Sansui Valve Amps, any good?

[DarrenHW]

Picked up a Sansui SM-12M today, pots are filthy and it's only working in the clean spots at the moment but it sounds like it has some potential. What's the view on Sansui valve amps, worth fettling or best left in the past?

[Audio Al]

No they are pants :D

I will help you dispose of it , put it in a box and I will get it collected ;)

Look here
http://www.ebay.ie/itm/VINTAGE-SANSUI-SM-12M-STEREO-VALVE-TUBE-AMPLIFIER-RECEIVER-FULLY-OPERATIONAL-/290993613799

:)

[Ali Tait]

Single ended EL84 I think, should sound nice, it's hard to make a poor EL84 amp.

[Firebottle]

Should sound reasonable I think.
Copy of the schematic for the amp section here: https://lh3.googleusercontent.com/-ROoR8rZy_oQ/VUih9B5ubzI/AAAAAAAAGKM/z2eTmNee5W8/s912/IMG_7672.JPG

Before you do anything with it replace the two grid coupling capacitors marked with a C in this photo:

http://i601.photobucket.com/albums/tt97/Paramotorpilot/Sansui%20SM12%20C%20output.jpg

This will ensure that the output valves and transformers are kept within their operating limits.

:)
Alan

[DarrenHW]

Thanks for the link Al, I have seen it but not much else written about it.

It does indeed use EL84 valves, the one's installed are mismatched and one of the transformers seems to have been replaced.

Thanks for the heads up Alan :thumbsup:, where did the photo come from, do you have any more info on this amp? I have got the schematic as it's miraculously still attached to the lid.

I've had it one for the last hour or so, the Bass pot is the worst of the lot and I only get a clean, balanced signal through both channels with this at one position, it is very bass light but I guess that's to be expected.

[Audio Al]

http://www.avforums.co.za/index.php?topic=18581.0

Here

Is yours as dirty as this one

[DarrenHW]

Thanks again Al, mine might actually be dirtier!

[Audio Al]

Thanks again Al, mine might actually be dirtier!

:eek::eek:

[DarrenHW]

Maybe not as dirty, but still...

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5325_zpsvz3ycxbl.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5325_zpsvz3ycxbl.jpg.html)

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5328_zps4vyhahus.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5328_zps4vyhahus.jpg.html)

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5335_zpschj5oqq5.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5335_zpschj5oqq5.jpg.html)

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5330_zpsiie0kk9w.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5330_zpsiie0kk9w.jpg.html)

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5334_zpshgt4wyj8.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5334_zpshgt4wyj8.jpg.html)

http://i1324.photobucket.com/albums/u606/drtwas/IMG_5332_zpsxbrm0sa0.jpg (http://s1324.photobucket.com/user/drtwas/media/IMG_5332_zpsxbrm0sa0.jpg.html)

[Wakefield Turntables]

Good luck with that one Darren!

[DarrenHW]

Cheers Andy, I think I'm building up the courage (or should that be stupidity?) to take it on. I've just unplugged it and hooked my Sony (which displaced my AU 101) back up and I'm missing the Sui already.

[TheMooN]

Sweet little receiver the 12M, were you to contract Sansui Valve Syndrome then the 1000A is a very nice step up iin the receiver line, should you to ever find yourself in a position to acquire an Au-111 Integrated, well :smoking:

http://www.sansui.us/AU-111.htm

[DarrenHW]

That is a good looking amp :stalks:.

[DarrenHW]

After looking into it I don't have the skills or the stones to take this on, I fear I'd be left with at best a box full of parts, at worst a box full of smoked parts. Any idea how much it would cost to have it "serviced"?

[Wakefield Turntables]

After looking into it I don't have the skills or the stones to take this on, I fear I'd be left with at best a box full of parts, at worst a box full of smoked parts. Any idea how much it would cost to have it "serviced"?

I've been in this position myself, sometimes my gusto gets in front of what I can actually do and I then realise that I have to get help. If this is a piece of kit that you really love I think cost will be irrelevant cos sometimes your heart takes over and I think it's these pieces of kit which generally stay in a system even if they are bettered by other boxes. I've certainly fell foul to this as well :). I'd probably send this to Nick Gorham and some other valve guru. Might cost a few quid but it'll be worth it.

[DarrenHW]

If there's one area of Audio DIY I can say with absolute certainty I've improved, it's knowing when I'm beaten :).

[mik_rik]

Advice on American forums is to ALWAYS change the Suzuki pio caps [the grey ones] and any Elna 'lytics.The other caps [none electrolytics should be ok] It will probably take less time and money than you think to get it fettled sound and reliability wise.If you do it yourself,change each cap one leg at a time,I find Russian caps to be exellent ,try K73-16 Mylar types.Can be easier working on a hard wired circuit as you don't have to unsolder /unscrew a pcb and try to figure where any wires that come off go:doh:. Good luck with your project ,you' got a very nice amp there - Mick

[Audio Al]

http://www.ampregen.com

This man knows his onions , Recommended ;)

[DarrenHW]

Mick - You make it sound so simple, maybe I will take another look under the bonnet?

Al - Thanks for the recommendation.

[TheMooN]

Unfortunatly, as Is the nature of the beast, the additional circuitry as sported integrally with Receivers and Integrated Amplifiers can be daunting at first examination, this chap in the Netherlands performes the sort of service I myself performed on a couple of my Au-111's and really should be the level to be considered should one wish to hear what the equipment is capable of.

http://www.vintageaudiorepair.nl/sansui/uksansui_au-111.html

[mik_rik]

Maybe the wisest course to take is to go on your gut feeling i.e if in doubt ,keep out.

[DarrenHW]

I agree Mick. I'd like to become more familiar with the inner workings and I'd really like to service it myself, but I don't want to end up wrecking it. As Roger suggests I found it quite daunting upon initial inspection but I'm going to take a more pragmatic look at it, I have to wait in for a delivery tomorrow so I'll take another look and go from there.

[DarrenHW]

I took another look at this today and taking Alan and Mick's advice to replace the Suzuki caps (didn't find any Elna's?) helped to break this down to a more manageable job. I initially thought I'd have to strip everything, but after looking at it I can see how a modular approach can be applied which is far less scary.


...I find Russian caps to be exellent ,try K73-16 Mylar types....

Any links to where I can get these from? I need some very low values, 0.05, 0.005, 0.02, 0.001, 0.01.

I thought it would also be prudent to change the supply caps too, do the same rules apply to valve amps, can I safely increase these by up to ~60%?

[mik_rik]

You've got pm. Mick