Arcam FMJ AV8 switching noise?

Discussion in 'AV Receivers & Amplifiers' started by Halcion, Nov 18, 2002.

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  1. Halcion

    Halcion
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    I had the pleasure of auditioning Arcam FMJ AV8 briefly on my holiday.

    Unfortunately it was hooked up to Revel F50 loudspeakers which I found (even in a well damped room) to be too harsh and forward for my taste.

    Anyway, the thing that got me worried was the switching noise or clicks when I either switched the input (i.e. analog RCA to PCM spdif) or playback mode (direct stereo bypass to DPL II).

    Is this common to all units? If not, what was causing this?

    The clicks when switching were very audible and quite disturbing imho.

    The power amp used was the new P 7 and the source was DV27.

    Also, is the direct analog bypass Effective for all six channels or ONLY for stereo inputs?

    regards,
    Halcyon
     
  2. Lowrider

    Lowrider
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    Funny that this guy I know compared the TAG with the Krell Showcase, and found the same problem with the Krell... :confused:

    He has Krell power, but now is probably getting the TAG AV...
     
  3. martintyler

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    I get similar stuff on my old Arcam AVR100. Not necessarily clicks, but a sharp switching delay. I was hoping more expensive units would handle this better.

    Another time its annoying is when you arent switching modes at all - just the DVD itself moves from 2ch to 5.1 or something. For example, watching Episode 2 Deleted scenes - when it switches from the 5.1 of one scene to the 2ch of the intro to the next you actually miss a second of the intro sound.

    Is this handled better on other systems?

    Martin
     
  4. Halcion

    Halcion
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    John Dawson,

    can you comment on the switching noise of AV8?

    Also, have you any plans for DTS 24/96, Circle Surround II, HDCD or Dolby headphone decoding? Are these even a technical possibility.


    Best regards,
    Halcyon
     
  5. John Dawson

    John Dawson
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    Hi Halcyon,

    I shall, as I always do, try to be frank and trust that you will respect that.

    After your post we looked at a couple of units in the lab and found no excessive switching noises - which (to date at least) ties in with field reports - i.e. no-one apart from yourself has reported anything untoward AFAIK. Having said that, because much of the analogue signal path is DC coupled (with servos), for reasons of sound quality, you can under certain circumstances get DC level shifts at the 1 - 2 millivolt level when switching between some functions or inputs. This is just about audible, but not in our opinion objectionable, nor does it get in the way of the music. Normal peak signal levels, for comparison, are 1 - 2 volts rms.

    That's all within our design parameters and also meets THX specifications BTW.

    I guess it would be helpful to know the place where you had the audition - send me a PM please, so we can investigate to see if there is something strange going on there.

    As to DTS 24/96 that requires a significant HW change so is not on the short term horizon. All such encoded discs are of course fully playable at 24 bit, 48 kHz sampling. Dolby headphones is a possibility - who wants this and how much would you pay for it? I am not sure without checking about HDCD - but all our DVD players support this anyway so I am not sure it's a big deal. Circle Surround? Who really wants that and why?

    All these algorithms have to be stored in flash and there is only so much room. They also have to be fully tested and paid for.....

    In conclusion, I am always interested to hear what people want but I am naturally cautious about trying to please all of the people all of the time :)

    Finally you asked about the 6/8 channel bypass - yes it is a true analogue bypass. Pushing the bypass button switches off the DSPs, with a useful further improvement in sound quality.

    Sincerely,

    John Dawson (Arcam)
     
  6. Halcion

    Halcion
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    Staffhorst/Utrecth/The Netherlands. More info in PM, as you requested.

    regards,
    Halcyon
     
  7. JonLeach

    JonLeach
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    Hi Martin, i have the same problem, i thought it was my DVD player causing this but obviously not. it can be so loud that it makes you worry about those expensive loud speakers.

    Can this be sorted???? My Arcam is still under warranty.

    The other thing it does is cause interferance lines on the TV screen when watching TErrestial TV.


    Jon
     
  8. NicolasB

    NicolasB
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    Me, and £100 (although I'd be happier if it were £50). For that I'd expect not only a good implementation of the algorithm but also a line-level output appropriate for feeding into an external headphone amp (in addition to the feed to a headphone jack).

    See, I think you potentially open up an entirely new market with this. Imagine you have a guy who is thinking about spending £3.5K-£4K on a home cinema system (processor, amp and speakers). He might be planning on getting, say, a Denon A11SR and hooking that up to B&W 1NT/CNT/SNT speakers with a Velodyne CHT15 sub. Not too bad a setup for the price. Now suppose that this guy actually rather likes listening through headphones. Instead of the previous system what he could do instead is spend £3.5K and buy an Arcam AV8 together with some Sennheiser 600 (or 580) headphones and a high grade headphone amp, perhaps an Earmax. This leaves him with massive upgrade potentiaal, but in the mean time the sound he will get from this combination will blow the Denon/CDM NT system totally out of the water.

    I'm speaking to some extent from personal experience, having had the chance to listen to the Dolby Headphone output from the Denon A1SR. This is a significant step up from the A11SR, and it was hooked into higher-quality front speakers, too - B&W Nautilus 805/HTM1 with CDM SNT rears plus REL Q400E subwoofer. The quality of the Dolby Headphone output (straight into my Sennheiser 600s without a headphone amp) was head-and-shoulders above the quality of the output from the speakers. The directional cues were not as strong, admittedly - front-to-back pans were very clear, but I might have had to stop and think about it to tell whether a static sound was in front of me or behind me. But in terms of clarity, lack of distortion, being able to perfectly resolve every individual sound out of the sound field, the headphones were so much better than the speakers it was barely even worth making the comparison.

    Of course, plenty of people actually don't like listening with headphones. It may be easy on the neighbours, but it's not the most sociable of activities. And people have preconceptions about headphone listening: you might have a hard time convincing those who have never actually listened to a decent pair of headphones just how good they can sound, not to mention convincing people that it is actually possible to distinguish between front and back sounds without using 5 separate sound sources to do it. So I don't know how many people would actually end up in the demographic I'm talking about. But you have to figure that there at least some.
     
  9. Halcion

    Halcion
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    This reminds me.

    Is there a working headphone output on FMJ AV8?

    Is it el-cheapo op-amp variety like in almost all prepros (except Anthem AVM20)?

    What output impedance does it have?

    regards,
    Halcy
     
  10. Halcion

    Halcion
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    AV8 has a headphone output at 5 Ohms. I don't know of it's quality.

    I will be auditioning AV8 (at home hopefully) within two weeks and will compare it's headphone output performance as well. I have a Class A solid state headphone amp with variable output impedance as a reference, so I can have something to compare to.

    Still no news on the switching noise...

    Regards,
    Halcyon
     

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