Re: [BUILD] Hairball Audio "Lola" Mic Pre - On Sale Now
« Reply #480 on: January 28, 2021, 08:12:49 PM »
Hi all,
I recently did a Lola DIY build, and I've got a few different issues.

-I'm getting clean audio through the preamp and into my DAW, but nothing registers on the Lola meter. When I first turn it on, or hit the phase switch, or hit the phantom power switch, I see a surge on the meter. But nothing registers on the meter when actual audio is coming through.

-When I push the phase switch, I get a very loud nasty pop. Also when turning the top gain knob/switch, as it hits each position, I get nasty pops. The pops get louder as I turn the gain down, and softer as I turn the gain up, counterintuitively.

-The op-amp on top (closest to the edge of the main PCB) has way hotter output transistors than the other op-amp. These are getting hot enough to burn a finger within a second of touching them.

Do any of these issues seem connected, or seem like something that's a common problem/easy fix for an intermediate level solderer/tinkerer? Or should I just jump to sending it in for repair?

Re: [BUILD] Hairball Audio "Lola" Mic Pre - On Sale Now
« Reply #481 on: February 04, 2021, 07:16:43 PM »

I have one of my three recent Lola builds that has issue with the DI signal. The MIC/Line signal may be inconsistent or scratchy when increasing volume, but fine once set, however the DI signal is very distorted and the wave image in my DAW looks heavily weighted to one side of the wave file. 

Is this representing some DC offset issue and where should I begin on troubleshooting? 

- Trouble build has JH990 op amps
- second build is identical, but tested perfect
- third build - I'll need to order a new output transformer when available or attempt to remedy one lead that was cut too short.




Re: [BUILD] Hairball Audio "Lola" Mic Pre - On Sale Now
« Reply #482 on: February 15, 2021, 09:42:11 PM »
    I'm about to build my first two Lolas.   They are both for customers of mine.   One guy asked if I could add a a HPF option at 80Hz or something?
Is that do-able with a simple Resistor-Capacitor combo on a switch without screwing anything up?



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