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What resistor are you using on the sansui amp?

thanhky1985

thanhky1985

Active Member
i am looking for resistors that can replace old resistors to sound like old resistors (thicker mids). i have tried large 1/2w and small 1/4w metal film. but it sounds thin wherever i use it. and i am planning to order new carbon resistors. and i am hesitating to buy 1/4 or 1/2w. but i find it strange that old sansui resistors are so big. is it the physical size of the carbon film lines that makes the difference (sound signature).
has anyone tried replacing new 1/2w carbon film in place of old 1/4w
on the left is 1/4w resistor, in the middle is 1/2, on the right is old 1/4w462582004_505569072484645_7217170120884397384_n.jpg
 
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I would replace OEM Sansui resistors [the brown ones] only if you have to. The relative size of modern replacements are of no real consequence. Modern methods of manufacturing lends itself to smaller examples of legacy devices. I have tested hundreds of Sansui resistors and find their tolerances pretty tight to stated value. This includes how close they are to their marked value and the percentage tolerances are very close. Modern metal film/carbon film subs tend to be on the low side in value and close to the lower end of the % tolerance in my experience. If you are replacing a resistor that is damaged/burnt find a replacement that is closest to the device you are replacing. Normally you replace by what you find but if it is burned the color bands are of little use to identify the value found. You then need to use part list/schematics.
 
I have tried replacing resisters in key position, such as feed back circuits. Installed Takman carbon, and can say I did not notice any change in sound. So I guess that's a good thing. They are crazy priced!
 
I have replace almost every resistor in my Sansuis , I never found one out of tolerances ( expect the ones that was burned) . Question is how much those carbon composition, old resistors, can hold their value in circuit , under load and heat . I’m guessing, not much .
I have replace resistors in the AU-8500 and AU-517-717 and I couldn’t tell the difference, indeed the amps are running cooler, but that was about it. (metal film at the pre-amp of the AU-8500, did tighten up the “loosely” bass )

Now , in other circuits that I have tried,such as “diamond differential” , “super feed forward” they make hell of a difference, that much , that I tend to bare the expense of
Z-foils at input and feedback .
FWIW, I tend to mix resistor brands, using Vishay and Koa-spears so I don’t get a “sound signature” ( I don’t know if this is correct but works for my ears ) , choosing 1% tolerance at 50ppm higher.
 
It’s going to be hit or miss and your ears are the judge. Try it in a single, contained circuit (like phono pre or tone) on a single channel and see if you like the change.

For me, I follow @aldena007’s lead and replace them if they’ve gone noisy or are burned. The carbon comps have been out of spec a few times on a few models but nothing that would warrant a shogun replacement.
 
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aldena007 said:
I would replace OEM Sansui resistors [the brown ones] only if you have to. The relative size of modern replacements are of no real consequence. Modern methods of manufacturing lends itself to smaller examples of legacy devices. I have tested hundreds of Sansui resistors and find their tolerances pretty tight to stated value. This includes how close they are to their marked value and the percentage tolerances are very close. Modern metal film/carbon film subs tend to be on the low side in value and close to the lower end of the % tolerance in my experience. If you are replacing a resistor that is damaged/burnt find a replacement that is closest to the device you are replacing. Normally you replace by what you find but if it is burned the color bands are of little use to identify the value found. You then need to use part list/schematics.
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i only found that the 2 1/2w 330r resistors in the output capacitor have drifted to 500r. and the rest of the resistors are mostly uneven between the 2 channels. and that's why i want to replace them because maybe i have OCD. i'm waiting for the postman to bring me the order from digikey today. it's a batch of dale rn60 resistors and yageo carbon film and metal film resistors. i tried to remove them from the am fm circuit to replace them in the main circuits like the equalizer and tone circuit. but at some values the am fm circuits don't have them. and i just realized one thing when using the method of attaching each left and right side are 2 different types. and using the balance button to listen to them. the dale seems to have less treble sound after the sound, the oem sansui resistor has more treble sound after. the dale seems to be quieter in the moments when there is no music. but the great thing is all the instrument details are still there and they seem to be harder and neater. but not as shiny as regular metal resistors.
 
Scott Muni said:
I have tried replacing resisters in key position, such as feed back circuits. Installed Takman carbon, and can say I did not notice any change in sound. So I guess that's a good thing. They are crazy priced!
Click to expand...
The resistor you mentioned I couldn't find anywhere, only metal film, but hearing it was expensive I gave up on trying it.
 
Sui-Yogi said:
I have replace almost every resistor in my Sansuis , I never found one out of tolerances ( expect the ones that was burned) . Question is how much those carbon composition, old resistors, can hold their value in circuit , under load and heat . I’m guessing, not much .
I have replace resistors in the AU-8500 and AU-517-717 and I couldn’t tell the difference, indeed the amps are running cooler, but that was about it. (metal film at the pre-amp of the AU-8500, did tighten up the “loosely” bass )

Now , in other circuits that I have tried,such as “diamond differential” , “super feed forward” they make hell of a difference, that much , that I tend to bare the expense of
Z-foils at input and feedback .
FWIW, I tend to mix resistor brands, using Vishay and Koa-spears so I don’t get a “sound signature” ( I don’t know if this is correct but works for my ears ) , choosing 1% tolerance at 50ppm higher.
Click to expand...
At first I thought like you, after reading articles about the noise of resistors. And I also replaced a lot of old carbon film resistors with metal film. But after replacing a lot, I realized one thing: the sound became harder, thinner, stronger and faster. It sounded more attractive in strong and fast rhythmic songs. But with slower, softer songs, it lost the sweetness and thick midrange of the sansui. And I followed the instructions to replace each resistor, attach them to one side and listen. It really changed the sound a lot. Every time I attached the old resistor back, I felt the sound was a bit thicker. Since that day, I no longer dare to use normal metal film resistors. Only the dale rn60 1k ohm resistor I am attaching at the input of the equalizer board. I will receive a batch of dale today, and it will probably take me a few weeks of testing.:)
 
Semanon said:
It’s going to be hit or miss and your ears are the judge. Try it in a single, contained circuit (like phono pre or tone) on a single channel and see if you like the change.

For me, I follow @aldena007’s lead and replace them if they’ve gone noisy or are burned. The carbon comps have been out of spec a few times on a few models but nothing that would warrant a shogun replacement.
Click to expand...
yes i am using the method you said. and now my boards are falling apart from too much heat contact with the soldering iron:biggrin:
 
thanhky1985 said:
yes i am using the method you said. and now my boards are falling apart from too much heat contact with the soldering iron:biggrin:
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Yep, that’s a problem with this vintage stuff. I invested in a used Metcal soldering station. Because it uses high frequency to power the tip, the heat delivered to the board and component is reduced. Stuff still comes apart sometimes, but less often than with constant heat irons.

thanhky1985 said:
But with slower, softer songs, it lost the sweetness and thick midrange of the sansui.
Click to expand...
In years gone by, I had different setups and tried to match the equipment to the music. I got tired of the chase and took the middle road. Good for everything, great for a few things, easy to work with.
 
You can really mess up a good Sansui by blanket replacement of resistors, without a thought of why a particular type was chosen.

I replace resistors from time to time, and just as an experiment I re-resistored an entire amplifier (my own), replacing all but a very few which I knew were used for a purpose. When you see just a few carbon composition resistors, maybe in a phono stage, or a pre-amp, they are there for a reason. Namely, how they sound - what they add to the presentation of sound. Change them, and while you might feel the amplifier sounds better, - some of its special sound character can be lost. :( Of course it's up to you what changes you make, there's no such thing as the 'Resistor Police' around here, just be aware that the returns from making such changes are not always as good as they seem. ;)
 
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In opinion and experimentation , replacing resistors and capacitors to one channel and leave the other “original” , the only information you can retrieve by that practice , is to notice the difference between channels and it’s far from a valid practice to decide if you like it or not.
To decide if the sound of the amp is falling into your hearing preferences after “recap or re-resistoring”, partly or “shoot-gunning“ you need to hear it in stereo.
So a valid approach for a good decision is to have two identical amps and perform
A-B-A listening sessions after restoring,partly or totally .
I have done it, as I have 3 xAU-X11 and along the restorations i have tried every possible; combination .
In my opinion on this particular circuitry, metal film is “unbeatable” the Sansui sound it’s at best !!!
Re-resistoring has nothing to do with the sound characteristics of the amp, it just betters it bests .
My 2 cent.
 
Just a note here. I see discussions about replacing carbon comp resistors with metal film. In the popular Sansuis of the seventies the "brown" OEM resistors are not carbon comp, they are carbon film. Sansui uses the abbreviation "C.R." for the resistors that are carbon based versus ceramic based "Ce.R." & metal "M.R." devices. I replace OEM carbon film resistors with modern carbon film. I only use metal film resistors to replace OEM fuse resistors known to be an unreliable device. In this case the metal film is used for it's "flameproof" characteristics not sonic superiority to carbon comp devices. Sansui calls out metal film as "M.R." in other applications. I don't ever recall running across a carbon comp resistor in the x0x0, x0x0db, QRx's. On carbon comp I replace w modern carbon film.
 
Hyperion said:
You can really mess up a good Sansui by blanket replacement of resistors, without a thought of why a particular type was chosen.

I replace resistors from time to time, and just as an experiment I re-resistored an entire amplifier (my own), replacing all but a very few which I knew were used for a purpose. When you see just a few carbon composition resistors, maybe in a phono stage, or a pre-amp, they are there for a reason. Namely how they sound - what they add to the presentation of sound. Change them, and while you might feel the amplifier sounds better, - some of its special sound character can be lost. :( Of course it's up to you what changes you make, there's no such thing as the 'Resistor Police' around here, just be aware that the returns from making such changes are not always as good as they seem. ;)
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yes. i have found 2 carbon composite resistors 1/2w at the ground drop of the signal line of the driver board. i changed it to metal film, but strangely after changing it the sound is completely different. i saw that so i put the old composite resistor back in. and now i am preparing to replace a resistor which is also carbon composite on the 62v power board, because recently i bought a mini oscilloscope. and i also tried poking at the lines before and after the carbon resistor. i saw the oscilloscope showing strong ripples after the resistors. i will get used to it and replace the dale rn60d resistor then i will try to check with the mini oscilloscope again. that might be interesting
 
Hyperion said:
Bạn thực sự có thể làm hỏng một chiếc Sansui tốt bằng cách thay thế toàn bộ các điện trở mà không cần suy nghĩ lý do tại sao lại chọn loại điện trở đó.

Thỉnh thoảng tôi thay thế điện trở, và chỉ để thử nghiệm, tôi đã thay thế toàn bộ bộ khuếch đại (của riêng tôi), thay thế tất cả trừ một số ít mà tôi biết là được sử dụng cho một mục đích. Khi bạn chỉ thấy một vài điện trở thành phần carbon, có thể trong một tầng phono hoặc một bộ tiền khuếch đại, thì chúng ở đó vì một lý do. Cụ thể là cách chúng phát ra âm thanh - chúng bổ sung gì vào cách trình bày âm thanh. Thay đổi chúng, và trong khi bạn có thể cảm thấy bộ khuếch đại nghe hay hơn, - một số đặc tính âm thanh đặc biệt của nó có thể bị mất. :( Tất nhiên, tùy thuộc vào bạn muốn thay đổi gì, không có cái gọi là 'Cảnh sát điện trở' ở đây, chỉ cần lưu ý rằng lợi nhuận từ việc thực hiện những thay đổi như vậy không phải lúc nào cũng tốt như vẻ bề ngoài.;)
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I usually try one at a time. Because when trying many at the same time. We will not know the exact characteristics of each position and each type of resistor. Today I just tested the carbon film yageo resistor and metal film yageo resistor at this location. Because according to the Sansui 2000 a rebuilding guide by the experts.They replaced this 560k ohm resistor. And they said it would reduce the noise. I was surprised after installing the yageo metal film resistor. The sound was sharper. Thinner. Just like the cheap Chinese boards. And I took it off immediately. And I put the yageo carbon film resistor in. Surprise. The sound is almost the same as the old oem resistor. But the midrange is back along with the bass and trebles. The oem resistor has the midrange brought forward.And I decided to replace the oem resistor after 30 minutes of listening and deciding. I did. I did not expect that a resistor on the electrical path would have such a big impact on the sound.1000000367.jpg
 
It can be misleading to decide about resistors in half an hour, it only takes 1 hour for the amplifier to warm up, even the new solders will take time to burn, you are changing parts that have worked in harmony for 50 years, the full performance of this changed part will take weeks or even months.
I also changed the resistors but this does not work a miracle, there are minimal differences, white is a little whiter, black is a little blacker.
What I see is that resistors do not change the balance of tones like capacitors, a quieter background and clearer separation of instruments.
 
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