[BUILD] Hairball Audio - Elements

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terrydactyl

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Apr 16, 2018
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Hairball Audio said:
What is the DC resistance (ohm tester) between one of the greens on your input transformer and each of the other leads?

Mike


BRN:  9.5
R:  2 ... (fluctuates a little)
W:  9.5
BLK:  2
GRN:  0.4
V:  323
GRY:  167.8
Y:  168.4
O:  0.2

 

terrydactyl

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Apr 16, 2018
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terrydactyl said:
BRN:  9.5
R:  2 ... (fluctuates a little)
W:  9.5
BLK:  2
GRN:  0.4
V:  323
GRY:  167.8
Y:  168.4
O:  0.2

I went back through the thread and read poster 'Darkus' had the exact same issue, same symptoms, and it turned out to be a bad input transformer...  Maybe? 

 

Echo North

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terrydactyl said:
I went back through the thread and read poster 'Darkus' had the exact same issue, same symptoms, and it turned out to be a bad input transformer...  Maybe?

Yes, you have a short in your primary.  Surprised you pass signal at all.

Email us: info(at)hairballaudio(dot)com
 

terrydactyl

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Hairball Audio said:
Yes, you have a short in your primary.  Surprised you pass signal at all.

Email us: info(at)hairballaudio(dot)com

Emailed.  Thank you so much!! 

Can't wait to build the next one!! 

-Terry
 

terrydactyl

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terrydactyl said:
Emailed.  Thank you so much!! 

Can't wait to build the next one!! 

-Terry

Apollogies for not following up.  Put the new input transformer in and holy moly!!!  I was getting some signal before but now...NOW.... I've got some serious gain!  This thing sounds friggin AWESOME.  It actually sounds really, really good. I'm especially liking the DI on it.  Wow! Thank you!!  So stoked!!!! 

 

lofi_beatsci

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Feb 17, 2018
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Hi Mike -

I've got a silver build I'm piecing together. For C301, I've got a 100pF ceramic cap rated for 50V. I see the other cap in that series (c300) is rated for 63V. Do you think the 50V will be alright coming in off the DI?

Thanks in advance.

-Matt
 

charlievela

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Nov 15, 2008
Messages
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Hi.

I just completed a pair of Coppers. Channel 1 is working perfectly, on channel 2 I made a dumb mistake and flipped Q600 and 601 (which I know is highlighted in the build guide, but my distractibility knows no bounds)

At first it wasn't passing signal at all, once I desoldered and flipped the components, I got a signal that was occasionally interrupted by a clicking sound, that only got worse over the next few minutes. Now there's no output and a continuous clicking that's modulated by the buttons on the front panel. I'm assuming I fried one or both of the components when I desoldered. Is there a way to verify? I'm going to try and place a mouser order right now just in case. But I want to be sure I didn't mess anything else up.


Video of the noise: https://www.youtube.com/watch?v=S3I30AVvva8
 

OwenAudio

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Feb 8, 2019
Messages
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Hi!  Putting together my first gold preamp, and first build.  When populating my board today with resistors I got to R604-3R9 and R605-3R9.  The color code on the resistor matches my reference material but the reading I get from them when measuring with my multimeter is 4.5 ohms.  That’s way outside the stated tolerance.  Is it a bad resistor?  Do I go with it?

Thanks,
Nate
 

Echo North

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Posting an email question here about transformers.

GA80071 (PM1000) as an input:

I'm working under the assumption this post is correct:
idylldon said:
Here's how I understand it:

Brown -- Primary Center Tap
Green and Blue -- Primary Leads
Yellow and White -- Secondary Leads (I've seen yellow labeled "cold" and white labeled "hot.")

Black must be an internal shield, but I've can't recall ever seeing it connected in any PM1000 channel I've racked and the black lead has always been cropped short.

Cheers,
--
Don

The PCB mount holes on the Elements are as follows Pin 1 (primary high) is the circled pad then down the line of 4 pins on that side it's 1-2-3-4 then pin 5 (primary high) is across from pin 4  then 5-6-7-8 with 8 being across from pin 1.

So white goes into pin 5 and yellow into pin 8.  On the primary side we don't know. Try green into 1 and blue into 4. Check your phase, if it's 180 swap those leads.

Brown unconnected and black to Pin 6 (ground).

Zobel network? No way of knowing, maybe start with the PM 1000 schematic zobel.

Output (EA2623):
Red primary high hole (either one)
Org primary low hole  (either one)

Blue/Brown Sec high holes
Green/Black Sec lo holes

Good luck.

Mike
 

ECS

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Mar 28, 2018
Messages
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Just finished a Copper and it's working great!  I just wanted to confirm you've changed the heatsink setup on the BA512... all the photos I see are of a large black heatsink but my op-amp shipped with a plain metal standoff screwed to the transistors.  Is this how these op-amps are shipping now?

Thanks!
 

ECS

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Mar 28, 2018
Messages
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Like I said the pre did work fine in a quick 5 minute mic test... I didn't check to see if the transitors or standoff got hot because the unit was enclosed.  Here are a couple of pictures... just looks a bit odd to me.

DCHdE9o.jpg

eIKPjQA.jpg
 

Echo North

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ECS said:
Just finished a Copper and it's working great!  I just wanted to confirm you've changed the heatsink setup on the BA512... all the photos I see are of a large black heatsink but my op-amp shipped with a plain metal standoff screwed to the transistors.  Is this how these op-amps are shipping now?

Thanks!

Hi,

Yes this is a more common heatsink set up for this topology which generally runs a little cooler. If you look around many manufactures use this method (purple audio for one) or no heatsink at all.

The original heatsink was always more decorative, it was overkill. Rising material cost forced to either raise prices or use a more affordable method. Since it was more decorative we couldn't justify raising prices.

Jens the designer of this op-amp @ Eisen Audio has been running them with this set up in his console projects for years.

Mike
 

ECS

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Mar 28, 2018
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Thanks for the clarification Mike! 

Just wanted to confirm it was correct... aesthetically I don't mind at all, not like I'm going to be looking at the thing.

Thanks again for all the great projects... I've got another 1176 build planned very soon!

~Eric
 

resilient

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Sep 3, 2005
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Location
Great Smoky Mountains
Hi Mike,

Built an Elements Gold last night.  It is unfortunately not working.  I haven't gone through the resistors to double check all of those yet, but wanted to check in with you here.  I get some noise when rotating the output knob, but that's it.  Nothing through the DI or XLR.

I should also have a 500 extender soon to take measurements.  I'll also try to find a way to post a pic of my soldering.  Currently the pic is too big.

Any thoughts on the noisy output knob?

Brandon
 

Echo North

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resilient said:
Hi Mike,

Built an Elements Gold last night.  It is unfortunately not working.  I haven't gone through the resistors to double check all of those yet, but wanted to check in with you here.  I get some noise when rotating the output knob, but that's it.  Nothing through the DI or XLR.

I should also have a 500 extender soon to take measurements.  I'll also try to find a way to post a pic of my soldering.  Currently the pic is too big.

Any thoughts on the noisy output knob?

Brandon

Well if it's not passing signal, you probably just have some DC in the output circuit you're amplifying.  Check all of your joints around those big caps by the input and output.  They can be tricky getting good flow into the ground plane pads.

Mike
 
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