[BUILD] Hairball Audio - Elements

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cmac

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Joined
Jan 14, 2016
Messages
13
Hairball Audio said:
Do you have another op-amp you can swap in to rule out a bad op-amp?

Alright, I finally got swapping a BA512 op amp from one of my working Copper Pres. It worked! Perhaps it got fried when the capacitors C505-506 blew? Anyway, that is definitely the issue, I tested the input output knobs and Pad switch. The preamp worked perfectly with the new Op Amp. I am to assume the easiest solution is to order a new one from hairball? They are so small I imagine it would be difficult, if not impossible, to troubleshoot? Glad its figured out! As always, thanks for the help.

Clinton
 

Echo North

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Joined
Jan 21, 2006
Messages
4,437
Location
Seattle, WA
cmac said:
Alright, I finally got swapping a BA512 op amp from one of my working Copper Pres. It worked! Perhaps it got fried when the capacitors C505-506 blew? Anyway, that is definitely the issue, I tested the input output knobs and Pad switch. The preamp worked perfectly with the new Op Amp. I am to assume the easiest solution is to order a new one from hairball? They are so small I imagine it would be difficult, if not impossible, to troubleshoot? Glad its figured out! As always, thanks for the help.

Clinton

Not impossible, but I find it easier just to get a new one.

Mike
 

EmoRiot

Active member
Joined
Mar 18, 2005
Messages
39
Location
Beautiful Downtown Burbank
Hey there Hairball. I started my build tonight and everything was going swimmingly stuffing my PCB with resistors until I got to the last three. Shown below...

p.jpeg


But the color bands on the resistors I have indicate, if I'm reading them correctly, that I have two 2M resistors and one 1M resistor - not 200k and 100k. I've got a picture of my resistors below as they were in my kit. Do I have the wrong resistors or am I reading these bands wrong?

p.jpeg
 

Fuzz Face

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Joined
Nov 22, 2018
Messages
142
Location
Anaheim
EmoRiot said:
Aha! I figured it out.

The orange band looked yellow to me. But if I recognize it at orange then the values make sense and I'm off and on my way with diodes and transistors.
Do you have a DMM? As stated in the build guide, you should double check resistors by measuring them. Then there’s no question
 

EmoRiot

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Mar 18, 2005
Messages
39
Location
Beautiful Downtown Burbank
Fuzz Face said:
Do you have a DMM? As stated in the build guide, you should double check resistors by measuring them. Then there’s no question

Yeah I had been testing them all night but the readings on those three were a little weird - but only when I was unsure of the bands. Once I set my DMM correctly for the expected resistance it all read as expected. Thanks!
 

iantaylorsutton

New member
Joined
Jan 12, 2019
Messages
2
Just finished my 2nd Copper mic pre kit (built the first one about 8 mos ago). Anyway, I've noticed that the first one I built has a significantly reduced output compared to the new one. Any thoughts on what might be causing this? I've included a picture showing how vastly different they are from each other; as shown both preamps are producing the same amount of signal from the same microphone with the same cable.

Thank you!

Ian
 

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Echo North

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Jan 21, 2006
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Seattle, WA
Swap the op-amps, see if the issue follows the op-amp.

iantaylorsutton said:
Just finished my 2nd Copper mic pre kit (built the first one about 8 mos ago). Anyway, I've noticed that the first one I built has a significantly reduced output compared to the new one. Any thoughts on what might be causing this? I've included a picture showing how vastly different they are from each other; as shown both preamps are producing the same amount of signal from the same microphone with the same cable.

Thank you!

Ian
 

iantaylorsutton

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Jan 12, 2019
Messages
2
Hairball Audio said:
Swap the op-amps, see if the issue follows the op-amp.

Thanks for the prompt reply. Good news. It turns out i'm just an idiot! I failed to take into consideration that the louder of the two preamps was also hitting my FET Rack before hitting my converters, and even in "bypass" mode and at unity gain was still bumping up the signal a few db.

Thanks again for your help!

Ian
 

Echo North

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iantaylorsutton said:
Thanks for the prompt reply. Good news. It turns out i'm just an idiot! I failed to take into consideration that the louder of the two preamps was also hitting my FET Rack before hitting my converters, and even in "bypass" mode and at unity gain was still bumping up the signal a few db.

Thanks again for your help!

Ian

Nice!  8)
 

curranm

Active member
Joined
Nov 11, 2012
Messages
39
just finished two copper preamps, everything works wonderfully(I Think) DI's. mic pre,and phantom power, BUT there was an audible "click" happening when I would have the phantom power engaged. This is NOT a click from pressing or engaging the switches this was a "click" ONLY when the phantom power was engaged. IT HAS gone away , BUT I am curious what this could have been. I was in BOTH preamps, but everything seems fine now...................
 

Walshy

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Joined
Feb 25, 2014
Messages
3
Location
Sydney, Australia
Hi,

Just finished 4 x Copper pre's and I'm glad to say I've had great success! They are sounding awesome!

Just a question though. I ran a 1k sine wave through each pre just to have a rudimentary look and listen at the distortion that occurs as the gain is increased. Everything is working fine (can't wait to colour a snare!!), however, I noticed that there is a steady 1db fluctuation when I have the gain cranked to 10. Over the course of 14 secs, the signal rises and falls by 1db (see pic attached). This is the same for each pre.

As I lower the gain, the amount of db of fluctuation decreases. It becomes negligible once gain is down to 3db and less.

Any thoughts? I'm a bit worried that the common denominator is the Lindell chassis

Cheers,

Walshy
 

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abeLovesDIY

Active member
Joined
Mar 30, 2020
Messages
28
Just finished my 3rd Bronze. Before powering up I tested continuity for shorts, and this one has a short between +16 and -16. Not sure where I messed up, any one run into this before?
IMG_20210521_193450629.jpg
 

abeLovesDIY

Active member
Joined
Mar 30, 2020
Messages
28
Mike helped me narrow it down to a bad op-amp DOA.
I had another Bronze with an issue: a short between +16 and +48 which I solved myself, but will post here in case anyone else has the issue on this or another Element Build. If you aren't careful, there is a VIA that is +48 near Fuse F100 (+16v). If you are sloppy you might get a bridge there.
 

camshash

Well-known member
Joined
Sep 4, 2021
Messages
52
Location
Michigan
Hi everyone, just wanted to post my solution to a problem I faced with one of my copper builds, and some of the things I learned along the way so others with similar experience in DIY can learn as well

After finishing the build I noticed a fairly loud hum, almost sounding like 60 hz hum. At first I thought it might have been a chassis ground loop issue, but had no way to localize the problem to either the copper unit or the chassis as I only have 1 chassis and this copper was my first 500 series.

I was missing a 100k ohm resistor in my kit for the mic input section (R502) which I improvised a 100k ohm Carbon comp. resistor instead of a Xicon metal film. I soon learned that carbon comp. resistors are inferior in pretty much every way to metal film; most importantly for sound quality. Carbon comps are much much noisier than metal film resistors, and with R502 being in the input section of the mic pre any noise here will be amplified down the line.

Swapped out R502 for a metal film and the problem still persisted. After getting a 500 series extender from diyre I was able to go through the elements test points listed on Hairballs website. https://help.hairballaudio.com/hc/en-us/articles/360047552954-Elements-Troubleshooting-Guide

1Khz sinewave at 0.200 VAC into the copper, all test points were going well until TP6. I was reading ~0.394 VAC at the violet lead from the input transformer when it should have been ~0.756 VAC. TP7 was also reading the same 0.394 when it should be 0.756, so the opamp was seeing nearly half the voltage it should be getting. Checked all resistor values, solder pads around transformed to make sure they were all clean with no wire insulation melted on them. Really stumped me what could be wrong.

From what I've read and what Mike echoed is that pretty much all bad transformers will not pass a signal at all, whereas mine was passing a fairly strong signal. At this time my next copper kit arrived and I tried swapping out input transformers.

Problem solved instantly, all test points passed and the hum was completely gone.

I also noticed I had to crank the output of my Signal generator more to get 0.200VAC seen at the bad Transformer input, which tells me the bad transformer wasn't drawing current as much

I want to thank Mike for being very helpful and quick with sending replacements parts

I am shocked at how much better these sound than my other mic pres. I feel like I've been recording into a wet sock my entire life now.
 

Mworthin

Well-known member
Joined
Apr 10, 2016
Messages
50
Hi everyone, just wanted to post my solution to a problem I faced with one of my copper builds, and some of the things I learned along the way so others with similar experience in DIY can learn as well

After finishing the build I noticed a fairly loud hum, almost sounding like 60 hz hum. At first I thought it might have been a chassis ground loop issue, but had no way to localize the problem to either the copper unit or the chassis as I only have 1 chassis and this copper was my first 500 series.

I was missing a 100k ohm resistor in my kit for the mic input section (R502) which I improvised a 100k ohm Carbon comp. resistor instead of a Xicon metal film. I soon learned that carbon comp. resistors are inferior in pretty much every way to metal film; most importantly for sound quality. Carbon comps are much much noisier than metal film resistors, and with R502 being in the input section of the mic pre any noise here will be amplified down the line.

Swapped out R502 for a metal film and the problem still persisted. After getting a 500 series extender from diyre I was able to go through the elements test points listed on Hairballs website. https://help.hairballaudio.com/hc/en-us/articles/360047552954-Elements-Troubleshooting-Guide

1Khz sinewave at 0.200 VAC into the copper, all test points were going well until TP6. I was reading ~0.394 VAC at the violet lead from the input transformer when it should have been ~0.756 VAC. TP7 was also reading the same 0.394 when it should be 0.756, so the opamp was seeing nearly half the voltage it should be getting. Checked all resistor values, solder pads around transformed to make sure they were all clean with no wire insulation melted on them. Really stumped me what could be wrong.

From what I've read and what Mike echoed is that pretty much all bad transformers will not pass a signal at all, whereas mine was passing a fairly strong signal. At this time my next copper kit arrived and I tried swapping out input transformers.

Problem solved instantly, all test points passed and the hum was completely gone.

I also noticed I had to crank the output of my Signal generator more to get 0.200VAC seen at the bad Transformer input, which tells me the bad transformer wasn't drawing current as much

I want to thank Mike for being very helpful and quick with sending replacements parts

I am shocked at how much better these sound than my other mic pres. I feel like I've been recording into a wet sock my entire life now.
I feel that way about my Element Golds.
 

Parabola

Member
Joined
Nov 28, 2018
Messages
7
Hello. I built 3 Gold kits last night and this morning. I took my time and put them like an assembly like to make sure I put every part in the correct place.

One of them works perfect with no issues.

The second one is intermittent. I might work and then it completely loses signal. Then it can start working again.

The third one doesn't pass signal at all. To make sure I don't have any loose joints, I reheated the solder to make sure it was flowing properly. Still nothing.

All the phantom LEDs are working.

Any thoughts?
 
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