MXR Envelope Filter subtle?

[Bernardduur]

OK, I build one and it works great! One down side: it has a volume drop and is quite subtle. Is this normal?

[zeta55]

Check out the build reports from the tonepad site, there's some mods to cure the volume drop there....At least I think so.

[Bernardduur]

Yes, I've done them, but then still is the effect a bit subtle

Maybe its normal; I never played with one before

[Mark Hammer]

It never quite reaches the most outrageous sounds of a Mutron but it is NOT subtle.  Possible the Q setting is wrong or a problem?  Possible it's not the "right" 4069?

[zeta55]

Well, I built one, did a few of the mods, reverse swep, and some cap change for bas responce. Don't really remember, but I do remember it doesn't suffer a volume drop.

/Krister

[Bernardduur]

OK, I noticed that I needed to add some push to the signal to make it work but this I already knew.

Without the push (tubescreamer or other pedal) it doesn't wah

[zeta55]

It should wah without the TS. I usualy put mine first in the pedalchain.

/Krister

OK, I noticed that I needed to add some push to the signal to make it work but this I already knew.

Without the push (tubescreamer or other pedal) it doesn't wah

[Bernardduur]

OK, it works; not following the mods as told on the tonepad site, because they will destroy the feeling. Just leave the 62k and the 100k as the bias and it works great.

My main problem were the IC's. I used ST 4069's and only when I replaced them with Philips versions, it came alive. I had some wah with the ST's, but with the Philips the wah got more pronounced.

The volume drop is now partly fixed, but I am satisfied. I replaced R2 with 100k, C4 with 0,01 µf.

Nice mod: replace R1 with a 5k pot (or in my case a trimpot); this make the whole effect more intense

[rhodes]

    If you think you want more volume, you can alter the gain in one of the op-amps either at the input stage or at the output stage. I often substitute pots for feedback of op-amps to have gain control in most of the circuits which do not have volume level controls.

[warioblast]

http://www.techniguitare.com/forum/viewtopic.php?t=239&postdays=0&postorder=asc&start=0 Yeah I know it's French...
Basically, the guy had a volume drop too and fixed it with those mods. He replaced
R1 3K6 -> 1K
R2 200K -> 100K
R16 100K ->  68K
C2 47nF -> 1uF NP
C4 100nF ->  33nF

Another guy wrote T.I. 4066 & 4069 chips are not working on this build.

[Bernardduur]

I did almost the same and now it works great!

On Tonepad a lot of builders suggest to alter the bias; DON'T DO IT! The wah gets stronger but you miss the "real" sound of the filter (and the reverse won't work). To get the filter stronger, add a 5k trimpot as R1 (dunno why this works, but it can get you real over-the-top sounds to a more subtle one)

[zeta55]

So it's working like it should now! great news, hope you enjoy it like I do mine.

/Krister

[czech-one-2]

''On Tonepad a lot of builders suggest to alter the bias; DON'T DO IT! The wah gets stronger but you miss the "real" sound of the filter (and the reverse won't work). To get the filter stronger, add a 5k trimpot as R1 (dunno why this works, but it can get you real over-the-top sounds to a more subtle one)''

''Basically, the guy had a volume drop too and fixed it with those mods. He replaced
R1 3K6 -> 1K
R2 200K -> 100K
R16 100K ->  68K
C2 47nF -> 1uF NP
C4 100nF ->  33nF ''


Apologies for the necro bump, but I found one thing incredibaly frustrating. There's all kinds of advice/mods out there to 'solve' the volume output, but nobody mentions R7, The input resistor. I tried all the above mods. Trim pot for R1 did very little. You can actually remove C4 and still not solve the volume drop. My advise to future builders, leave the bias stock and just cut R7 in half [200k to 100k]. The whole circuit reacts favorably to a hotter input signal, and at 100k theres even a slight boost. I'm sharing cause really, one resistor solves the issue.