED?"

It looks as though they should be connected directly to the 15V input (Which also has an "LED" pad) The way this is labeled might cause one to actually connect both pads to an LED :shock:

Better yet, shouldn't the Bias voltage (Vbb) be equal to Vdd -1 volt? Why are they all connected together?

Can someone shed some light on this?
To explain more on the layout, the red +15V traces are your VDD. They all need to be jumpered together as per the note says. The BBD's don't connect directly to the VDD. The LED is being used as the pedal indicator (it's always on once the pedals plugged in) and to bias the bbds. So the positive end of the LED goes to +15V, the negative end of the LED will be your VBB. If I remember right, the RED LED will cause a 1.5V-2V voltage drop. So that's where your VDD and VBB will be. Way to get major bang for buck out of parts!
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