Thanks both, that’s some great knowledge — thank you.
I mistakenly thought this unit had a decoder built in, but the diagrams within the guide do seem to allude to there being a separate decoder external to this amp. Having knowledge of old amps but not surround units doesn’t help!
I did change input to the 6CH terminals, but for it to work I had to change the way the speakers were connected to the amp — the result was rubbish, and the sub still didn’t work.
This is the current state of play at the rear (pics attached). The single male plug goes to the powered sub woofer. Input is via the ‘CD’ terminals as the phono input needs to be grounded (never had to do this apart from for turntables).
It’s frustrating as it’s so nearly there. The clarity offered by my centre and main speakers is excellent but the set up lacks the depth in bass.
The phono input on your 393
is for a turntable. It's set up for a moving magnet cartridge (MM) hence the grounding terminal. Don't put any line level sources through this. They'll be far too powerful for the MM input, plus there's an equalisation curve applied which boosts bass and cuts treble to compensate for the way vinyl is cut with low bass and higher treble. (It's called RIAA Equalisation and it helps prevent the needle mistracking.)
CD, TV/DBS, VCR, DVD/LD and TAPE are all line level inputs and available for your to use.
Your sub isn't going to get a signal unless there's something attached to the subwoofer socket of the 6CH DISCRETE INPUT section. Any cone movement you're feeling is background noise which can come from the receiver, the sub lead, and the powered subwoofer amp when everything is turned up to max.
The only ways you're going to get a signal into the sub is either to use an external 6CH decoder (or a source with 6CH out), or have a sub with Hi-Level inputs which takes its signal from the front left and right channels. There are pros and cons for each.
External decoder: Pros
• basic units are cheap - Start at £20-£25
• will auto-detect and decode DD and DTS
• offer multiple inputs: usually a couple of opticals, a coaxial and a stereo audio
External decoder: Cons
• source switching means getting out of your chair to push a button
• cheaper units don't decode ProLogic II. They make a simulated surround which might not be that effective
• there's no level control for the individual channels
This last point means you need to use the receiver to set-up speaker levels along with the sub controls, so if there's a difference in the sound balance between the way the decoder works and how the receiver handles direct sources decoded by ProLogic then you're stuffed. The channel balance is going to be off.
Subwoofer with High-Level Input: Pros
• doesn't draw any power from the receiver's speaker outputs
• subject to the sub's performance, it greatly enhances the front L&R channel performance
• sub is always running
Subwoofer with High-Level Input: Cons
• you need to find a sub with the feature. Not all have it
• there's no bass enhancement for the surround channels
Changing the amp might seem like a big step, but it's one I think you should at least consider. Here are some pros:
• subwoofer connection issues go away
• updated audio processing: Dolby ProLogic II, DD/DTS, HD-audio from Blu-ray
• updated inputs: HDMI
• updated speaker setup:
1) done for you automatically with a set-up mic and wizard
2) room EQ - the amp/receiver listens not just to the volume from each speaker but also the tone of it as affected by its room position
• new features such as HDMI ARC. This is both audio signal and control of the amp from your TV
1) You switch the TV on, the amp comes on automatically. Same for power off
2) The TV speakers mute automatically
3) You change the volume with the TV remote (or your Sky / Virgin remote) and the amp volume changes
• unless you buy a bottom of the range amp, you're likely to get more amp power which gives you better dynamics
• per-input audio trim to correct for sources being too loud / too quiet relative to each other
• Dolby Digital features such as Night Mode (bass and treble boost when using low volume) and the ability to limit or expand the dynamic range. This gives you control how the amp portrays action and explosions
• (with Yamaha amps and receivers) one-touch preset buttins which remember source and audio decoding modes for up to 4 inputs; Yamaha's
Scene Memory feature
There's a
Yamaha RX-V673 here for sale complete with box, remote, setup mic from a seller on the Wirral. The price is £100 with no bids and it finishes at 12 midday today (Sun 4th Dec). Everything I have listed above is featured in this amp. Ebay listing; item number 255859729804
