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Sansui AU-101 blown left channel - where / how to repair? help...


deenhameed
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Hello,

 

New forum member, so here's an intro on a bit of an unhappy note...

 

I bought a Sansui AU-101 amplifier off gumtree a few months ago on my first steps to vintage audio and loved the musicality and warmth of the sound. It also had a great sounding phono-stage and the whole kit was a great little retreat from all the technology around me. Not to mention that I fluked on just the kind of sound I like with no idea of what i am doing..

 

Yesterday afternoon, in my infinite wisdom, i thought I would try connecting this old JBL subwoofer to add some low-end to the speakers, and since the subwoofer had pass-through connections of some sort, I connected the wires from the amp to the s/w and then on to the speakers.  I had also connected the jacks from the amp to the line-level input on the s/w.

 

There was no sound from the s/w, athough it powered up (it may well be broken already as it's just been lying around in the basement for ages) and the speakers played properly. Wen I moved the s/w to listen closer, I yanked the left-channel speaker wire off the subwoofer.

 

Since the, there is no sound from the left channel. Obviously, I've wired the speakers back! I thought perhaps the speaker had packed it (not such a biggie), switched wires to the other speaker and same thing. Tried to listen in on headphones through the headphone jack and the left channel is _dead_.

 

I pulled the fuse at the back and it is fine..

 

So it appears I've trashed my little 40-yr old amp... I am become the Destroyer of Amps..

 

That's my intro and a plea... I do really like this amp, and would like to get it back if i can. I didn't pay much for it' and surely there's a bunch of gear that will sound better, etc, but I've loved listening to this setup and would love to have it back (at least on the way to 'greater' things).

 

Is it good as gone? or are these old things simple enough that a transistor or a little doo-dah can be replaced to make it better? Is there someone you can recommend me? I live in Sydney and will go wherever I need to in Sydney to give it another shot at life.. Obviously, my specialty is breaking things, not fixing them. I wouldn't mind getting the amp recapped as I've heard only good things can come out of it...

 

Please help... :'(

 

Deen

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Hi,

 

The AU101 is a great little amplifier, and the problem with your unit won't be terminal.

 

It sounds like you have shorted the left channel speaker output, and if you are lucky it will be just the 1.5A protection fuse for that channel that has blown. At worst the output transistors for the left channel may have blown, but that is fixable (in fact just about any fault is fixable on these amps).

 

Are you comfortable with removing the top cover from the unit - with the unit unplugged from the mains of course. There are two 1.5A fuses located side by side in the centre of the main circuit board, you could check if one of these have blown. If so you could replace it with a 1.5A quick/fast blow fuse (important - do not fit a time lag/slow blow fuse). Put the cover back on, and then see if that has fixed the problem. 

 

I am happy to have a look at it, and also talk to you about recapping etc. 

 

Cheers

 

John

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Thanks John & Pete_mac,

 

Just after I posted, I thought I'd try and pop the cover off and see if there was anything obvious, and sure enough, there were the two fuses; one of them was blown. I swapped them around and plugged in my headphones, and yep, the left channel came back on!!! yayyy.... I was going to Jaycar and look for a replacement fuse (although I couldn't tell what amp of fuse it was). Your advice about the quick-blow fuse is most appreciated. I'll make sure I ask for it specifically when I go to Jaycar (now!)..

 

The insides are incredibly clean! I wonder if someone has already got into it and fixed anything prior to sale. I'll try and see if I can figure out how to post a picture later in the day and you can perhaps tell me if it perhaps has been already recapped. The only issue with the amp is some very light crackling on the volume knob if it hasn't been used for a few days... it goes away when I do the ritual turning of the knobs three times left & right before pressing play... I expected the pots inside to be all cruddy but instead there almost no dust in there and all the connections are quite glossy (not dulled)...

 

I'm so pleased it isn't termiinal... I'll give it a listen for a couple of weeks (without blowing things up) and will be in touch about recapping...

 

Thanks a lot for the prompt reply and this has really made my day! Love the internet!

 

Deen

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Got the fuses from Jaycar... easy as pie, thanks John...

Plugged them in and everything works perfectly ... :D

Pic on the inside as promised..

Insides don't look quite as old as I would've thought... so has it been refurbished already? Or will it get better with new caps? Either way, I couldn't be happier at the moment. :)

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Thanks John,

 

That's great news! That's a pretty vintage amp and I'm glad it still around, thanks to your help.

 

I've borrowed a Marantz PM-52 this afternoon which has more wattage as a back up for the potential recap of the au-101, but although it sounds quite nice, it doesn't have the airiness and musicality in the highs that the sansui does... Don't know how to put it but I feel there is more detail and 'happiness' in the sansui... Everything is much more intimate and organic. It's a great amp for folk, country and jazzy stuff with a sort of acoustic quality to the music..

 

In contrast the PM-52 feels a little removed, like a cd player vs record...It's wierd to say it, but the Marantz seems to be in a hurry to do things; it sounds hollow.. It does things clinically and is nicer if I play rock but i think it's giving me a heachache... I'll be happy to go back to the Sansui :)

 

For now, I've unplugged the Sansui and letting the Marantz playfor a while. It hasn't been used in a very long time. Maybe it will settle in.

 

 

If the original caps still have it in them to sound the way they do, then I think i will be genuinely thrilled with a tuneup and new caps.. Thank you so much for all your help so far. Can you please PM me you have a minute how we could go about it? I'm not in a hurry to get it done so whenever it suits you will be fine..

 

 

 

Deen

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I may have been wrong about the pm 52. It's been running for a few hours now and the sound is not so shrill. It still has the nice soundstage and detail, but sounds warmer and quite nice at the low volumes its running atm.. still not the emotional intimate sound the sansui has but something appealing about this amp.

 

The phono on the au-101 hammers this into the ground though..

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Thanks SS & AJ, yeah, I really like that amp; it changes everything in some tiny way and makes it just that little bit more enjoyable...  It has a couple of quirks, with how it will once in a while place instruments, but that just makes it interesting to listen to. I'm also wishing I could get that sound but with more wattage to drive larger speakers, but for the kind of listening / music, I think I'm just being needy..  ;)

 

@SS - heheh... if I ever part with the AU-101, I'll let you know... I googled the 505 and that's a pretty amp. Just like the 101 but more switches... nice.

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Nice amp, i have one myself and found it very sweet - interesting to read they are easy to fix.

 

I use it on a pair of 15w 1970's B&O speakers and it sounds modern and very good - amazing how we caught up on the latest stuff when there is really good vintage gear out there.

 

I'm interested in what different caps would do but i think ill keep it original as it is fine.

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True, there's nothing wrong with the sound at the moment, but from what i understood of reading sna in the last day...  :) ... no one has recapped and then said that the sound was worse than before... That said, knowing that the amp is pretty much original DOES make me pause ... (but not stop)..

 

I'm curious to see how it plays against the marantz pm64ii which is a quarter a class amp and apparently has been rated quite highly against some quite reputable brands. If I prefer the au101 to the pm52, i'll have to shake down a nice vintage big sansui  :D

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  • 5 years later...

Its very addictive.

l Started with AU101's got another two, all capped and modded.

One 101 sits in the family room and sounds magic.

 

Then l moved onto a AU505, then another and another.

2 are capped and modded the third will probely get done sooner rather than later.

To keep the piece l let one 101 go and will let another depart as well.

 

NO l'm not addicted l could give it anytime.........eh maybe.

 

If your in Melbourne your welcome to listen.

 

regards Bruce

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