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Denon AVR-3801 Pre-out into a Stereo Amp

Discussion in 'AV Receivers & Amplifiers' started by Mad Max, Jun 5, 2001.

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  1. Mad Max

    Mad Max
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    Hi everyone...

    Ok, have had good advice on this board about a way to have the best of both worlds... Stereo and HC.

    The good advice is to connect the pre-out (Main left + right) from the Denon into an Input of the Stereo Amp. Then set the Stereo Amp's power output to a fixed level (using an SPL meter to level it) so that the Denon controls the Output for HC. This allows me to have a good stereo performance using a dedicated amp + good main speakers, and have a great HC setup, putting less load on the Denon's Amp stage.

    I'm sold to the Idea, but have one strong doubt... I'm not sure of how the atenuation will come out when I fiddle with the Denon's Volume knob. when I set the Volume knob on the Denon to 0db, then use the SPL meter to level everything up, everything will be fine, but what happens when i turn down the volume on the Denon ? If I lower the volume to -20db, will the atenuation on the Audio Amp still be correct for the HC setup without changing the power knob on the Stereo Amp ? If I use the SPL meter again, will the reading still be leveled thru all my 5 speakers ?

    It's the only doubt I have... By the way, what audio-only Amps do you recomend starting with? I haven't started looking yet, and would like to have 3 or 4 models to start with. From there, auditioning + research + dealer's advice should do the trick.

    Thanks for your help

    Rui
     
  2. bighairy

    bighairy
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    Rui,

    My system is also a bit of a hybrid of home cinema and hi-fi. At the centre of a tangled web sits a Yamaha DSP-E800 processor. This is just like one of their home cinema amps but lacks a power amp for the main speakers. It can drive a centre and two rears.

    The main output from the Yamaha is fed into a fairly old Mission Cyrus One (mark two) which is an integrated stereo amp. The centre channel is fed to another Mission Cyrus One (mark one) which I picked up second hand. The centre feed is actually split and fed to both left and right channels so I bi-amp the centre speaker. The rear channels are driven by the Yamaha (I guess I should look for another Mission :) Bi-amping the centre has noticeably improved the detail in the treble. (My front speakers are Linn Index II's and an old Linn Centrix I also picked up second hand to match my Index's. Rears are Mission 77DS because they are discrete!)

    I set up without the aid of an SPL and basically I played the Yamaha's test tone, set the volume on the Yam to a reasonable to high level (about halfway round its travel) and then set the volumes on the Missions to match the rear speakers. In practice both missions sit at around half their volume travel and never get touched. I don't turn them off and the Yamaha is very well behaved and doesn't send pops down the wire.

    I can still use the main speakers without going through the Yamaha, but in practice, since I started listening to my CD's via the DVD the DAC in the Yamaha sounds better than the one in the DVD player and I get to use remote control for the volume :) In your case the only thing you need to do was note what volume you set on the stereo amp and return to it when you go back to cinema.

    I did have one problem with the centre channel. The older Mark one Mission used a fixed earth and the Yamaha uses a floating earth. This led to a nasty hum from the centre. This was sorted by disconnecting the Mission from its mains earth. I'm not convinced this is 100% safe, but I've got modern wiring and RCD's to trust if anything goes wrong!
     
  3. Mad Max

    Mad Max
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    Great setup, but I was thinking about something a little different... Getting a separate pre-power for Stereo only, and connecting a good CD player directly to it.

    My problem is with home cinema. I have the feeling that when the system is well balanced at a certain volume, it will not be balanced when I change volume, mainly because the two amps (HC and Audio) might have a different power output.

    This would mean that at a certain volume, Center + Main would sound perfect, but when I changed volume (ONLY on the HC amp, not touching the Audio Amp's volume knob) the system would not sound too good, because the center would either sound too loud or too low... Is this clearly explained ?

    Has anybody tested this ? EX: set up a similar system for 0DB with an SPL, then move the volume up/down a bit, and re-test to check if everything is still balanced on all the 5 speakers ?
     
  4. Guest

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    Mad Max

    Gbb's system is not different to what you are trying to achieve since s/he is connecting the pre-out from the DSP into a line in on the integrated (your suggestion of a pre/power will behave in the same way).

    I too will ultimately end up with a system as you describe (don't wish to compromise on 2-ch) but haven't got all the kit yet. You asked for recommendations re: amps to audition - it'd help if you could give us an idea of your budget. BTW I'm a strong believer in picking up amps and speakers s/h. Some extraordinary hi-end bargains to be had... :D
     
  5. Mad Max

    Mad Max
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    Yes, I was also thinking second hand, but I wanna audition some new beforehand. For a 2 Ch amp, I was thinking that £600 to £1000 should get me something very good. The speakers I will think about later, since I have a couple of brands in mind, but I really need ideas for 2Ch Amp.

    Thanks

    P.S. Sorry, has ANYBODY actually measured (SPL-wise) Mains and Centre with a fixed position on the 2Ch volume, and 2 different positions on the 5Ch ?
     
  6. Guest

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    Severnoaks are selling ex-demo Rotel (i am a fan) 985mk2 (thx ultra) for £450, (110 good watts X 5) it's a bit of a bargain, you could bi-amp your main left and right (again i am a fan) and have a spare channel!

    SteveEX
     
  7. Reiner

    Reiner
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    Mad Max, for the initial "calibration" of the stereo amp in 'AV mode' set the volume knob to 50% (12 o'clock or whatever).
    Now balance all channels using the SPL meter, adjust the fronts volume with the stereo amp's volume knob and the center/rears via the AV amp's setup.
    Once this is done remember or mark the stereo amp's volume knob position (let's say 11 o'clock).

    When you now switch from stereo to AV set the stereo amp's volume to the known position (e.g. 11 o'clock) and don't touch it anymore, the entire (system) volume is now controlled via the AV amp (volume knob or remote) and remains balanced for all channels no matter how loud you go.

    [ 06-06-2001: Message edited by: Reiner ]
     
  8. Mad Max

    Mad Max
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    Hi Reiner... Are you sure about this ?

    I understand the principle pretty well, thanks for explainig though. I'm just wondering if you tested this, or payed atention to it ?

    The Denon has 7X 105w (So they say).

    Imagine I buy a really good 2Ch Amp (Lets say 2X250w).

    Now, I will do as you say, and calibrate the system for 0Db (50%), and mark the position on the 2Ch amp for later use.

    Now, let's say that at test volume, the 7Ch outputs 70W, and, since I calibrated the 2Ch, it also outputs 70W. If i increase to 90w on the 7Ch are you sure that the output on the 2Ch will only be 90 ? Don't forget it's a lot more powerfull, and therefore it might increase easier, making the 1st setting wrong for that level of output...

    Am I being clear ? I'm not sure ...
     
  9. dood

    dood
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    see my reply to a similar thread earlier.I use a Denon 3300 for HT and Cyrus sraight line and XPA bi-amping mains, with Arcam CD and Wadia DAC doing the music duties. It works very well. Your concerns regarding the proportionate changes in output using the Denon's volume control are understandable but I have not encountered problems with my setup. My HT sounds fine and balanced at low and high volumes.
     
  10. Mad Max

    Mad Max
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    Hi dood,

    Thanks for the info... That's exactly what I wanted to ear :). Now to look for a 2Ch Amp... Or do I get new speakers first ? Damn, too many options get me confused
    :rolleyes: :D .
     
  11. bighairy

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    I agree with "the dood" [name that film...]. It doesn't matter about the relative powers of different amplifiers as long as they are being driven by the same pre-amp and volume control. I have three different amps, none the same model and as long as I keep the external amp volumes at the same point, everything stays fine all the way through the volume levels.

    Now you come to mention it, however, it is quite a testament to the "linearity" of modern electronics that this is the case. I'd never even thought this would be a problem as my first ever home cinema system was based around a processor that had no internal amps and therefore used multiple external systems (bits of old crap midi-systems!)

    Oh and BTW I'm a bloke :)
     
  12. Reiner

    Reiner
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    Yes, I am sure. With the initial adjustemnt you will compensate for the different gain in the (power) amplifiers.
    The different power rating is not an issue here, it would merely allow the 2-channel power amp to go "louder" (when e.g. listening to CD) or deliver better dynamics.
     
  13. Mad Max

    Mad Max
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    Thanks gbb and reiner...

    It's linearity the term I was looking for, but since you don't detect a problem, and I'm not too picky, it should be ok then.

    Next step: Choose great main speakers :D

    Max
     
  14. Mad Max

    Mad Max
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    Yes, I'm back (sorry)... Ok, I've been thinking, and after all this, have come to the thought that I might be better off with a simple power amp connected to the pre-out of the denon. Is this a worse solution ? It's simpler, since the denon would only be used as a simple pass-through to the analog signal, and do all the work without the complicated setup of a second integrated.

    So, how badly will the Denon (used as a pre) alter the signal ?

    Cheers

    Rui

    P.S. I know I'm a pain, but bear with me for a little longer...

    [ 18-06-2001: Message edited by: Mad Max ]
     

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