Sansui AU 999 Left Channel Out Restoration And Mods Done
Item History & Price
| Reference Number: Avaluer:29709598 | Type: Integrated Amplifier |
| Brand: Sansui |
Read the reviews after kevzep preamp mods have been done?70wpc 4 ohm 50wpc 8ohm-Left channel went out recently. Im guessing it has something to do with the bass switch which was a little noisy when i'd flip it, or the fact i tried to run a tube buffer out from the headphone jack. Only played with the bass controls for a week after not using for several months. Anyway, sounds good out of right channel, and my tech doesnt really have time to look at it right now. Could u...se the money so offering it up to someone that wants to repair.. It was my daily amp for hours a day. Probably did over 600 hours since mods were done before left channel went out.- This housing has a few dings and scrapes but looks better in person imo. As you can see the tuner and -20db selector switches are broken and still need to be replaced if you so choose. I have tested their function and they work A OK.-1 Speaker terminal black cover is off and can be replaced as shown in the photo-Some screws on housing were lost when removed to do the upgrades.List of mods and restorations done
Kevzep mod done to the preamp section has really helped it come alive! Also stereo fun mods done.The amp sounds great. I've been powering Bang and Olufsen Penta 2's with it, and they are a good match. Better than the stock amps, and a Yamaha PC2002 imo. The power caps were replaced with Nichicon Super throughs. Kevzep modOn the F1209 Boards
Replace R759 with the 3.3KΩ
Replace R761 with 1.0KΩ
Replace R769 with 2.2KΩ
Now, remove R755. You will put the 1megΩ resistor on the trace side of the board though the hole which is connected to the BASE of TR705, you will then connect the other end of this resistor on the trace which connects to the COLLECTOR of TR705....
Replace R763 with the 100Ω.....Stereofun modsMod 1A 2.2 uf Polypropylene at the C801 driver board position instead of the 1.0 uf stock mylar.Result: No appreciable difference until the amp gets cranked up to moderate or high output. Here the 2.2 shows better performance in the highest notes, but only gives little to no benefit in the low end.Mod#2Replacing the C807 bipolar feedback cap to Nichicon Muse 100uf/50v. Replacing feedback resistor R819 with a .5w metal film type for better temperature coefficient and replacing it's paralleled ceramic cap on the back with a CoG type as well as the low pass ceramic C803. (thanks Leestereo)Mouser part number for the ceramic low noise caps: 581-SR211A560JAR, 581-SR211A150JAR
Result: Noticeable - cleaner sound.Mod#3
The goal here is to get the current through the differential input pair within 1%. replaced differential input pair, TR801/803 with a low-noise, high-gain, high band-with set of transistors ZTX795A's, Result: Cleaner and more spatial sound. It is like the amp has gone audiophile. Prepare to hear more heavily breathing jazz musicians on old recordings :music:. Sounds very good and can play for hours with no issues. Amp has great clarity.
This was the most advance amp Sansui made at the time (70-72 production) and geared towards audiophiles.Video available by following this link here before mods done--- https://www.youtube.com/watch?v=_YFT-c0-ISk&t=3s
50 watts a channel at 8 ohm,
70 watts a channel at 4 ohm.Missing knobs for -20db setting which is used to decrease volume for changes in records where noise could be increased. Another selector switch knob is missing that is labeled tuner, although there's another tuner selection knob. Can clearly be seen in one picture. Interesting tone controls. The lower ones have three settings , and effect how drastic the tone controls up top are, if at all since there's also a lower off setting for bass midrange and treble.
Kevzep mod done to the preamp section has really helped it come alive! Also stereo fun mods done.The amp sounds great. I've been powering Bang and Olufsen Penta 2's with it, and they are a good match. Better than the stock amps, and a Yamaha PC2002 imo. The power caps were replaced with Nichicon Super throughs. Kevzep modOn the F1209 Boards
Replace R759 with the 3.3KΩ
Replace R761 with 1.0KΩ
Replace R769 with 2.2KΩ
Now, remove R755. You will put the 1megΩ resistor on the trace side of the board though the hole which is connected to the BASE of TR705, you will then connect the other end of this resistor on the trace which connects to the COLLECTOR of TR705....
Replace R763 with the 100Ω.....Stereofun modsMod 1A 2.2 uf Polypropylene at the C801 driver board position instead of the 1.0 uf stock mylar.Result: No appreciable difference until the amp gets cranked up to moderate or high output. Here the 2.2 shows better performance in the highest notes, but only gives little to no benefit in the low end.Mod#2Replacing the C807 bipolar feedback cap to Nichicon Muse 100uf/50v. Replacing feedback resistor R819 with a .5w metal film type for better temperature coefficient and replacing it's paralleled ceramic cap on the back with a CoG type as well as the low pass ceramic C803. (thanks Leestereo)Mouser part number for the ceramic low noise caps: 581-SR211A560JAR, 581-SR211A150JAR
Result: Noticeable - cleaner sound.Mod#3
The goal here is to get the current through the differential input pair within 1%. replaced differential input pair, TR801/803 with a low-noise, high-gain, high band-with set of transistors ZTX795A's, Result: Cleaner and more spatial sound. It is like the amp has gone audiophile. Prepare to hear more heavily breathing jazz musicians on old recordings :music:. Sounds very good and can play for hours with no issues. Amp has great clarity.
This was the most advance amp Sansui made at the time (70-72 production) and geared towards audiophiles.Video available by following this link here before mods done--- https://www.youtube.com/watch?v=_YFT-c0-ISk&t=3s
50 watts a channel at 8 ohm,
70 watts a channel at 4 ohm.Missing knobs for -20db setting which is used to decrease volume for changes in records where noise could be increased. Another selector switch knob is missing that is labeled tuner, although there's another tuner selection knob. Can clearly be seen in one picture. Interesting tone controls. The lower ones have three settings , and effect how drastic the tone controls up top are, if at all since there's also a lower off setting for bass midrange and treble.
