"Sansui sound", does it come from preamp or power amp?

Kreshna · Mar 21, 2014

Well I have read a lot about distinctive "Sansui sound". Some describe it as "warmth, tubelike", while some say that Sansui is a bright amplifier. As for me, Sansui gives JBL titanium dome tweeter clear and clean HF - as opposed to a particular brand of amplifier that almost made me hate the tweeters.

Nonetheless, I wonder: where does the "Sansui sound" come from? Is that from the preamp part, or the power amp part? For example, my AU-7900 has separate mode. If I use the preamp part while using a separate power amp (which is not Sansui), will I keep the distinctive Sansui sound?

canuckaudiog · Mar 21, 2014

It's both.

Changing out one part will alter the sound and you will be "mixing" sound, so to speak. This is a nice thing to do though if there's something you don't like. For example, older Sansui amps can tend to sound a bit slow and loose in the bass, you could run the pre amp into a more modern power amplifier and tighten things up. But you would lose some of that Sansui sound.

Kreshna · Mar 21, 2014

canuckaudiog said:
It's both.

Changing out one part will alter the sound and you will be "mixing" sound, so to speak. This is a nice thing to do though if there's something you don't like. For example, older Sansui amps can tend to sound a bit slow and loose in the bass, you could run the pre amp into a more modern power amplifier and tighten things up. But you would lose some of that Sansui sound.

I see, thanks.

Now, supposed the output transistors are damaged beyond repair, so I have to replace them with other models. It I would lose some of the Sansui sound, would I?

Robisme · Mar 21, 2014

Kreshna said:
I see, thanks.

Now, supposed the output transistors are damaged beyond repair, so I have to replace them with other models. It I would lose some of the Sansui sound, would I?

If you use comparable transistors, it will sound the same.:yes:

Rob

Kreshna · Mar 21, 2014

Robisme said:
If you use comparable transistors, it will sound the same.:yes:

Rob

I see, thanks! I'll be alright, then.

JOMARK911 · Mar 21, 2014

Try to get a more powerfull main amp , to pair with your 7900.
Or even get a bigger integrated, like au 11000 or 20000 .
So you stay in the sansui sound , all the way.

Kreshna · Mar 21, 2014

JOMARK911 said:
Try to get a more powerfull main amp , to pair with your 7900.
Or even get a bigger integrated, like au 11000 or 20000 .
So you stay in the sansui sound , all the way.

I see, so if I used the AU-7900 as preamp, while using non-Sansui as power amp, then I'll still stay in the Sansui sound, won't I?

It's not that I hunger for more power; it's that the 7900 seems to have problem in its power amp section, namely crackling and popping sound from the right channel - so severe that the amp goes to protection mode eventually.

I have swapped right and left channel (using the amp's reverse switch), yet the crackling and popping stays coming from the right channel, so I guess it's not the preamp, but the power amp. It's not from volume knob either, since turning the knob doesn't affect the crackling and popping sound at all. It's not dirty clamps either, since the crackling and popping is still there whether I use speaker A or speaker B.

It may take quite a time to fix, so as temporary fix, will I be fine by using the 7900 as preamp only?

Dswankey · Mar 21, 2014

I used my AU-717 as a Pre into my Luxman M-2000 power amp for a short bit I really liked it. At the time it was the only piece of gear that I had with pre-outs I use another Luxman now. I do have a AU-5500 that I plan on hooking up to my my Dynaco ST 70 tube amp. I'm looking forward to see how it sounds.

Good question as I've wondered about this too.

Zekeman · Mar 22, 2014

Your 7900 needs to be restored.

tobyj17 · Mar 22, 2014

I wouldn't run it even in separated mode because the power amp is still powered up. Whatever is crackling could fail and/or cause other things to fail and it could cause a smoke show and make the repair a lot more expensive.

Kreshna · Mar 22, 2014

Zekeman said:
Your 7900 needs to be restored.

Which component(s) should be on my shopping list? I think all capacitors need to be replaced, but capacitors aside, what components should be my priority? Maybe output transistors?

skippy124 · Mar 22, 2014

Kreshna said:
Which component(s) should be on my shopping list? I think all capacitors need to be replaced, but capacitors aside, what components should be my priority? Maybe output transistors?

For the power amp section, (if you are getting popping/noise from this section), consider replacing the 2SA798 differential pairs, the VD1212 diodes, and the fuse resistors as well as the electros. Also the bias pots with multi turn versions.

Cheers

John

Kreshna · Mar 22, 2014

skippy124 said:
For the power amp section, (if you are getting popping/noise from this section), consider replacing the 2SA798 differential pairs, the VD1212 diodes, and the fuse resistors as well as the electros. Also the bias pots with multi turn versions.

Cheers

John

Ah, I see. Thanks!

Kreshna · Mar 22, 2014

Regarding to the 2SA798 transistors, what does label like 26G or 66G mean? Duh.

The most common seems to be 14G.

skippy124 · Mar 22, 2014

The letter is the gain ranking - F = 250-500, and G = 400-800. Either are suitable for the 7900.

The numbers are probably production batch numbers or some other manufacturer marking.

Cheers

John

Kreshna · Mar 22, 2014

skippy124 said:
The letter is the gain ranking - F = 250-500, and G = 400-800. Either are suitable for the 7900.

The numbers are probably production batch numbers or some other manufacturer marking.

Cheers

John

I see, thanks again. Anyway, there's quite a lot of 2SA798s from Hong Kong. Are they original? Are they safe to buy?

VD1212 diodes are harder to find, any clue where could I find them?

jpb6793 · Mar 22, 2014

You will find most people at Ak will say to stay away from purchasing from overseas areas like china, singapore etc...they are a haven for counterfeits. I'm sure there are reputable dealers but it's touch and go

pete_mac · Mar 22, 2014

Kreshna said:
VD1212 diodes are harder to find, any clue where could I find them?

A pair of 1N4148 diodes in series is what is used to replace the VD1212s.

Lots of pics on the forum showing how this is done. :thmbsp:

Kreshna · Mar 22, 2014

pete_mac said:
A pair of 1N4148 diodes in series is what is used to replace the VD1212s.

Lots of pics on the forum showing how this is done. :thmbsp:

You mean like this? Putting them in serial?

jpb6793 said:
You will find most people at Ak will say to stay away from purchasing from overseas areas like china, singapore etc...they are a haven for counterfeits. I'm sure there are reputable dealers but it's touch and go

I see.

lr11 · Apr 14, 2014

I can not help on the repair question other than just do or have a complete rehab done. The 7900 makes a great pre-amp and it will still have the Sansui sound. It will give you options that most pre-amps couldn't even come close to.

"Sansui sound", does it come from preamp or power amp?

...but I have to know.

On a quest for high fidelity

...but I have to know.

Sansui Enthusiast

...but I have to know.

Super Member

...but I have to know.

Lunatic Member

AK Subscriber

Comfortably Numb

...but I have to know.

Super Member

...but I have to know.

...but I have to know.

Super Member

...but I have to know.

AK Member

Super Member

...but I have to know.

New Member

Similar threads