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

[TillM]

https://www.mouser.de/ProductDetail/Xicon/271-10-RC?qs=sGAEpiMZZMukHu%252bjC5l7YRdhprvJnAl%252bmxxG7BawCo8%3d

 

[Ethan1997]

https://www.mouser.de/ProductDetail/Xicon/271-10-RC?qs=sGAEpiMZZMukHu%252bjC5l7YRdhprvJnAl%252bmxxG7BawCo8%3d

Much appreciated, thank you!!

 

[eelcobakker]

Make sure you have the output fully clockwise.  Yes try a different set of op-amps.  If that fixes it, swap them around until you can find the bad one.

Mike

Hi Mike, I tried a different set of op-amps with the output fully clockwise. I also tried disconnecting the meter daughterboard. Still the nasty distortion. What else might I try?

Thanks,
Eelco

 

[Echo North]

Hi Mike, I tried a different set of op-amps with the output fully clockwise. I also tried disconnecting the meter daughterboard. Still the nasty distortion. What else might I try?

Thanks,
Eelco

Is it the same with the mic input and DI input?

Mike

 

[eelcobakker]

Is it the same with the mic input and DI input?

Mike

Yep, same results.

Eelco

 

[Echo North]

Yep, same results.

Eelco

Where are you located? In the USA or elsewhere?

Mike

 

[eelcobakker]

Where are you located? In the USA or elsewhere?

Mike

Amsterdam, The Netherlands.

 

[alexkfong]

OK, I finally got a chance to really work on the Lola, and I ... blew it. Literally.

It looks like R37 and R31 have some damage after the unit started to smoke when I plugged it into my lunchbox. I can't tell if R36 and R32 are affected. But the opamps are clearly the problem. Any advice on how to proceed? To be honest, I don't think my newbie soldering technique is up to snuff to handle the tight confines of the opamp, and I'm sure that's what went wrong. I'm certain I got the components correct ...

Another question on the Grayhill switch. It ... doesn't seem to turn at all. I should have really checked it before putting in the stop pin. Again, any help much appreciated.

Thanks,
Alex

 

[Echo North]

Amsterdam, The Netherlands.

Usually distortion is in the op-amp stage, seems like that is not your problem.  Have you triple checked that that all components are in the correct place, soldered well?  You may try re-flowing components.

Mike

 

[Echo North]

OK, I finally got a chance to really work on the Lola, and I ... blew it. Literally.

It looks like R37 and R31 have some damage after the unit started to smoke when I plugged it into my lunchbox. I can't tell if R36 and R32 are affected. But the opamps are clearly the problem. Any advice on how to proceed? To be honest, I don't think my newbie soldering technique is up to snuff to handle the tight confines of the opamp, and I'm sure that's what went wrong. I'm certain I got the components correct ...

Another question on the Grayhill switch. It ... doesn't seem to turn at all. I should have really checked it before putting in the stop pin. Again, any help much appreciated.

Thanks,
Alex

Op-amp issues are usually the 171/181 output transistors being swapped, the diodes clipped to them being in backwards/busted, the clip that holds the diode touching the diode legs, or a resistor touching the screw in the front which holds the diode clip.

Not sure about the Grayhill. Do you have the knob on it? It's VERY hard to turn without the knob on it.

Mike

 

[alexkfong]

Op-amp issues are usually the 171/181 output transistors being swapped, the diodes clipped to them being in backwards/busted, the clip that holds the diode touching the diode legs, or a resistor touching the screw in the front which holds the diode clip.

Not sure about the Grayhill. Do you have the knob on it? It's VERY hard to turn without the knob on it.

Both of these comments help so much! I do not have the knob on yet.

I reread the DIY990 build guide. I can't believe I missed the paragraph about the direction of the diodes coupled to the output transistors. None of the other potential problems you listed are visible on the opamps I stuffed. I'll inspect and reverse the diodes  when I have time this weekend. (That has got to be the problem.)

Would you recommend replacing all the 10 ohm resistors or just the two that appear damaged? Also ... do you think I should replace the output transistors and diodes since I've already trimmed the leads? If so, is there a mouser link available? (I saw in a prior post someone has already linked to the 10 ohm resistors.)

Sorry ... definitely learning a lot from this experience! (Which I hope will lead me to FET compressor kit later.) Thanks again!

 

[Echo North]

Both of these comments help so much! I do not have the knob on yet.

I reread the DIY990 build guide. I can't believe I missed the paragraph about the direction of the diodes coupled to the output transistors. None of the other potential problems you listed are visible on the opamps I stuffed. I'll inspect and reverse the diodes  when I have time this weekend. (That has got to be the problem.)

Would you recommend replacing all the 10 ohm resistors or just the two that appear damaged? Also ... do you think I should replace the output transistors and diodes since I've already trimmed the leads? If so, is there a mouser link available? (I saw in a prior post someone has already linked to the 10 ohm resistors.)

Sorry ... definitely learning a lot from this experience! (Which I hope will lead me to FET compressor kit later.) Thanks again!

Hi,

Wouldn't hurt to replace.

Part numbers are:
271-10-RC
MJE171G
MJE181G
1N914BTR

Mike

 

[eelcobakker]

Usually distortion is in the op-amp stage, seems like that is not your problem.  Have you triple checked that that all components are in the correct place, soldered well?  You may try re-flowing components.

Mike

Hi Mike, I checked all components as far as possible (a bit harder now everything is soldered to the board), and reflowed some suspicious joints. Still the same distortion. Should I post some pictures of my build? Maybe I'm overlooking something here.

Thanks,
Eelco

 

[Echo North]

Hi Mike, I checked all components as far as possible (a bit harder now everything is soldered to the board), and reflowed some suspicious joints. Still the same distortion. Should I post some pictures of my build? Maybe I'm overlooking something here.

Thanks,
Eelco

Photo's rarely help, electronics is about measurements, but that get's tricky with 500 series stuff as it's in an enclosure.  You could definitely post some, and I can look.

Repair option as well:
https://www.hairballaudio.com/build-support-services

Mike

 

[Scimitar]

Thought that this link might be of interest to existing and prospective owners.

https://youtu.be/JjV36ub5ybI

The lead vocals of this cover of Ed Sheeran's "Shape of You" were recorded using a Hairball Audio Lola.
It is very definitely one of the first pre's that I reach for, particularly if I am looking for something that is silky smooth, but still full of character.

 

[Echo North]

Thought that this link might be of interest to existing and prospective owners.

https://youtu.be/JjV36ub5ybI

The lead vocals of this cover of Ed Sheeran's "Shape of You" were recorded using a Hairball Audio Lola.
It is very definitely one of the first pre's that I reach for, particularly if I am looking for something that is silky smooth, but still full of character.

Nice!

 

[alexkfong]

Hi,

My preamp is working! But I also have the attenuator problem in that output goes to 0 when the output knob is around 11 o'clock.

Is there a region of the board I should specifically be searching for problems or is the whole piece in play? I checked the transformer wires and can see they have been installed correctly.

Thanks!
Alex

 

[ramtazz]

Hi Mike... I assembled my Lola Mic Pre kit w/ the 990 opamps.  The basic unit works fine except for the last 2 steps on the grayhill... they seem to be highly distorted regardless of output level on the attenuator. This is regardless of Mic or DI input. 

Also the metering does not work at all...  Nothing feels warm in the circuit.  I have a power supply on order since I cannot test anything when its inside of my API Lunchbox thing. 

Help...

Bill

 

[TillM]

Check the soldering work from the grayhill Switch. Seams to me like solder bridges.
Check if the connector cable from the LED sits flush in.
Also check your soldering and resistors.

 

[Echo North]

Hi,

My preamp is working! But I also have the attenuator problem in that output goes to 0 when the output knob is around 11 o'clock.

Is there a region of the board I should specifically be searching for problems or is the whole piece in play? I checked the transformer wires and can see they have been installed correctly.

Thanks!
Alex

Seems probably normal....the attenuation is so low there you can't hear the signal anymore.  It's really dependent on how loud your signal is.