DP32SD onboard preamps

[bnwitt]

So, I now have my DP32SD setup on its rack and am getting ready to start recording. I have numerous external preamps. WA-273, Joe Meek OneQ and several Art units. I use them all for different color. I did a forum search, and the consensus seems to be that the onboard preamps of the DP32SD are transparent. So, I'd like to use my externals to color my signals for recording. I read one post that said the sticky "Production Tricks" explained how to defeat the onboard preamps and bring in a line level from an external preamp. I couldn't find the link in that sticky to that procedure. I'll keep looking. I'm assuming I just turn the level knobs to line and dial the external preamp to drive the proper level on the DP32SD. But of course, that wouldn't really bypass the onboard preamps. If they are transparent it wouldn't matter.
Also, does anyone know what brand the onboard preamps are? Are they the ROHM BA4580RF-E2 op amps?

 

[Phil Tipping]

You're right the pre-amps cannot be bypassed completely, but if you turn the trim down, they will not be pushed so hard so are less likely to colour the signal.

The schematics show BC560CG transistors and BA4580RF-E2 op-amps, so not sure if you're asking whether they are ROHM specifically. You probably already know this but you can find specs for most components by searching for their name and the word 'datasheet' e.g.

https://www.onsemi.com/pdf/datasheet/bc560c-d.pdf

https://fscdn.rohm.com/en/products/databook/datasheet/ic/amp_linear/opamp/ba4580rf-e.pdf

If you are concerned with noise, a member posted some noise tests on the machine a while ago, so maybe try searching for those. There may also be some close-up photos of the PCBs so you can confirm the components used match the schematic; either that or take it apart and have a look... but be careful