[BUILD] Hairball Audio "Lola" Mic Pre - On Sale Now

[Echo North]

Nice work Tata!

Have a look at the datasheet:
http://cdn.sparkfun.com/datasheets/Components/General%20IC/lm3916.pdf

In the data sheet R1 and R2 work together to set the meter sensitivity and the LED brightness. On the Lola those are R111, and R112.

Mike

 

[Acotler]

I just added it back to the build guide. It's after the tools section at the start.

Mike

Thanks Mike! The jfets did the trick. The di sounds great now. I built my second Lola this weekend and tested it today. No issues at all. They both sound great. Thanks again for the help, and also for the excellent build guide.

-Austin

 

[sonicsix]

hey there
I'm finally building the 2nd of a pair of Lolas I bought back in Feb 2015 (yes I know)
I'm presently stuffing the main board but it looks like I have one 100pF feeback cap (C7 and C9) and two 680pF zobel (C2) in my kit - instead of the other way around.  I was kind of hopefully wondering if I could sub one of the 680s for a 100pF???
thnx
Jeff

 

[Echo North]

hey there
I'm finally building the 2nd of a pair of Lolas I bought back in Feb 2015 (yes I know)
I'm presently stuffing the main board but it looks like I have one 100pF feeback cap (C7 and C9) and two 680pF zobel (C2) in my kit - instead of the other way around.  I was kind of hopefully wondering if I could sub one of the 680s for a 100pF???
thnx
Jeff

No, you'll lower the HP filter.

Send in a missing parts form:

Hairballaudio.com/missing

Should work with nothing in there in the mean time.

Mike

 

[sonicsix]

awesome
thnx

 

[sonicsix]

hi Mike

it turns out theres no foot in mouth emoji but I just found the other 100pF hiding behind 1000µF..

so I actually just have an extra 680pF,  which is right in line with my past experiences w/ Hairball (lola, 2x fet rack revA).  extra parts, not missing ones.  you guys are awesome.
and thanks for the quick response anyway

Jeff

 

[Echo North]

hi Mike

it turns out theres no foot in mouth emoji but I just found the other 100pF hiding behind 1000µF..

so I actually just have an extra 680pF,  which is right in line with my past experiences w/ Hairball (lola, 2x fet rack revA).  extra parts, not missing ones.  you guys are awesome.
and thanks for the quick response anyway

Jeff

Great!

 

[fiddlefro]

Hi There,
Just wondering if you can give me any general guidelines for where to start troubleshooting a meter problem.
As far as I can tell, the LOLA (with JH990c+ opamps) is functioning correctly.  At least, it sounds fantastic and has tons of lovely gain.

Unfortunately, only the bottom three meter LEDs seem to work.  I'm happy to take the thing apart and start trying to solve the issue, but I thought maybe I'd check here first for a clue or even just advice on some best practices and troubleshooting guidelines when tackling this issue.

Thanks
d

 

[Echo North]

Hi There,
Just wondering if you can give me any general guidelines for where to start troubleshooting a meter problem.
As far as I can tell, the LOLA (with JH990c+ opamps) is functioning correctly.  At least, it sounds fantastic and has tons of lovely gain.

Unfortunately, only the bottom three meter LEDs seem to work.  I'm happy to take the thing apart and start trying to solve the issue, but I thought maybe I'd check here first for a clue or even just advice on some best practices and troubleshooting guidelines when tackling this issue.

Thanks
d

Few thoughts....

1) other LEDs are backwards
2) or there is a component error or bad joint on the meter PCB causing the meter to run low

Mike

 

[dudeitsree]

Hello!  I built two Lolas and chose the DIY 990 opamps.  It seems for some reason both of the opamps from the second pre are not working.  I have swapped them around and Isolated the issue to the opamps, both pres work with the working pair of opamps I built first.  Neither the DI or the Mic input work, I have verified the components are in the correct places and there are no shorts anywhere and also re flowed the solder points too.  I am at a loss, surely I made a mistake I have yet to discover but it literally just doesn't work, no smoke, no fire, no sound.  Any Ideas? 

 

[Echo North]

Hello!  I built two Lolas and chose the DIY 990 opamps.  It seems for some reason both of the opamps from the second pre are not working.  I have swapped them around and Isolated the issue to the opamps, both pres work with the working pair of opamps I built first.  Neither the DI or the Mic input work, I have verified the components are in the correct places and there are no shorts anywhere and also re flowed the solder points too.  I am at a loss, surely I made a mistake I have yet to discover but it literally just doesn't work, no smoke, no fire, no sound.  Any Ideas?

Hard to say. There are lots of semis on there. They are sensitive to heat and static. The 1n914s damage easily, could be anything.

You could email us if you want build versions. We could give you the w/ Lola kit price which is $40/each.

Mike

 

[csavetman]

Hi Mike,

One of my Lola's is starting to act up today.
Audio seems fine, but something strange is going on with the metering.
With playback stopped, I toggled from vu to peak , meters started lighting up sporadically. Toggling back didn't help. Meters were just dancing around, going all the way to red peak led, then back down. (All this with no audio going to unit)
No weird noise coming from unit at all when this occurs.
I checked out meter PCB and noticed I forgot to solder 2 pins on the toggle (the 2 that are slightly off by themselves).
I soldered those, thinking that HAD to be the culprit.  Nope.
I swapped Lola's in the lunchbox just to check. That wasn't it either.
Didn't see any solder bridges on meter PCB.
Any idea what to check?

thanks
Carlos

 

[Echo North]

Hi Mike,

One of my Lola's is starting to act up today.
Audio seems fine, but something strange is going on with the metering.
With playback stopped, I toggled from vu to peak , meters started lighting up sporadically. Toggling back didn't help. Meters were just dancing around, going all the way to red peak led, then back down. (All this with no audio going to unit)
No weird noise coming from unit at all when this occurs.
I checked out meter PCB and noticed I forgot to solder 2 pins on the toggle (the 2 that are slightly off by themselves).
I soldered those, thinking that HAD to be the culprit.  Nope.
I swapped Lola's in the lunchbox just to check. That wasn't it either.
Didn't see any solder bridges on meter PCB.
Any idea what to check?

thanks
Carlos

Hmmmm hard to say. Maybe a bad switch? Really could be anything on the meter PCB.  Do you have another unit? if you switch the meter pcbs does the issue follow the meter pcb?

 

[csavetman]

Hmmmm hard to say. Maybe a bad switch? Really could be anything on the meter PCB.  Do you have another unit? if you switch the meter pcbs does the issue follow the meter pcb?

I seem to have gotten it working now. I reflowed a couple of solder joints around the toggle switch and on one of the meter board's  IC's that seemed a little light on solder. Seems all good now.

thanks
Carlos

 

[Echo North]

I seem to have gotten it working now. I reflowed a couple of solder joints around the toggle switch and on one of the meter board's  IC's that seemed a little light on solder. Seems all good now.

thanks
Carlos

Ya what you're describing sounded like a suspect joint/switch.

 

[Wazatron]

Hello all! I'm working on my first (hopefully first of at least 2...) Lola build, and thankfully I stopped to do testing before moving to the meter PCB, as I've hit a snag.

Problem:
DI works fine, but when using a mic I get no sound from the mic itself; instead I get some really wicked noise as I turn the gain up. There doesn't seem to be a difference with phantom power engaged or not. I've exported a quick recording of the noise in case it might be helpful in pinpointing the root issue here: https://soundcloud.com/wazatron/lola-test/s-yIxUj

Troubleshooting (so far):
I've looked through the board here as well as the Lola troubleshooting doc on the Hairball Audio site and have begun stepping through what I see as the most likely issues.
[list type=decimal]
[*]I've checked the DI connection and its solder joints
[*]Checked solder joints overall, reflowed anything that looked less than great
[*]I've started checking resistors, but I did check all with a DMM and organized them with the handy print-out guides from the site, so hopefully I didn't screw that up
[/list]

Unfortunately I don't have a lot of testing equipment. The only things I have are my lunchbox itself and a DMM. Most of my building experience has been with pedals, so I've done quite a bit of soldering and wiring, but nothing (until now) more complicated. But I believe all my joint and wiring look good.

Any thoughts, especially with the sound I'm getting (you can hear the noise generating from the unit increase and decrease as I alter the gain) would be appreciated!

Oh also one random question: the post on the output attenuator is REALLY long, so much so that the knob can't sit flush against the front panel and sticks out further than the knob for the Gain switch. Is this by design with the most updated kits?

Thanks everyone!

 

[Echo North]

Hello all! I'm working on my first (hopefully first of at least 2...) Lola build, and thankfully I stopped to do testing before moving to the meter PCB, as I've hit a snag.

Problem:
DI works fine, but when using a mic I get no sound from the mic itself; instead I get some really wicked noise as I turn the gain up. There doesn't seem to be a difference with phantom power engaged or not. I've exported a quick recording of the noise in case it might be helpful in pinpointing the root issue here: https://soundcloud.com/wazatron/lola-test/s-yIxUj

Troubleshooting (so far):
I've looked through the board here as well as the Lola troubleshooting doc on the Hairball Audio site and have begun stepping through what I see as the most likely issues.
[list type=decimal]
[*]I've checked the DI connection and its solder joints
[*]Checked solder joints overall, reflowed anything that looked less than great
[*]I've started checking resistors, but I did check all with a DMM and organized them with the handy print-out guides from the site, so hopefully I didn't screw that up
[/list]

Unfortunately I don't have a lot of testing equipment. The only things I have are my lunchbox itself and a DMM. Most of my building experience has been with pedals, so I've done quite a bit of soldering and wiring, but nothing (until now) more complicated. But I believe all my joint and wiring look good.

Any thoughts, especially with the sound I'm getting (you can hear the noise generating from the unit increase and decrease as I alter the gain) would be appreciated!

Oh also one random question: the post on the output attenuator is REALLY long, so much so that the knob can't sit flush against the front panel and sticks out further than the knob for the Gain switch. Is this by design with the most updated kits?

Thanks everyone!

You don't want to knob flush on the panel. It'll just drag on it and cause the pot to turn weird. You want it to float off, then match the gain switch to the same hight.

If your DI works but you mic input does not, there is an issue with the DI/Mic switching. The Relay that controls the DI/Mic input is set to DI in it's "normal" position. When you power the unit, it switches to mic. When you insert a 1/4" connector into the DI it breaks a ground connection and switches it to DI.

So when you power on, the relay switch is either A) not getting power to it or B) the relay is damaged.

Start by making sure every leg on the relay is solder correctly.

Mike

 

[Carl Cress]

Well I finished the first of 4 Lolas and I have a meter issue (see attached photo). The red LED and the first white LED are statically on and the meter does not respond to audio. The unit itself works fine on  DI, line and mic w/phantom. So I rechecked component location twice, floated every solder connection on the meter PCB and checked the ribbon cable continuity when connected. Any thoughts on this?

 

[Echo North]

Well I finished the first of 4 Lolas and I have a meter issue (see attached photo). The red LED and the first white LED are statically on and the meter does not respond to audio. The unit itself works fine on  DI, line and mic w/phantom. So I rechecked component location twice, floated every solder connection on the meter PCB and checked the ribbon cable continuity when connected. Any thoughts on this?

Make sure all the IC's are in right (don't mix up the 071 and 072) and polarized correctly. Check the 4 1N914 diodes.

Mike

 

[Carl Cress]

Hi Mike,
Please see attached photo. I did check all those things. Any thoughts? could it be the main board? any other thoughts?