[BUILD] Hairball Audio - Elements

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Johnnigrah said:
Oops my bad for not specifying. I have the copper kit

Hairball Audio said:
Johnnigrah said:
Hey guys!
My entire build works great, except for the +48V button and the LED.
The signal comes through fine with a dynamic mic, but with a condenser there is no signal, regardless of if the phantom power button is pressed or not.
I've already tried the different cables/different mics deal, so it has to be something with the electronics.

Thanks!

What unit do you have? Copper, Bronze, or Gold?

Mike

We had two bad input transformers that displayed a similar behavior. Not saying that's the issue, but let's run a test.

Try this, you can remove the module from the rack, no need to power it.  Grab you DMM and set it to measure Ω/resistance. Place one probe on either green (wire) pad.  Now test that against each of the other pads. Which pads have less than 1Ω of resistance to the green? 

Thanks,

Mike
 
I found that the orange one (and of course green measured against green) is < 1ohm. What does this mean?

Hairball Audio said:
Johnnigrah said:
Oops my bad for not specifying. I have the copper kit

Hairball Audio said:
Johnnigrah said:
Hey guys!
My entire build works great, except for the +48V button and the LED.
The signal comes through fine with a dynamic mic, but with a condenser there is no signal, regardless of if the phantom power button is pressed or not.
I've already tried the different cables/different mics deal, so it has to be something with the electronics.

Thanks!

What unit do you have? Copper, Bronze, or Gold?

Mike

We had two bad input transformers that displayed a similar behavior. Not saying that's the issue, but let's run a test.

Try this, you can remove the module from the rack, no need to power it.  Grab you DMM and set it to measure Ω/resistance. Place one probe on either green (wire) pad.  Now test that against each of the other pads. Which pads have less than 1Ω of resistance to the green? 

Thanks,

Mike
 
Johnnigrah said:
I found that the orange one (and of course green measured against green) is < 1ohm. What does this mean?

Hairball Audio said:
Johnnigrah said:
Oops my bad for not specifying. I have the copper kit

Hairball Audio said:
Johnnigrah said:
Hey guys!
My entire build works great, except for the +48V button and the LED.
The signal comes through fine with a dynamic mic, but with a condenser there is no signal, regardless of if the phantom power button is pressed or not.
I've already tried the different cables/different mics deal, so it has to be something with the electronics.

Thanks!

What unit do you have? Copper, Bronze, or Gold?

Mike

We had two bad input transformers that displayed a similar behavior. Not saying that's the issue, but let's run a test.

Try this, you can remove the module from the rack, no need to power it.  Grab you DMM and set it to measure Ω/resistance. Place one probe on either green (wire) pad.  Now test that against each of the other pads. Which pads have less than 1Ω of resistance to the green? 

Thanks,

Mike

It means your input transformer is probably not the problem, that is normal.

Obviously you've checked the components in the +48 box on the PCB? Values are correct? Re-flowed solder?

If you can attach a clip lead to a ground point and the other to the circuit side of the +48 fuse and plug the unit in. Enable phantom and measure the DC, see if you get +48(ish) after the fuse.

Mike
 
Just now tried both of those things and still no luck unfortunately

Hairball Audio said:
Johnnigrah said:
I found that the orange one (and of course green measured against green) is < 1ohm. What does this mean?

Hairball Audio said:
Johnnigrah said:
Oops my bad for not specifying. I have the copper kit

Hairball Audio said:
Johnnigrah said:
Hey guys!
My entire build works great, except for the +48V button and the LED.
The signal comes through fine with a dynamic mic, but with a condenser there is no signal, regardless of if the phantom power button is pressed or not.
I've already tried the different cables/different mics deal, so it has to be something with the electronics.

Thanks!

What unit do you have? Copper, Bronze, or Gold?

Mike

We had two bad input transformers that displayed a similar behavior. Not saying that's the issue, but let's run a test.

Try this, you can remove the module from the rack, no need to power it.  Grab you DMM and set it to measure Ω/resistance. Place one probe on either green (wire) pad.  Now test that against each of the other pads. Which pads have less than 1Ω of resistance to the green? 

Thanks,

Mike

It means your input transformer is probably not the problem, that is normal.

Obviously you've checked the components in the +48 box on the PCB? Values are correct? Re-flowed solder?

If you can attach a clip lead to a ground point and the other to the circuit side of the +48 fuse and plug the unit in. Enable phantom and measure the DC, see if you get +48(ish) after the fuse.

Mike
 
Update: tried resoldering the fuse and 48V section again, and even tried the unit in different spaces in my lunchbox.
Upon checking with DMM I still do not have the 48V signal for some reason

Johnnigrah said:
Just now tried both of those things and still no luck unfortunately

Hairball Audio said:
Johnnigrah said:
I found that the orange one (and of course green measured against green) is < 1ohm. What does this mean?

Hairball Audio said:
Johnnigrah said:
Oops my bad for not specifying. I have the copper kit

Hairball Audio said:
Johnnigrah said:
Hey guys!
My entire build works great, except for the +48V button and the LED.
The signal comes through fine with a dynamic mic, but with a condenser there is no signal, regardless of if the phantom power button is pressed or not.
I've already tried the different cables/different mics deal, so it has to be something with the electronics.

Thanks!

What unit do you have? Copper, Bronze, or Gold?

Mike

We had two bad input transformers that displayed a similar behavior. Not saying that's the issue, but let's run a test.

Try this, you can remove the module from the rack, no need to power it.  Grab you DMM and set it to measure Ω/resistance. Place one probe on either green (wire) pad.  Now test that against each of the other pads. Which pads have less than 1Ω of resistance to the green? 

Thanks,

Mike

It means your input transformer is probably not the problem, that is normal.

Obviously you've checked the components in the +48 box on the PCB? Values are correct? Re-flowed solder?

If you can attach a clip lead to a ground point and the other to the circuit side of the +48 fuse and plug the unit in. Enable phantom and measure the DC, see if you get +48(ish) after the fuse.

Mike
 
You have no 48V on the front panel side of the fuse? What about the edge card side?

What are you using for your ground reference lead?

Mike
 
On both sides of the fuse I'm getting <1V for some reason...

I referenced both with grounded metal and a negative battery terminal. The other fuses are getting ~15V but nothing on this specific fuse.

Hairball Audio said:
You have no 48V on the front panel side of the fuse? What about the edge card side?

What are you using for your ground reference lead?

Mike
 
Johnnigrah said:
On both sides of the fuse I'm getting <1V for some reason...

I referenced both with grounded metal and a negative battery terminal. The other fuses are getting ~15V but nothing on this specific fuse.

Hairball Audio said:
You have no 48V on the front panel side of the fuse? What about the edge card side?

What are you using for your ground reference lead?

Mike

If you're not getting anything on the edge card side something is either:

1) wrong with your rack +48 supply
2) you measurement method
3) or the +48 edge card finger, or slot has gunk on it so they are no making contact.

Nothing other than the gold finger and the card connector sit between that fuse leg and your rack +48 supply.

Did you try another module in that spot. Does the +48 work?

Mike
 
You are the MAN, Mike.

I took everything out of my rack unit and noticed some bad connections in the unit itself. I resoldered them and viola!

Perfection.

Thanks so much for bearing with me and my funny little problem haha.

Cheers!
 
Hi folks!

I'm just about pulling the trigger and trying out my wings with the silver platform...

My ultimate goal is to create somewhat Quad 8/Pacifica-ish sounding unit, and according to the folklore found in the internet the best transformer options "tonewise" would be Cinemag's CMOQ-2S output and CM75101 input transformers.
The DOA would be Seventh circle's SC10. I've not done any real calculations yet, but I just thought that these three would be the main "tonefactors".

Nevertheless, you are suggesting using CM2511 as the input transformer. Since there's no datasheet available on the CM75101 (at least I didn't find one), I thought posting here... (I also contacted Cinemag, but haven't got any reply yet.)

So my question is are CM75101 and CM2511 interchangeable? Is there any significant or notable differences between the two, as far as the electric operating or the sound is concerned?

Thank you!
Finbase
 
finbase said:
Hi folks!

I'm just about pulling the trigger and trying out my wings with the silver platform...

My ultimate goal is to create somewhat Quad 8/Pacifica-ish sounding unit, and according to the folklore found in the internet the best transformer options "tonewise" would be Cinemag's CMOQ-2S output and CM75101 input transformers.
The DOA would be Seventh circle's SC10. I've not done any real calculations yet, but I just thought that these three would be the main "tonefactors".

Nevertheless, you are suggesting using CM2511 as the input transformer. Since there's no datasheet available on the CM75101 (at least I didn't find one), I thought posting here... (I also contacted Cinemag, but haven't got any reply yet.)

So my question is are CM75101 and CM2511 interchangeable? Is there any significant or notable differences between the two, as far as the electric operating or the sound is concerned?

Thank you!
Finbase

Hello again!

Okey, here's some info from Cinemag, if anyone else is interested in making the Quad8-stylish pre:

QuadEight and the Pacifica used the CM-75101A...  ...The CMOQ-2S is a very good choice.  If you want less of the vintage steel sound, the CMOQ-2L (50% high-nickel + 50%    steel) is.  (They may have used a 49% nickel alloy for the Pacifica, but that is only what I have heard and not been able to document.)...

...The CM-2511... was never used by QuadEight.  It has a taller lamination stack and the inductance of the primary is a little higher.  It will handle a little more signal level.  CM-75101A and CM-2511 are interchangeable...


OK, I'll guess it's my time to start gathering the more detailed specs. The building instructions on Hairball Audio's website are very coherent!

BTW, hats off for the Cinemag! They're customer service has been always very friendly and fast. Throughout all my DIY projects this far they've been extremely polite even towards a guy like me, who is a complete novice as far as electronics are concerned. They seem to take all their customer seriously. Rare kind of geneorisity!

Best,
finbase
 
Hey guys. I just completed my second copper build. For those who haven't pulled the trigger on one of the elements preamps, I highly recommend it. It's very easy, clearly instructed, and cheap!

I had one issue that I resolved, but I wanted to share it with you all.

Upon completing the build, I popped the unit into my rack and hooked up a dynamic mic. No output. The 48V light would come on, so I knew something was working. I saw an earlier recommendation that no sound may mean some of the 3 fuses were blowing due to a current surge. I double checked all my resistor values and cap values. Finally I realized I had swapped the PNP and NPN transistors like a dummy...  :eek:

I swapped them to the correct positions and boom! It worked like a champ! Smooth analog goodness for the rest of my days.
 
Hi all, I'm undertaking a Gold build and have really enjoyed it so far.  I've built a number of other projects (including a Rev D and a PM1K racking job)...great kit and very well documented.

I've come up against a bit of a challenge with figuring out which of the three multilayer ceramic caps are which.  The Gold build calls for a 33pF in C302, a 680pF in C500 and a 10pF in C504.  None of the caps have codes on them (or, if they do, are so small I can't see them even with my magnifying glass)...

My DMM has the ability to test capacitors, but I'm getting very odd readings.  I've got one which tests a 1.15nF (1150pF), one which tests at .19nF (190pF) and one which tests at .24nF (240pF).

I'd guess that my DMM isn't able to accurately gauge the values of these caps because they're so small, but I'm thinking that I'm probably okay assuming that the "1150pF" cap is actually the 680pF, the "240pF" cap is actually the 33pF, and the "190pF" cap is the 10pF.  This appears to be possibly correct, as the "240pF" cap has a smaller leg spacing, matching the holes for C302.

I've included a picture of each cap and the reading from my DMM...any help would be greatly appreciated!

 

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mattvon said:
Hi all, I'm undertaking a Gold build and have really enjoyed it so far.  I've built a number of other projects (including a Rev D and a PM1K racking job)...great kit and very well documented.

I've come up against a bit of a challenge with figuring out which of the three multilayer ceramic caps are which.  The Gold build calls for a 33pF in C302, a 680pF in C500 and a 10pF in C504.  None of the caps have codes on them (or, if they do, are so small I can't see them even with my magnifying glass)...

My DMM has the ability to test capacitors, but I'm getting very odd readings.  I've got one which tests a 1.15nF (1150pF), one which tests at .19nF (190pF) and one which tests at .24nF (240pF).

I'd guess that my DMM isn't able to accurately gauge the values of these caps because they're so small, but I'm thinking that I'm probably okay assuming that the "1150pF" cap is actually the 680pF, the "240pF" cap is actually the 33pF, and the "190pF" cap is the 10pF.  This appears to be possibly correct, as the "240pF" cap has a smaller leg spacing, matching the holes for C302.

I've included a picture of each cap and the reading from my DMM...any help would be greatly appreciated!

The codes are on there. You just need to get in good light and look very close. There are three digits, last one is the number of zeros. So 680 will be "681".

But ya reading small black numbers on darker blue can be tricky, proper light is the key.

The issue is that your DMM leads have capacitance, which makes reading lower values very hard.  If all else fails, try them as you've noted.

http://www.eevblog.com/forum/testgear/measure-pf-with-fluke87v/

Thanks,

Mike

Mike
 
Hi Mike, thanks very much for your reply.  I was able to see that there are markings on the caps, but was barely able to see them at all, even under bright light.  I am pretty sure I have them in the right positions--it followed the erroneous readings of my DMM, so I'm thinking they're right, but...

I finished up the build and got the unit in my rack.  The good news--I have DI and it sounds great!  The bad news--I don't have any signal when running a mic into the unit (and the DI unplugged)...not sure if this might be related to my ceramic cap issue or some other part of the build.  I tested another 500-series preamp in the same slot, so my mic->cable->patchbay->500-series rack input is known good.

Thoughts?  I'm hoping it's a bonehead simple issue...I can provide pics if it would be helpful.  Thanks in advance!
 
mattvon said:
Hi Mike, thanks very much for your reply.  I was able to see that there are markings on the caps, but was barely able to see them at all, even under bright light.  I am pretty sure I have them in the right positions--it followed the erroneous readings of my DMM, so I'm thinking they're right, but...

I finished up the build and got the unit in my rack.  The good news--I have DI and it sounds great!  The bad news--I don't have any signal when running a mic into the unit (and the DI unplugged)...not sure if this might be related to my ceramic cap issue or some other part of the build.  I tested another 500-series preamp in the same slot, so my mic->cable->patchbay->500-series rack input is known good.

Thoughts?  I'm hoping it's a bonehead simple issue...I can provide pics if it would be helpful.  Thanks in advance!

There is a very common issue that causes that.

The DI Relay has 8 pins and 6 of those pins are close together and the other 2 (power pins) are on the other end of the relay. If you miss soldering those 2 pins, which happens a lot, only your DI will work.

If it's not that there is most likely another issue causing your relay not to get power. Without power, the relay "normal mode" is set to DI input.

Mike
 
Hi all.

Just assembled two Copper kits. I did have one extra 100K resistor in both of the kits. Resistor R502 is installed and i couldnt find any use to the extra 100K´s.  I didnt see another 100K in the BOM either.

Safe to plug in or do i have a fried unit? In other words, should there be another 100k somewhere else than R502?
 
darkus said:
Hi all.

Just assembled two Copper kits. I did have one extra 100K resistor in both of the kits. Resistor R502 is installed and i couldnt find any use to the extra 100K´s.  I didnt see another 100K in the BOM either.

Safe to plug in or do i have a fried unit? In other words, should there be another 100k somewhere else than R502?

I don't have access to the BOMs right now. It's likely we simply tossed an extra 100k in all those kits.

The units are fused, you can't really hurt them. Give them a try!

Mike
 
Yah ok, so i did just that. Im having slight issues here, if anyone knows whats going on please, help  :eek:

I dont know how much gain i should have comparing to a pre like Lola, but both seem kinda quiet and they distort fast! Its almost like i cannot get any peaks to hit 0 in my daw, peaks stop around -8 and then the wave just starts clipping.

The other of the two is even more quiet. Ive tried to switch opamps, no luck there. I have grainhill mods in both of them (in and out)
 
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