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Thread: Quad 306 Upgrade-parts?

  1. #11
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

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    Chris,

    I have tried to collate all your various bits of advice on the Quad 306 so far. Am I right in my summary (below). There is also a question...

    Thanks,

    Richard.

    Quad 306 Mods.

    Replace 6 x 1N4003 diodes, D5,6,7,8,9,10 on each channel with UF4007. Also D13.

    2. Replace R24 and R25 from 2x 22R ie 44 ohms, to 27R and 30R ie 57 ohms

    3. Replace TR1 with a 2N5087 PNP and TR3 a 2N5088 - both Fairchild brand low noise transistors.

    4. CR2 normally a j503 is replaced by a ON brand LM317 D2T its adj terminal delivering 2.85ma on its own without any assistance from the output - ie output left unconnected,( A 317 appears to be much better than the miserable 0.56ma from a J503 as the current source for above transistors.
    The 317 substitutes perfectly, with no turn on or turn off issues.)

    5. Replace R17 and R18 - 560R with 5 watt metal film round types ( not wirewound ) .

    No Caps over the zenner diodes!

    No Cap changes.

    Is the LM317D2T just a simple like-for-like replacement for the J503 but the middle pin disconnected?

    I don’t understand this: “ The changes to make are replacing Cr2 with a LM317 to supply current
    just from that devices adjustment terminal ie 1.3ma vs Cr2 .05ma
    using a Dpak device soldered under the board.”

    What is a Dpak device (Google is of little use - some form of packaging?).

    Thanks,

    Richard

  2. #12
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

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    Hi Richard
    The changes you outline from my thread " my day improving audio equipment"
    mirror pretty well exactly what I have done to my own 306's
    I have also changed the TLC271 to be a LME49710 and added a
    mosfet across the LM317 -see below

    The TO92 package LM317Z is going to be much easier to fit with just 2 of its
    pins. I have just done some tests on a LM317LZ TO92 device @ 6.9v and it delivers
    1.53 ma. I will do some tests on the other packages and see if current changes.
    I am using ON brand LM317D2T in my own 306's. Will try and post results tomorrow
    for other packages,

    You need to carefully follow the different pinouts relative to where they
    replace what was originally there, referring to TR1 and TR3

    Another nice change is to add a SMD 2N7002 mosfet across the LM317
    here using that surface mount device, its drain connects to LM317 input
    and gate and source both to adjustment, current then lowers slightly to
    1.46ma., and current delivery appears even more stable.

    A TO92 LM317Z with the flat side facing you, legs down is Adj in the left
    and In on the Right

    The use of just using the adjustment pin is not covered very well by
    Texas Instruments, as they describe that pins current much lower at 100ua
    being returned to the output, But measurements I have taken show current
    available is very stable, being effectively the inverted input of the regulator
    when viewed as an op amp. It would appear current from the output internally
    assists the adjustment pin when the output is floated.

    A look and see would be to connect a LED in a test circuit to observe the
    adjustment pin happily delivering sufficient current to illuminate that device
    so V+ say 12v to LM317 In , adj to LED anode and LED cathode to gnd

    I have all of these parts in drawers here, send me a PM as I can post them to you
    if that would help.

    Cheers / Chris
    Last edited by Light Dependant Resistor; 21-07-2016 at 11:01.

  3. #13
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

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    Thanks Chris very much indeed.

    PM sent.

    BW

    Richard

    PS I got this error:

    Light Dependant Resistor has exceeded their stored private messages quota and cannot accept further messages until they clear some space.

  4. #14
    Join Date: Sep 2013

    Location: North Island New Zealand

    Posts: 1,757
    I'm Chris.

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    Hi Richard
    Space cleared

    Cheers / Chris

  5. #15
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

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    Hi Richard,
    Thread here on 306 mods may be of use: http://www.pinkfishmedia.net/forum/s...ead.php?t=4983

    There are a few companies offering upgrade parts kits, Dado already mentioned: http://www.dadaelectronics.eu/

    There is one in Doncaster which is not far from you http://www.redhillaudio.co.uk/
    Ooops, I see they have moved to Chesterfield since I last visited, still close though.

    Hope that's some help

  6. #16
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

    Default

    Quote Originally Posted by Qwin View Post
    Hi Richard,
    Thread here on 306 mods may be of use: http://www.pinkfishmedia.net/forum/s...ead.php?t=4983

    There are a few companies offering upgrade parts kits, Dado already mentioned: http://www.dadaelectronics.eu/

    There is one in Doncaster which is not far from you http://www.redhillaudio.co.uk/
    Ooops, I see they have moved to Chesterfield since I last visited, still close though.

    Hope that's some help
    Thanks; I ordered the DADA kit yesterday and posted a question on their forum about altering the zeners to faster ones. (Answer - don't bother).

    I'll look at the RedHill site as well.

    Thanks,

    Richard.
    My Gear:
    Source component/s:
    Cambridge CXC Cd player; Inspire Apollo deck + Roksan Nima arm + Ortofon 2M Black; Denon TU-580RD tuner; Logitech Squeezebox Touch. Rpi with Volumio. RME DAC.

    Amplification: WD KEL84+ valve amp; Rega Brio, Quad 306 (DADA modded, - in reserve)). Trichord Dino2 & Dino+ PS;

    Wiim mini, Wiim Pro, Wiim ProPlus streamers

    Loudspeakers:
    Living Voice Auditorium IBX-R2.
    Q Acoustics 2010 in the 'study'.

    Cables/stands: Chords; Van Dammes 4mm

    Any other hi-fi bits:
    Apple MacMini Pro; Senn HD598, 467,
    Linear PSs for Rpi and DAC. Pure mains conditioning.

  7. #17
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default

    I was considering going the 306 route a while back, so I had look at the upgrade options available at the time.

    One thing I don't like, is putting large binding posts on the back as replacements for the original banana sockets, so I use these whenever I need to renew that type:



    They are "Hirschmann" brand, are solid Brass (no through hole so sealed for speaker use), Gold plated and rated at 32Amp. RS do them at £2.04 each with free delivery.
    RS #787-2350 Red
    RS #787-2357 Black

  8. #18
    Join Date: Oct 2012

    Location: NE England

    Posts: 4,173
    I'm Jez.

    Default

    I'll not comment further than this but IMO there are no worthwhile upgrades to the 306 other than fitting bigger smoothing caps.
    Arkless Electronics-Engineered to be better. Tel. 01670 530674 (after 1pm)

    Modded Thorens TD150, Audio Technica AT-1005 MkII, Technics EPC-300MC, Arkless Hybrid MC phono stage, Arkless passive pre, Arkless 50WPC Class A SS power amp, (or) Arkless modded Leak Stereo 20, Modded Kef Reference 105/3's
    ReVox PR99, Studer B62, Ferrograph Series 7, Tandberg TCD440, Hitachi FT-5500MkI, also FT-5500MkII
    Digital: Yamaha CDR-HD1500 (Digital Swiss army knife-CD recorder, player, hard drive, DAC and ADC in one), PC files via 24/96 sound card and SPDIF, modded Philips CD850, modded Philips CD104, modded DPA Little Bit DAC. Sennheiser HD580 cans with Arkless Headphone amp.
    Cables- free interconnects that come with CD players, mains leads from B&Q, dead kettles etc, extension leads from Tesco

  9. #19
    Join Date: Nov 2010

    Location: Sheffield/Peak District. UK

    Posts: 574
    I'm Richard.

    Default

    Thanks Ken and Jez; understood.
    BW

    Richard.

    I'll report back when/if I do all the upgrades!
    My Gear:
    Source component/s:
    Cambridge CXC Cd player; Inspire Apollo deck + Roksan Nima arm + Ortofon 2M Black; Denon TU-580RD tuner; Logitech Squeezebox Touch. Rpi with Volumio. RME DAC.

    Amplification: WD KEL84+ valve amp; Rega Brio, Quad 306 (DADA modded, - in reserve)). Trichord Dino2 & Dino+ PS;

    Wiim mini, Wiim Pro, Wiim ProPlus streamers

    Loudspeakers:
    Living Voice Auditorium IBX-R2.
    Q Acoustics 2010 in the 'study'.

    Cables/stands: Chords; Van Dammes 4mm

    Any other hi-fi bits:
    Apple MacMini Pro; Senn HD598, 467,
    Linear PSs for Rpi and DAC. Pure mains conditioning.

  10. #20
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default

    Upgrade is probably the wrong description, its more like a refresh.
    The Dada kit has larger value smoothing caps as you mention Jez and replaces some of the other ageing electrolytics with same value. It upgrades a few of the parts to a slightly higher spec to match what Quad did themselves for the 606mkII 707 and 909. The speaker output sockets were not high quality and with age/use don't always give a good connection, I've seen examples that barely stopped the banana plugs falling out, so new parts help there.
    So nothing major in what's done, for the most part its just bringing things back to as new performance.

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