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Power Amp Shoot - out the lights! Dynavector HX1.2 vs Meridian 557 vs Quad QSP

Discussion in 'audio' started by tenpercenter, Feb 4, 2019.

  1. S-Man

    S-Man Kinkless Tetrode Admirer

    I had a UK built 606 which sounded dull and boring.
    I also had a Chinese built 909. Superb amp. I tried bypassing the Quadlink and totally disagree with DADA!
     
  2. sq225917

    sq225917 situation engineer

    Moppit, did you used to work in cambridge?
     
  3. Moppit

    Moppit pfm Member

    Oddly, yes as a student in the late 80's...soldering switched mode power supplies then for Philips CCTV.. but that was a long, long time ago!

    No connections with Quad if that is what you mean?...and not in the hifi business either..
     
  4. hamjam

    hamjam pfm Member

    I have to ask. Was the HX1.2 the Mk1 or 2 variant? I’ve had both and the Mk2 was a significant step up to the previous
     
  5. sls4321

    sls4321 pfm Member

    I've had 909 stereo, 909 mono and QMP. Only the latter have a fully balanced XLR input, if not using Ampbus. They also have a button on the front and standby mode. Great amps and great value.
     
  6. DavidS

    DavidS pfm Member

    Damn you all , I just purchased a qsp to power my arc 2s
     
    Last edited: Feb 12, 2019 at 12:06 PM
    tenpercenter and Record Genie like this.
  7. Record Genie

    Record Genie Ultrasonic record cleaner

    I know there are opinions both ways on whether the 909's Quadlink is a good thing or not, but I think I'm going to leave mine alone.. What equipment were you using with your 909, and what happened to the sound when you bypassed/removed the Quadlink?

    I've never owned a 606, but perhaps you had an earlier one before Quad switched to a toroidal transformer? From what I've read, 606's with square case edges have conventional transformers, and 606's with beveled case edges have toroids.. Just for confusion, apparently Quad made the transformer production change before the case change, so there are some late square case 606's fitted with toroids from the factory..
     
  8. Record Genie

    Record Genie Ultrasonic record cleaner

    Always wanted Quad 909 monos, probably a good match for thirsty Shahinian Obelisks, but I've never seen any for sale in North America!

    Would love to hear your thoughts on how the 909, 909 Monos, and the QMP's all compare to each other!

    Back when I used one of my 909's with a 99 pre-amp, CD and tuner, Quadlink was convenient and Quad says it's a balanced connection, but I found the 99 pre-amp was not the strongest part of that package. My 909's sound better with other equipment, with attention paid to their low 775mv input sensitivity..

    Looks like QMP's have Quadlink, RCAs, and XLRs, but the 909 user manual shows the 909 Mono with only an RCA input, is that right?
     
  9. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It will be a balanced to unbalanced converter IC or same made up from separate op amps... or even the crude single op amp version... All other Quad amps with balanced inputs do it this way and they are VERY unlikely to have made a fully natively balanced version of the current dumping topology.
     
  10. sq225917

    sq225917 situation engineer

    Moppit, just checking. I worked with your namesake, late 98-02.
     
  11. hifinutt

    hifinutt hifinutt

    the qsp certainly sounds very interesting , even if one reviewer got cross with it becuase it wont take spades . a number of places have these at 699 new and that sounds like a stone cold bargain

    https://positive-feedback.com/Issue59/quad.htm
     
  12. sq225917

    sq225917 situation engineer

    No Irish, no dogs as well?
     
  13. S-Man

    S-Man Kinkless Tetrode Admirer

    The 909 with Quadlink bypassed sounded bright. The Quadlink circuit is a couple of OP275 opamps, the single ended inputs have some input filtering. Maybe without this filtering the power amp is susceptible to RF? Oddly, the balanced input doesn't have any RF filtering, I guess Quad expected it could only to be connected to thier own preamps using the Quadlink and that they have some control over the bandwidth of those.

    My 606 had a toroid. FWIW, unless the toroid has an interwinding screen I prefer EI transformers.
    Stan Curtis claims to have tweaked the 606 and he normally designs rather good sounding stuff, so I do wonder if mine was sub par.
     
    Record Genie likes this.
  14. Moppit

    Moppit pfm Member

    Yep, got mine from Lintone Audio - great service. Arrived next day. Brand new unit, still sealed.

    I agree with the review - fresh out of the box it sounded good, but once warmed up I'm sure things sound even better - I don't believe this stuff normally as my Naim did not really change much between cold/hot.

    I would not say it gets hot though. Mildly warm perhaps.

    The other bonus is it looks nice in my Millenium Falcon...:D
     
  15. sls4321

    sls4321 pfm Member

    Yes, that is correct.

    The 909 Mono are very rare. I got them from a dealer in Germany and sold them to a guy in Norway! £1,000 both ends of the deal, and the QMP cost £1,500, sold for £1,300. So if you want the grunt and better connectivity and standby with buttons on the front, far better to get a pair of QMP as even if you could find 909 Mono, the QMP cost very little more.
     
    Record Genie likes this.
  16. spiderbox

    spiderbox pfm Member

    Note Arcs are not a particularly difficult speaker to drive but Obelisks are another matter, so you may get different results with those.
     
  17. christray

    christray pfm Member

    Had 306,405 and 909 all excellent plug them in and forget unlike some of the expensive amps I have owned. Highly recommended.
     

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