EHX - Electric Mistress Flanger  [schematic]

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1218
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

theehman wrote:One of my Mistresses:

Image
Sweet!

Same circuit as the other ones?
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
theehman
Diode Debunker
Information
Posts: 710
Joined: 16 Aug 2007, 16:52
Location: Clear Creek, IN
Has thanked: 98 times
Been thanked: 105 times
Contact:

Post by theehman »

Bernardduur wrote:
Sweet!

Same circuit as the other ones?
No Filter Matrix switch, but otherwise it's the same.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

User avatar
shanike
Information
Posts: 5
Joined: 16 Aug 2010, 07:27

Post by shanike »

Here's mine:

Image

it says EH5100 D on the circuit board, and the lines are more edgy than those on pictures posted in this thread before. I would like to perform the same volume drop mod, but I'm unsure where to solder the proper parts. I'm no electrical engineer, but I know how to solder. I already have an 0,22uF capacitor and 10K resistor.

if there's anyone who could possibly give me a hint I would be very grateful.

thanks,

Alex

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1218
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

I now have a EH-5200 1A on the bench. Will post guts + schematic later
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
shanike
Information
Posts: 5
Joined: 16 Aug 2010, 07:27

Post by shanike »

Bernardduur wrote:I now have a EH-5200 1A on the bench. Will post guts + schematic later
that would be sweet, thanks a lot for the effort!

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1218
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

Guts:
Image

Image

Image

Image


Schematic:
Image

Image

Image

Differences with the other 18V units I've seen:
- no buffered bypass
- BIAS / feedback part different

Weird thing: the knobs are folded around the back of the PCB; as they use these EHX potmeters (w/ the half circle shafts) the knob's rotation is completely wrong :D
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
theehman
Diode Debunker
Information
Posts: 710
Joined: 16 Aug 2007, 16:52
Location: Clear Creek, IN
Has thanked: 98 times
Been thanked: 105 times
Contact:

Post by theehman »

Bernardduur wrote:
Weird thing: the knobs are folded around the back of the PCB; as they use these EHX potmeters (w/ the half circle shafts) the knob's rotation is completely wrong :D
Very common in EH pedals.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

User avatar
JRM
Information
Posts: 24
Joined: 06 Aug 2010, 20:57
my favorite amplifier: Laney Cub 10 'cause it's mine!
Location: Lisbon - Portugal

Post by JRM »

I would like to build a 9V version but I'm a little bit confused. I already have several schematics and a PCB drawing but I'm not sure they're faithfull to the original. Can samebody help me out?

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1218
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

The schematics of my 9V unit:

PSU:
Image

Clock:
Image

Audio:
Image
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

User avatar
JRM
Information
Posts: 24
Joined: 06 Aug 2010, 20:57
my favorite amplifier: Laney Cub 10 'cause it's mine!
Location: Lisbon - Portugal

Post by JRM »

Thank you Bernardduur. Now I can compare it with the schem I have.

User avatar
shanike
Information
Posts: 5
Joined: 16 Aug 2010, 07:27

Post by shanike »

would anyone happen to have schems/guts for eh5100 D?

User avatar
cpm
Resistor Ronker
Information
Posts: 276
Joined: 29 Oct 2008, 09:55
Location: spain
Been thanked: 50 times

Post by cpm »

shanike wrote:would anyone happen to have schems/guts for eh5100 D?
mine is 5100D
https://www.freestompboxes.org/viewtopic.php?f=10&t=6142

the schematic than is around the web is almost accurate, the only difference is some more caps on the board, all doing some filtering on power and the clock/LFO sections. The main audio path is as drawn on the schematic.

at the moment i only have guts pics from the trace side.

User avatar
shanike
Information
Posts: 5
Joined: 16 Aug 2010, 07:27

Post by shanike »

cpm wrote:
shanike wrote:would anyone happen to have schems/guts for eh5100 D?
...at the moment i only have guts pics from the trace side.
even those would help if you can post, so I can compare a bit...

User avatar
JRM
Information
Posts: 24
Joined: 06 Aug 2010, 20:57
my favorite amplifier: Laney Cub 10 'cause it's mine!
Location: Lisbon - Portugal

Post by JRM »

Is it true that SAD1024A is now out of production and unavailable from any regular supplier? If so, how can we replace it to build a clone of the 9V EH-EM?

User avatar
theehman
Diode Debunker
Information
Posts: 710
Joined: 16 Aug 2007, 16:52
Location: Clear Creek, IN
Has thanked: 98 times
Been thanked: 105 times
Contact:

Post by theehman »

JRM wrote:Is it true that SAD1024A is now out of production and unavailable from any regular supplier? If so, how can we replace it to build a clone of the 9V EH-EM?
Yes, the SAD1024 has been out of production for quite a while now.
There's info over at the DIY forum to make it with an MN3007.
Ron Neely II
Electro-Harmonix info: http://electroharmonix.vintageusaguitars.com
Home of RonSound effects: http://www.ronsound.com
fx schematics and repairs

User avatar
JRM
Information
Posts: 24
Joined: 06 Aug 2010, 20:57
my favorite amplifier: Laney Cub 10 'cause it's mine!
Location: Lisbon - Portugal

Post by JRM »

Thanks Theehman! I'll see what I can find. Of course it will not be exactly the same (tone) but I hope it doesn't get to far from the "real thing".

User avatar
fernieite
Information
Posts: 28
Joined: 29 Jan 2010, 02:34
Location: Toronto, Canada. Age: Early 60s
Has thanked: 2 times
Been thanked: 8 times

Post by fernieite »

I've got a EH5101A - 9 volt version, if anyone needs some pics. Pot dates to 1981.

User avatar
JRM
Information
Posts: 24
Joined: 06 Aug 2010, 20:57
my favorite amplifier: Laney Cub 10 'cause it's mine!
Location: Lisbon - Portugal

Post by JRM »

Pics are always welcome! Thanks.

User avatar
fernieite
Information
Posts: 28
Joined: 29 Jan 2010, 02:34
Location: Toronto, Canada. Age: Early 60s
Has thanked: 2 times
Been thanked: 8 times

Post by fernieite »

fernieite wrote:I've got a EH5101A - 9 volt version, if anyone needs some pics. Pot dates to 1981.
Here they are (sorry for the crappy photos )
9V EM board.JPG
9V EM trace.JPG

User avatar
Bernardduur
Transistor Tuner
Information
Posts: 1218
Joined: 24 Aug 2007, 07:36
my favorite amplifier: Welagen - ODR
Location: Losser.........
Has thanked: 94 times
Been thanked: 732 times

Post by Bernardduur »

Looks like mine!
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

Post Reply