big muff opamp version

[lucaneo]

I built this version http://topopiccione.atspace.com/pjimages/EHBigMuff1977.pdf

I heard two original bm3 op amp big muff, the 77 version and the 78...my clone sounds similar, but the original versions has more volume ( the double)and  more opened tone (maybe more bass). There is more precision in my tones, but also more cold.... So I love the original 77 and 78 version... Could someone told me some modification? I just want the original sound, mine is similar. 
I'm sure that there are some mistakes in the schem!

http://it.youtube.com/watch?v=0tzY-XxPYuY&feature=related this is a youtube video

[nelson]

I did that project and drew that schematic - to my knowledge there are no errors in the schematic.

It has been verified by completely independent reverse engineering - it is exactly the same as this one for example

http://analogguru.100free.com/193/schematics/EH_BigMuffPi_OP-77.gif

No two pedals will sound *identical*. EH are renound for subbing components with whatever was cheap and on hand - not to mention component tolerances etc.

[lucaneo]

No, I'm sure, there is something wrong in the clone... Every  original bm3  has the double of the volume than the clone...you can try a 77, a 78 and you'll have a lot of volume and more opened sound, as the youtube sample. Maybe no two pedal sound identical, but all the originals are very very similar and all the clones are different.

[theehman]

Could you repost the files you worked from?  I'll take a look at them.

[lucaneo]

http://topopiccione.atspace.com/pjimages/EHBigMuff1977.pdf  theehman this is the project I've built... 

[theehman]

That looks OK.  Can you post a pic or 2 of your board?  I suspect you've got a wrong component or some miswiring.

[Rodgre]

Interestingly enough, I've tried 4 times to build a clone of my original op-amp BMP (which I adore, but would like to clone in a smaller box...and so I can make one for every room in the house ) and every one of them has had the problem of being too quiet as well. I guess I'm not crazy!

Roger

[Gila_Crisis]

if you need it, this is my vero layout

[lucaneo]

Interestingly enough, I've tried 4 times to build a clone of my original op-amp BMP (which I adore, but would like to clone in a smaller box...and so I can make one for every room in the house ) and every one of them has had the problem of being too quiet as well. I guess I'm not crazy!

Roger

Every room loool
By the way too quiet, what do you mean?

To theehman : what do u think about this project? Mine is the same of Gila, but the wiring is the classic true by pass mode ( general guitar gadgets style )

[theehman]

The schematic you posted seems to be a reworked version of the original EH schematic.  I do have a different EH op-amp schematic which I will try to find tonight and compare.  Barring that, I can open up an op-amp unit and check it against the schematic.

[lucaneo]

thanks, it will be great to obtain the real bm3 big muff schematic...I really love the original!

[nelson]

thanks, it will be great to obtain the real bm3 big muff schematic...I really love the original!

Where do you think these schematics came from?

[Rodgre]

I've checked the schematic that I worked from and it matched my real BMP3. I went through a couple periods of obsessing over it and retraced my real one over and over, and tried to perf it up a bunch of times, and then I finally made a pc layout and that's the one that finally worked for me, though like I said, the output level is quiet compared to the real thing.

Roger

[Gila_Crisis]

it would be lovely if you could post your schem and layout, i'm curious to take a look at it

[nelson]

There is a third and fourth style Opamp big muff.

The Opamp Muff in the two versions of the Deluxe Big muff are different to either the 77 or 78.

I am going to do a project for one of the deluxe versions.

[Gila_Crisis]

yep the deluxe big muff opamp muff are a bit different, of coarse they are supplied with 1/-15Volt but i saw there here and there 2 or 3 components that are different, and this is something i wanna try to see if it change something

[nelson]

yep the deluxe big muff opamp muff are a bit different, of coarse they are supplied with 1/-15Volt but i saw there here and there 2 or 3 components that are different, and this is something i wanna try to see if it change something

They are not supplied by 15v bipolar......

One is Bipolar 5v(EH3053). The other type with the OTA based compressor section as opposed to the fet is 9v(EH3054).

A number of the EHX deluxe series are supplied with +/-15v. But not the Deluxe Big muff.

[Gila_Crisis]

do you mean it?
i got 2 schem i found on japanese sites about the Deluxe BM and both have a 15v bipolar supply

[lucaneo]

I've checked the schematic that I worked from and it matched my real BMP3. I went through a couple periods of obsessing over it and retraced my real one over and over, and tried to perf it up a bunch of times, and then I finally made a pc layout and that's the one that finally worked for me, though like I said, the output level is quiet compared to the real thing.

Roger

Cool!! Could you post it please? Also the tones are a little different? thanks

[nelson]

do you mean it?
i got 2 schem i found on japanese sites about the Deluxe BM and both have a 15v bipolar supply

I have those schematics too (seen the thread). They don't show bipolar, they show single polarity +15v.

Personally, I think this is a mistake, or EHX subbed some of the transformers in some units. Bernaduur measured 9v on his Deluxe which matches the japanese deluxe except for V+.