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

Oooo that sounds great! I'd definitely be interested in one of those!

So, I ordered 4 Lolas, and I've built 2 so far.

One of them is having a strange issue with the meter, where it will slowly creep up. It has no affect on it's audio performance at all. It will just randomly creep up higher and higher the longer that it is on. For a while, you can sort of "clear" the meter by switching between ppm/vu, but eventually, it will just hang out in the upper range.

Again, it has no other issues. I pulled the meter board out and visually inspected it...I'm not seeing anything strange.

Any ideas?

mattjhuber said:

So, I ordered 4 Lolas, and I've built 2 so far.

One of them is having a strange issue with the meter, where it will slowly creep up. It has no affect on it's audio performance at all. It will just randomly creep up higher and higher the longer that it is on. For a while, you can sort of "clear" the meter by switching between ppm/vu, but eventually, it will just hang out in the upper range.

Again, it has no other issues. I pulled the meter board out and visually inspected it...I'm not seeing anything strange.

Any ideas?

Click to expand...

Something is off with the meter.  Could be a bad cap or diode, solder bridge, anything really.  Have a close look.  When you get done with all of them if you still can't sort it we an have a look at.

Mike

I made a Lola w/ DIY 990's. No issues at first but now the LED meter doesn't work. The pre still works and the meter lights blink  once when I press the Line or the Polarity button but not the +48 button. Also, when I flick the PPM/VU switch the meter lights blink once, but don't work. Any idea how to go about troubleshooting this?

discord said:

I made a Lola w/ DIY 990's. No issues at first but now the LED meter doesn't work. The pre still works and the meter lights blink  once when I press the Line or the Polarity button but not the +48 button. Also, when I flick the PPM/VU switch the meter lights blink once, but don't work. Any idea how to go about troubleshooting this?

Click to expand...

Well at the very least it sounds isolated to the meter board.  The first thing I would check for if it worked, then did not, are shorts.  Look for any of the tall vertical resistors leaning and making contact with anything else.  If you see any suspicious solder joints re-flow them.

Mike

Need some troubleshooting assistance.. Built the Lola and the DIY 990 DOA, the preamp works but only with the 1/4" input on the front. Assuming it has something to do with the relays.. I've reflowed the relays handling the mic input but no difference. Any thoughts?

newgeography said:

Need some troubleshooting assistance.. Built the Lola and the DIY 990 DOA, the preamp works but only with the 1/4" input on the front. Assuming it has something to do with the relays.. I've reflowed the relays handling the mic input but no difference. Any thoughts?

Click to expand...

Make sure you have solder all 8 relay pins.

If that does not work it's possible your relay control transistor died.  If the relay is not getting power, you're stuck in DI mode.

Mike

Hi.
I just build one of these and the preamp works as expected but the meter is constantly pegged. Here's a possible reason: I was supplied with a (c106) 3.3 uf instead of the 2.2 uf  specified in the schematic. Now I thought I recalled reading somewhere that with capacitors you can go slightly over, not under. So figured it was intentionally good. Something tells me it's not so  8)

It sounds beautiful by the way. Really, really like the sound.

Peter

lordnielson said:

Hi.
I just build one of these and the preamp works as expected but the meter is constantly pegged. Here's a possible reason: I was supplied with a (c106) 3.3 uf instead of the 2.2 uf  specified in the schematic. Now I thought I recalled reading somewhere that with capacitors you can go slightly over, not under. So figured it was intentionally good. Something tells me it's not so  8)

It sounds beautiful by the way. Really, really like the sound.

Peter

Click to expand...

That cap shouldn't be the issue.  Make sure none of the vertical  resistors are touching and check your components.

Mike

Fixed it. One unsoldered ribbon connector leg on the mainboard  :-[

Merry Christmas.

Hiya,

It seems that most people in this thread are building from the kits, with all parts supplied, but due to the New Zealand dollar being so crap, it works out cheaper for me to order just the pcb & transformers and transformers and source the rest of the components here, (I already have a lot of the parts here leftover from other projects) and attempt the metalwork myself.

Anyway, I've managed to source some pushbutton switches the same as what comes with the kit, except that I can only get red, yellow or green instead of the blue that comes with the kit.
Now, the actual colour doesn't bother me, but the blue has a 3.5v nominal voltage, where as the red, yellow and green that I have access to have a 1.5v nominal voltage.

Where should I be looking in the circuit to get a lower voltage for the leds? A resistor change somehwere?Am I looking at the 470r or the 1k?  I've been staring at the schematic over and over, but I feel like I'm missing the basic and obvious.

cheers,
Steve

Hey Mike!

I thought the build was pretty straight forward and I was confident with my construction with the LOLA. I had built a pair of the FET500s as well as a bunch of others (VP312s and JLM LA500s) - So I didn't think the LOLA was too crazy for my skill set.

I got the JE-990 prebuilt DOAs, but when I powered the LOLA up, it instantly started to smoke. Looks like R32 is black (charred)  in the middle of the resistor now.

Any ideas? Any insight would be awesome.

Here is a picture of it.

Thanks so much Mike!

M.

junomat said:

Hey Mike!

I thought the build was pretty straight forward and I was confident with my construction with the LOLA. I had built a pair of the FET500s as well as a bunch of others (VP312s and JLM LA500s) - So I didn't think the LOLA was too crazy for my skill set.

I got the JE-990 prebuilt DOAs, but when I powered the LOLA up, it instantly started to smoke. Looks like R32 is black (charred)  in the middle of the resistor now.

Any ideas? Any insight would be awesome.

Here is a picture of it.

Thanks so much Mike!

M.

Click to expand...

R32 is the voltage supply (-) to DOA 1. If that is burning something is wrong with DOA 1. You got them built from us? That's weird as they would have been tested.

Pull DOA 1 and look at all of the vertical components to see if any are pushed over and leads are touching. Look at the resistors by the screw heads that attach the clips to output transistors.  There should be a resistor that's leg is turned 45 degrees away from the screw head to prevent a short.

If nothing is touching, we may just need to send you a new DOA. Send us an e-mail.

Thanks!

Mike

Upon further viewing, I see that R31 is also charred in addition to R32. Does that change anything?

We did get the DOAs from you. The prebuilt ones...

The DOA looks good to me. Did you want me to take pictures?

And will I have to replace both resistors?

junomat said:

Upon further viewing, I see that R31 is also charred in addition to R32. Does that change anything?

We did get the DOAs from you. The prebuilt ones...

The DOA looks good to me. Did you want me to take pictures?

And will I have to replace both resistors?

Click to expand...

31 and 32 are linked as they carry the same current path. We'll get a new one out to you today with new 10Ω R's.

Mike

Hairball Audio said:

junomat said:

Upon further viewing, I see that R31 is also charred in addition to R32. Does that change anything?

We did get the DOAs from you. The prebuilt ones...

The DOA looks good to me. Did you want me to take pictures?

And will I have to replace both resistors?

Click to expand...

31 and 32 are linked as they carry the same current path. We'll get a new one out to you today with new 10Ω R's.

Mike

Click to expand...

Wonderful! Thanks so much Mike! Cant wait to dive in with the Lola!!!!

Have a question about seating the DIY 990 op-amps into the op-amp sockets. How do I do this? Mine are loose and the manual doesn't explain this. Cheers.

applespace said:

Have a question about seating the DIY 990 op-amps into the op-amp sockets. How do I do this? Mine are loose and the manual doesn't explain this. Cheers.

Click to expand...

You have to push them in hard.  Try holding the sides of the PCB, line up the pins in the sockets and push down.  They'll go in with a little force and be solid.

Mike

Thanks Mike. Yeah I was being too cautious.

I've built 2 and they're both working, but one of them is metering lower than the other. Do you know where/what meter pcb could be causing this? Nothing looks out of place.

Thanks for your help.

applespace said:

Thanks Mike. Yeah I was being too cautious.

I've built 2 and they're both working, but one of them is metering lower than the other. Do you know where/what meter pcb could be causing this? Nothing looks out of place.

Thanks for your help.

Click to expand...

Mixed up resistor values or a bad diode would be my guess.

Mike