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Thread: Get a "load" of this

  1. #1
    Join Date: Apr 2012

    Location: South West of England

    Posts: 222
    I'm Will.

    Default Get a "load" of this

    Decided I needed a better test load, so I built one.

    A bit more versatile than just a big resistor on some binding posts, it has a few features:

    • Two completely independent channels, optionally paralleled with a switch
    • Each channel switchable between 3.75, 7.5, 15 and 30 ohms
    • BNC outputs for monitoring as well as 10:1 attenuated BNCs for all outputs
    • Outputs include a direct singled ended monitor, as well as two separately earthed outputs to monitor bridged amplifiers or perform impedance measurements with the load in series with the DUT.
    • Chassis earth brought out to a post to earth to where is strategic for the particular testing situation if noise issues crop up.


    Each resistor is 50W rated and the heatsinks were salvaged from an old MOSFET PA amp. I don't intend to run the resistors near their power rating, if I did I would probably point a big fan at the thing.

    The attenuated outputs have an output-Z of approx 900 ohms but this shouldn't pose an issue with a short run of coax to a scope or audio interface.









    Radford Revival
    www.radfordrevival.co.uk

  2. #2
    Join Date: Feb 2013

    Location: W Lothian

    Posts: 38,593
    I'm Grant.

    Default

    Now thats a bit of kit. No holds barred quality.you could start a line of those
    Regards,
    Grant ....

    I've said it before and I'll say it again: democracy simply-doesn't-work
    .... ..... ...... ...... ................... ..... ..... ..... ..... .....
    DENON DV2900 - TWIN PRO MONOBLOCK AMPLIFIERS - XIANG SHENG DAC\PRE\HEADPHONE AMP - AVANTREE OASIS CLASS 1 BLUETOOTH - AUDIO TECHNICA ATH-MSR7 & OPPO PM-3 PLANAR HEADPHONES - WIN10 JRIVER23, DEEZER HiFi - ECHO DOT - SMSL M6 MINIDAC - FULL RANGE TWIN TELEFUNKEN's - Q ACOUSTIC BT3 actives - CANTON SUB - MAINS REGENERATED.

  3. #3
    Join Date: Apr 2012

    Location: Southall, West London

    Posts: 30,188
    I'm Geoff.

    Default

    Neat. Like it.
    Mr. Tact!

    "when common sense, logic and plausibility are ruled out. All that remain are lies and foolishness"


    Gear: MMs/ADCs/Low output MC's/One rare Japanese SUT/one scarce British phono stage/various tonearms/two hefty Japanese DD TT's/hefty Japanese BD TT/smaller Japanese BD TT and small British BD TT. One CD transport/3 CD players/2 jitter buster/2 DACs/Valve buffer. One MD deck. One tuner. Two TVC pre-amps/two valve pre-amps/solid state pre-amp/passive pre-amp. Current dumping power-amp or either of two Class A SS power-amp or Class A EL34 valve monos or big Japanese (part Class A) integrated. Big dual concentric speakers/Smaller dual concentric speakers/two way British compacts and full range speakers, amongst others. And too much more to list!

  4. #4
    Join Date: Apr 2012

    Location: South West of England

    Posts: 222
    I'm Will.

    Default

    Quote Originally Posted by struth View Post
    Now thats a bit of kit. No holds barred quality.you could start a line of those
    Thank you

    If I was making them for someone else I would do a few things a little differently - for one I would screw the resistors to the heatsink and use heatsink compound as opposed to using thermal glue
    Radford Revival
    www.radfordrevival.co.uk

  5. #5
    Join Date: Jan 2017

    Location: Kansas City, Missouri

    Posts: 590
    I'm Nathan.

    Default

    I want one of those on my bench. It would save me a ton of time hooking up jumpers, and searching for adapters and probes.

    Nice work!

    Sent from my Z981 using Tapatalk

  6. #6
    Join Date: Apr 2012

    Location: South West of England

    Posts: 222
    I'm Will.

    Default

    Quote Originally Posted by nthall View Post
    I want one of those on my bench. It would save me a ton of time hooking up jumpers, and searching for adapters and probes.

    Nice work!

    Sent from my Z981 using Tapatalk
    Indeed, it makes ones life much easier. This was long overdue.
    Radford Revival
    www.radfordrevival.co.uk

  7. #7
    Join Date: Oct 2012

    Location: The Black Country

    Posts: 3,802
    I'm Alan.

    Default

    Nice construction and great heatsinking. I like a good heatsink

  8. #8
    Join Date: Apr 2012

    Location: South West of England

    Posts: 222
    I'm Will.

    Default

    Quote Originally Posted by Firebottle View Post
    Nice construction and great heatsinking. I like a good heatsink
    They should do the trick, I have no idea what their capacity is but I don't intend to drive this too hard anyway!
    Radford Revival
    www.radfordrevival.co.uk

  9. #9
    Join Date: Mar 2014

    Location: Co. Durham

    Posts: 127
    I'm Nigel.

    Default

    Very nicely designed and put together.

    I would happily pay for one of those. It almost looks as if it should have Tektronix stamped on the front panel.

    If it were mine I would probably add a switched 2 F capacitor to each channel to test amplifier stability, and possibly a moving coil meter to provide a rough indication of the amplifier's power output.

  10. #10
    Join Date: Aug 2012

    Location: Hartlepool UK

    Posts: 1,285
    I'm Alan.

    Default

    Excellent job Will and a very useful bit of kit

    Alan
    Turntable - Garrard 401/Jelco 750L/Ortofon Kontrapunkt B, Pioneer PLC 590, SME 3009/2 , Denon DL103R - DIY Paradise Phono stage - Reel 2 Reel Studer A810, Otari MX55,Tascam BR20 - Digital HTPC / Young Dac - Preamp - DIY B4, 821, Power Amp's DIY Voyager Mono Block, Speakers Tannoy precision 6.4 / Wilmslow Kit Volt BM220.8 / Scanspeak D2905/9500

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