EH - Low Frequency Compressor

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EH - Low Frequency Compressor

Postby xaxxop » 26 Jun 2008, 18:50

Hello people!!!

someone have Electro-Harmonix Low Frequency Compressor for pics inside? or layout

:hmmm:

thank you!!!!! :thumbsup
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Re: EH - Low Frequency Compressor

Postby borislavgajic » 26 Jun 2008, 20:58

I have this schematic........ :idea:
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Re: EH - Low Frequency Compressor

Postby Bernardduur » 26 Jun 2008, 23:32

Wow........

It still amazes me there are so much old EHX pedals I NEVER heard of...... this is one of em :)

Must try to build this one for my bass work.......... nice addition; 18V compressor with a Muff tone stack :)
'No more....... loud music.......'
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Re: EH - Low Frequency Compressor

Postby xaxxop » 27 Jun 2008, 06:51

borislavgajic wrote:I have this schematic........ :idea:


:shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock: :shock:
thank you man!!!!!!!!!

borislavgajic my genio!


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Re: EH - Low Frequency Compressor

Postby borislavgajic » 27 Jun 2008, 09:30

You are wellcome .....I am glad to help you :thumbsup
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Re: EH - Low Frequency Compressor

Postby xaxxop » 29 Jun 2008, 02:03

borislavgajic wrote:You are wellcome .....I am glad to help you :thumbsup



thank you friend, but missing component values in the schematic :scratch: .
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Re: EH - Low Frequency Compressor

Postby xaxxop » 29 Jun 2008, 15:13

:hmmm:
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Re: EH - Low Frequency Compressor

Postby borislavgajic » 29 Jun 2008, 21:18

it is hard to say ........pot is 250 k...or 470k....... (you can experiment to see)
I entered som corrections on schem ....but ???? good luck Leandro :thumbsup
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Re: EH - Low Frequency Compressor

Postby electrosonic » 03 Feb 2009, 23:33

I am resurrecting an old post here... I have one of these and can take some photos if anyone is interested.

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Re: EH - Low Frequency Compressor

Postby electrosonic » 04 Feb 2009, 01:01

Image

Image

Image

With daylight shining through the PCB...

Image
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Re: EH - Low Frequency Compressor

Postby borislavgajic » 04 Feb 2009, 10:37

thanks for pictures :applause:
could you tell us what is written on potentiometers...?
....and what is the sound like???

thank you

boris

o.....and you have 3080 and 741 IC-s....on schematic,there is only one ic....???
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Re: EH - Low Frequency Compressor

Postby xaxxop » 04 Feb 2009, 12:31

:shock: thank you so so so so much!!!!!!!!!!
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Re: EH - Low Frequency Compressor

Postby xaxxop » 04 Feb 2009, 14:49

Image

Image


Component list:

R1= 1K
R2= 1K
R3= 33K
R4= 2.2M
R5= 220K
R6= 220K
R7= 47K
R8= 470K
R9= 47K
R10= ?
R11= 47K
R12= 680K
R13= 47K
R14= 4.7K
R15= ?
R16= ?
R17= 1M
R18= 10K
R19= ?
R20= ?
R21= ?
R22= 10K

Q1-Q6= ?

C1-C11= ?
C12= .47u
C13= .47u
C14-C16= ?

P1-P3= ?

D1-D3= ?

IC1= 741
IC2= 3080


more info? :hmmm:
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Re: EH - Low Frequency Compressor

Postby borislavgajic » 04 Feb 2009, 14:51

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Re: EH - Low Frequency Compressor

Postby xaxxop » 04 Feb 2009, 15:08

borislavgajic wrote:blackfinger looks the same as your photos???
boris

:idea:


it's true, maybe others components for bass :scratch:
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Re: EH - Low Frequency Compressor

Postby electrosonic » 04 Feb 2009, 23:57

I went through and checked what you came up with. Component list:

R1= 1K -- yes
R2= 1K -- yes
R3= 33K --yes
R4= 2.2M --yes
R5= 220K --yes
R6= 220K --yes
R7= 47K --yes
R8= 470K --yes
R9= 47K --yes
R10= ? --- 390 k
R11= 47K --yes
R12= 680K --yes
R13= 47K -- yes
R14= 4.7K -- yes
R15= ? -- 470k
R16= ? -- 120k
R17= 1M -- yes
R18= 10K
R19= ? -- 4.7k
R20= ? -- 100k
R21= ? 1.5M
R22= 10K

Q1-Q6= ? -- Q1, Q2, Q5,Q6 BC309 (Photo of Q2 attached)
Q3, Q4 BC239



C1-C11= ?
C1 - 10uF/16v
C2, C3, C7, C8, C9, C10 - 0.1 uF ? See the photo below
C4 - 100uF /16v
C5 - 10uF / 35v
C6 - 100uF / 16v
C11 - ?? Marked "0.1 T" and below that "100/10"

C12= .47u
C13= .47u
C14-C16= ? C14 and C15 are the same markings on one side - "134" and below that "N150" the other side "27" and below that "5%"
C16 markings - "Z5F" below that "560" and below that +- 10% - (560 pF guess)

P1-P3= Not exactly sure, but I took a better picture

Image

D1-D3=

D1 --Yellow band and red band .. numbered 959
D2 / D3 I think they are the same

IC1= 741
IC2= 3080
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Re: EH - Low Frequency Compressor

Postby borislavgajic » 16 Feb 2009, 14:29

:D I found this schematic......it is blackfinger.....but looks very much like this compressor......
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Re: EH - Low Frequency Compressor

Postby hereIam2010 » 13 Jun 2009, 15:51

This is my first post in this forum, so first of all Hi Everybody :wink:

I own a EXH Low Frequency Compressor myself and I've been trying to find a schematic for quite a while. Of course, I opened it up, mine is also the two-IC-version so the schematic that borislavgajic posted, obviously doesn't apply to mine. I just found out about the similarity to the BlackFinger and with the help of this thread - especially electrosonic and xaxxop's posts - I traced the board and created a schematic.
The R and C parts values are exactly the same as electrosonic's but the part styles differ sometimes. The diodes in my LFC are standard silicon 1n4148. C11 is most likely a 100n cap, at least this value it makes the most sense in this tone control stage. On the other side, this capacitor differs from the rest of the 100n caps that are on this board, so this is still the part with the biggest uncertainty. C14 and C15 are probably 27 pF and C16 is definitely 560p as mine is labeled like this. The Volume and Tone pots are 100k, the Sustain pot is most probably 1M, but I'm not exactly sure about this.
I used the same part names as in the previous posts.
So, here is the schematic that I made, a lot of part values differ from the Black Finger, some parts are added or left out. The funny thing about it is that R20, R21 and C14 are the ones that are soldered on the back side, so it seems to me that they added those afterwards or they used the same PCBs for both pedals.

Image Image

And for comparison, again the Black Finger schematic:
Image

I use my LFC for guitar and I absolutly love this pedal. It adds some extra presence to the tone, takes out some mids and gives it some kind of HiFi style (hard to describe), and the compression is smooth and clean. It adds some extra hiss to the signal though, hardly audible but it's definitely there. But that's worth it, I basically have it on all the time.
It would be great to hear it in comparison to an old Black Finger (not the tube one), but those ones are as rare as the LFC is...

I hope there aren't too many mistakes in the schematic, if you find some, let me know.
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Re: EH - Low Frequency Compressor

Postby Broadcaster » 13 Jun 2009, 17:23

Just to make this even more confuse, here is another schematic for the blackfinger... including the parts around the 3080.

Image

I have long been intrigued by the discrete version of the LFC, but never really understood it, maybe Q2 is FET alike the squeezer? Nah, I just don't get it :oops: .
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Re: EH - Low Frequency Compressor

Postby branleur » 02 Jan 2010, 00:31

Hi everybody :D

I'm very intersting about the one IC version of the EHX LowFrequencyCompressor. But the schematic posted by HereIam2010 is not aviable! :?
Could anybody post another corrected schematic of the EHX LFC. :D

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