Tuesday, May 10, 2011

Sansui AU-217

The Sansui AU-217 is a 30W RMS per channel integrated amplifier from 1974 with a damping factor of 80. Total power consumption was 145W. Hence it packs quite a punch and was able to drive my Celestion SL6S with ease.

The stock unit sounded bass heavy with some high frequency roll-off. Details are semi 'veil-ed'. The stock AU-4400 had a more balance presentation but lack the punch of the AU-217. Personally I prefer the AU-4400 to the AU-217.

Front

Rear
The AU-217 was later recapped using silver mica's, OSCON, Panasonic FC and ECA, Wima and Rubycon. Generic EC were deployed in the non-audio sections.

Once recapped, the AU-217 can be a real shocker! Most of my visitors who heard it though it was atleast a 70-90W RMS per channel unit as it was able to make my Celestion SL6S sing with ease - packs a much bigger punch than the Arcam Alpha 8 power amp of 50W RMS per channel!

The quality of reproduction is heavily influence by the four 100uF 50V caps which are arranged in a 'L-shape' next to the large PSU caps. The other influential EC caps are the two 470uF 50V caps near the middle of the motherboard.

Please note there is a group of ceramic caps on the opposite side of the amp (away from the transformer) which influence the HF and should be replace with caution.

On my AU-217, replacing the large PSU caps resulted in extremely minor improvements.

In the past, the unit was only slightly warmish after running the unit for atleast 8-12hrs a day during the weekends.

Since you are unable to bypass the tone controls, it was necessary to replace all the non-EC capacitors there. I replaced them using Wima's of equivalent value and the effort was immediately rewarded with a fluid and transparent presentation - eventhough the tone controls were left at '0'.

Weakness includes limited connectivity to single pair of speakers,and, no speaker selector.

Otherwise quality sound at low power consumption!!!
View from rear after recapping

View from side after recapping


12 comments:

  1. Excellent post! I'm about to recap my AU-217 in the next month or so. It's going to be my first recap but the unit definitely needs it -- lower frequencies on one channel can sound distorted / static-y.

    Would you recommend replacing the PSU caps for the minor improvement? And, would you recommend replacing the ceramic HF caps? I'm pretty good with a soldering iron (and if I mess up, my coworkers are better) so nothing would be difficult.

    Great job!

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  2. Hi sailorben,

    As per in the post, did not find the ROI worthwhile after I changed the main PSU caps.

    Recommend you leave the ceramic HF to last and replace only the other electrolytics first.

    Replacing the poly's in the tone controls will definately help since these can't be bypass.

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  3. Hi there,

    just bought a sansui au-217 for myself, the unit plays well and the sound is good. I noticed one speaker (chanel) consistently has less low (less movement and punch)

    Do u thinks caps are the problem here ? Could also try cleaning the front panel ?

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  4. Hi Paulus,

    If the stereo image presented (assuming spkrs are properly placed, etc) is in the middle when the balance setting is at zero, then it is working fine - that is how stereo functions.

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  5. Hi would you have a list of capacitors you have used in this job? what was cost of them?

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  6. Hi Radek,

    Apologies, no.

    What I do remember is the medium size caps near the PSU caps are Panasonic FC e.g arrange like an "L".

    The PSU caps was not a well known brand.

    Used Wima(s) to replace the misc poly(s) in the tone controls.

    The blue/purple caps in the pix are OSCON though you can use Panasonic FC, Elna(s) etc - really depends on how deep your pockets are. The other caps hidden by the phono board were Rubycon - black colour caps in the pix.

    All cap values are as per original.

    Please do note the small value ceramic(s) on the extreme end are used for "tonal ladders" and are of pretty good quality. You need to be careful when replacing them.

    The other cap to be careful with is the yellow ROE near the centre of the pix. You should use something better than what I initially chose, maybe a Paper-In-Oil cap (PIO) as it has quite an impact on the overally tonal quality.

    Best wishes!

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  7. Sorry, left out the last part of your query. If I remember correctly, cost for the parts was about SGD$50.

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  8. Have sold the AU-217 a while back to the friend of the buyer for my newly recapped AU-5900 acting as pre-amp to drive two Arcam Alpha 9(s) as mono-blocks!

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  9. I just picked up one of these, and upon getting it home, realized that the one channel was a bit weak. I cleaned all switches and pots as best possible, checked all fuses werent cracked, and swapped inputs and outputs. It balances fine at the headphones, so would this suggest it isn't in the preamp section? Is the MKii schematic applicable to the Mki? As well, does anyone have similar experiences?

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  10. Apologies as have not review Mk2 schematics.

    I do remember there was some mention of the Mk2 in DIYAUDIO and the circuit had many 35V capacitors vs 50V components in Mk1.

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  11. I own an au-217. It shows some problems now. The relay inside the amplifier goes OFF when the amp is switched ON. For few seconds we can hear a rattling sound (like scratching) before it goes OFF. Please you give me some advice to rectify it.. what all areas should I check to correct it??
    I will be thankful if you can reply me at prabhaindus@gmail.com

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  12. Suggest you take it to a proper repair shop.

    Otherwise you could damage your speakers or worst, especially if you are not electronically trained!

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