hifisonix

Hifisonix Micro Ripple Eater

Written by

bonsai

in

Click here to buy a Micro Ripple Eater PCB in the Shop


This simple ripple eater (aka MRE) can deliver up to 10A per supply rail (provided it is suitably heatsinked!) and will reduce mains related ripple on amplifier supply rails by up to 40 dB and as much as 50 dB at HF.

The board is small, compact and easy to mount virtually anywhere within the amplifier chassis. You can use a single ripple eater to comfortably power stereo amplifiers of up to 100W per channel, or you can use one per channel to clean up the supply rails on higher power amplifiers. The series pass transistors are not critical and any 15A TO3-P or TO247 type packaged devices will work.

The Hifisonix MRE makes a perfect upgrade to class A amplifiers where the usually heavy load current can cause excessive supply rail ripple. At 2.5A load current, the MRE 100/120 Hz supply rail ripple is under 20mV vs 1~2V pk to pk using a standard rectifier + reservoir capacitor setup. At higher frequencies in the audio band, it is even better and with good amplifier construction and cable dressing, can be well below 10mV pk~pk. Further, the slow start-up of the MRE helps to reduce switch-on thumps from the speakers.

Download the PDF build doc below (updated 4th December 2022)

Micro Ripple Eater Download
Micro Ripple Eater BOM Oct 2021 Download


Can the MRE be used with amplifiers that have supply rails > 50V?

The MRE is designed to work with amplifiers with supply rails of up to +-50V. If you want to use it with higher supply rails, the voltage rating of the capacitors has to be increased. The maximum diameter on C1 and C2 is 16mm and on C3 and C4 10mm. The transistors specified in the BOM are good for up to +-80V supply rails.

(Note: The pictures show the slightly older version of the MRE. The newer version is a bit smaller. The Hifisonix Universal Chassis drill pattern accepts the newer version of the MRE – the older layout version is no longer available)

Comments

18 responses to “Hifisonix Micro Ripple Eater”

  1. Bonsai avatar
    Bonsai

    Daniel,
    here is the info you want:-

    1. The Ripple Eater PSU PCB is sold by Jim’s audio and is a complete PSU with rectifier and smoothing caps and the + and – ripple eater filters on board. Note, this board was updated about 1 year after it was initially released and the ripple eater output transistors are now NJW TO3P devices – i.e. high current, high power.

    2. The micro ripple eater is a smaller board that I sell on the Hifisonix shop that has just the ripple eater circuit on board for both the + and – power supply.

    Both units will provide sufficient power for the kx2, sx and nx amplifiers – details are in the relevant documentation.

    You can of course use them with any amplifier within the component voltage rating constraints.

    Regards

    Andrew

  2. Daniel avatar
    Daniel

    Hi! What are the differencies between “Ripple Eater” and “Micro Ripple Eater”?
    Since I’ve bought the “Ripple Eater” PCB’s, and I’m ready to purchase the components, I’m wondering if it worth to change my plans and go for the Micro. Of course this depends on how significant are the differencies between those two (excluding the size of the boards).
    So, any advice from you would be very useful.
    Thank you in advance!

  3. Anand avatar
    Anand

    Andrew, thanks for answering. I am using (1) MRE for *each* channel. The main amp boards have 470uf decoupling caps for each rail. Sadly, I don’t think that C3 and C4 on the MRE can be upgraded to a larger value due to the size restriction. So I am left wondering if I can change the 470uf decoupling caps on the main amp board to 1000uf. Here is a link to the discussion that has started regarding this: https://www.diyaudio.com/community/threads/fh9hvx-budget-conscious-100w-class-ab-for-lean-times.353512/page-70#post-7355940

  4. Bonsai avatar
    Bonsai

    Hello Anand, I seemed to have missed this. Thanks for your kind words.

    No, you do not need a cap bank but you will need local de-coupling/reservoir caps. I would recommend 1000-2000uF placed on the output of the MRE.

  5. Anand avatar
    Anand

    Hi! Is there a requirement/recommendation to use a cap bank after this MRE in a **Class AB** 100 watt amplifier designs (i.e. assuming a quiescent bias 93dB efficient?

    Thanks again for all you do!

  6. José C R Fardo avatar
    José C R Fardo

    Yes got It. Thanks

  7. admin avatar
    admin

    Jose, you will lose 1.5 to 2 volts across the MRE. With +-12 V secondaries you will get about 16 V out and after the MRE about 14 V. Ideally, you want 13-0-13 V secondaries.

  8. Jose C R Fardo avatar
    Jose C R Fardo

    Hello Bonsai

    Please confirm. I need +/- 15VDC for my JLH 2003. Useing one single MRE board and 2x simple linear PSU for each channel

    https://pt.aliexpress.com/item/32860363859.html?spm=a2g0o.detail.0.0.41e37302ufBEuM&gps-id=pcDetailBottomMoreThisSeller&scm=1007.13339.291025.0&scm_id=1007.13339.291025.0&scm-url=1007.13339.291025.0&pvid=4c8f7680-3308-4f65-8a48-88199a90ab94&_t=gps-id%3ApcDetailBottomMoreThisSeller%2Cscm-url%3A1007.13339.291025.0%2Cpvid%3A4c8f7680-3308-4f65-8a48-88199a90ab94%2Ctpp_buckets%3A668%232846%238109%231935&pdp_ext_f=%7B%22sku_id%22%3A%2265353497256%22%2C%22sceneId%22%3A%223339%22%7D&pdp_npi=2%40dis%21BRL%2155.58%2143.35%21%21%21%21%21%4021032fa416722356565986884e1375%2165353497256%21rec&gatewayAdapt=glo2bra

    the transformer secondaries shoul be 12 – 0 – 12V

    Thanks a lot in advance for suport

  9. admin avatar
    admin

    Simon, you cannot unfortunately use mosfets or IGBT’s for the ripple eaters. you have to use bipolar devices.

  10. Simon avatar
    Simon

    hi there:
    I was wondering if I could use MOSFET(or IGBT) instead of general purpose transistor? Do I have to modify schematic?

  11. Bonsai avatar
    Bonsai

    Ricardo

    This should work

    Regards

    Andrew

  12. Ricardo avatar
    Ricardo

    Hi, can this ripple eater be used with 78 Volt supplies by increasing capacitor voltages and using something like MJL 4281s?
    I’m thinking about using them for an Adcom GFA 555 Mk2

  13. Bonsai avatar
    Bonsai

    Its not critical, but you should have some minimum load on the output. 🙂

  14. Nickson avatar
    Nickson

    Hi Andrew,

    Are load resistors R1 R2 really needed? After all, R5 R6 quite cope with their role.

    Best regards,
    Nickson

  15. Bonsai avatar
    Bonsai

    Tony R1 and R2 should be 10K

    Thanks for highlighting this – I will put a not on the build doc and update the PCB’s on the next batch.

  16. Tony avatar
    Tony

    Hi
    What is the value for R1 & R2 – 1k or 10k .
    PCB=1k & Bom=10k?
    Regzards
    Tony

  17. Bonsai avatar
    Bonsai

    Hello Vladimir – it’s between 1-2 volts depending upon load. At full load it will be about 2 volts.

  18. Vladimir avatar
    Vladimir

    Hi
    What is voltage drop on ripple eater

    Regaeds
    Vladimir

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