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500 Series Rack Shootout
Old 7th December 2020
  #1
Gear Nut
 
500 Series Rack Shootout

There has been a lot of discussion on here lately about 500 series racks since a power supply is a vital component in audio gear.

I was curious if there would be an audible difference with the same audio, same modules, but in different 500 series racks. I decided to run some audio samples through a pair of 500 series Pultec EQP-500As, moving them between 6 different 500 series racks. Some of the racks have linear power supplies, some have SMPSs. Some of the racks have an internal power supply, some have external. In each case, the left channel Pultec was mounted in the left most slot, the right channel Pultec was mounted in the right most slot (This was done to see if the right channel picked up more noise from the power supply on the racks with internal power supplies).

For audio, I just used some samples that come with Presonus Studio One. For variety, the first part of the sample is country inspired acoustic then followed by a sample of electronic music. The end of the sample is a stretch of silence to analyze the noise of each unit. At first glance, I didn't find any real discernable difference in noise from any of the racks or from left and right channel. Settings used on the Pultecs were 3 Boost 3 Atten at 60 Hz, 10 bandwidth, 3 Boost at 10kHz, 3 Atten at 20kHz.

Here is the link to download all 6 rack files, plus the original unprocessed file:

https://www.dropbox.com/sh/1ra3i442l...4ibWoIxGa?dl=0

I only have a free dropbox account, so I'm not sure how many downloads it will allow before they cut it off. If you do download, please add to the discussion below on your thoughts.

After a bit of discussion I'd be happy to reveal the identity of each rack.
Old 7th December 2020
  #2
Lives for gear
 
Nick Morris's Avatar
 
🎧 15 years
checking them out now. Very interested to see how this goes as I am about to dive in to 500 land for the first time and would like to find the right chassis.
Old 8th December 2020
  #3
Lives for gear
 
Nick Morris's Avatar
 
🎧 15 years
On blind listening I had a preference for C. I’m going to take a harder look and scope them out in the daw. I was expecting to hear more noise differences than I did. Maybe B had slightly more noise than the others?
Old 8th December 2020 | Show parent
  #4
Gear Nut
 
Quote:
Originally Posted by Nick Morris ➡️
On blind listening I had a preference for C. I’m going to take a harder look and scope them out in the daw. I was expecting to hear more noise differences than I did. Maybe B had slightly more noise than the others?
Yeah I was also surprised the noise on all of them was so close. I think they’re all within 1 dB or so. I was expecting the internally powered ones to maybe have more noise, especially in the right channel right next to the power supply, but at least for this test that didn’t seem to be the case.

By the way, if anyone is interest. The racks used in this test, in no particular order:

API 6B (internal Linear PS)
Rupert Neve Design R6 (internal SMPS)
Heritage OST4 (external SMPS)
JLM Sidekick (external SMPS)
Aphex USB 500 (internal, I believe SMPS)
API “Six Pack” (very early lunchbox, has a big exterior power supply that I believe is linear)

Identities with the sound clips to be revealed after more feedback. I don’t have “golden ears” but felt like I could pick out some differences between these audio clips. Not sure if that’s just personal bias since it wasn’t a blind test for me, so I’m genuinely curious on any feedback on this as a blind test from people with better ears.
Old 13th December 2020
  #5
Gear Nut
 
🎧 10 years
wow the differences are so small. crazy!

would be intresting how the cheaper bento & midas lunchboxes compare to them.
Old 29th December 2020
  #6
Gear Nut
 
Anyone else take a listen? More feedback on this would be much appreciated.
Old 20th January 2021 | Show parent
  #7
Here for the gear
I hear very little, if any, difference in all examples. I'd like to know which unit is associated with what example as I am in the market to get started in the 500 world. Also, some of the 'obsolete' or older units really aren't an option, as I am finding that they are rare or discontinued. (Not sure why it was important for you to include those and make us salivate..lol)
I'd've much rather you had findings on units that are currently available for purchase one way or another... but, oh well; can't complain about your free assessments.


BTW- Concerning the costs? Here's what I found....

AVERAGE PRICES

API 500 6B $664
Rupert Neve Design R6 - $569
Heritage OST4 -$349
JLM Sidekick- $505
Aphex USB 500 - Used (couldn't find New) $425
API “Six Pack” - none found
Old 6 days ago | Show parent
  #8
Here for the gear
 
🎧 5 years
Quote:
Originally Posted by James7800 ➡️
Anyone else take a listen? More feedback on this would be much appreciated.
I'm willing to bet the two APIs are B and E. The rest sound thin in comparison.

Could you reveal which is which?
Old 6 days ago | Show parent
  #9
Gear Nut
 
Quote:
Originally Posted by AJBoutilier ➡️
I'm willing to bet the two APIs are B and E. The rest sound thin in comparison.

Could you reveal which is which?
Thanks for the feedback. I'd prefer to get more feedback from others before posting results, but I'll send you a PM with results.
Old 6 days ago
  #10
TJe
Gear Addict
 
Perhaps the differences would be more obvious with more extreme settings and the boxes filled with a compressor and a preamp on top of the EQ,as well?
For me all the examples you posted sound very close.I like F example slightly better maybe but not sure.
Thanks for your work anyway,I would like you post the results.
Old 5 days ago
  #11
Lives for gear
 
Thanks for the samples.

I prefered A (more weight) and the F (nice color).

Can you PM the results please?

Best regards,
Daniel.
Old 4 days ago
  #12
Gear Nut
 
I appreciate the feedback here. After a few more posts with feedback, I'll reveal results on which unit it which.
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