Friday, June 3, 2011

Onix OA-20/2


Heard my 1st Onix amp in 1988, a OA-20. Should have bought it then...
Front
Slant view
More than 20 years later, chance upon a OA-20/2 in good working condition - not making the same mistake twice!

The Onix deserve it's well earn reputation of a great performing unit with grunt- an excellent example of British audio quality. Although rated at a lowly 30W RMS and weight a mere 4kg, it is no push over. The unit was hardly warm after running for a few hours with the volume at 7 o'clock. This was more than enough to drive my honeycombs to a decent volume in a room 30ftx20ft.

After warm-up, the Onix was revealing. The mid and HF was fluid when playing a CD of well recorded piano pieces. Bass could be better but acceptable, may consider a recap later on (since it has been over 20 years).
Top
Back

Component view from back
Little wonder these units are seldom available in the resale market. And are quickly snapped up when they became available!

Update - 30Jul2011

Finally decided to perform maintenance on the electrolytic capacitors in the power amplifier section, as the reproduction seem a little muddle on critical passages.

Upon closer inspection, notice the unit had been repaired before and a unknown brand of EC, "Sun" was used in the power rectifier section as well as one side of the power amplifier. Replaced the 100uf 10V with Panasonic FC and the original 4.7uf 50V with Panasonic ECA of equal values in the power amp section. Left the Sun EC in the power rectifier section as that should be adequate for the task. Using better quality EC and substituiting the pairs of EC in the power amp section provided the desired results. Source is the Sony CDP-333ESA which is now connected directly to the Onix without the tube buffer. The Onix is now driving my Mission 753 Freedom's via 1.5m of the original QED Silver Anniversary (with enough silver to cover most of the cable diameter).

Original amp section
Capacitors replaced from power amp section



Update - 6Aug2011

Using the Musical Fidelity Tubalog DAC with the Sony CDP, my daughter commented the reproduction of piano was surprisingly realistic. The missing portion are weight of the high notes. Have only been using the Onix during weekends since the last update.

Will re-update after letting it run in over the next two weekends before deciding if I will perform any other maintainence.

6 comments:

  1. Hi, nice review. I think OA20/2 was a Tony Brady effort, produced in UK by Cymbol the Tony Brady's brand after Onix beforeExposure . It should date back to 1991-1992 ca.
    Daniele

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  2. Had a Exposure XX before.

    Personally prefer the Onix better.

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  3. Sold item to raise funds for furthering my speaker projects

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  4. Onix OA20 was my first amp, hooked up to a pair of EPOS ES11's and fed by a Marantz CD65II-SE of the late 1980's. Low cost, relatively, and an amazing sound.

    It died while I was abroad. Looking back, I should have just boxed it until I returned to the UK a few years later to get it looked at, as the replacement was a NAD319, which was the last of the "unrepairables" and konked out after 2 years!

    The ES11's are still going strong, now connected to a Marantz 6004 AMP.

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  5. Does anyone know anyone interested to buy an Onix OA20 with phono stage. It has konked out and here in Sweden I don't know anyone who can fix it?Cosmetically excellent. Alternatively I am interested in anyone who can fix it to it's past audio glory :) Sorry if this is not in the correct postings.

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    Replies
    1. Any reputable electronic repair shop should be ok

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