stay at home type 69 project

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  1. I don't know I haven't completed mine yet, but I'm pretty sure there are no regulators or diodes on the pcbs' because they are NOT 500 series, therefore why would they be needed.
  2. You could put them in any case that they would fit.
  3. You need a 24v PSU, the pcb is just the single circuit board for the Helios module & nothing else.
Points taken. Would you like to sell one of your PCBs? If so, please PM seymourgler_at_gmail_dot_com
Thanks and cheers!
 
Points taken. Would you like to sell one of your PCBs? If so, please PM seymourgler_at_gmail_dot_com
Thanks and cheers!
I can sell you one for sure. If you have a look at the docs in the link on the first page I believe the boards I have are the H9mR version. Maybe take a look at the docs to make sure it's what you want.
 
Anyone considered a line only version for just an EQ? Could use the 1:1 JT-11-HPC and then lower the gain to smaller steps.
 
Not in 500 series format, I don't think. And Ian has separate eq and gain makeup PCBs, I think.
 
Hey all, long time reader first time poster. Thanks to dogears and co for this wonderful project and all the great tips.

I've assembled one of the H9M modules (rev 1 board with the changes to the voltage regulator described earlier in the thread). It's passing signal cleanly and generally sounds great, but I'm running into two issues:

-High EQ band isn't working - nothing changes as I rotate the pot. Mid and Low bands are working properly.
-Encountering a low level noise (audio file attached) that is omnipresent regardless of EQ/Pad/HPF/48v being in or out.

Wondering if anyone might have tips on where to start hunting these issues down? Thanks!

Edit: looks like attaching an audio file might not have worked, it's here as well: https://samply.app/p/DtmAeJE3LOI589bwBBxd
 

Attachments

  • H9M noise.wav
    1 MB
The high shelf issue should be straightforward to diagnose, if the other bands of the EQ are working fine - it's just SW6 and the associated resistors and capacitors. The fact it's not working at all suggests either the connection between R22/RV2 and the switch wiper; or the connections between caps and ground (attenuation section) or caps and R27 (boost side); or the switch itself. My suspicion would be the wiper or the switch if it's not working at all.

For the low level noise, what level are we talking about? If -100dBu for example, that might not be anything to worry about. Does it change in level or nature if you boost gain / use the EQ or HPF / engage the pad? How do you have the module hooked up - what's the signal chain? Have you tried a loopback test, or tried the module in a different 500 series slot?
 
Thanks for the response! Found a bad solder joint going to the switch, that fixed it.

Re: the noise, turns out this is being caused by my new AML 1084 - whichever slot is directly to the right of it picks up that noise, even if nothing is plugged in. Clearly not an issue with the Helios build.

This thing sounds great - time to finish my second unit!
 
I just picked up a 500 rack and was looking for some preamps to fill it. So many of the old open source projects are dead. I'm excited to find a project that's still active! I have a lot of reading to do.
 
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