VFE Bumblebee - no swell

[zachlovescoffee]

Hello! My first VFE build almost done!

I just finished my pedal last night and test drove it. Turned on first stomp and it is the quietest and smoothest compressor I've ever used. It sounds amazing. However! There is no swell effect. I can't seem to get it to trigger and I've tried the tuning method suggested in the build doc.

I found this thread with a similar issue but I cannot determine that the OPs issue was ever resolved. https://www.madbeanpedals.com/forum/index.php?topic=31323.15

I also noticed he's using an OP2134 instead of the OP134 in the build docs. Is that intentional? Or is the build doc a typo? I installed a OP134 in mine.

I also didn't have the .68uf cap so I used a 1uf cap.

Any thoughts or suggestions on what to try next would be appreciated, especially if you sorted it.

[Aentons]

I found this thread with a similar issue but I cannot determine that the OPs issue was ever resolved. https://www.madbeanpedals.com/forum/index.php?topic=31323.15

Jimi's issue was that his 5457 jfet was not in spec.

He is using a 2134 not a 134. A 134 will not work

[benny_profane]

I found this thread with a similar issue but I cannot determine that the OPs issue was ever resolved. https://www.madbeanpedals.com/forum/index.php?topic=31323.15

Jimi's issue was that his 5457 jfet was not is spec.

He is using a 2134 not a 134. A 134 will not work

Yes, the trimmer will only help with fine adjustments. You'll need a JFET as discussed in the build doc and the linked thread. Where were you seeing reference to an OP134?

[Zerro]

BF245B has Ugs very similar to 5457.

[zachlovescoffee]

I found this thread with a similar issue but I cannot determine that the OPs issue was ever resolved. https://www.madbeanpedals.com/forum/index.php?topic=31323.15

Jimi's issue was that his 5457 jfet was not is spec.

He is using a 2134 not a 134. A 134 will not work

Yes, the trimmer will only help with fine adjustments. You'll need a JFET as discussed in the build doc and the linked thread. Where were you seeing reference to an OP134?

The BOM indicates OPA134. I figured it was a typo until I actually found one on Mouser's site. So, I bought it. But I actually installed an OPA2134PGA.

Do you think the 1uf cap in place of the .68uf cap matters?

So I definitely need a 5457 that has voltage between 1.25 - 1.5? Any idea where I can buy a bunch? I just bought a transistor measuring tool.

[madbean]

According to the pdf linked in the Store, the BOM lists OPA2134a and has links to both Mouser and smallbear for the chip. However, it's possible I made a typo when I first released the doc, then corrected and re-uploaded but forgot to mention in the Errata section (that would have been a couple ago so I honestly don't remember).

https://www.madbeanpedals.com/projects/_folders/VFE/pdf/VFE_Bumblebee.pdf

[oeslicoalfin]

Willing to try mmbf5457? It will probably be within spec. You can get SMD adapters at effects layouts or just get one all soldered up and ready for leads at lectric-fx if you don't like soldering SMD parts. Looks like Mouser, Digi-Key, and Tayda are out of mmbf5457, so lectric-fx may be your only option right now.

[zachlovescoffee]

Totally! I bought some but unsure if I mounted it correctly. It's not doing anything for the swell even using the tuning walk through. The volume is also REALLY low even with the level cranked. I have to dime out that guitar to make it sound good. Here's a picture of how I constructed the SMD onto a chip.

[zachlovescoffee]

Okie dokie still no gas. I bought some SMDs from AionFX which were guaranteed to be in the right range but no swell effect. The compressor sounds fantastic. I did some board measurements and found some odd ones. I'm not certain how to interpret these so I'm looking to you smart dudes to lend a hand and maybe point me in the right direction.

[benny_profane]

Flip the orientation of the JFET. It looks backward. Also, Aion does not 'guarantee' specs—the copy says that 'nearly all of them are within the Vgs(off) range of -1.0V to -1.5V (average: 1.21V).' Did you test the particular device to ensure it's in the range?

[zachlovescoffee]

Fair enough on the guarantee. I misquoted it without malintention. I did not test it as I'm not 100% certain how to do so.

Which JFET? The 2N5457 (as SMD)?

[benny_profane]

Fair enough on the guarantee. I misquoted it without malintention. I did not test it as I'm not 100% certain how to do so.

Which JFET? The 2N5457 (as SMD)?

No worries, just didn't want you to think that it would 100% work since this circuit is picky. Search for RG Keen's methods of testing. And yes, the 2n5457 on the breakout board looks like it should be rotated 180°.

[zachlovescoffee]

I rotated it and while the pedal does sound better I still have absolutely no swell. I'll look for the method and see what I can figure out! I have about 15 more SMDs I can try and will report back.

My voltages look off don't they?

[zachlovescoffee]

I got some vero board to build a JFET tester. Does anyone have a good wiring diagram for how to build one? Or pictures of one you've built?

This is what I bought. Do you think it will work?

ElectroCookie Mini PCB Prototype Board Solderable Breadboard for DIY Electronics, Compatible for Mini Arduino Soldering Projects, Gold-Plated (6 Pack, Multicolor) https://www.amazon.com/dp/B081MSKJJX/ref=cm_sw_r_cp_api_i_E8YXM5XP0A9HBF1E2S25?_encoding=UTF8&psc=1

[jimilee]

I got some vero board to build a JFET tester. Does anyone have a good wiring diagram for how to build one? Or pictures of one you've built?

This is what I bought. Do you think it will work?

ElectroCookie Mini PCB Prototype Board Solderable Breadboard for DIY Electronics, Compatible for Mini Arduino Soldering Projects, Gold-Plated (6 Pack, Multicolor) https://www.amazon.com/dp/B081MSKJJX/ref=cm_sw_r_cp_api_i_E8YXM5XP0A9HBF1E2S25?_encoding=UTF8&psc=1

Tagboard has some great jfet tester layouts.


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