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Converting a DBX 161 into a 160Vu
Old 13th June 2016
  #1
Here for the gear
 

Converting a DBX 161 into a 160Vu

Same exact guts and PCB, the 161 was designed to be interfaced with unbalanced equipment and the 160vu in a balanced studio environment.

The output stage of the 160vu runs on +/-26 voltage rails and I've always thought it sounded good. Adds a bit of beef and girth to the sound The input stage is nice as well, great RF protection and No coupling capacitors.

So go snagg some 161s and get your tech to mod em, or fire up a soldering iron.
The cost of parts is about 10$

(RIP ebay prices)

Heres your Roadmap
https://i.imgsafe.org/e5c71c13eb.jpg


CHAZZZZZZ
Old 13th June 2016
  #2
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I just heard a 161 and am very familiar with the 160vu, the 160 sounded deeper/thicker great compressor.
Old 13th June 2016
  #3
A 160VU asymetrical output stage will clip at +21 dbu. A 161 modified with an inverter output will clip at +27 dbu, 6 db more headroom than the 160VU.

The output opamp on the 160VU runs at + - 16 volts. That can be upped to + - 22 volts so a higher voltage opamp can be used to increase headroom.
Old 13th June 2016
  #4
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Quote:
Originally Posted by Jim Williams View Post
A 160VU asymetrical output stage will clip at +21 dbu. A 161 modified with an inverter output will clip at +27 dbu, 6 db more headroom than the 160VU.

The output opamp on the 160VU runs at + - 16 volts. That can be upped to + - 22 volts so a higher voltage opamp can be used to increase headroom.
The output stage takes a tap off the power supply pre regulator which the schematic says is 24v but in practice I've found it to be more 26-8v
Old 14th June 2016
  #5
I've seen it vary from 23 to 29 volts. There are a pair of 2.2k dropping resistors to lower that voltage to the opamp, a LM301. Those resistors are changed to deliver + - 22 volts to a high voltage opamp. That will increase output drive and headroom. Additional large capacitance is used to lower AC ripple of the unregulated rails to 20 mv. With the 90+ db PSRR of the opamp, the outputs are then free of any rippple and are very quiet. The VCA hiss then dominates the noise floor.
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