What's the low cutoff frequency of the NE-80100 DOAs? Do they attenuate down very low bass (below 50 or so Hz) by default?
I found two module cards in my junk pile and thought I should quickly test before ditch. Turns out they are working, no humming, no crackling. Haven't measured in detail but bass loss is clearly visible on LED metre, some -2dB or -3db on very-low kick drum from a drum machine that goes ridiculously low, so not necessarily a bad thing ; ) Overall 'louder' and 'rounder', like Mr Rumble gone. Other than than, the overall freq spectrum sounds fine. But was wondering whether this is a feature of the DAO or me feeding it wrong.
In quick test I fed from gear output driver with cap, wired directly to the module card input, where a volume pot sits shunted to ground before the actual NE-80100 summing AMP. So this might be creating a HPF ? Should feed low (near zero) impedance, I assume ?
Or is the loss in bass because I run the DOA underpowered? It needs +/+22V but that tranny only puts out a max. of 22/22 unloaded (PSU trimmed to +/-21.95V), so unhealthy and underspecc'ed for the test and DOA runs out of steam ?
Thanks for observations, insights and experiences with these DOAs.
---
Here's the schematics of the card module (see NA80169(MA)).
And the very quick-and-dirty test rig showing the actual modules. The second pot is an AUX amp feeding directly into the DOA summing node onboard, hence the toggle switch.
I found two module cards in my junk pile and thought I should quickly test before ditch. Turns out they are working, no humming, no crackling. Haven't measured in detail but bass loss is clearly visible on LED metre, some -2dB or -3db on very-low kick drum from a drum machine that goes ridiculously low, so not necessarily a bad thing ; ) Overall 'louder' and 'rounder', like Mr Rumble gone. Other than than, the overall freq spectrum sounds fine. But was wondering whether this is a feature of the DAO or me feeding it wrong.
In quick test I fed from gear output driver with cap, wired directly to the module card input, where a volume pot sits shunted to ground before the actual NE-80100 summing AMP. So this might be creating a HPF ? Should feed low (near zero) impedance, I assume ?
Or is the loss in bass because I run the DOA underpowered? It needs +/+22V but that tranny only puts out a max. of 22/22 unloaded (PSU trimmed to +/-21.95V), so unhealthy and underspecc'ed for the test and DOA runs out of steam ?
Thanks for observations, insights and experiences with these DOAs.
---
Here's the schematics of the card module (see NA80169(MA)).
And the very quick-and-dirty test rig showing the actual modules. The second pot is an AUX amp feeding directly into the DOA summing node onboard, hence the toggle switch.
