PEV500 (Neumann PEVb / PEVc in API500 format)

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[silent:arts]

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Joined
Jun 4, 2004
Messages
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Location
Berlin, Germany
While looking on the Neumann PEVc schematic floating around the web I always thought this would be a cool project for a 500 series module. We found that there were several different versions of this EQ, some with 4 discrete op amps (Neumann OA10), some with 5 discrete op amps, and there was also a PEVb with different gain steps.
For our PEV500 we decided to go with five OA11N op amps, our own mixture of the Neumann OA10 and OA12 using 10 transistors each. Gain steps are either original PEVb, PEVc, 1 dB steps only (PEV-M1), or 0,5 dB steps (PEV-M2).

PEV500_01.jpg
PEV500_02.jpg


PEV500 Schematic
PEV500 PCBs
PEV500 Parts List
PEV-B Resistors
PEV-C Resistors
PEV-M1 Resistors
PEV-M2 Resistors
OA11N

#PEV500 on Instagram
 
Hi Volker.
What is the difference in the gain steps of the B and C?
Also the difference in transformers.
I’ve got a pair of old W491’s and a pair of W695’s I racked up.
I love them.
I’ve heard pev’s sound fantastic and are hard to find.
These look awesome.
I’m kind of interested.
Thanks
Andy

While looking on the Neumann PEVc schematic floating around the web I always thought this would be a cool project for a 500 series module. We found that there were several different versions of this EQ, some with 4 discrete op amps (Neumann OA10), some with 5 discrete op amps, and there was also a PEVb with different gain steps.
For our PEV500 we decided to go with five OA11N op amps, our own mixture of the Neumann OA10 and OA12 using 10 transistors each. Gain steps are either original PEVb, PEVc, 1 dB steps only (PEV-M1), or 0,5 dB steps (PEV-M2).

PEV500_01.jpg
PEV500_02.jpg


PEV500 Schematic
PEV500 PCBs
PEV500 Parts List
PEV-B Resistors
PEV-C Resistors
PEV-M1 Resistors
PEV-M2 Resistors
OA11N

#PEV500 on Instagram
 
Hi Volker.
What is the difference in the gain steps of the B and C?
Also the difference in transformers.
I’ve got a pair of old W491’s and a pair of W695’s I racked up.
I love them.
I’ve heard pev’s sound fantastic and are hard to find.
These look awesome.
I’m kind of interested.
Thanks
Andy
B : high and low are 0 3 6 9 12 15 db steps
C : high and low are 0 2 4 6 9 15 db steps
 
@Andybb
Like @ratrace posted the gain steps for 60 Hz and 10 kHz are ± 3 / 6 / 9 / 12 / 15 dB with the B version, and ± 2 / 4 / 6 / 9 / 15 dB with the C version.
The mid band is identical (± 2 / 4 / 6 / 8 dB).

For your transformer decision the most important thing is the level you want to drive them, the Lundahl is fine up to 15 dBu, if you have higher levels take the Pikatron.
 
Hi @[silent:arts],

I just emailed about a pair of PEV-Cs and am curious if there is an assembly guide?

Thank you!
 
Just finished my pair of C’s w Pikatrons!
I’m overjoyed by how thunderous, punchy, tight, clear, and vibey these things are. So far I’ve only tested on synth bass, drum buss, and mix buss and I’m blown away! The magic and weight that these add as soon as you insert them (with all settings at 0) is enough to justify the cost of admission. Even at extreme settings, these hold up extremely well. Compared to a UAD Pultec I had on a mixbuss, the former sounded hazy and loose compared to the PEV’s. 11/10 would consider having a rack of these!

I have to also mention that Volker is an absolute delight to deal with. Thank you for making amazing things!!
 
What is the purpose of (optional?) RT*1 (620Ω)?
I don't see it on the original Neumann PEVc schematic.

Schematic says, If it's installed, R*18 should be 47Ω; if not it is 1K6Ω.
 
Just finished building the DOA's and I did a continuity test on the pins. It seems that the labeling of the "COM" and "OUT" pins is reversed in the OA11N pdf.
 

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