Noisy VFe Focus Build

[BigK]

Hi Guys,

I finished my Focus build last night and very pleased with what it can do. I've only been building pedals for the last 6 months or so and not really had any problems apart from accidentally using a 100k resistor instead of a 100r once so just after a bit of guidance.

It does seem to generate a lot of hiss at higher level/mix combinations than I would expect. Nothing massive but I would definitely need to use a noise suppressor its that noticeable. I haven't put it in an enclosure yet as I'm in the middle of a house move and my pillar drill etc are in storage so that might help, but wondered if anyone else has made one and noticed this too or if there is something wrong with my build? Maybe a noisy IC?

I've used OPA2134 from farnell and Wima/Nichicon caps. The only thing that are cheaper are the .22uF Electrolytics on the board and switching I used were cheaper JB capacitors from Tayda but they measured up well within spec.

Any thoughts?

TIA

[madbean]

Have you tried turning the makeup gain trimmer all the way down? This could help in reducing noise. My guess is the active filter stages is where it's coming from. If you turn the Mix knob all the way CCW does the hiss go away?

[BigK]

Have you tried turning the makeup gain trimmer all the way down? This could help in reducing noise. My guess is the active filter stages is where it's coming from. If you turn the Mix knob all the way CCW does the hiss go away?

Will try the makeup trimmer. If I turn the mix knob full ccw the noise does go away at the same level settings.

I've tried a couple of other IC's from other builds in all positions and if anything the noise is a little worse with this set. But I don't think its the IC's at this point. it only seems to be at when the level up at about 20-25% it starts to become noticeable and its already boosting the level quite a bit at that point. it starts clipping the input on my helix at about a third of the way up so the output is massive - I'm going to double check my resistor values.

Could it be the resistors I've used they are cheap 1% metal film from a pack apart from the 1.43k? or am I just being picky?

I've built an Ice scream and a The Scream as well as a few other pedals with those resistors and they are both very quiet.