EHX - Echoflanger  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
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Fender3D
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Post by Fender3D »

I opened this thread https://www.freestompboxes.org/viewtopic ... 28&t=22623 in order to collect info on BBDs' clocks...
No replies so far, I wish you a better luck than I had, Scruffie :hug:

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Scruffie
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Post by Scruffie »

I got in contact with our old friend graemey who's going to take some measurements of his echoflanger unit, i'll post them up in that thread once i've got 'em :thumbsup

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Scruffie
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Post by Scruffie »

Posted them in your BBD clock thread and i'll post them here for posterity too.

EHX Echoflanger Frequencies courtesy of Graemey's Stompbox Secrets, taken at Pin1 of the 4013.

Tune - CW
Width - CCW
Rate - CCW
Feedback - CCW
Filter Matrix 341kHz
Double Track 110.9khZ

Tune - CCW
Width - CCW
Rate - CCW
Feedback - CCW
Filter Matix 54.5kHz
Double Track 17.71kHz

Tune - CW
Width - CW
Rate - CCW
Feedback - CCW
Flange 439-50kHz
Chorus 114-82kHz

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Scruffie
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Post by Scruffie »

Minor update!

The 3007 Echoflanger i'm doing with Lectric FX is still in progress, a rather large break was taken after the first go due to both parties having other shit to do.

Anyway, back on it and here's what's what.

The circuit works great but, charge pump on board or not (fixed 18V supply tried stand alone didn't change much) and layout fixes, among other minor issues there was still some heterodyning on board from the dual clock/buffer set up.
While using 2 x 4049 was in current limits of the charge pump (the max clock reading is only about 550kHz) the excess drain made issues worse so a single chip will now be used like the original, experimenting if it should be split between the 2 chips or just buffer the what i'll call 'high chip' is in progress, on the protos. It worked fine with it only buffering (in the popular 1 in to 2 set up) the high clock chip, but to test that adds no ill effects to the second chip we're doing further testing.

We added some extra filtering too, nothing massive, some simple 15kHz-ish filters at the input of each BBD as is fairly standard practice (and the original lacked) which seems to have taken care of most of the issues and cut noise down considerably without affecting tone.

Speaking of noise, to the person who mentioned MN3001s as a suitable substitute to the original SAD's as "they were dual 512 stage chips" on a whim I did try them after some hacking and as I suspected, the added gain needed to recover the massive losses (remembering that SAD's actually add gain) made an already high noise circuit unbearable... there's a fairly good reason they were lost to obscurity (even the MN3004 can be a bit of a noisy chip!).

Some added minor filtering updates other than that, mainly in the LFO/VCO (a bit of filtering in the feedback loop in the gain stage pre/including the VCO considering where you want to say it starts reduced some annoying thump at high depths and on the LFO its self) and it should be a go this year.

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Post by Scruffie »

Oh and I collected some readings from another 2 units after helping people debug them and set the clock to the factory setting.

1st Unit.

Settings
Tune - CW
Width - CCW
Rate - CCW
Feedback - CCW

Filter Matrix - 250kHz
Double Track - 66kHZ

Settings
Tune - CCW
Width - CCW
Rate - CCW
Feedback - CCW

Filter Matrix - 36kHz
Double Track - 10kHz

Settings
Tune - CW
Width - CW
Rate - CCW
Feedback - CCW

Flanger 35 - 330kHz
Chorus 14 - 20khZ

Second Unit

Settings
Tune - CW
Width - CCW
Rate - CCW
Feedback - CCW

Filter Matrix - 261kHz
Double Track - 81kHZ

Settings
Tune - CCW
Width - CCW
Rate - CCW
Feedback - CCW

Filter Matrix - 43kHz
Double Track - 14kHz

Settings
Tune - CW
Width - CW
Rate - CCW
Feedback - CCW

Flanger 40 - 365kHz
Chorus 20 - 28khZ

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Post by n.d »

Bump... or not.
I contacted Stass, he sent me some pictures of his build.
I am now redrawing his layout - a 3007 modified SAD layout.
I expect it´ll take me a week or so to finish it. I will then post it here so you guys can correct it, check for errors, make suggestions, etc.

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Post by n.d »

Hello everyone. Here you have a zip containing Stass`schematics, the lo res layout he gave me a few months back, and my unverified - and perhaps unfinished -redraw of said layout.
Please let us know if you find any problems, or make any corrections.
Attachments
echoflanger.zip
chems, stass layout, MY unverified layout
(700.31 KiB) Downloaded 349 times

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Post by Stasss »

Hello!I sorry, for the error in the scheme:

1)--C29 must be disconnected from pin7 NE570 and connected to the output of the filter---pin7 IC9B(LM4558)

2)Output pin3 (7815) (+)C4 is disconnected from R1-R2-and is connected to +15V

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Post by n.d »

I will FIX the layout as soon as I can.

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Post by Steab »

Hi guys!

The dream of many kid seems to come real on this thread..
Any uptade about the mistake founded on the zip pack?
Thanks

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Post by Steab »

I've found all I need to build it!
Check lectric-fx website and dandy chorus!
:thumbsup

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Post by Stasss »

Hi, everyone! I have finished the project 3007 Echoflanger from the website Lectric-FX. The scheme works very well! But there is a problem. When switching the CHORUS mode - FLANGE is heard loud POOOOP......!! Help, give advice how to get rid of it? Whether someone from you had such problem? Excuse for bad English, I am Russian.

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Steab
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Post by Steab »

Stasss wrote:Hi, everyone! I have finished the project 3007 Echoflanger from the website Lectric-FX. The scheme works very well! But there is a problem. When switching the CHORUS mode - FLANGE is heard loud POOOOP......!! Help, give advice how to get rid of it? Whether someone from you had such problem? Excuse for bad English, I am Russian.
Hi Stass,

I think you have to create an account on madbean forum, the Lectric FX team have a corner on it!

When I build mine, I were in trouble at a time and they help me..

See you soon on madbean :D

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n.d
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Post by n.d »

I´m on it. I will compare what I have wit that dandy circuit.

PS. Did anyone try my layout?

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nelson
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Post by nelson »

Cool

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Dr Tony Balls
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Post by Dr Tony Balls »

nelson wrote: 05 Apr 2012, 15:24 Not allowed to edit posts?

Anyway, ignore previous schematic. Biasing for MN3007 wrong.

Here.
I have two questions regarding this schematic. This really relates to the original schematic but Paul's re-draw here is much easier to follow so we'll go with that.

1. Are C6 (50uF) and C7 (50uF) redundant parts? This looks to me like they could be replaced with a 25uF bipolar cap, but there may be something specific I am unaware of.

2. Are C4 (470uF), C12 (1uF tant), and C13 (1uF tant) redundant? They're all caps to ground hanging off the 15V supply rail. I could see maybe a 100nF cap in addition to the 470uF one, but the two tantalums have me scratching my head. Again this may be something i'm unaware of.


edit: sorry the file didnt come through. Its on page 4 of this topic, file link: download/file.php?id=17571

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Post by mauman »

Dr Tony Balls wrote: 15 Jan 2024, 20:55 I have two questions regarding this schematic. This really relates to the original schematic but Paul's re-draw here is much easier to follow so we'll go with that.

1. Are C6 (50uF) and C7 (50uF) redundant parts? This looks to me like they could be replaced with a 25uF bipolar cap, but there may be something specific I am unaware of.

2. Are C4 (470uF), C12 (1uF tant), and C13 (1uF tant) redundant? They're all caps to ground hanging off the 15V supply rail. I could see maybe a 100nF cap in addition to the 470uF one, but the two tantalums have me scratching my head. Again this may be something i'm unaware of.
1. Yes, C6/C7 together are just a DIY bipolar 25 uF.
2. C4 is a reservoir for +15 supply, and maybe a bit of noise mitigation after the 15V regulator. C12 and C13 are decoupling and reservoir caps for IC5P and IC2P respectively. You're right, 100 nF MLCC are more common for this function, and they're often placed right across the power leads of each IC.

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Post by Dr Tony Balls »

Thanks for the explanation!

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