Quad 77 integrated amp query

Discussion in 'DIY Discussion' started by abg, Jul 29, 2008.

  1. abg

    abg

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    Hello

    I thought I would register here and ask some advice about a quad 77 amp integrated amplifier..

    I have not seen this before but it seems the quad 77 has been altered.. on the back panel in the center where the company name is printed there is a variable resister or capacitor..

    Does anyone have any idea why this might have been put here? or should I ask quad?

    Thanks
     
    abg, Jul 29, 2008
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  2. abg

    zanash

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    I'm quite familiar with the 77 series ......

    is this a bit of kit that you have ?

    if so can you put up a pic.

    I can think of several uses for a variable resistor ..but none as I recall would be a quad fit or mod ......

    it sounds like someone has added this afterwards....may be to attenuate an input ?

    The complexed controls of the 77 would have made it easy to fit any such attenuation on the main board and operated from the large two way remote .....

    if you can provide more information it would help
     
    zanash, Jul 30, 2008
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  3. abg

    abg

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    Well I only just got hold of it, and plugged in my quad 11s..

    Seems its a gain control on either the input or the output?

    Anyway I have supplied some pictures would be great if you get a chance to look at it.. I'm a big fan of quad ever since owning the 303 but I'm not too clued up on the insides.

    My worry is, whether this 'mod' is going to affect the overall aspect of the amp? Also would removing it and soldering the two pulled out resitsters back into the board 'get it back' to it original state..

    In the attached pics you'll see the pot at the back in inbetween the rca inputs and C18 power socket connected with the white, yelow and green cable.. It looks like a neat job but is it really any use?.. I mean who on earth would 'doctor' a nice amp like this?

    Many thanks
    A
     

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    abg, Jul 30, 2008
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  4. abg

    zanash

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    oh dear ........!!!

    now I'm guessing here as I cant see exactly from the pics ...

    but I think is a volume control ....say if the handset was missing or dead ....as its hooked upto the power amp sections.

    do you have the remote ?

    the down side is that the cheap carbon pot[?] will screw the sound if the signal is passing through. It could be cleaver and using the chip volume resistor ladder ....if so it won't screw the sound....

    without a closer look its hard to say much more .....and its only an educated guess
     
    zanash, Jul 30, 2008
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  5. abg

    abg

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    No I have no remote, but obviously I can still control the volume at the front..

    When you say chip volume resister ladder.. the connections to both ends of the pot cable are soldered onto one end of a resister which has been risen one side.. so one leg pulled out of the board with the other left in and the cable soldered to the pulled leg..

    I am thinking if i just solder the resisters back into the board.

    Will get better pics tonight.

    Many Thanks for the educated guess..
    Do you think Quad could service this for me and get it back to its original state.?
     
    abg, Jul 30, 2008
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  6. abg

    zanash

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    yes quad could ...but I don't know if they would ...

    of course you can ...derrr [vol on front panel]

    how do you access all the controls without the remote ?

    my 77 pre has loads of stuff that you can only use from the handset..

    yes close up pics of the take off area will be useful

    I've the schematics of the 77 pre but thats not going to be a lot of use ....you can get the schems for the 77 series from quad for a couple of quid ....

    quad are very good service wise .....there happy to answer questions too ....
     
    zanash, Jul 30, 2008
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  7. abg

    abg

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    Well I have on the front just the source/ balance and volume controls.. is there more?
     
    abg, Jul 30, 2008
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  8. abg

    zanash

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    the pre is stuffed with rather good and useful tone controls ....had a quick scoure of the web ....using the way back machine using this address..http://www.quad-hifi.co.uk

    goes back to april 97 but doesn't give downloads of the manuals like later versions

    these are the specs for the 77 int [if you don't have them ]

    Quad 77 int.

    Signal Bus: Up to 32 77-Series productsInputs: Source 1, Source 2 and Tape
    Inputs Source 1&2 Tape
    Input sensitivity 100 or 300 or 775mV 100 or 300 or 775mV
    Load Impedance 33kOhms 33kOhms
    Signal/Noise >100dB >100dB
    Outputs Preamp Out Tape Out
    Output level 775mV same as input level
    Source impedance 850Ohms 300Ohms

    Interchannel balance:
    +/-0.1 dB with volume control varied from maximum to -70dB
    Maximum Power Output:
    84W into 8Ohm <0.5% dtot 115W into 4Ohms <0.5% dtot
    Maximum Current Output:
    11A peak per channel
    Distortion (total harmonic):
    Continuous sine wave into 8Ohm resistive load
    20Hz any level up to 70W <0.005% (22kHz bandwidth)
    1kHz any level up to 70W <0.005% (22kHz bandwidth)
    20kHz any level up to 70W <0.01% (80kHz bandwidth)
    Output internal impedanceand DC offset:
    1.5µH in parallel with 0.05Ohm, DC offset <20mV
    Frequency response:
    -0.3dB at 20Hz and 20kHz
    (ref 1kHz): -3dB at 3Hz and 50kHz
    Power response (ref 1kHz):
    -0.75dB at 10Hz and 20kHz
    Crosstalk:
    <-90dB at 1kHz
    Hum and Noise:
    -105dB ref. 75W (22kHz measurement bandwidth unweighted)
    Stability:
    Unconditionally stable with any load and any signal
    AC input:
    110-120V or 220-240V, 30-350VA, depending on signal level
    Weight:
    6.3kg
    Dimensions:
    321mm wide; 65mm high; 300mm deep

    this shows that you can alter the input selectivety of each input ..via the handset effectively used to match inputs of say a cdp with a high output ....

    It will be worth contacting quad to get the remote control codes or go experiment with one of those universal units ...you may get lucky and find the hiden features ....

    but it will be worth having a chat with quad to see if they can send you the schematics and user manual for the unit.
     
    zanash, Jul 31, 2008
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  9. abg

    abg

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    ahha

    some specs.. nice to see it on paper..

    I might contact quad about the docs.. I did speak with someone on ebay who said he offer me an original quad remote for 125 saying they cost 300! new!..

    about the mod, I just gave in yesterday and removed the soldered the pot.. and put the legs of both resister back into the board.. was worried for a minute because on the second resister the solder didnt look like it was sticking to the top of the circuitry, must have gone below and anyway, i switched it on and its pumping music out so happily.. so i'm sure I did a fine job.

    Thanks
     
    abg, Jul 31, 2008
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  10. abg

    zanash

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    great work ....
     
    zanash, Jul 31, 2008
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  11. abg

    jakes

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    quad 77 coffee table remote

    Good Day One & All,

    I have a 77 integrated amp with the large remote. does any1 know how 2 access the slope controls on the remote??

    Jakes

    The New Old Quad Guy
     
    jakes, Oct 14, 2008
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  12. abg

    zanash

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    on my pre amp

    you have to select eq and then use one of the page down buttons ...

    quad will send you a copy of the manual if you ask there normally one of the helpfull lot !
     
    zanash, Oct 14, 2008
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  13. abg

    goonerboy

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    Quad 77 Remote Problems

    Hi all,new to the forum so please be patient ! I have just purchased a Quad 77 pre and power amp combo but the remote is broken,i spoke to Quad and they said a rough estimate of £50.00 to repair it,they said from their experience that the rechargable batteries are normally the fault ! Anyone on here come across other problems that can occur ! Whilst i'm here do i need the remote to adjust the tone controls on the pre without the remote ! Any help would be gratefully received
     
    goonerboy, Jul 29, 2009
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  14. abg

    zanash

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    yes I've had two sets replaced ....its not hard to open the unit up and replace them with like ......they do need to be desoldered but I'd expect that new ones should be available at rs ....

    that would be my first action ...then if the unit was still at fault I'd contact quad again
     
    zanash, Jul 30, 2009
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  15. abg

    shagx

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    Hello,

    Can someone please help I have a Quad 77 pre with the remote. The thing is the batteries were removed years ago can someone please tell me which way around the batteries fit..
    I have just purchased 4 AA rechargeable tagged batteries to try and bring some life back to my old remote.
     
    shagx, Aug 7, 2009
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  16. abg

    zanash

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    I thought it said on the pcb ?

    if you examine the pcb traces to a cap ot ic ...you should be able to tell from the component orientation ...
     
    zanash, Aug 8, 2009
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  17. abg

    shagx

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    It doesnt show any markings indicating the orientation of the batteries on my pcb. I have tried all batteries with negative at the top of the remote, this did actually bring the remote up and when put in the cradel to charge indicated a charge was going on.
    When I returned within the hour the remote was dead and the display had vanished, seems to had somehow flattened the batteries.
    Can anyone help me out here

    Cheers
     
    shagx, Aug 9, 2009
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  18. abg

    zanash

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    ok ....opened mine up ....

    all the negatives are to the top [nearest edge of the pcb]....

    so that right ...


    as I recall it takes a good deal of time to charge the batts

    obvilously don't switch the pre amp off at the back!
     
    zanash, Aug 9, 2009
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  19. abg

    shagx

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    thanks for your help
     
    shagx, Aug 10, 2009
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  20. abg

    wilsonlaidlaw

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    I know this is a slightly old thread but........HELP!!!

    I had a minor tragedy last week. An electrician doing some re-wiring work on our house, managed to knock the small Quad 77 remote off my bedside table and then to cap it all, stepped on with his size 12 boots. It broke in half and is totally beyond repair. Quad have none of the small remotes left.

    If I buy an All in One trainable remote, would any kind 77 owner who has a working remote, be willing to train it for me. It is only the integrated 77, albeit having had a total rebuild and very extensive upgrade by Peter Hickman at Fidele (highly recommended - makes a Q77 integrated better than the Meridian 551 I have down in France). Therefore, it only needs the simpler commands - sit, stay, paw, etc (just joking). Obviously I would include return postage with the All in One.

    I am quite a severe arthritic and when I get a flare up, I can be bedridden for 4 or 5 days. The remote on my bedroom system with the Quad is then a godsend.

    Wilson
     
    wilsonlaidlaw, Nov 16, 2011
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