Volume discontinuity mystery (1 Viewer)

[bradcb]

Hi there! I'm a beginner cobbling together a frankensystem, and I have hit a dead end trying to troubleshoot an odd behavior: The volume knob on my receiver seems to have no effect on the volume I hear, except it "snaps" to a new level at a few key points:

• -∞ (min): No sound from speakers
• -99dB to -21dB: Uniformly too quiet
• -20dB to 0 dB (max): Uniformly too loud!

When I refer to volume positions from -∞ to 0dB, those are values displayed on the receiver's screen as I turn the main volume knob.

Did I do something wrong, or is my receiver broken? Normally I'd assume the receiver is broken, but I'm attempting kind of a weird setup so I wanted another opinion. Details follow.

I'm using a Kenwood VR-505 Audio Video Surround Receiver (Manual). It's wired up to:

• A pair of Bose 901 Series IV speakers (Manual) wired to the front right and left channels.
• A turntable with a Pyle preamp (PP444) wired to the AUX input
• A 1Mii bluetooth receiver (B06+) wired to the CD/DVD input.
• (Sometimes) The 901s' active EQ, wired to the VIDEO 2/MONITOR out/in.

Prior to the current setup, I had the turntable and 901s wired to a Yamaha R-N303BL. I wasn't using the preamp because the receiver had one built in, and I wasn't using the EQ because the receiver had no tape loop or preamp loop. I had no issues playing the turntable or bluetooth except that the 901s are muddy without their EQ. I was gifted the Kenwood used and thought I'd try to get the EQ working with it.

Observations I've made on the new setup:

Playback from bluetooth, with EQ: I set the input to CD/DVD, change the input mode to ANALOG, and turn on the MONITOR function. It's quite loud, but the sound quality is definitely improved - I can tell the EQ is doing its job. The odd behavior of the receiver's volume knob is as described above, except that it's quite loud (without changing) from -99dB to -21dB and jumps to painful at -20dB. Changing the volume from my phone works - that is, it seems to affect the signal from the bluetooth receiver to the amplifier.

Playback from turntable, with EQ: I set the input to AUX and turn on the MONITOR function. Even at the -99dB position, setting the needle on the edge of the record generates a hiss loud enough to be uncomfortable. I'm not willing to test the -20dB position.

Playback from bluetooth, without EQ: That is, I've entirely unplugged the EQ from the system. I set the input to CD/DVD, change the input mode to ANALOG, disengage MONITOR. Similar behavior to bluetooth with EQ but everything is quieter (and not EQ'd).

Playback from turntable, without EQ: Up to -21dB it's almost too quiet to hear; at -20dB it snaps to a reasonable volume.

So at this point I'm confident that it's not the turntable, not the speakers themselves, not the EQ (although I'm not sure I'm using it right), and I don't think it's the preamp or the bluetooth device since I'm seeing the same odd behavior for both inputs. I haven't found a description of this behavior in any manuals or anywhere online. Does anyone have a guess about what could be going on?